Search Results: "reg"

20 August 2020

Bits from Debian: Lenovo, Infomaniak, Google and Amazon Web Services (AWS), Platinum Sponsors of DebConf20

We are very pleased to announce that Lenovo, Infomaniak, Google and Amazon Web Services (AWS), have committed to supporting DebConf20 as Platinum sponsors. lenovologo As a global technology leader manufacturing a wide portfolio of connected products, including smartphones, tablets, PCs and workstations as well as AR/VR devices, smart home/office and data center solutions, Lenovo understands how critical open systems and platforms are to a connected world. infomaniaklogo Infomaniak is Switzerland's largest web-hosting company, also offering backup and storage services, solutions for event organizers, live-streaming and video on demand services. It wholly owns its datacenters and all elements critical to the functioning of the services and products provided by the company (both software and hardware). Googlelogo Google is one of the largest technology companies in the world, providing a wide range of Internet-related services and products such as online advertising technologies, search, cloud computing, software, and hardware. Google has been supporting Debian by sponsoring DebConf for more than ten years, and is also a Debian partner sponsoring parts of Salsa's continuous integration infrastructure within Google Cloud Platform. AWSlogo Amazon Web Services (AWS) is one of the world's most comprehensive and broadly adopted cloud platform, offering over 175 fully featured services from data centers globally (in 77 Availability Zones within 24 geographic regions). AWS customers include the fastest-growing startups, largest enterprises and leading government agencies. With these commitments as Platinum Sponsors, Lenovo, Infomaniak, Google and Amazon Web Services are contributing to make possible our annual conference, and directly supporting the progress of Debian and Free Software, helping to strengthen the community that continues to collaborate on Debian projects throughout the rest of the year. Thank you very much for your support of DebConf20! Participating in DebConf20 online The 21st Debian Conference is being held Online, due to COVID-19, from August 23rd to 29th, 2020. There are 7 days of activities, running from 10:00 to 01:00 UTC. Visit the DebConf20 website at https://debconf20.debconf.org to learn about the complete schedule, watch the live streaming and join the different communication channels for participating in the conference.

18 August 2020

Lisandro Dami n Nicanor P rez Meyer: Stepping down as Qt 6 maintainers

After quite some time maintaining Qt in Debian both Dmitry Shachnev and I decided to not maintain Qt 6 when it's published (expected in December 2020, see https://wiki.qt.io/Qt_6.0_Release). We will do our best to keep the Qt 5 codebase up and running.

We **love** Qt, but it's a huge codebase and requires time and build power, both things that we are currently lacking, so we decided it's time for us to step down and pass the torch. And a new major version seems the right point to do that.

We will be happy to review and/or sponsor other people's work or even occasionally do uploads, but we can't promise to do it regularly.

Some things we think potential Qt 6 maintainers should be familiar with are, of course, C++ packaging (specially symbols files) and CMake, as Qt 6 will be built with it.

We also encourage prospective maintainers to remove the source's -everywhere-src suffixes and just keep the base names as source package names: qtbase6, qtdeclarative6, etc.

It has been an interesting ride all these years, we really hope you enjoyed using Qt.

Thanks for everything,

Dmitry and Lisandro.Note 20200818 12:12 ARST: I was asked if the move has anything to do with code quality or licensing. The answer is a huge no, Qt is a **great** project which we love. As stated before it's mostly about lack of free time to properly maintain it.


16 August 2020

Bits from Debian: Debian turns 27!

Today is Debian's 27th anniversary. We recently wrote about some ideas to celebrate the DebianDay, you can join the party or organise something yourselves :-) Today is also an opportunity for you to start or resume your contributions to Debian. For example, you can scratch your creative itch and suggest a wallpaper to be part of the artwork for the next release, have a look at the DebConf20 schedule and register to participate online (August 23rd to 29th, 2020), or put a Debian live image in a DVD or USB and give it to some person near you, who still didn't discover Debian. Our favorite operating system is the result of all the work we do together. Thanks to everybody who has contributed in these 27 years, and happy birthday Debian!

14 August 2020

Russell Coker: Jitsi on Debian

I ve just setup an instance of the Jitsi video-conference software for my local LUG. Here is an overview of how to set it up on Debian. Firstly create a new virtual machine to run it. Jitsi is complex and has lots of inter-dependencies. It s packages want to help you by dragging in other packages and configuring them. This is great if you have a blank slate to start with, but if you already have one component installed and running then it can break things. It wants to configure the Prosody Jabber server and a web server and my first attempt at an install failed when it tried to reconfigure the running instances of Prosody and Apache. Here s the upstream install docs [1]. They cover everything fairly well, but I ll document the configuration I wanted (basic public server with password required to create a meeting). Basic Installation The first thing to do is to get a short DNS name like j.example.com. People will type that every time they connect and will thank you for making it short. Using Certbot for certificates is best. It seems that you need them for j.example.com and auth.j.example.com.
apt install curl certbot
/usr/bin/letsencrypt certonly --standalone -d j.example.com,auth.j.example.com -m you@example.com
curl https://download.jitsi.org/jitsi-key.gpg.key   gpg --dearmor > /etc/apt/jitsi-keyring.gpg
echo "deb [signed-by=/etc/apt/jitsi-keyring.gpg] https://download.jitsi.org stable/" > /etc/apt/sources.list.d/jitsi-stable.list
apt-get update
apt-get -y install jitsi-meet
When apt installs jitsi-meet and it s dependencies you get asked many questions for configuring things. Most of it works well. If you get the nginx certificate wrong or don t have the full chain then phone clients will abort connections for no apparent reason, it seems that you need to edit /etc/nginx/sites-enabled/j.example.com.conf to use the following ssl configuration:
ssl_certificate /etc/letsencrypt/live/j.example.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/j.example.com/privkey.pem;
Then you have to edit /etc/prosody/conf.d/j.example.com.cfg.lua to use the following ssl configuration:
key = "/etc/letsencrypt/live/j.example.com/privkey.pem";
certificate = "/etc/letsencrypt/live/j.example.com/fullchain.pem";
It seems that you need to have an /etc/hosts entry with the public IP address of your server and the names j.example.com j auth.j.example.com . Jitsi also appears to use the names speakerstats.j.example.com conferenceduration.j.example.com lobby.j.example.com conference.j.example.com conference.j.example.com internal.auth.j.example.com but they aren t required for a basic setup, I guess you could add them to /etc/hosts to avoid the possibility of strange errors due to it not finding an internal host name. There are optional features of Jitsi which require some of these names, but so far I ve only used the basic functionality. Access Control This section describes how to restrict conference creation to authenticated users. The secure-domain document [2] shows how to restrict access, but I ll summarise the basics. Edit /etc/prosody/conf.avail/j.example.com.cfg.lua and use the following line in the main VirtualHost section:
        authentication = "internal_hashed"
Then add the following section:
VirtualHost "guest.j.example.com"
        authentication = "anonymous"
        c2s_require_encryption = false
        modules_enabled =  
            "turncredentials";
         
Edit /etc/jitsi/meet/j.example.com-config.js and add the following line:
        anonymousdomain: 'guest.j.example.com',
Edit /etc/jitsi/jicofo/sip-communicator.properties and add the following line:
org.jitsi.jicofo.auth.URL=XMPP:j.example.com
Then run commands like the following to create new users who can create rooms:
prosodyctl register admin j.example.com
Then restart most things (Prosody at least, maybe parts of Jitsi too), I rebooted the VM. Now only the accounts you created on the Prosody server will be able to create new meetings. You should be able to add, delete, and change passwords for users via prosodyctl while it s running once you have set this up. Conclusion Once I gave up on the idea of running Jitsi on the same server as anything else it wasn t particularly difficult to set up. Some bits were a little fiddly and hopefully this post will be a useful resource for people who have trouble understanding the documentation. Generally it s not difficult to install if it is the only thing running on a VM.

Markus Koschany: My Free Software Activities in July 2020

Welcome to gambaru.de. Here is my monthly report (+ the first week in August) that covers what I have been doing for Debian. If you re interested in Java, Games and LTS topics, this might be interesting for you. Debian Games
Debian Java Misc Debian LTS This was my 53. month as a paid contributor and I have been paid to work 15 hours on Debian LTS, a project started by Rapha l Hertzog. In that time I did the following: ELTS Extended Long Term Support (ELTS) is a project led by Freexian to further extend the lifetime of Debian releases. It is not an official Debian project but all Debian users benefit from it without cost. The current ELTS release is Debian 8 Jessie . This was my 26. month and I have been paid to work 13,25 hours on ELTS. Thanks for reading and see you next time.

Keith Packard: picolibc-news

Picolibc Updates I thought work on picolibc would slow down at some point, but I keep finding more things that need work. I spent a few weeks working in libm and then discovered some important memory allocation bugs in the last week that needed attention too. Cleaning up the Picolibc Math Library Picolibc uses the same math library sources as newlib, which includes code from a range of sources: The original SunPro math code had been split into two levels at some point:
  1. IEEE-754 functions. These offer pure IEEE-754 semantics, including return values and exceptions. They do not set the POSIX errno value. These are all prefixed with __ieee754_ and can be called directly by applications if desired.
  2. POSIX functions. These can offer POSIX semantics, including setting errno and returning expected values when errno is set.
New Code Sponsored by ARM Szabolcs Nagy and Wilco Dijkstra's work in the last few years has been to improve the performance of some of the core math functions, which is much appreciated. They've adopted a more modern coding style (C99) and written faster code at the expense of a larger memory foot print. One interesting choice was to use double computations for the float implementations of various functions. This makes these functions shorter and more accurate than versions done using float throughout. However, for machines which don't have HW double, this pulls in soft double code which adds considerable size to the resulting binary and slows down the computations, especially if the platform does support HW float. The new code also takes advantage of HW fused-multiply-add instructions. Those offer more precision than a sequence of primitive instructions, and so the new code can be much shorter as a result. The method used to detect whether the target machine supported fma operations was slightly broken on 32-bit ARM platforms, where those with 'float' fma acceleration but without 'double' fma acceleration would use the shorter code sequence, but with an emulated fma operation that used the less-precise sequence of operations, leading to significant reductions in the quality of the resulting math functions. I fixed the double fma detection and then also added float fma detection along with implementations of float and double fma for ARM and RISC-V. Now both of those platforms get fma-enhanced math functions where available. Errno Adventures I'd submitted patches to newlib a while ago that aliased the regular math library names to the __ieee754_ functions when the library was configured to not set errno, which is pretty common for embedded environments where a shared errno is a pain anyways. Note the use of the word can in remark about the old POSIX wrapper functions. That's because all of these functions are run-time switchable between _IEEE_ and _POSIX_ mode using the _LIB_VERSION global symbol. When left in the usual _IEEE_ mode, none of this extra code was ever executed, so these wrapper functions never did anything beyond what the underlying __ieee754_ functions did. The new code by Nagy and Dijkstra changed how functions are structured to eliminate the underlying IEEE-754 api. These new functions use tail calls to various __math_ error reporting functions. Those can be configured at library build time to set errno or not, centralizing those decisions in a few functions. The result of this combination of source material is that in the default configuration, some library functions (those written by Nagy and Dijkstra) would set errno and others (the old SunPro code) would not. To disable all errno references, the library would need to be compiled with a set of options, -D_IEEE_LIBM to disable errno in the SunPro code and -DWANT_ERRNO=0 to disable errno in the new code. To enable errno everywhere, you'd set -D_POSIX_MODE to make the default value for _LIB_VERSION be _POSIX_ instead of _IEEE_. To clean all of this up, I removed the run-time _LIB_VERSION variable and made that compile-time. In combination with the earlier work to alias the __ieee754_ functions to the regular POSIX names when _IEEE_LIBM was defined this means that the old SunPro POSIX functions now only get used when _IEEE_LIBM is not defined, and in that case the _LIB_VERSION tests always force use of the errno setting code. In addition, I made the value of WANT_ERRNO depend on whether _IEEE_LIBM was defined, so now a single definition (-D_IEEE_LIBM) causes all of the errno handling from libm to be removed, independent of which code is in use. As part of this work, I added a range of errno tests for the math functions to find places where the wrong errno value was being used. Exceptions As an alternative to errno, C also provides for IEEE-754 exceptions through the fenv functions. These have some significant advantages, including having independent bits for each exception type and having them accumulate instead of sharing errno with a huge range of other C library functions. Plus, they're generally implemented in hardware, so you get exceptions for both library functions and primitive operations. Well, you should get exceptions everywhere, except that the GCC soft float libraries don't support them at all. So, errno can still be useful if you need to know what happened in your library functions when using soft floats. Newlib has recently seen a spate of fenv support being added for various architectures, so I decided that it would be a good idea to add some tests. I added tests for both primitive operations, and then tests for library functions to check both exceptions and errno values. Oddly, this uncovered a range of minor mistakes in various math functions. Lots of these were mistakes in the SunPro POSIX wrapper functions where they modified the return values from the __ieee754_ implementations. Simply removing those value modifications fixed many of those errors. Fixing Memory Allocator bugs Picolibc inherits malloc code from newlib which offers two separate implementations, one big and fast, the other small and slow(er). Selecting between them is done while building the library, and as Picolibc is expected to be used on smaller systems, the small and slow one is the default. Contributed by someone from ARM back in 2012/2013, nano-mallocr reminds me of the old V7 memory allocator. A linked list, sorted in address order, holds discontiguous chunks of available memory. Allocation is done by searching for a large enough chunk in the list. The first one large enough is selected, and if it is large enough, a chunk is split off and left on the free list while the remainder is handed to the application. When the list doesn't have any chunk large enough, sbrk is called to get more memory. Free operations involve walking the list and inserting the chunk in the right location, merging the freed memory with any immediately adjacent chunks to reduce fragmentation. The size of each chunk is stored just before the first byte of memory used by the application, where it remains while the memory is in use and while on the free list. The free list is formed by pointers stored in the active area of the chunk, so the only overhead for chunks in use is the size field. Something Something Padding To deal with the vagaries of alignment, the original nano-mallocr code would allow for there to be 'padding' between the size field and the active memory area. The amount of padding could vary, depending on the alignment required for a particular chunk (in the case of memalign, that padding can be quite large). If present, nano-mallocr would store the padding value in the location immediately before the active area and distinguish that from a regular size field by a negative sign. The whole padding thing seems mysterious to me -- why would it ever be needed when the allocator could simply create chunks that were aligned to the required value and a multiple of that value in size. The only use I could think of was for memalign; adding this padding field would allow for less over-allocation to find a suitable chunk. I didn't feel like this one (infrequent) use case was worth the extra complexity; it certainly caused me difficulty in reading the code. A Few Bugs In reviewing the code, I found a couple of easy-to-fix bugs. Time For Testing Once I had uncovered a few bugs in this code, I decided that it would be good to write a few tests to exercise the API. With the tests running on four architectures in nearly 60 variants, it seemed like I'd be able to uncover at least a few more failures: These new tests did find bugs. But not where I expected them. Which is why I'm so fond of testing. GCC Optimizations One of my tests was to call calloc and make sure it returned a chunk of memory that appeared to work or failed with a reasonable value. To my surprise, on aarch64, that test never finished. It worked elsewhere, but on that architecture it hung in the middle of calloc itself. Which looked like this:
void * nano_calloc(malloc_size_t n, malloc_size_t elem)
 
    ptrdiff_t bytes;
    void * mem;
    if (__builtin_mul_overflow (n, elem, &bytes))
     
    RERRNO = ENOMEM;
    return NULL;
     
    mem = nano_malloc(bytes);
    if (mem != NULL) memset(mem, 0, bytes);
    return mem;
 
Note the naming here -- nano_mallocr uses nano_ prefixes in the code, but then uses #defines to change their names to those expected in the ABI. (No, I don't understand why either). However, GCC sees the real names and has some idea of what these functions are supposed to do. In particular, the pattern:
foo = malloc(n);
if (foo) memset(foo, '\0', n);
is converted into a shorter and semantically equivalent:
foo = calloc(n, 1);
Alas, GCC doesn't take into account that this optimization is occurring inside of the implementation of calloc. Another sequence of code looked like this:
chunk->size = foo
nano_free((char *) chunk + CHUNK_OFFSET);
Well, GCC knows that the content of memory passed to free cannot affect the operation of the application, and so it converted this into:
nano_free((char *) chunk + CHUNK_OFFSET);
Remember that nano_mallocr stores the size of the chunk just before the active memory. In this case, nano_mallocr was splitting a large chunk into two pieces, setting the size of the left-over part and placing that on the free list. Failing to set that size value left whatever was there before for the size and usually resulted in the free list becoming quite corrupted. Both of these problems can be corrected by compiling the code with a couple of GCC command-line switches (-fno-builtin-malloc and -fno-builtin-free). Reworking Malloc Having spent this much time reading through the nano_mallocr code, I decided to just go through it and make it easier for me to read today, hoping that other people (which includes 'future me') will also find it a bit easier to follow. I picked a couple of things to focus on:
  1. All newly allocated memory should be cleared. This reduces information disclosure between whatever code freed the memory and whatever code is about to use the memory. Plus, it reduces the effect of un-initialized allocations as they now consistently get zeroed memory. Yes, this masks bugs. Yes, this goes slower. This change is dedicated to Kees Cook, but please blame me for it not him.
  2. Get rid of the 'Padding' notion. Every time I read this code it made my brain hurt. I doubt I'll get any smarter in the future.
  3. Realloc could use some love, improving its efficiency in common cases to reduce memory usage.
  4. Reworking linked list walking. nano_mallocr uses a singly-linked free list and open-codes all list walking. Normally, I'd switch to a library implementation to avoid introducing my own bugs, but in this fairly simple case, I think it's a reasonable compromise to open-code the list operations using some patterns I learned while working at MIT from Bob Scheifler.
  5. Discover necessary values, like padding and the limits of the memory space, from the environment rather than having them hard-coded.
Padding To get rid of 'Padding' in malloc, I needed to make sure that every chunk was aligned and sized correctly. Remember that there is a header on every allocated chunk which is stored before the active memory which contains the size of the chunk. On 32-bit machines, that size is 4 bytes. If the machine requires allocations to be aligned on 8-byte boundaries (as might be the case for 'double' values), we're now going to force the alignment of the header to 8-bytes, wasting four bytes between the size field and the active memory. Well, the existing nano_mallocr code also wastes those four bytes to store the 'padding' value. Using a consistent alignment for chunk starting addresses and chunk sizes has made the code a lot simpler and easier to reason about while not using extra memory for normal allocation. Except for memalign, which I'll cover in the next section. realloc The original nano_realloc function was as simple as possible:
mem = nano_malloc(new_size);
if (mem)  
    memcpy(mem, old, MIN(old_size, new_size));
    nano_free(old);
 
return mem;
However, this really performs badly when the application is growing a buffer while accumulating data. A couple of simple optimizations occurred to me:
  1. If there's a free chunk just after the original location, it could be merged to the existing block and avoid copying the data.
  2. If the original chunk is at the end of the heap, call sbrk() to increase the size of the chunk.
The second one seems like the more important case; in a small system, the buffer will probably land at the end of the heap at some point, at which point growing it to the size of available memory becomes quite efficient. When shrinking the buffer, instead of allocating new space and copying, if there's enough space being freed for a new chunk, create one and add it to the free list. List Walking Walking singly-linked lists seem like one of the first things we see when learning pointer manipulation in C:
for (element = head; element; element = element->next)
    do stuff ...
However, this becomes pretty complicated when 'do stuff' includes removing something from the list:
prev = NULL;
for (element = head; element; element = element->next)
    ...
    if (found)
        break;
    ...
    prev = element
if (prev != NULL)
    prev->next = element->next;
else
    head = element->next;
An extra variable, and a test to figure out how to re-link the list. Bob showed me a simpler way, which I'm sure many people are familiar with:
for (ptr = &head; (element = *ptr); ptr = &(element->next))
    ...
    if (found)
        break;
*ptr = element->next;
Insertion is similar, as you would expect:
for (ptr = &head; (element = *ptr); ptr = &(element->next))
    if (found)
        break;
new_element->next = element;
*ptr = new_element;
In terms of memory operations, it's the same -- each 'next' pointer is fetched exactly once and the list is re-linked by performing a single store. In terms of reading the code, once you've seen this pattern, getting rid of the extra variable and the conditionals around the list update makes it shorter and less prone to errors. In the nano_mallocr code, instead of using 'prev = NULL', it actually used 'prev = free_list', and the test for updating the head was 'prev == element', which really caught me unawares. System Parameters Any malloc implementation needs to know a couple of things about the system it's running on:
  1. Address space. The maximum range of possible addresses sets the limit on how large a block of memory might be allocated, and hence the size of the 'size' field. Fortunately, we've got the 'size_t' type for this, so we can just use that.
  2. Alignment requirements. These derive from the alignment requirements of the basic machine types, including pointers, integers and floating point numbers which are formed from a combination of machine requirements (some systems will fault if attempting to use memory with the wrong alignment) along with a compromise between memory usage and memory system performance.
I decided to let the system tell me the alignment necessary using a special type declaration and the 'offsetof' operation:
typedef struct  
    char c;
    union  
    void *p;
    double d;
    long long ll;
    size_t s;
      u;
  align_t;
#define MALLOC_ALIGN        (offsetof(align_t, u))
Because C requires struct fields to be stored in order of declaration, the 'u' field would have to be after the 'c' field, and would have to be assigned an offset equal to the largest alignment necessary for any of its members. Testing on a range of machines yields the following alignment requirements:
Architecture Alignment
x86_64 8
RISC-V 8
aarch64 8
arm 8
x86 4
So, I guess I could have just used a constant value of '8' and not worried about it, but using the compiler-provided value means that running picolibc on older architectures might save a bit of memory at no real cost in the code. Now, the header containing the 'size' field can be aligned to this value, and all allocated blocks can be allocated in units of this value. memalign memalign, valloc and pvalloc all allocate memory with restrictions on the alignment of the base address and length. You'd think these would be simple -- allocate a large chunk, align within that chunk and return the address. However, they also all require that the address can be successfully passed to free. Which means that the allocator needs to do some tricks to make it all work. Essentially, you allocate 'lots' of memory and then arrange that any bytes at the head and tail of the allocation can be returned to the free list. The tail part is easy; if it's large enough to form a free chunk (which must contain the size and a 'next' pointer for the free list), it can be split off. Otherwise, it just sits at the end of the allocation being wasted space. The head part is a bit tricky when it's not large enough to form a free chunk. That's where the 'padding' business came in handy; that can be as small as a 'size_t' value, which (on 32-bit systems) is only four bytes. Now that we're giving up trying to reason about 'padding', any extra block at the start must be big enough to hold a free block, which includes the size and a next pointer. On 32-bit systems, that's just 8 bytes which (for most of our targets) is the same as the alignment value we're using. On 32-bit systems that can use 4-byte alignment, and on 64-bit systems, it's possible that the alignment required by the application for memalign and the alignment of a chunk returned by malloc might be off by too small an amount to create a free chunk. So, we just allocate a lot of extra space; enough so that we can create a block of size 'toosmall + align' at the start and create a free chunk of memory out of that. This works, and at least returns all of the unused memory back for other allocations. Sending Patches Back to Newlib I've sent the floating point fixes upstream to newlib where they've already landed on master. I've sent most of the malloc fixes, but I'm not sure they really care about seeing nano_mallocr refactored. If they do, I'll spend the time necessary to get the changes ported back to the newlib internal APIs and merged upstream.

13 August 2020

Sven Hoexter: An Average IT Org

Supply chain attacks are a known issue, and also lately there was a discussion around the relevance of reproducible builds. Looking in comparison at an average IT org doing something with the internet, I believe the pressing problem is neither supply chain attacks nor a lack of reproducible builds. The real problem is the amount of prefabricated binaries supplied by someone else, created in an unknown build environment with unknown tools, the average IT org requires to do anything. The Mess the World Runs on By chance I had an opportunity to look at what some other people I know use, and here is the list I could compile by scratching just at the surface: Of course there are also all the script language repos - Python, Ruby, Node/Typescript - around as well. Looking at myself, who's working in a different IT org but with a similar focus, I have the following lingering around on my for work laptop and retrieved it as a binary from a 3rd party: Yes some of that is even non-free and might contain spyw^telemetry. Takeway I By guessing based on Pareto Principle probably 80% of the software mentioned above is also open source software. But, and here we leave Pareto behind, close to none is build by the average IT org from source. Why should the average IT org care about advanced issues like supply chain attacks on source code and mitigations, when it already gets into very hot water the day DockerHub closes down, HashiCorp moves from open core to full proprietary or Elastic decides to no longer offer free binary builds? The reality out there seems to be that infrastructure of "modern" IT orgs is managed similar to the Windows 95 installation of my childhood. You just grab running binaries from somewhere and run them. The main difference seems to be that you no longer have the inconvenience of downloading a .xls from geocities you've to rename to .rar and that it's legal. Takeway II In the end the binary supply is like a drug for the user, and somehow the Debian project is also just another dealer / middle man in this setup. There are probably a lot of open questions to think about in that context. Are we the better dealer because we care about signed sources we retrieve from upstream and because we engage in reproducible build projects? Are our own means of distributing binaries any better than a binary download from github via https with a manual checksum verification, or the Debian repo at download.docker.com? Is the approach of the BSD/Gentoo ports, where you have to compile at least some software from source, the better one? Do I really want to know how some of the software is actually build? Or some more candid ones like is gnutls a good choice for the https support in apt and how solid is the gnupg code base? Update: Regarding apt there seems to be some movement.

12 August 2020

Michael Stapelberg: Linux distributions: Can we do without hooks and triggers?

Hooks are an extension feature provided by all package managers that are used in larger Linux distributions. For example, Debian uses apt, which has various maintainer scripts. Fedora uses rpm, which has scriptlets. Different package managers use different names for the concept, but all of them offer package maintainers the ability to run arbitrary code during package installation and upgrades. Example hook use cases include adding daemon user accounts to your system (e.g. postgres), or generating/updating cache files. Triggers are a kind of hook which run when other packages are installed. For example, on Debian, the man(1) package comes with a trigger which regenerates the search database index whenever any package installs a manpage. When, for example, the nginx(8) package is installed, a trigger provided by the man(1) package runs. Over the past few decades, Open Source software has become more and more uniform: instead of each piece of software defining its own rules, a small number of build systems are now widely adopted. Hence, I think it makes sense to revisit whether offering extension via hooks and triggers is a net win or net loss.

Hooks preclude concurrent package installation Package managers commonly can make very little assumptions about what hooks do, what preconditions they require, and which conflicts might be caused by running multiple package s hooks concurrently. Hence, package managers cannot concurrently install packages. At least the hook/trigger part of the installation needs to happen in sequence. While it seems technically feasible to retrofit package manager hooks with concurrency primitives such as locks for mutual exclusion between different hook processes, the required overhaul of all hooks seems like such a daunting task that it might be better to just get rid of the hooks instead. Only deleting code frees you from the burden of maintenance, automated testing and debugging. In Debian, there are 8620 non-generated maintainer scripts, as reported by find shard*/src/*/debian -regex ".*\(pre\ post\)\(inst\ rm\)$" on a Debian Code Search instance.

Triggers slow down installing/updating other packages Personally, I never use the apropos(1) command, so I don t appreciate the man(1) package s trigger which updates the database used by apropos(1). The process takes a long time and, because hooks and triggers must be executed serially (see previous section), blocks my installation or update. When I tell people this, they are often surprised to learn about the existance of the apropos(1) command. I suggest adopting an opt-in model.

Unnecessary work if programs are not used between updates Hooks run when packages are installed. If a package s contents are not used between two updates, running the hook in the first update could have been skipped. Running the hook lazily when the package contents are used reduces unnecessary work. As a welcome side-effect, lazy hook evaluation automatically makes the hook work in operating system images, such as live USB thumb drives or SD card images for the Raspberry Pi. Such images must not ship the same crypto keys (e.g. OpenSSH host keys) to all machines, but instead generate a different key on each machine. Why do users keep packages installed they don t use? It s extra work to remember and clean up those packages after use. Plus, users might not realize or value that having fewer packages installed has benefits such as faster updates. I can also imagine that there are people for whom the cost of re-installing packages incentivizes them to just keep packages installed you never know when you might need the program again

Implemented in an interpreted language While working on hermetic packages (more on that in another blog post), where the contained programs are started with modified environment variables (e.g. PATH) via a wrapper bash script, I noticed that the overhead of those wrapper bash scripts quickly becomes significant. For example, when using the excellent magit interface for Git in Emacs, I encountered second-long delays when using hermetic packages compared to standard packages. Re-implementing wrappers in a compiled language provided a significant speed-up. Similarly, getting rid of an extension point which mandates using shell scripts allows us to build an efficient and fast implementation of a predefined set of primitives, where you can reason about their effects and interactions. magit needs to run git a few times for displaying the full status, so small overhead quickly adds up.

Incentivizing more upstream standardization Hooks are an escape hatch for distribution maintainers to express anything which their packaging system cannot express. Distributions should only rely on well-established interfaces such as autoconf s classic ./configure && make && make install (including commonly used flags) to build a distribution package. Integrating upstream software into a distribution should not require custom hooks. For example, instead of requiring a hook which updates a cache of schema files, the library used to interact with those files should transparently (re-)generate the cache or fall back to a slower code path. Distribution maintainers are hard to come by, so we should value their time. In particular, there is a 1:n relationship of packages to distribution package maintainers (software is typically available in multiple Linux distributions), so it makes sense to spend the work in the 1 and have the n benefit.

Can we do without them? If we want to get rid of hooks, we need another mechanism to achieve what we currently achieve with hooks. If the hook is not specific to the package, it can be moved to the package manager. The desired system state should either be derived from the package contents (e.g. required system users can be discovered from systemd service files) or declaratively specified in the package build instructions more on that in another blog post. This turns hooks (arbitrary code) into configuration, which allows the package manager to collapse and sequence the required state changes. E.g., when 5 packages are installed which each need a new system user, the package manager could update /etc/passwd just once. If the hook is specific to the package, it should be moved into the package contents. This typically means moving the functionality into the program start (or the systemd service file if we are talking about a daemon). If (while?) upstream is not convinced, you can either wrap the program or patch it. Note that this case is relatively rare: I have worked with hundreds of packages and the only package-specific functionality I came across was automatically generating host keys before starting OpenSSH s sshd(8) . There is one exception where moving the hook doesn t work: packages which modify state outside of the system, such as bootloaders or kernel images. Even that can be moved out of a package-specific hook, as Fedora demonstrates.

Conclusion Global state modifications performed as part of package installation today use hooks, an overly expressive extension mechanism. Instead, all modifications should be driven by configuration. This is feasible because there are only a few different kinds of desired state modifications. This makes it possible for package managers to optimize package installation.

11 August 2020

Dirk Eddelbuettel: RcppSimdJson 0.1.1: More Features

A first update following for the exciting RcppSimdJson 0.1.0 release last month is now on CRAN. Version 0.1.1 brings further enhancements such direct parsing of raw chars, working with compressed files as well as much expanded querying ability all thanks to Brendan, some improvements to our demos thanks to Daniel as well as a small fix via a one-liner borrowed from upstream for a reported UBSAN issue. RcppSimdJson wraps the fantastic and genuinely impressive simdjson library by Daniel Lemire and collaborators. Via very clever algorithmic engineering to obtain largely branch-free code, coupled with modern C++ and newer compiler instructions, it results in parsing gigabytes of JSON parsed per second which is quite mindboggling. The best-case performance is faster than CPU speed as use of parallel SIMD instructions and careful branch avoidance can lead to less than one cpu cycle use per byte parsed; see the video of the talk by Daniel Lemire at QCon (also voted best talk). The detailed list of changes follows.

Changes in version 0.1.1 (2020-08-10)
  • Corrected incorrect file deletion when mixing local and remote files (Brendan in #34) closing #33.
  • Added support for raw vectors, compressed files, and compressed downloads (Dirk and Brendan in #36, #39, and #45 closing #35 and addressing issues raised in #40 and #44).
  • Examples in two demos are now more self-sufficient (Daniel Lemire and Dirk in #42).
  • Expanded query functionality to include single, flat, and nested queries (Brendan in #45 closing #43).
  • Split error handling parameters from error_ok/on_error into parse_error_ok/on_parse_error and query_error_ok/on_query_error (Brendan in #45).
  • One-line upstream change to address sanitizer error on cast.

Courtesy of CRANberries, there is also a diffstat report for this release. For questions, suggestions, or issues please use the issue tracker at the GitHub repo. If you like this or other open-source work I do, you can now sponsor me at GitHub. For the first year, GitHub will match your contributions.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

10 August 2020

Dirk Eddelbuettel: nanotime 0.3.1: Misc Build Fixes for Yuge New Features!

The nanotime 0.3.0 release four days ago was so exciting that we decided to do it again! Kidding aside, and fairly extensive tests notwithstanding we were bitten by a few build errors: who knew clang on macOS needed extra curlies to be happy, another manifestation of Solaris having no idea what a timezone setting America/New_York is, plus some extra pickyness from the SAN tests and whatnot. So Leonardo and I gave it some extra care over the weekend, uploaded it late yesterday and here we are with 0.3.1. Thanks again to CRAN for prompt processing even though they are clearly deluged shortly before their (brief) summer break. nanotime relies on the RcppCCTZ package for (efficient) high(er) resolution time parsing and formatting up to nanosecond resolution, and the bit64 package for the actual integer64 arithmetic. Initially implemented using the S3 system, it has benefitted greatly from work by Leonardo Silvestri who rejigged internals in S4 and now added new types for periods, intervals and durations. The NEWS snippet adds full details.

Changes in version 0.3.1 (2020-08-09)
  • Several small cleanups to ensure a more robust compilation (Leonardo and Dirk in #75 fixing #74).
  • Show Solaris some extra love by skipping tests and examples with a timezone (Dirk in #76).

Thanks to CRANberries there is also a diff to the previous version. More details and examples are at the nanotime page; code, issue tickets etc at the GitHub repository. If you like this or other open-source work I do, you can now sponsor me at GitHub. For the first year, GitHub will match your contributions.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

Russ Allbery: rra-c-util 8.3

In this release of my utility library for my other packages, I finally decided to drop support for platforms without a working snprintf. This dates back to the early 2000s and a very early iteration of this package. At the time, there were still some older versions of UNIX without snprintf at all. More commonly, it was buggy. The most common problem was that it would return -1 if the buffer wasn't large enough rather than returning the necessary size of the buffer. Or, in some cases, it wouldn't support a buffer size of 0 and a NULL buffer to get the necessary size. At the time I added this support for INN and some other packages, Solaris had several of these issues. But C99 standardized the correct snprintf behavior, and slowly every maintained operating system was fixed. (I forget whether it was fixed in Solaris 8 or Solaris 9, but regardless, Solaris has had a working snprintf for many years.) Meanwhile, the replacement function (Patrick Powell's version, also used by mutt and other packages) was a huge wad of code and a corresponding test suite. Over time, I've increased the aggressiveness of linters to try to catch more dangerous C pitfalls, and that's required carrying more and more small modifications plus a preamble to disable various warnings that I didn't want to try to fix. The straw that broke the camel's back was Clang's new case fallthrough warning. Clang stopped supporting the traditional /* fallthrough */ comment. It now prefers [[clang:fallthrough]] syntax, but of course older compilers choke on that. It does support the GCC __attribute__((__fallthrough__)) syntax, but older compilers don't like that construction because they think it's an empty statement. It was a mess, and I decided the time had come to drop this support effort. At this point, if you're still running an operating system without C99 snprintf, I think it's essentially a retrocomputing or at least extremely stable legacy production situation, and you're unlikely to want the latest and greatest releases of new software. Hopefully that assumption is correct, or at least correct enough. (I realize the right solution to this problem is probably for me to use Gnulib for portability. But converting to it is a whole other project with a lot of other implications and machinery, and I'm not sure that's what I want to spend time on.) Also in this release is a fix for network tests on hosts with no IPv4 addresses (more on this when I release the next version of remctl), fixes for style issues found by Perl::Critic::Freenode, and some other test suite improvements. You can get the latest version from the rra-c-util distribution page.

Arnaud Rebillout: GoAccess 1.4, a detailed tutorial

GoAccess v1.4 was just released a few weeks ago! Let's take this chance to write a loooong tutorial. We'll go over every steps to install and operate GoAccess. This is a tutorial aimed at those who don't play sysadmin every day, and that's why it's so long, I did my best to provide thorough explanations all along, so that it's more than just a "copy-and-paste" kind of tutorial. And for those who do play sysadmin everyday: please try not to fall asleep while reading, and don't hesitate to drop me an e-mail if you spot anything inaccurate in here. Thanks! Introduction So what's GoAccess already? GoAccess is a web log analyzer, and it allows you to visualize the traffic for your website, and get to know a bit more about your visitors: how many visitors and hits, for which pages, coming from where (geolocation, operating system, web browser...), etc... It does so by parsing the access logs from your web server, be it Apache, NGINX or whatever. GoAccess gives you different options to display the statistics, and in this tutorial we'll focus on producing a HTML report. Meaning that you can see the statistics for your website straight in your web browser, under the form of a single HTML page. For an example, you can have a look at the stats of my blog here: http://goaccess.arnaudr.io. GoAccess is written in C, it has very few dependencies, it had been around for about 10 years, and it's distributed under the MIT license. Assumptions This tutorial is about installing and configuring, so I'll assume that all the commands are run as root. I won't prefix each of them with sudo. I use the Apache web server, running on a Debian system. I don't think it matters so much for this tutorial though. If you're using NGINX it's fine, you can keep reading. Also, I will just use the name SITE for the name of the website that we want to analyze with GoAccess. Just replace that with the real name of your site. I also assume the following locations for your stuff: If you have your stuff in /srv/SITE/ log,www instead, no worries, just adjust the paths accordingly, I bet you can do it. Installation The latest version of GoAccess is v1.4, and it's not yet available in the Debian repositories. So for this part, you can follow the instructions from the official GoAccess download page. Install steps are explained in details, so there's nothing left for me to say :) When this is done, let's get started with the basics. We're talking about the latest version v1.4 here, let's make sure:
$ goaccess --version
GoAccess - 1.4.
...
Now let's try to create a HTML report. I assume that you already have a website up and running. GoAccess needs to parse the access logs. These logs are optional, they might or might not be created by your web server, depending on how it's configured. Usually, these log files are named access.log, unsurprisingly. You can check if those logs exist on your system by running this command:
find /var/log -name access.log
Another important thing to know is that these logs can be in different formats. In this tutorial we'll assume that we work with the combined log format, because it seems to be the most common default. To check what kind of access logs your web server produces, you must look at the configuration for your site. For an Apache web server, you should have such a line in the file /etc/apache2/sites-enabled/SITE.conf:
CustomLog $ APACHE_LOG_DIR /SITE/access.log combined
For NGINX, it's quite similar. The configuration file would be something like /etc/nginx/sites-enabled/SITE, and the line to enable access logs would be something like:
access_log /var/log/nginx/SITE/access.log
Note that NGINX writes the access logs in the combined format by default, that's why you don't see the word combined anywhere in the line above: it's implicit. Alright, so from now on we assume that yes, you have access log files available, and yes, they are in the combined log format. If that's the case, then you can already run GoAccess and generate a report, for example for the log file /var/log/apache2/access.log
goaccess \
    --log-format COMBINED \
    --output /tmp/report.html \
    /var/log/apache2/access.log
It's possible to give GoAccess more than one log files to process, so if you have for example the file access.log.1 around, you can use it as well:
goaccess \
    --log-format COMBINED \
    --output /tmp/report.html \
    /var/log/apache2/access.log \
    /var/log/apache2/access.log.1
If GoAccess succeeds (and it should), you're on the right track! All is left to do to complete this test is to have a look at the HTML report created. It's a single HTML page, so you can easily scp it to your machine, or just move it to the document root of your site, and then open it in your web browser. Looks good? So let's move on to more interesting things. Web server configuration This part is very short, because in terms of configuration of the web server, there's very little to do. As I said above, the only thing you want from the web server is to create access log files. Then you want to be sure that GoAccess and your web server agree on the format for these files. In the part above we used the combined log format, but GoAccess supports many other common log formats out of the box, and even allows you to parse custom log formats. For more details, refer to the option --log-format in the GoAccess manual page. Another common log format is named, well, common. It even has its own Wikipedia page. But compared to combined, the common log format contains less information, it doesn't include the referrer and user-agent values, meaning that you won't have it in the GoAccess report. So at this point you should understand that, unsurprisingly, GoAccess can only tell you about what's in the access logs, no more no less. And that's all in term of web server configuration. Configuration to run GoAccess unprivileged Now we're going to create a user and group for GoAccess, so that we don't have to run it as root. The reason is that, well, for everything running unattended on your server, the less code runs as root, the better. It's good practice and common sense. In this case, GoAccess is simply a log analyzer. So it just needs to read the logs files from your web server, and there is no need to be root for that, an unprivileged user can do the job just as well, assuming it has read permissions on /var/log/apache2 or /var/log/nginx. The log files of the web server are usually part of the adm group (though it might depend on your distro, I'm not sure). This is something you can check easily with the following command:
ls -l /var/log   grep -e apache2 -e nginx
As a result you should get something like that:
drwxr-x--- 2 root adm 20480 Jul 22 00:00 /var/log/apache2/
And as you can see, the directory apache2 belongs to the group adm. It means that you don't need to be root to read the logs, instead any unprivileged user that belongs to the group adm can do it. So, let's create the goaccess user, and add it to the adm group:
adduser --system --group --no-create-home goaccess
addgroup goaccess adm
And now, let's run GoAccess unprivileged, and verify that it can still read the log files:
setpriv \
    --reuid=goaccess --regid=goaccess \
    --init-groups --inh-caps=-all \
    -- \
    goaccess \
    --log-format COMBINED \
    --output /tmp/report2.html \
    /var/log/apache2/access.log
setpriv is the command used to drop privileges. The syntax is quite verbose, it's not super friendly for tutorials, but don't be scared and read the manual page to learn what it does. In any case, this command should work, and at this point, it means that you have a goaccess user ready, and we'll use it to run GoAccess unprivileged. Integration, option A - Run GoAccess once a day, from a logrotate hook In this part we wire things together, so that GoAccess processes the log files once a day, adds the new logs to its internal database, and generates a report from all that aggregated data. The result will be a single HTML page. Introducing logrotate In order to do that, we'll use a logrotate hook. logrotate is a little tool that should already be installed on your server, and that runs once a day, and that is in charge of rotating the log files. "Rotating the logs" means moving access.log to access.log.1 and so on. With logrotate, a new log file is created every day, and log files that are too old are deleted. That's what prevents your logs from filling up your disk basically :) You can check that logrotate is indeed installed and enabled with this command (assuming that your init system is systemd):
systemctl status logrotate.timer
What's interesting for us is that logrotate allows you to run scripts before and after the rotation is performed, so it's an ideal place from where to run GoAccess. In short, we want to run GoAccess just before the logs are rotated away, in the prerotate hook. But let's do things in order. At first, we need to write a little wrapper script that will be in charge of running GoAccess with the right arguments, and that will process all of your sites. The wrapper script This wrapper is made to process more than one site, but if you have only one site it works just as well, of course. So let me just drop it on you like that, and I'll explain afterward. Here's my wrapper script:
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#!/bin/bash
# Process log files /var/www/apache2/SITE/access.log,
# only if /var/lib/goaccess-db/SITE exists.
# Create HTML reports in $1, a directory that must exist.
set -eu
OUTDIR=
LOGDIR=/var/log/apache2
DBDIR=/var/lib/goaccess-db
fail()   echo >&2 "$@"; exit 1;  
[ $# -eq 1 ]   fail "Usage: $(basename $0) OUTPUT_DIRECTORY"
OUTDIR=$1
[ -d "$OUTDIR" ]   fail "'$OUTDIR' is not a directory"
[ -d "$LOGDIR" ]   fail "'$LOGDIR' is not a directory"
[ -d "$DBDIR"  ]   fail "'$DBDIR' is not a directory"
for d in $(find "$LOGDIR" -mindepth 1 -maxdepth 1 -type d); do
    site=$(basename "$sitedir")
    dbdir=$DBDIR/$site
    logfile=$d/access.log
    outfile=$OUTDIR/$site.html
    if [ ! -d "$dbdir" ]   [ ! -e "$logfile" ]; then
        echo "  Skipping site '$site'"
        continue
    else
        echo "  Processing site '$site'"
    fi
    setpriv \
        --reuid=goaccess --regid=goaccess \
        --init-groups --inh-caps=-all \
        -- \
    goaccess \
        --agent-list \
        --anonymize-ip \
        --persist \
        --restore \
        --config-file /etc/goaccess/goaccess.conf \
        --db-path "$dbdir" \
        --log-format "COMBINED" \
        --output "$outfile" \
        "$logfile"
done
So you'd install this script at /usr/local/bin/goaccess-wrapper for example, and make it executable:
chmod +x /usr/local/bin/goaccess-wrapper
A few things to note: As is, the script makes the assumption that the logs for your site are logged in a sub-directory /var/log/apache2/SITE/. If it's not the case, adjust that in the wrapper accordingly. The name of this sub-directory is then used to find the GoAccess database directory /var/lib/goaccess-db/SITE/. This directory is expected to exist, meaning that if you don't create it yourself, the wrapper won't process this particular site. It's a simple way to control which sites are processed by this GoAccess wrapper, and which sites are not. So if you want goaccess-wrapper to process the site SITE, just create a directory with the name of this site under /var/lib/goaccess-db:
mkdir -p /var/lib/goaccess-db/SITE
chown goaccess:goaccess /var/lib/goaccess-db/SITE
Now let's create an output directory:
mkdir /tmp/goaccess-reports
chown goaccess:goaccess /tmp/goaccess-reports
And let's give a try to the wrapper script:
goaccess-wrapper /tmp/goaccess-reports
ls /tmp/goaccess-reports
Which should give you:
SITE.html
At the same time, you can check that GoAccess populated the database with a bunch of files:
ls /var/lib/goaccess-db/SITE
Setting up the logrotate prerotate hook At this point, we have the wrapper in place. Let's now add a pre-rotate hook so that goaccess-wrapper runs once a day, just before the logs are rotated away. The logrotate config file for Apache2 is located at /etc/logrotate.d/apache2, and for NGINX it's at /etc/logrotate.d/nginx. Among the many things you'll see in this file, here's what is of interest for us: In the config file, there is also this snippet:
prerotate
    if [ -d /etc/logrotate.d/httpd-prerotate ]; then \
        run-parts /etc/logrotate.d/httpd-prerotate; \
    fi; \
endscript
It indicates that scripts in the directory /etc/logrotate.d/httpd-prerotate/ will be executed before the rotation takes place. Refer to the man page run-parts(8) for more details... Putting all of that together, it means that logs from the web server are rotated once a day, and if we want to run scripts just before the rotation, we can just drop them in the httpd-prerotate directory. Simple, right? Let's first create this directory if it doesn't exist:
mkdir -p /etc/logrotate.d/httpd-prerotate/
And let's create a tiny script at /etc/logrotate.d/httpd-prerotate/goaccess:
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#!/bin/sh
exec goaccess-wrapper /tmp/goaccess-reports
Don't forget to make it executable:
chmod +x /etc/logrotate.d/httpd-prerotate/goaccess
As you can see, the only thing that this script does is to invoke the wrapper with the right argument, ie. the output directory for the HTML reports that are generated. And that's all. Now you can just come back tomorrow, check the logs, and make sure that the hook was executed and succeeded. For example, this kind of command will tell you quickly if it worked:
journalctl   grep logrotate
Integration, option B - Run GoAccess once a day, from a systemd service OK so we've just seen how to use a logrotate hook. One downside with that is that we have to drop privileges in the wrapper script, because logrotate runs as root, and we don't want to run GoAccess as root. Hence the rather convoluted syntax with setpriv. Rather than embedding this kind of thing in a wrapper script, we can instead run the wrapper script from a [systemd][] service, and define which user runs the wrapper straight in the systemd service file. Introducing systemd niceties So we can create a systemd service, along with a systemd timer that fires daily. We can then set the user and group that execute the script straight in the systemd service, and there's no need for setpriv anymore. It's a bit more streamlined. We can even go a bit further, and use systemd parameterized units (also called templates), so that we have one service per site (instead of one service that process all of our sites). That will simplify the wrapper script a lot, and it also looks nicer in the logs. With this approach however, it seems that we can't really run exactly before the logs are rotated away, like we did in the section above. But that's OK. What we'll do is that we'll run once a day, no matter the time, and we'll just make sure to process both log files access.log and access.log.1 (ie. the current logs and the logs from yesterday). This way, we're sure not to miss any line from the logs. Note that GoAccess is smart enough to only consider newer entries from the log files, and discard entries that are already in the database. In other words, it's safe to parse the same log file more than once, GoAccess will do the right thing. For more details see "INCREMENTAL LOG PROCESSING" from man goaccess. systemd]: https://freedesktop.org/wiki/Software/systemd/ Implementation And here's how it all looks like. First, a little wrapper script for GoAccess:
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#!/bin/bash
# Usage: $0 SITE DBDIR LOGDIR OUTDIR
set -eu
SITE=$1
DBDIR=$2
LOGDIR=$3
OUTDIR=$4
LOGFILES=()
for ext in log log.1; do
    logfile="$LOGDIR/access.$ext"
    [ -e "$logfile" ] && LOGFILES+=("$logfile")
done
if [ $ #LOGFILES[@]  -eq 0 ]; then
    echo "No log files in '$LOGDIR'"
    exit 0
fi
goaccess \
    --agent-list \
    --anonymize-ip \
    --persist \
    --restore \
    --config-file /etc/goaccess/goaccess.conf \
    --db-path "$DBDIR" \
    --log-format "COMBINED" \
    --output "$OUTDIR/$SITE.html" \
    "$ LOGFILES[@] "
This wrapper does very little. Actually, the only thing it does is to check for the existence of the two log files access.log and access.log.1, to be sure that we don't ask GoAccess to process a file that does not exist (GoAccess would not be happy about that). Save this file under /usr/local/bin/goaccess-wrapper, don't forget to make it executable:
chmod +x /usr/local/bin/goaccess-wrapper
Then, create a systemd parameterized unit file, so that we can run this wrapper as a systemd service. Save it under /etc/systemd/system/goaccess@.service:
[Unit]
Description=Update GoAccess report - %i
ConditionPathIsDirectory=/var/lib/goaccess-db/%i
ConditionPathIsDirectory=/var/log/apache2/%i
ConditionPathIsDirectory=/tmp/goaccess-reports
PartOf=goaccess.service
[Service]
Type=oneshot
User=goaccess
Group=goaccess
Nice=19
ExecStart=/usr/local/bin/goaccess-wrapper \
 %i \
 /var/lib/goaccess-db/%i \
 /var/log/apache2/%i \
 /tmp/goaccess-reports
So, what is a systemd parameterized unit? It's a service to which you can pass an argument when you enable it. The %i in the unit definition will be replaced by this argument. In our case, the argument will be the name of the site that we want to process. As you can see, we use the directive ConditionPathIsDirectory= extensively, so that if ever one of the required directories does not exist, the unit will just be skipped (and marked as such in the logs). It's a graceful way to fail. We run the wrapper as the user and group goaccess, thanks to User= and Group=. We also use Nice= to give a low priority to the process. At this point, it's already possible to test. Just make sure that you created a directory for the GoAccess database:
mkdir -p /var/lib/goaccess-db/SITE
chown goaccess:goaccess /var/lib/goaccess-db/SITE
Also make sure that the output directory exists:
mkdir /tmp/goaccess-reports
chown goaccess:goaccess /tmp/goaccess-reports
Then reload systemd and fire the unit to see if it works:
systemctl daemon-reload
systemctl start goaccess@SITE.service
journalctl   tail
And that should work already. As you can see, the argument, SITE, is passed in the systemctl start command. We just append it after the @, in the name of the unit. Now, let's create another GoAccess service file, which sole purpose is to group all the parameterized units together, so that we can start them all in one go. Note that we don't use a systemd target for that, because ultimately we want to run it once a day, and that would not be possible with a target. So instead we use a dummy oneshot service. So here it is, saved under /etc/systemd/system/goaccess.service:
[Unit]
Description=Update GoAccess reports
Requires= \
 goaccess@SITE1.service \
 goaccess@SITE2.service
[Service]
Type=oneshot
ExecStart=true
As you can see, we simply list the sites that we want to process in the Requires= directive. In this example we have two sites named SITE1 and SITE2. Let's ensure that everything is still good:
systemctl daemon-reload
systemctl start goaccess.service
journalctl   tail
Check the logs, both sites SITE1 and SITE2 should have been processed. And finally, let's create a timer, so that systemd runs goaccess.service once a day. Save it under /etc/systemd/system/goaccess.timer.
[Unit]
Description=Daily update of GoAccess reports
[Timer]
OnCalendar=daily
RandomizedDelaySec=1h
Persistent=true
[Install]
WantedBy=timers.target
Finally, enable the timer:
systemctl daemon-reload
systemctl enable --now goaccess.timer
At this point, everything should be OK. Just come back tomorrow and check the logs with something like:
journalctl   grep goaccess
Last word: if you have only one site to process, of course you can simplify, for example you can hardcode all the paths in the file goaccess.service instead of using a parameterized unit. Up to you. Daily operations So in this part, we assume that you have GoAccess all setup and running, once a day or so. Let's just go over a few things worth noting. Serve your report Up to now in this tutorial, we created the reports in /tmp/goaccess-reports, but that was just for the sake of the example. You will probably want to save your reports in a directory that is served by your web server, so that, well, you can actually look at it in your web browser, that was the point, right? So how to do that is a bit out of scope here, and I guess that if you want to monitor your website, you already have a website, so you will have no trouble serving the GoAccess HTML report. However there's an important detail to be aware of: GoAccess shows all the IP addresses of your visitors in the report. As long as the report is private it's OK, but if ever you make your GoAccess report public, then you should definitely invoke GoAccess with the option --anonymize-ip. Keep an eye on the logs In this tutorial, the reports we create, along with the GoAccess databases, will grow bigger every day, forever. It also means that the GoAccess processing time will grow a bit each day. So maybe the first thing to do is to keep an eye on the logs, to see how long it takes to GoAccess to do its job every day. Also, maybe you'd like to keep an eye on the size of the GoAccess database with:
du -sh /var/lib/goaccess-db/SITE
If your site has few visitors, I suspect it won't be a problem though. You could also be a bit pro-active in preventing this problem in the future, and for example you could break the reports into, say, monthly reports. Meaning that every month, you would create a new database in a new directory, and also start a new HTML report. This way you'd have monthly reports, and you make sure to limit the GoAccess processing time, by limiting the database size to a month. This can be achieved very easily, by including something like YEAR-MONTH in the database directory, and in the HTML report. You can handle that automatically in the wrapper script, for example:
sfx=$(date +'%Y-%m')
mkdir -p $DBDIR/$sfx
goaccess \
    --db-path $DBDIR/$sfx \
    --output "$OUTDIR/$SITE-$sfx.html" \
    ...
You get the idea. Further notes Migration from older versions With the --persist option, GoAccess keeps all the information from the logs in a database, so that it can re-use it later. In prior versions, GoAccess used the Tokyo Cabinet key-value store for that. However starting from v1.4, GoAccess dropped this dependency and now uses its own database format. As a result, the previous database can't be used anymore, you will have to remove it and restart from zero. At the moment there is no way to convert the data from the old database to the new one. If you're interested, this is discussed upstream at [#1783][bug-1783]. Another thing that changed with this new version is the name for some of the command-line options. For example, --load-from-disk was dropped in favor of --restore, and --keep-db-files became --persist. So you'll have to look at the documentation a bit, and update your script(s) accordingly. Other ways to use GoAccess It's also possible to do it completely differently. You could keep GoAccess running, pretty much like a daemon, with the --real-time-html option, and have it process the logs continuously, rather than calling it on a regular basis. It's also possible to see the GoAccess report straight in the terminal, thanks to libncurses, rather than creating a HTML report. And much more, GoAccess is packed with features. Conclusion I hope that this tutorial helped some of you folks. Feel free to drop an e-mail for comments.

Arnaud Rebillout: GoAccess 1.4, a detailed tutorial

GoAccess v1.4 was just released a few weeks ago! Let's take this chance to write a loooong tutorial. We'll go over every steps to install and operate GoAccess. This is a tutorial aimed at those who don't play sysadmin every day, and that's why it's so long, I did my best to provide thorough explanations all along, so that it's more than just a "copy-and-paste" kind of tutorial. And for those who do play sysadmin everyday: please try not to fall asleep while reading, and don't hesitate to drop me an e-mail if you spot anything inaccurate in here. Thanks! Introduction So what's GoAccess already? GoAccess is a web log analyzer, and it allows you to visualize the traffic for your website, and get to know a bit more about your visitors: how many visitors and hits, for which pages, coming from where (geolocation, operating system, web browser...), etc... It does so by parsing the access logs from your web server, be it Apache, NGINX or whatever. GoAccess gives you different options to display the statistics, and in this tutorial we'll focus on producing a HTML report. Meaning that you can see the statistics for your website straight in your web browser, under the form of a single HTML page. For an example, you can have a look at the stats of my blog here: https://goaccess.arnaudr.io. GoAccess is written in C, it has very few dependencies, it had been around for about 10 years, and it's distributed under the MIT license. Assumptions This tutorial is about installing and configuring, so I'll assume that all the commands are run as root. I won't prefix each of them with sudo. I use the Apache web server, running on a Debian system. I don't think it matters so much for this tutorial though. If you're using NGINX it's fine, you can keep reading. Also, I will just use the name SITE for the name of the website that we want to analyze with GoAccess. Just replace that with the real name of your site. I also assume the following locations for your stuff: If you have your stuff in /srv/SITE/ log,www instead, no worries, just adjust the paths accordingly, I bet you can do it. Installation The latest version of GoAccess is v1.4, and it's not yet available in the Debian repositories. So for this part, you can follow the instructions from the official GoAccess download page. Install steps are explained in details, so there's nothing left for me to say :) When this is done, let's get started with the basics. We're talking about the latest version v1.4 here, let's make sure:
$ goaccess --version
GoAccess - 1.4.
...
Now let's try to create a HTML report. I assume that you already have a website up and running. GoAccess needs to parse the access logs. These logs are optional, they might or might not be created by your web server, depending on how it's configured. Usually, these log files are named access.log, unsurprisingly. You can check if those logs exist on your system by running this command:
find /var/log -name access.log
Another important thing to know is that these logs can be in different formats. In this tutorial we'll assume that we work with the combined log format, because it seems to be the most common default. To check what kind of access logs your web server produces, you must look at the configuration for your site. For an Apache web server, you should have such a line in the file /etc/apache2/sites-enabled/SITE.conf:
CustomLog $ APACHE_LOG_DIR /SITE/access.log combined
For NGINX, it's quite similar. The configuration file would be something like /etc/nginx/sites-enabled/SITE, and the line to enable access logs would be something like:
access_log /var/log/nginx/SITE/access.log
Note that NGINX writes the access logs in the combined format by default, that's why you don't see the word combined anywhere in the line above: it's implicit. Alright, so from now on we assume that yes, you have access log files available, and yes, they are in the combined log format. If that's the case, then you can already run GoAccess and generate a report, for example for the log file /var/log/apache2/access.log
goaccess \
    --log-format COMBINED \
    --output /tmp/report.html \
    /var/log/apache2/access.log
It's possible to give GoAccess more than one log files to process, so if you have for example the file access.log.1 around, you can use it as well:
goaccess \
    --log-format COMBINED \
    --output /tmp/report.html \
    /var/log/apache2/access.log \
    /var/log/apache2/access.log.1
If GoAccess succeeds (and it should), you're on the right track! All is left to do to complete this test is to have a look at the HTML report created. It's a single HTML page, so you can easily scp it to your machine, or just move it to the document root of your site, and then open it in your web browser. Looks good? So let's move on to more interesting things. Web server configuration This part is very short, because in terms of configuration of the web server, there's very little to do. As I said above, the only thing you want from the web server is to create access log files. Then you want to be sure that GoAccess and your web server agree on the format for these files. In the part above we used the combined log format, but GoAccess supports many other common log formats out of the box, and even allows you to parse custom log formats. For more details, refer to the option --log-format in the GoAccess manual page. Another common log format is named, well, common. It even has its own Wikipedia page. But compared to combined, the common log format contains less information, it doesn't include the referrer and user-agent values, meaning that you won't have it in the GoAccess report. So at this point you should understand that, unsurprisingly, GoAccess can only tell you about what's in the access logs, no more no less. And that's all in term of web server configuration. Configuration to run GoAccess unprivileged Now we're going to create a user and group for GoAccess, so that we don't have to run it as root. The reason is that, well, for everything running unattended on your server, the less code runs as root, the better. It's good practice and common sense. In this case, GoAccess is simply a log analyzer. So it just needs to read the logs files from your web server, and there is no need to be root for that, an unprivileged user can do the job just as well, assuming it has read permissions on /var/log/apache2 or /var/log/nginx. The log files of the web server are usually part of the adm group (though it might depend on your distro, I'm not sure). This is something you can check easily with the following command:
ls -l /var/log   grep -e apache2 -e nginx
As a result you should get something like that:
drwxr-x--- 2 root adm 20480 Jul 22 00:00 /var/log/apache2/
And as you can see, the directory apache2 belongs to the group adm. It means that you don't need to be root to read the logs, instead any unprivileged user that belongs to the group adm can do it. So, let's create the goaccess user, and add it to the adm group:
adduser --system --group --no-create-home goaccess
addgroup goaccess adm
And now, let's run GoAccess unprivileged, and verify that it can still read the log files:
setpriv \
    --reuid=goaccess --regid=goaccess \
    --init-groups --inh-caps=-all \
    -- \
    goaccess \
    --log-format COMBINED \
    --output /tmp/report2.html \
    /var/log/apache2/access.log
setpriv is the command used to drop privileges. The syntax is quite verbose, it's not super friendly for tutorials, but don't be scared and read the manual page to learn what it does. In any case, this command should work, and at this point, it means that you have a goaccess user ready, and we'll use it to run GoAccess unprivileged. Integration, option A - Run GoAccess once a day, from a logrotate hook In this part we wire things together, so that GoAccess processes the log files once a day, adds the new logs to its internal database, and generates a report from all that aggregated data. The result will be a single HTML page. Introducing logrotate In order to do that, we'll use a logrotate hook. logrotate is a little tool that should already be installed on your server, and that runs once a day, and that is in charge of rotating the log files. "Rotating the logs" means moving access.log to access.log.1 and so on. With logrotate, a new log file is created every day, and log files that are too old are deleted. That's what prevents your logs from filling up your disk basically :) You can check that logrotate is indeed installed and enabled with this command (assuming that your init system is systemd):
systemctl status logrotate.timer
What's interesting for us is that logrotate allows you to run scripts before and after the rotation is performed, so it's an ideal place from where to run GoAccess. In short, we want to run GoAccess just before the logs are rotated away, in the prerotate hook. But let's do things in order. At first, we need to write a little wrapper script that will be in charge of running GoAccess with the right arguments, and that will process all of your sites. The wrapper script This wrapper is made to process more than one site, but if you have only one site it works just as well, of course. So let me just drop it on you like that, and I'll explain afterward. Here's my wrapper script:
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#!/bin/bash
# Process log files /var/www/apache2/SITE/access.log,
# only if /var/lib/goaccess-db/SITE exists.
# Create HTML reports in $1, a directory that must exist.
set -eu
OUTDIR=
LOGDIR=/var/log/apache2
DBDIR=/var/lib/goaccess-db
fail()   echo >&2 "$@"; exit 1;  
[ $# -eq 1 ]   fail "Usage: $(basename $0) OUTPUT_DIRECTORY"
OUTDIR=$1
[ -d "$OUTDIR" ]   fail "'$OUTDIR' is not a directory"
[ -d "$LOGDIR" ]   fail "'$LOGDIR' is not a directory"
[ -d "$DBDIR"  ]   fail "'$DBDIR' is not a directory"
for d in $(find "$LOGDIR" -mindepth 1 -maxdepth 1 -type d); do
    site=$(basename "$sitedir")
    dbdir=$DBDIR/$site
    logfile=$d/access.log
    outfile=$OUTDIR/$site.html
    if [ ! -d "$dbdir" ]   [ ! -e "$logfile" ]; then
        echo "  Skipping site '$site'"
        continue
    else
        echo "  Processing site '$site'"
    fi
    setpriv \
        --reuid=goaccess --regid=goaccess \
        --init-groups --inh-caps=-all \
        -- \
    goaccess \
        --agent-list \
        --anonymize-ip \
        --persist \
        --restore \
        --config-file /etc/goaccess/goaccess.conf \
        --db-path "$dbdir" \
        --log-format "COMBINED" \
        --output "$outfile" \
        "$logfile"
done
So you'd install this script at /usr/local/bin/goaccess-wrapper for example, and make it executable:
chmod +x /usr/local/bin/goaccess-wrapper
A few things to note: As is, the script makes the assumption that the logs for your site are logged in a sub-directory /var/log/apache2/SITE/. If it's not the case, adjust that in the wrapper accordingly. The name of this sub-directory is then used to find the GoAccess database directory /var/lib/goaccess-db/SITE/. This directory is expected to exist, meaning that if you don't create it yourself, the wrapper won't process this particular site. It's a simple way to control which sites are processed by this GoAccess wrapper, and which sites are not. So if you want goaccess-wrapper to process the site SITE, just create a directory with the name of this site under /var/lib/goaccess-db:
mkdir -p /var/lib/goaccess-db/SITE
chown goaccess:goaccess /var/lib/goaccess-db/SITE
Now let's create an output directory:
mkdir /tmp/goaccess-reports
chown goaccess:goaccess /tmp/goaccess-reports
And let's give a try to the wrapper script:
goaccess-wrapper /tmp/goaccess-reports
ls /tmp/goaccess-reports
Which should give you:
SITE.html
At the same time, you can check that GoAccess populated the database with a bunch of files:
ls /var/lib/goaccess-db/SITE
Setting up the logrotate prerotate hook At this point, we have the wrapper in place. Let's now add a pre-rotate hook so that goaccess-wrapper runs once a day, just before the logs are rotated away. The logrotate config file for Apache2 is located at /etc/logrotate.d/apache2, and for NGINX it's at /etc/logrotate.d/nginx. Among the many things you'll see in this file, here's what is of interest for us: In the config file, there is also this snippet:
prerotate
    if [ -d /etc/logrotate.d/httpd-prerotate ]; then \
        run-parts /etc/logrotate.d/httpd-prerotate; \
    fi; \
endscript
It indicates that scripts in the directory /etc/logrotate.d/httpd-prerotate/ will be executed before the rotation takes place. Refer to the man page run-parts(8) for more details... Putting all of that together, it means that logs from the web server are rotated once a day, and if we want to run scripts just before the rotation, we can just drop them in the httpd-prerotate directory. Simple, right? Let's first create this directory if it doesn't exist:
mkdir -p /etc/logrotate.d/httpd-prerotate/
And let's create a tiny script at /etc/logrotate.d/httpd-prerotate/goaccess:
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2
#!/bin/sh
exec goaccess-wrapper /tmp/goaccess-reports
Don't forget to make it executable:
chmod +x /etc/logrotate.d/httpd-prerotate/goaccess
As you can see, the only thing that this script does is to invoke the wrapper with the right argument, ie. the output directory for the HTML reports that are generated. And that's all. Now you can just come back tomorrow, check the logs, and make sure that the hook was executed and succeeded. For example, this kind of command will tell you quickly if it worked:
journalctl   grep logrotate
Integration, option B - Run GoAccess once a day, from a systemd service OK so we've just seen how to use a logrotate hook. One downside with that is that we have to drop privileges in the wrapper script, because logrotate runs as root, and we don't want to run GoAccess as root. Hence the rather convoluted syntax with setpriv. Rather than embedding this kind of thing in a wrapper script, we can instead run the wrapper script from a [systemd][] service, and define which user runs the wrapper straight in the systemd service file. Introducing systemd niceties So we can create a systemd service, along with a systemd timer that fires daily. We can then set the user and group that execute the script straight in the systemd service, and there's no need for setpriv anymore. It's a bit more streamlined. We can even go a bit further, and use systemd parameterized units (also called templates), so that we have one service per site (instead of one service that process all of our sites). That will simplify the wrapper script a lot, and it also looks nicer in the logs. With this approach however, it seems that we can't really run exactly before the logs are rotated away, like we did in the section above. But that's OK. What we'll do is that we'll run once a day, no matter the time, and we'll just make sure to process both log files access.log and access.log.1 (ie. the current logs and the logs from yesterday). This way, we're sure not to miss any line from the logs. Note that GoAccess is smart enough to only consider newer entries from the log files, and discard entries that are already in the database. In other words, it's safe to parse the same log file more than once, GoAccess will do the right thing. For more details see "INCREMENTAL LOG PROCESSING" from man goaccess. systemd]: https://freedesktop.org/wiki/Software/systemd/ Implementation And here's how it all looks like. First, a little wrapper script for GoAccess:
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#!/bin/bash
# Usage: $0 SITE DBDIR LOGDIR OUTDIR
set -eu
SITE=$1
DBDIR=$2
LOGDIR=$3
OUTDIR=$4
LOGFILES=()
for ext in log log.1; do
    logfile="$LOGDIR/access.$ext"
    [ -e "$logfile" ] && LOGFILES+=("$logfile")
done
if [ $ #LOGFILES[@]  -eq 0 ]; then
    echo "No log files in '$LOGDIR'"
    exit 0
fi
goaccess \
    --agent-list \
    --anonymize-ip \
    --persist \
    --restore \
    --config-file /etc/goaccess/goaccess.conf \
    --db-path "$DBDIR" \
    --log-format "COMBINED" \
    --output "$OUTDIR/$SITE.html" \
    "$ LOGFILES[@] "
This wrapper does very little. Actually, the only thing it does is to check for the existence of the two log files access.log and access.log.1, to be sure that we don't ask GoAccess to process a file that does not exist (GoAccess would not be happy about that). Save this file under /usr/local/bin/goaccess-wrapper, don't forget to make it executable:
chmod +x /usr/local/bin/goaccess-wrapper
Then, create a systemd parameterized unit file, so that we can run this wrapper as a systemd service. Save it under /etc/systemd/system/goaccess@.service:
[Unit]
Description=Update GoAccess report - %i
ConditionPathIsDirectory=/var/lib/goaccess-db/%i
ConditionPathIsDirectory=/var/log/apache2/%i
ConditionPathIsDirectory=/tmp/goaccess-reports
PartOf=goaccess.service
[Service]
Type=oneshot
User=goaccess
Group=goaccess
Nice=19
ExecStart=/usr/local/bin/goaccess-wrapper \
 %i \
 /var/lib/goaccess-db/%i \
 /var/log/apache2/%i \
 /tmp/goaccess-reports
So, what is a systemd parameterized unit? It's a service to which you can pass an argument when you enable it. The %i in the unit definition will be replaced by this argument. In our case, the argument will be the name of the site that we want to process. As you can see, we use the directive ConditionPathIsDirectory= extensively, so that if ever one of the required directories does not exist, the unit will just be skipped (and marked as such in the logs). It's a graceful way to fail. We run the wrapper as the user and group goaccess, thanks to User= and Group=. We also use Nice= to give a low priority to the process. At this point, it's already possible to test. Just make sure that you created a directory for the GoAccess database:
mkdir -p /var/lib/goaccess-db/SITE
chown goaccess:goaccess /var/lib/goaccess-db/SITE
Also make sure that the output directory exists:
mkdir /tmp/goaccess-reports
chown goaccess:goaccess /tmp/goaccess-reports
Then reload systemd and fire the unit to see if it works:
systemctl daemon-reload
systemctl start goaccess@SITE.service
journalctl   tail
And that should work already. As you can see, the argument, SITE, is passed in the systemctl start command. We just append it after the @, in the name of the unit. Now, let's create another GoAccess service file, which sole purpose is to group all the parameterized units together, so that we can start them all in one go. Note that we don't use a systemd target for that, because ultimately we want to run it once a day, and that would not be possible with a target. So instead we use a dummy oneshot service. So here it is, saved under /etc/systemd/system/goaccess.service:
[Unit]
Description=Update GoAccess reports
Requires= \
 goaccess@SITE1.service \
 goaccess@SITE2.service
[Service]
Type=oneshot
ExecStart=true
As you can see, we simply list the sites that we want to process in the Requires= directive. In this example we have two sites named SITE1 and SITE2. Let's ensure that everything is still good:
systemctl daemon-reload
systemctl start goaccess.service
journalctl   tail
Check the logs, both sites SITE1 and SITE2 should have been processed. And finally, let's create a timer, so that systemd runs goaccess.service once a day. Save it under /etc/systemd/system/goaccess.timer.
[Unit]
Description=Daily update of GoAccess reports
[Timer]
OnCalendar=daily
RandomizedDelaySec=1h
Persistent=true
[Install]
WantedBy=timers.target
Finally, enable the timer:
systemctl daemon-reload
systemctl enable --now goaccess.timer
At this point, everything should be OK. Just come back tomorrow and check the logs with something like:
journalctl   grep goaccess
Last word: if you have only one site to process, of course you can simplify, for example you can hardcode all the paths in the file goaccess.service instead of using a parameterized unit. Up to you. Daily operations So in this part, we assume that you have GoAccess all setup and running, once a day or so. Let's just go over a few things worth noting. Serve your report Up to now in this tutorial, we created the reports in /tmp/goaccess-reports, but that was just for the sake of the example. You will probably want to save your reports in a directory that is served by your web server, so that, well, you can actually look at it in your web browser, that was the point, right? So how to do that is a bit out of scope here, and I guess that if you want to monitor your website, you already have a website, so you will have no trouble serving the GoAccess HTML report. However there's an important detail to be aware of: GoAccess shows all the IP addresses of your visitors in the report. As long as the report is private it's OK, but if ever you make your GoAccess report public, then you should definitely invoke GoAccess with the option --anonymize-ip. Keep an eye on the logs In this tutorial, the reports we create, along with the GoAccess databases, will grow bigger every day, forever. It also means that the GoAccess processing time will grow a bit each day. So maybe the first thing to do is to keep an eye on the logs, to see how long it takes to GoAccess to do its job every day. Also, maybe you'd like to keep an eye on the size of the GoAccess database with:
du -sh /var/lib/goaccess-db/SITE
If your site has few visitors, I suspect it won't be a problem though. You could also be a bit pro-active in preventing this problem in the future, and for example you could break the reports into, say, monthly reports. Meaning that every month, you would create a new database in a new directory, and also start a new HTML report. This way you'd have monthly reports, and you make sure to limit the GoAccess processing time, by limiting the database size to a month. This can be achieved very easily, by including something like YEAR-MONTH in the database directory, and in the HTML report. You can handle that automatically in the wrapper script, for example:
sfx=$(date +'%Y-%m')
mkdir -p $DBDIR/$sfx
goaccess \
    --db-path $DBDIR/$sfx \
    --output "$OUTDIR/$SITE-$sfx.html" \
    ...
You get the idea. Further notes Migration from older versions With the --persist option, GoAccess keeps all the information from the logs in a database, so that it can re-use it later. In prior versions, GoAccess used the Tokyo Cabinet key-value store for that. However starting from v1.4, GoAccess dropped this dependency and now uses its own database format. As a result, the previous database can't be used anymore, you will have to remove it and restart from zero. At the moment there is no way to convert the data from the old database to the new one. If you're interested, this is discussed upstream at [#1783][bug-1783]. Another thing that changed with this new version is the name for some of the command-line options. For example, --load-from-disk was dropped in favor of --restore, and --keep-db-files became --persist. So you'll have to look at the documentation a bit, and update your script(s) accordingly. Other ways to use GoAccess It's also possible to do it completely differently. You could keep GoAccess running, pretty much like a daemon, with the --real-time-html option, and have it process the logs continuously, rather than calling it on a regular basis. It's also possible to see the GoAccess report straight in the terminal, thanks to libncurses, rather than creating a HTML report. And much more, GoAccess is packed with features. Conclusion I hope that this tutorial helped some of you folks. Feel free to drop an e-mail for comments.

8 August 2020

Reproducible Builds: Reproducible Builds in July 2020

Welcome to the July 2020 report from the Reproducible Builds project. In these monthly reports, we round-up the things that we have been up to over the past month. As a brief refresher, the motivation behind the Reproducible Builds effort is to ensure no flaws have been introduced from the original free software source code to the pre-compiled binaries we install on our systems. (If you re interested in contributing to the project, please visit our main website.)

General news At the upcoming DebConf20 conference (now being held online), Holger Levsen will present a talk on Thursday 27th August about Reproducing Bullseye in practice , focusing on independently verifying that the binaries distributed from ftp.debian.org were made from their claimed sources. Tavis Ormandy published a blog post making the provocative claim that You don t need reproducible builds , asserting elsewhere that the many attacks that have been extensively reported in our previous reports are fantasy threat models . A number of rebuttals have been made, including one from long-time contributor Reproducible Builds contributor Bernhard Wiedemann. On our mailing list this month, Debian Developer Graham Inggs posted to our list asking for ideas why the openorienteering-mapper Debian package was failing to build on the Reproducible Builds testing framework. Chris Lamb remarked from the build logs that the package may be missing a build dependency, although Graham then used our own diffoscope tool to show that the resulting package remains unchanged with or without it. Later, Nico Tyni noticed that the build failure may be due to the relationship between the FILE C preprocessor macro and the -ffile-prefix-map GCC flag. An issue in Zephyr, a small-footprint kernel designed for use on resource-constrained systems, around .a library files not being reproducible was closed after it was noticed that a key part of their toolchain was updated that now calls --enable-deterministic-archives by default. Reproducible Builds developer kpcyrd commented on a pull request against the libsodium cryptographic library wrapper for Rust, arguing against the testing of CPU features at compile-time. He noted that:
I ve accidentally shipped broken updates to users in the past because the build system was feature-tested and the final binary assumed the instructions would be present without further runtime checks
David Kleuker also asked a question on our mailing list about using SOURCE_DATE_EPOCH with the install(1) tool from GNU coreutils. When comparing two installed packages he noticed that the filesystem birth times differed between them. Chris Lamb replied, realising that this was actually a consequence of using an outdated version of diffoscope and that a fix was in diffoscope version 146 released in May 2020. Later in July, John Scott posted asking for clarification regarding on the Javascript files on our website to add metadata for LibreJS, the browser extension that blocks non-free Javascript scripts from executing. Chris Lamb investigated the issue and realised that we could drop a number of unused Javascript files [ ][ ][ ] and added unminified versions of Bootstrap and jQuery [ ].

Development work

Website On our website this month, Chris Lamb updated the main Reproducible Builds website and documentation to drop a number of unused Javascript files [ ][ ][ ] and added unminified versions of Bootstrap and jQuery [ ]. He also fixed a number of broken URLs [ ][ ]. Gonzalo Bulnes Guilpain made a large number of grammatical improvements [ ][ ][ ][ ][ ] as well as some misspellings, case and whitespace changes too [ ][ ][ ]. Lastly, Holger Levsen updated the README file [ ], marked the Alpine Linux continuous integration tests as currently disabled [ ] and linked the Arch Linux Reproducible Status page from our projects page [ ].

diffoscope diffoscope is our in-depth and content-aware diff utility that can not only locate and diagnose reproducibility issues, it provides human-readable diffs of all kinds. In July, Chris Lamb made the following changes to diffoscope, including releasing versions 150, 151, 152, 153 & 154:
  • New features:
    • Add support for flash-optimised F2FS filesystems. (#207)
    • Don t require zipnote(1) to determine differences in a .zip file as we can use libarchive. [ ]
    • Allow --profile as a synonym for --profile=-, ie. write profiling data to standard output. [ ]
    • Increase the minimum length of the output of strings(1) to eight characters to avoid unnecessary diff noise. [ ]
    • Drop some legacy argument styles: --exclude-directory-metadata and --no-exclude-directory-metadata have been replaced with --exclude-directory-metadata= yes,no . [ ]
  • Bug fixes:
    • Pass the absolute path when extracting members from SquashFS images as we run the command with working directory in a temporary directory. (#189)
    • Correct adding a comment when we cannot extract a filesystem due to missing libguestfs module. [ ]
    • Don t crash when listing entries in archives if they don t have a listed size such as hardlinks in ISO images. (#188)
  • Output improvements:
    • Strip off the file offset prefix from xxd(1) and show bytes in groups of 4. [ ]
    • Don t emit javap not found in path if it is available in the path but it did not result in an actual difference. [ ]
    • Fix ... not available in path messages when looking for Java decompilers that used the Python class name instead of the command. [ ]
  • Logging improvements:
    • Add a bit more debugging info when launching libguestfs. [ ]
    • Reduce the --debug log noise by truncating the has_some_content messages. [ ]
    • Fix the compare_files log message when the file does not have a literal name. [ ]
  • Codebase improvements:
    • Rewrite and rename exit_if_paths_do_not_exist to not check files multiple times. [ ][ ]
    • Add an add_comment helper method; don t mess with our internal list directly. [ ]
    • Replace some simple usages of str.format with Python f-strings [ ] and make it easier to navigate to the main.py entry point [ ].
    • In the RData comparator, always explicitly return None in the failure case as we return a non-None value in the success one. [ ]
    • Tidy some imports [ ][ ][ ] and don t alias a variable when we do not use it. [ ]
    • Clarify the use of a separate NullChanges quasi-file to represent missing data in the Debian package comparator [ ] and clarify use of a null diff in order to remember an exit code. [ ]
  • Other changes:
    • Profile the launch of libguestfs filesystems. [ ]
    • Clarify and correct our contributing info. [ ][ ][ ][ ][ ][ ]
Jean-Romain Garnier also made the following changes:
  • Allow passing a file with a list of arguments via diffoscope @args.txt. (!62)
  • Improve the output of side-by-side diffs by detecting added lines better. (!64)
  • Remove offsets before instructions in objdump [ ][ ] and remove raw instructions from ELF tests [ ].

Other tools strip-nondeterminism is our tool to remove specific non-deterministic results from a completed build. It is used automatically in most Debian package builds. In July, Chris Lamb ensured that we did not install the internal handler documentation generated from Perl POD documents [ ] and fixed a trivial typo [ ]. Marc Herbert added a --verbose-level warning when the Archive::Cpio Perl module is missing. (!6) reprotest is our end-user tool to build same source code twice in widely differing environments and then checks the binaries produced by each build for any differences. This month, Vagrant Cascadian made a number of changes to support diffoscope version 153 which had removed the (deprecated) --exclude-directory-metadata and --no-exclude-directory-metadata command-line arguments, and updated the testing configuration to also test under Python version 3.8 [ ].

Distributions

Debian In June 2020, Timo R hling filed a wishlist bug against the debhelper build tool impacting the reproducibility status of hundreds of packages that use the CMake build system. This month however, Niels Thykier uploaded debhelper version 13.2 that passes the -DCMAKE_SKIP_RPATH=ON and -DBUILD_RPATH_USE_ORIGIN=ON arguments to CMake when using the (currently-experimental) Debhelper compatibility level 14. According to Niels, this change:
should fix some reproducibility issues, but may cause breakage if packages run binaries directly from the build directory.
34 reviews of Debian packages were added, 14 were updated and 20 were removed this month adding to our knowledge about identified issues. Chris Lamb added and categorised the nondeterministic_order_of_debhelper_snippets_added_by_dh_fortran_mod [ ] and gem2deb_install_mkmf_log [ ] toolchain issues. Lastly, Holger Levsen filed two more wishlist bugs against the debrebuild Debian package rebuilder tool [ ][ ].

openSUSE In openSUSE, Bernhard M. Wiedemann published his monthly Reproducible Builds status update. Bernhard also published the results of performing 12,235 verification builds of packages from openSUSE Leap version 15.2 and, as a result, created three pull requests against the openSUSE Build Result Compare Script [ ][ ][ ].

Other distributions In Arch Linux, there was a mass rebuild of old packages in an attempt to make them reproducible. This was performed because building with a previous release of the pacman package manager caused file ordering and size calculation issues when using the btrfs filesystem. A system was also implemented for Arch Linux packagers to receive notifications if/when their package becomes unreproducible, and packagers now have access to a dashboard where they can all see all their unreproducible packages (more info). Paul Spooren sent two versions of a patch for the OpenWrt embedded distribution for adding a build system revision to the packages manifest so that all external feeds can be rebuilt and verified. [ ][ ]

Upstream patches The Reproducible Builds project detects, dissects and attempts to fix as many currently-unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of these patches, including: Vagrant Cascadian also reported two issues, the first regarding a regression in u-boot boot loader reproducibility for a particular target [ ] and a non-deterministic segmentation fault in the guile-ssh test suite [ ]. Lastly, Jelle van der Waa filed a bug against the MeiliSearch search API to report that it embeds the current build date.

Testing framework We operate a large and many-featured Jenkins-based testing framework that powers tests.reproducible-builds.org. This month, Holger Levsen made the following changes:
  • Debian-related changes:
    • Tweak the rescheduling of various architecture and suite combinations. [ ][ ]
    • Fix links for 404 and not for us icons. (#959363)
    • Further work on a rebuilder prototype, for example correctly processing the sbuild exit code. [ ][ ]
    • Update the sudo configuration file to allow the node health job to work correctly. [ ]
    • Add php-horde packages back to the pkg-php-pear package set for the bullseye distribution. [ ]
    • Update the version of debrebuild. [ ]
  • System health check development:
    • Add checks for broken SSH [ ], logrotate [ ], pbuilder [ ], NetBSD [ ], unkillable processes [ ], unresponsive nodes [ ][ ][ ][ ], proxy connection failures [ ], too many installed kernels [ ], etc.
    • Automatically fix some failed systemd units. [ ]
    • Add notes explaining all the issues that hosts are experiencing [ ] and handle zipped job log files correctly [ ].
    • Separate nodes which have been automatically marked as down [ ] and show status icons for jobs with issues [ ].
  • Misc:
    • Disable all Alpine Linux jobs until they are or Alpine is fixed. [ ]
    • Perform some general upkeep of build nodes hosted by OSUOSL. [ ][ ][ ][ ]
In addition, Mattia Rizzolo updated the init_node script to suggest using sudo instead of explicit logout and logins [ ][ ] and the usual build node maintenance was performed by Holger Levsen [ ][ ][ ][ ][ ][ ], Mattia Rizzolo [ ][ ] and Vagrant Cascadian [ ][ ][ ][ ].

If you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:

Dirk Eddelbuettel: RVowpalWabbit 0.0.15: Some More CRAN Build Issues

Another maintenance RVowpalWabbit package update brought us to version 0.0.15 earlier today. We attempted to fix one compilation error on Solaris, and addressed a few SAN/UBSAN issues with the gcc build. As noted before, there is a newer package rvw based on the excellent GSoC 2018 and beyond work by Ivan Pavlov (mentored by James and myself) so if you are into Vowpal Wabbit from R go check it out. CRANberries provides a summary of changes to the previous version. More information is on the RVowpalWabbit page. Issues and bugreports should go to the GitHub issue tracker. If you like this or other open-source work I do, you can now sponsor me at GitHub. For the first year, GitHub will match your contributions.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

7 August 2020

Jonathan Dowland: Vimwiki

At the start of the year I begun keeping a daily diary for work as a simple text file. I've used various other approaches for this over the years, including many paper diaries and more complex digital systems. One great advantage of the one-page text file was it made assembling my weekly status report email very quick, nearly just a series of copies and pastes. But of course there are drawbacks and room for improvement. vimwiki is a personal wiki plugin for the vim and neovim editors. I've tried to look at it before, years ago, but I found it too invasive, changing key bindings and display settings for any use of vim, and I use vim a lot. I decided to give it another look. The trigger was actually something completely unrelated: Steve Losh's blog post "Coming Home to vim". I've been using vim for around 17 years but I still learned some new things from that blog post. In particular, I've never bothered to Use The Leader for user-specific shortcuts. The Leader, to me, feels like a namespace that plugins should not touch: it's like the /usr/local of shortcut keys, a space for the local user only. Vimwiki's default bindings include several incorporating the Leader. Of course since I didn't use the leader, those weren't the ones that bothered me: It turns out I regularly use carriage return and backspace for moving the cursor around in normal mode, and Vimwiki steals both of those. It also truncates the display of (what it thinks are) URIs. It turns out I really prefer to see exactly what's in the file I'm editing. I haven't used vim folds since I first switched to it, despite them being why I switched. Disabling all the default bindings and URI concealing stuff and Vimwiki is now much less invasive and I can explore its features at my own pace:
let g:vimwiki_key_mappings =   'all_maps': 0,  
let g:vimwiki_conceallevel = 0
let g:vimwiki_url_maxsave = 0 
Followed by explicitly configuring the bindings I want. I'm letting it steal carriage return. And yes, I've used some Leader bindings after all.
nnoremap <leader>ww :VimwikiIndex<cr>
nnoremap <leader>wi :VimwikiDiaryIndex<cr>
nnoremap <leader>wd :VimwikiMakeDiaryNote<cr>
nnoremap <CR> :VimwikiFollowLink<cr>
nnoremap <Tab> :VimwikiNextLink<cr>
nnoremap <S-Tab> :VimwikiPrevLink<cr>
nnoremap <C-Down> :VimwikiDiaryNextDay<cr>
nnoremap <C-Up> :VimwikiDiaryPrevDay<cr>
,wd (my leader) now brings me straight to today's diary page, and I can create separate, non-diary pages for particular work items (e.g. a Ticket reference) that will span more than one day, and keep all the relevant stuff in one place.

6 August 2020

Dirk Eddelbuettel: nanotime 0.3.0: Yuge New Features!

A fresh major release of the nanotime package for working with nanosecond timestamps is hitting CRAN mirrors right now. nanotime relies on the RcppCCTZ package for (efficient) high(er) resolution time parsing and formatting up to nanosecond resolution, and the bit64 package for the actual integer64 arithmetic. Initially implemented using the S3 system, it has benefitted greatly from work by Leonardo Silvestri who rejigged internals in S4 and now added new types for periods, intervals and durations. This is what is commonly called a big fucking deal!! So a really REALLY big thank you to my coauthor Leonardo for all these contributions. With all these Yuge changes patiently chisseled in by Leonardo, it took some time since the last release and a few more things piled up. Matt Dowle corrected something we borked for integration with the lovely and irreplacable data.table. We also switched to the awesome yet minimal tinytest package by Mark van der Loo, and last but not least we added the beginnings of a proper vignette currently at nine pages but far from complete. The NEWS snippet adds full details.

Changes in version 0.3.0 (2020-08-06)
  • Use tzstr= instead of tz= in call to RcppCCTZ::parseDouble()) (Matt Dowle in #49).
  • Add new comparison operators for nanotime and charcters (Dirk in #54 fixing #52).
  • Switch from RUnit to tinytest (Dirk in #55)
  • Substantial functionality extension in with new types nanoduration, nanoival and nanoperiod (Leonardo in #58, #60, #62, #63, #65, #67, #70 fixing #47, #51, #57, #61, #64 with assistance from Dirk).
  • A new (yet still draft-ish) vignette was added describing the four core types (Leonardo and Dirk in #71).
  • A required compilation flag for Windows was added (Leonardo in #72).
  • RcppCCTZ function are called in new 'non-throwing' variants to not trigger exeception errors (Leonardo in #73).

We also have a diff to the previous version thanks to CRANberries. More details and examples are at the nanotime page; code, issue tickets etc at the GitHub repository. If you like this or other open-source work I do, you can now sponsor me at GitHub. For the first year, GitHub will match your contributions.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

Chris Lamb: The Bringers of Beethoven

This is a curiously poignant work to me that I doubt I would ever be able to communicate. I found it about fifteen years ago, along with a friend who I am quite regrettably no longer in regular contact with, so there was some complicated nostalgia entangled with rediscovering it today. What might I say about it instead? One tell-tale sign of 'good' art is that you can find something new in it, or yourself, each time. In this sense, despite The Bringers of Beethoven being more than a little ridiculous, it is somehow 'good' music to me. For example, it only really dawned on me now that the whole poem is an allegory for a GDR-like totalitarianism. But I also realised that it is not an accident that it is Beethoven himself (quite literally the soundtrack for Enlightenment humanism) that is being weaponised here, rather than some fourth-rate composer of military marches or one with a problematic past. That is to say, not only is the poem arguing that something universally recognised as an unalloyed good can be subverted for propagandistic ends, but that is precisely the point being made by the regime. An inverted Clockwork Orange, if you like. Yet when I listen to it again I can't help but laugh. I think of the 18th-century poet Alexander Pope, who first used the word bathos to refer to those abrupt and often absurd transitions from the elevated to the ordinary, contrasting it with the concept of pathos, the sincere feeling of sadness and tragedy. I can't think of two better words.

5 August 2020

Holger Levsen: 20200805-debconf7

DebConf7 This tshirt is 13 years old and from DebConf7. DebConf7 was my 5th DebConf and took place in Edinburgh, Scotland. And finally I could tell people I was a DD :-D Though as you can guess, that's yet another story to be told. So anyway, Edinburgh. I don't recall exactly whether the video team had to record 6 or 7 talk rooms on 4 floors, but this was probably the most intense set up we ran. And we ran a lot, from floor to floor, and room to room. DebConf7 was also special because it had a very special night venue, which was in an ex-church in a rather normal building, operated as sort of community center or some such, while the old church interior was still very much visible as in everything new was build around the old stuff. And while the night venue was cool, it also ment we (video team) had no access to our machines over night (or for much of the evening), because we had to leave the university over night and the networking situation didn't allow remote access with the bandwidth needed to do anything video. The night venue had some very simple house rules, like don't rearrange stuff, don't break stuff, don't fix stuff and just a few little more and of course we broke them in the best possible way: Toresbe with the help of people I don't remember fixed the organ, which was broken for decades. And so the house sounded in some very nice new old tune and I think everybody was happy we broke that rule. I believe the city is really nice from the little I've seen of it. A very nice old town, a big castle on the hill :) I'm not sure whether I missed the day trip to Glasgow to fix video things or to rest or both... Another thing I missed was getting a kilt, for which Phil Hands made a terrific design (update: the design is called tartan and was made by Phil indeed!), which spelled Debian in morse code. That was pretty cool and the kilts are really nice on DebConf group pictures since then. And if you've been wearing this kilt regularily for the last 13 years it was probably also a sensible investment. ;) It seems I don't have that many more memories of this DebConf, British power plugs and how to hack them comes to my mind and some other stuff here and there, but I remember less than previous years. I'm blaming this on the intense video setup and also on the sheer amount of people, which was the hightest until then and for some years, I believe maybe even until Heidelberg 8 years later. IIRC there were around 470 people there and over my first five years of DebConf I was incredible lucky to make many friends in Debian, so I probably just hung out and had good times.

Dirk Eddelbuettel: RcppCCTZ 0.2.8: Minor API Extension

A new minor release 0.2.8 of RcppCCTZ is now on CRAN. RcppCCTZ uses Rcpp to bring CCTZ to R. CCTZ is a C++ library for translating between absolute and civil times using the rules of a time zone. In fact, it is two libraries. One for dealing with civil time: human-readable dates and times, and one for converting between between absolute and civil times via time zones. And while CCTZ is made by Google(rs), it is not an official Google product. The RcppCCTZ page has a few usage examples and details. This package was the first CRAN package to use CCTZ; by now at least three others do using copies in their packages which remains less than ideal. This version adds three no throw variants of three existing functions, contributed again by Leonardo. This will be used in an upcoming nanotime release which we are finalising now.

Changes in version 0.2.8 (2020-08-04)
  • Added three new nothrow variants (for win32) needed by the expanded nanotime package (Leonardo in #37)

We also have a diff to the previous version thanks to CRANberries. More details are at the RcppCCTZ page; code, issue tickets etc at the GitHub repository. If you like this or other open-source work I do, you can now sponsor me at GitHub. For the first year, GitHub will match your contributions.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

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