Search Results: "abi"

18 July 2024

Enrico Zini: meson, includedir, and current directory

Suppose you have a meson project like this: meson.build:
project('example', 'cpp', version: '1.0', license : ' ', default_options: ['warning_level=everything', 'cpp_std=c++17'])
subdir('example')
example/meson.build:
test_example = executable('example-test', ['main.cc'])
example/string.h:
/* This file intentionally left empty */
example/main.cc:
#include <cstring>
int main(int argc,const char* argv[])
 
    std::string foo("foo");
    return 0;
 
This builds fine with autotools and cmake, but not meson:
$ meson setup builddir
The Meson build system
Version: 1.0.1
Source dir: /home/enrico/dev/deb/wobble-repr
Build dir: /home/enrico/dev/deb/wobble-repr/builddir
Build type: native build
Project name: example
Project version: 1.0
C++ compiler for the host machine: ccache c++ (gcc 12.2.0 "c++ (Debian 12.2.0-14) 12.2.0")
C++ linker for the host machine: c++ ld.bfd 2.40
Host machine cpu family: x86_64
Host machine cpu: x86_64
Build targets in project: 1
Found ninja-1.11.1 at /usr/bin/ninja
$ ninja -C builddir
ninja: Entering directory  builddir'
[1/2] Compiling C++ object example/example-test.p/main.cc.o
FAILED: example/example-test.p/main.cc.o
ccache c++ -Iexample/example-test.p -Iexample -I../example -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -Wpedantic -Wcast-qual -Wconversion -Wfloat-equal -Wformat=2 -Winline -Wmissing-declarations -Wredundant-decls -Wshadow -Wundef -Wuninitialized -Wwrite-strings -Wdisabled-optimization -Wpacked -Wpadded -Wmultichar -Wswitch-default -Wswitch-enum -Wunused-macros -Wmissing-include-dirs -Wunsafe-loop-optimizations -Wstack-protector -Wstrict-overflow=5 -Warray-bounds=2 -Wlogical-op -Wstrict-aliasing=3 -Wvla -Wdouble-promotion -Wsuggest-attribute=const -Wsuggest-attribute=noreturn -Wsuggest-attribute=pure -Wtrampolines -Wvector-operation-performance -Wsuggest-attribute=format -Wdate-time -Wformat-signedness -Wnormalized=nfc -Wduplicated-cond -Wnull-dereference -Wshift-negative-value -Wshift-overflow=2 -Wunused-const-variable=2 -Walloca -Walloc-zero -Wformat-overflow=2 -Wformat-truncation=2 -Wstringop-overflow=3 -Wduplicated-branches -Wattribute-alias=2 -Wcast-align=strict -Wsuggest-attribute=cold -Wsuggest-attribute=malloc -Wanalyzer-too-complex -Warith-conversion -Wbidi-chars=ucn -Wopenacc-parallelism -Wtrivial-auto-var-init -Wctor-dtor-privacy -Weffc++ -Wnon-virtual-dtor -Wold-style-cast -Woverloaded-virtual -Wsign-promo -Wstrict-null-sentinel -Wnoexcept -Wzero-as-null-pointer-constant -Wabi-tag -Wuseless-cast -Wconditionally-supported -Wsuggest-final-methods -Wsuggest-final-types -Wsuggest-override -Wmultiple-inheritance -Wplacement-new=2 -Wvirtual-inheritance -Waligned-new=all -Wnoexcept-type -Wregister -Wcatch-value=3 -Wextra-semi -Wdeprecated-copy-dtor -Wredundant-move -Wcomma-subscript -Wmismatched-tags -Wredundant-tags -Wvolatile -Wdeprecated-enum-enum-conversion -Wdeprecated-enum-float-conversion -Winvalid-imported-macros -std=c++17 -O0 -g -MD -MQ example/example-test.p/main.cc.o -MF example/example-test.p/main.cc.o.d -o example/example-test.p/main.cc.o -c ../example/main.cc
In file included from ../example/main.cc:1:
/usr/include/c++/12/cstring:77:11: error:  memchr  has not been declared in  :: 
   77     using ::memchr;
                  ^~~~~~
/usr/include/c++/12/cstring:78:11: error:  memcmp  has not been declared in  :: 
   78     using ::memcmp;
                  ^~~~~~
/usr/include/c++/12/cstring:79:11: error:  memcpy  has not been declared in  :: 
   79     using ::memcpy;
                  ^~~~~~
/usr/include/c++/12/cstring:80:11: error:  memmove  has not been declared in  :: 
   80     using ::memmove;
                  ^~~~~~~
 
It turns out that meson adds the current directory to the include path by default:
Another thing to note is that include_directories adds both the source directory and corresponding build directory to include path, so you don't have to care.
It seems that I have to care after all. Thankfully there is an implicit_include_directories setting that can turn this off if needed. Its documentation is not as easy to find as I'd like (kudos to Kangie on IRC), and hopefully this blog post will make it easier for me to find it in the future.

17 July 2024

Dirk Eddelbuettel: Rcpp 1.0.13 on CRAN: Some Updates

rcpp logo The Rcpp Core Team is once again pleased to announce a new release (now at 1.0.13) of the Rcpp package. It arrived on CRAN earlier today, and has since been uploaded to Debian. Windows and macOS builds should appear at CRAN in the next few days, as will builds in different Linux distribution and of course r2u should catch up tomorrow too. The release was uploaded last week, but not only does Rcpp always gets flagged because of the grandfathered .Call(symbol) but CRAN also found two packages regressing which then required them to take five days to get back to us. One issue was known; another did not reproduce under our tests against over 2800 reverse dependencies leading to the eventual release today. Yay. Checks are good and appreciated, and it does take time by humans to review them. This release continues with the six-months January-July cycle started with release 1.0.5 in July 2020. As a reminder, we do of course make interim snapshot dev or rc releases available via the Rcpp drat repo as well as the r-universe page and repo and strongly encourage their use and testing I run my systems with these versions which tend to work just as well, and are also fully tested against all reverse-dependencies. Rcpp has long established itself as the most popular way of enhancing R with C or C++ code. Right now, 2867 packages on CRAN depend on Rcpp for making analytical code go faster and further, along with 256 in BioConductor. On CRAN, 13.6% of all packages depend (directly) on Rcpp, and 59.9% of all compiled packages do. From the cloud mirror of CRAN (which is but a subset of all CRAN downloads), Rcpp has been downloaded 86.3 million times. The two published papers (also included in the package as preprint vignettes) have, respectively, 1848 (JSS, 2011) and 324 (TAS, 2018) citations, while the the book (Springer useR!, 2013) has another 641. This release is incremental as usual, generally preserving existing capabilities faithfully while smoothing our corners and / or extending slightly, sometimes in response to changing and tightened demands from CRAN or R standards. The move towards a more standardized approach for the C API of R leads to a few changes; Kevin did most of the PRs for this. Andrew Johnsom also provided a very nice PR to update internals taking advantage of variadic templates. The full list below details all changes, their respective PRs and, if applicable, issue tickets. Big thanks from all of us to all contributors!

Changes in Rcpp release version 1.0.13 (2024-07-11)
  • Changes in Rcpp API:
    • Set R_NO_REMAP if not already defined (Dirk in #1296)
    • Add variadic templates to be used instead of generated code (Andrew Johnson in #1303)
    • Count variables were switches to size_t to avoid warnings about conversion-narrowing (Dirk in #1307)
    • Rcpp now avoids the usage of the (non-API) DATAPTR function when accessing the contents of Rcpp Vector objects where possible. (Kevin in #1310)
    • Rcpp now emits an R warning on out-of-bounds Vector accesses. This may become an error in a future Rcpp release. (Kevin in #1310)
    • Switch VECTOR_PTR and STRING_PTR to new API-compliant RO variants (Kevin in #1317 fixing #1316)
  • Changes in Rcpp Deployment:
    • Small updates to the CI test containers have been made (#1304)

Thanks to my CRANberries, you can also look at a diff to the previous release Questions, comments etc should go to the rcpp-devel mailing list off the R-Forge page. Bugs reports are welcome at the GitHub issue tracker as well (where one can also search among open or closed issues). If you like this or other open-source work I do, you can sponsor me at GitHub.

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

Kalyani Kenekar: Securing Your Website: Installing and Configuring Nginx with SSL

Logo Nginx

The Initial Encounter: I recently started to work with Nginx to explore the requirements on how to configure a then so called server block. It s quite different than within Apache. But there are a tons of good websites out there which do explain the different steps and options quite well. I also realized quickly that I need to be able to configure my Nginx setups in a way so the content is delivered through https with some automatic redirection from http URLs.
  • Let s install Nginx

Installing Nginx
$ sudo apt update
$ sudo apt install nginx

Checking your Web Server
  • We can check now nginx service is active or inactive
Output
  nginx.service - A high performance web server and a reverse proxy server
     Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
     Active: active (running) since Tue 2024-02-12 09:59:20 UTC; 3h ago
       Docs: man:nginx(8)
   Main PID: 2887 (nginx)
      Tasks: 2 (limit: 1132)
     Memory: 4.2M
        CPU: 81ms
     CGroup: /system.slice/nginx.service
              2887 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
              2890 nginx: worker process
  • Now we successfully installed nginx and it in running state.

How To Secure Nginx with Let s Encrypt on Debian 12
  • In this documentation, you will use Certbot to obtain a free SSL certificate for Nginx on Debian 12 and set up your certificate.

Step 1 Installing Certbot $ sudo apt install certbot python3-certbot-nginx
  • Certbot is now ready to use, but in order for it to automatically configure SSL for Nginx, we need to verify some of Nginx s configuration.

Step 2 Confirming Nginx s Configuration
  • Certbot needs to be able to find the correct server block in your Nginx configuration for it to be able to automatically configure SSL. Specifically, it does this by looking for a server_name directive that matches the domain you request a certificate for. To check, open the configuration file for your domain using nano or your favorite text editor.
$ sudo vi /etc/nginx/sites-available/example.com
 server  
    listen 80;
    root /var/www/html/;
    index index.html;
    server_name example.com
    location /  
        try_files $uri $uri/ =404;
     
    location /test.html  
        try_files $uri $uri/ =404;
        auth_basic "admin area";
        auth_basic_user_file /etc/nginx/.htpasswd;
     
 
  • Fillup above data your project wise and then save the file, quit your editor, and verify the syntax of your configuration edits.
$ sudo nginx -t

Step 3 Obtaining an SSL Certificate
  • Certbot provides a variety of ways to obtain SSL certificates through plugins. The Nginx plugin will take care of reconfiguring Nginx and reloading the config whenever necessary. To use this plugin, type the following command line.
$ sudo certbot --nginx -d example.com
  • The configuration will be updated, and Nginx will reload to pick up the new settings. certbot will wrap up with a message telling you the process was successful and where your certificates are stored.
Output
IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/example.com/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/example.com/privkey.pem
   Your cert will expire on 2024-05-12. To obtain a new or tweaked
   version of this certificate in the future, simply run certbot again
   with the "certonly" option. To non-interactively renew *all* of
   your certificates, run "certbot renew"
 - If you like Certbot, please consider supporting our work by:
   Donating to ISRG / Let's Encrypt:   https://letsencrypt.org/donate
   Donating to EFF:                    https://eff.org/donate-le
  • Your certificates are downloaded, installed, and loaded.
$ sudo nginx -t
  • If you get an error, reopen the server block file and check for any typos or missing characters. Once your configuration file s syntax is correct, reload Nginx to load the new configuration.
$ sudo systemctl reload nginx
  • Try reloading your website using https:// and notice your browser s security indicator. It should indicate that the site is properly secured, usually with a lock icon.
Now your website is secure by SSL usage.

12 July 2024

Reproducible Builds: Reproducible Builds in June 2024

Welcome to the June 2024 report from the Reproducible Builds project! In our reports, we outline what we ve been up to over the past month and highlight news items in software supply-chain security more broadly. As always, if you are interested in contributing to the project, please visit our Contribute page on our website. Table of contents:
  1. Next Reproducible Builds Summit dates announced
  2. GNU Guix patch review session for reproducibility
  3. New reproducibility-related academic papers
  4. Misc development news
  5. Website updates
  6. Reproducibility testing framework


Next Reproducible Builds Summit dates announced We are very pleased to announce the upcoming Reproducible Builds Summit, set to take place from September 17th 19th 2024 in Hamburg, Germany. We are thrilled to host the seventh edition of this exciting event, following the success of previous summits in various iconic locations around the world, including Venice, Marrakesh, Paris, Berlin and Athens. Our summits are a unique gathering that brings together attendees from diverse projects, united by a shared vision of advancing the Reproducible Builds effort. During this enriching event, participants will have the opportunity to engage in discussions, establish connections and exchange ideas to drive progress in this vital field. Our aim is to create an inclusive space that fosters collaboration, innovation and problem-solving. If you re interesting in joining us this year, please make sure to read the event page which has more details about the event and location. We are very much looking forward to seeing many readers of these reports there.

GNU Guix patch review session for reproducibility Vagrant Cascadian will holding a Reproducible Builds session as part of the monthly Guix patch review series on July 11th at 17:00 UTC. These online events are intended to encourage everyone everyone becoming a patch reviewer and the goal of reviewing patches is to help Guix project accept contributions while maintaining our quality standards and learning how to do patch reviews together in a friendly hacking session.

Development news In Debian this month, 4 reviews of Debian packages were added, 11 were updated and 14 were removed this month adding to our knowledge about identified issues. Only one issue types was updated, though, explaining that we don t vary the build path anymore.
On our mailing list this month, Bernhard M. Wiedemann wrote that whilst he had previously collected issues that introduce non-determinism he has now moved on to discuss about mitigations , in the sense of how can we avoid whole categories of problem without patching an infinite number of individual packages . In addition, Janneke Nieuwenhuizen announced the release of two versions of GNU Mes. [ ][ ]
In openSUSE news, Bernhard M. Wiedemann published another report for that distribution.
In NixOS, with the 24.05 release out, it was again validated that our minimal ISO is reproducible by building it on a virtual machine with no access to the binary cache.
What s more, we continued to write patches in order to fix specific reproducibility issues, including Bernhard M. Wiedemann writing three patches (for qutebrowser, samba and systemd), Chris Lamb filing Debian bug #1074214 against the fastfetch package and Arnout Engelen proposing fixes to refind and for the Scala compiler [ .
Lastly, diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues. This month, Chris Lamb uploaded two versions (270 and 271) to Debian, and made the following changes as well:
  • Drop Build-Depends on liblz4-tool in order to fix Debian bug #1072575. [ ]
  • Update tests to support zipdetails version 4.004 that is shipped with Perl 5.40. [ ]

Website updates There were a number of improvements made to our website this month, including Akihiro Suda very helpfully making the <h4> elements more distinguishable from the <h3> level [ ][ ] as well as adding a guide for Dockerfile reproducibility [ ]. In addition Fay Stegerman added two tools, apksigcopier and reproducible-apk-tools, to our Tools page.

Reproducibility testing framework The Reproducible Builds project operates a comprehensive testing framework running primarily at tests.reproducible-builds.org in order to check packages and other artifacts for reproducibility. In June, a number of changes were made by Holger Levsen, including:
  • Marking the virt(32 64)c-armhf nodes as down. [ ]
  • Granting a developer access to the osuosl4 node in order to debug a regression on the ppc64el architecture. [ ]
  • Granting a developer access to the osuosl4 node. [ ][ ]
In addition, Mattia Rizzolo re-aligned the /etc/default/jenkins file with changes performed upstream [ ] and changed how configuration files are handled on the rb-mail1 host. [ ], whilst Vagrant Cascadian documented the failure of the virt32c and virt64c nodes after initial investigation [ ].

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:

Freexian Collaborators: Monthly report about Debian Long Term Support, June 2024 (by Roberto C. S nchez)

Like each month, have a look at the work funded by Freexian s Debian LTS offering.

Debian LTS contributors In June, 18 contributors have been paid to work on Debian LTS, their reports are available:
  • Adrian Bunk did 47.0h (out of 74.25h assigned and 11.75h from previous period), thus carrying over 39.0h to the next month.
  • Arturo Borrero Gonzalez did 6.0h (out of 6.0h assigned).
  • Bastien Roucari s did 20.0h (out of 20.0h assigned).
  • Ben Hutchings did 15.5h (out of 16.0h assigned and 8.0h from previous period), thus carrying over 8.5h to the next month.
  • Chris Lamb did 18.0h (out of 18.0h assigned).
  • Daniel Leidert did 4.0h (out of 8.0h assigned and 2.0h from previous period), thus carrying over 6.0h to the next month.
  • Emilio Pozuelo Monfort did 23.25h (out of 49.5h assigned and 10.5h from previous period), thus carrying over 36.75h to the next month.
  • Guilhem Moulin did 4.5h (out of 13.0h assigned and 7.0h from previous period), thus carrying over 15.5h to the next month.
  • Lee Garrett did 17.0h (out of 25.0h assigned and 35.0h from previous period), thus carrying over 43.0h to the next month.
  • Lucas Kanashiro did 5.0h (out of 10.0h assigned and 10.0h from previous period), thus carrying over 15.0h to the next month.
  • Markus Koschany did 40.0h (out of 40.0h assigned).
  • Ola Lundqvist did 10.0h (out of 6.5h assigned and 17.5h from previous period), thus carrying over 14.0h to the next month.
  • Roberto C. S nchez did 5.25h (out of 7.75h assigned and 4.25h from previous period), thus carrying over 6.75h to the next month.
  • Santiago Ruano Rinc n did 22.5h (out of 14.5h assigned and 8.0h from previous period).
  • Sean Whitton did 6.5h (out of 6.0h assigned and 0.5h from previous period).
  • Stefano Rivera did 0.5h (out of 0.0h assigned and 10.0h from previous period), thus carrying over 9.5h to the next month.
  • Sylvain Beucler did 9.0h (out of 24.5h assigned and 35.5h from previous period), thus carrying over 51.0h to the next month.
  • Thorsten Alteholz did 14.0h (out of 14.0h assigned).

Evolution of the situation In June, we have released 31 DLAs. Notable security updates in June included:
  • git: multiple vulnerabilities, which may result in privilege escalation, denial of service, and arbitrary code execution
  • sendmail: SMTP smuggling allowed remote attackers bypass SPF protection checks
  • cups: arbitrary remote code execution
Looking further afield to the broader Debian ecosystem, LTS contributor Bastien Roucari s also patched sendmail in Debian 12 (bookworm) and 11 (bullseye) in order to fix the previously mentioned SMTP smuggling vulnerability. Furthermore, LTS contributor Thorsten Alteholz provided fixes for the cups packages in Debian 12 (bookworm) and 11 (bullseye) in order to fix the aforementioned arbitrary remote code execution vulnerability. Additionally, LTS contributor Ben Hutchings has commenced work on an updated backport of Linux kernel 6.1 to Debian 11 (bullseye), in preparation for bullseye transitioning to the responsibility of the LTS (and the associated closure of the bullseye-backports repository). LTS Lucas Kanashiro also began the preparatory work of backporting parts of the rust/cargo toolchain to Debian 11 (bullseye) in order to make future updates of the clamav virus scanner possible. June was the final month of LTS for Debian 10 (as announced on the debian-lts-announce mailing list). No additional Debian 10 security updates will be made available on security.debian.org. However, Freexian and its team of paid Debian contributors will continue to maintain Debian 10 going forward for the customers of the Extended LTS offer. Subscribe right away if you sill have Debian 10 which must be kept secure (and which cannot yet be upgraded).

Thanks to our sponsors Sponsors that joined recently are in bold.

10 July 2024

Russell Coker: Computer Adavances in the Last Decade

I wrote a comment on a social media post where someone claimed that there s no computer advances in the last 12 years which got long so it s worth a blog post. In the last decade or so new laptops have become cheaper than new desktop PCs. USB-C has taken over for phones and for laptop charging so all recent laptops support USB-C docks and monitors with USB-C docks built in have become common. 4K monitors have become cheap and common and higher than 4K is cheap for some use cases such as ultra wide. 4K TVs are cheap and TVs with built-in Android computers for playing internet content are now standard. For most use cases spinning media hard drives are obsolete, SSDs large enough for all the content most people need to store are cheap. We have gone from gigabit Ethernet being expensive to 2.5 gigabit being cheap. 12 years ago smart phones were very limited and every couple of years there would be significant improvements. Since about 2018 phones have been capable of doing most things most people want. 5yo Android phones can run the latest apps and take high quality pics. Any phone that supports VoLTE will be good for another 5+ years if it has security support. Phones without security support still work and are quite usable apart from being insecure. Google and Samsung have significantly increased their minimum security support for their phones and the GKI project from Google makes it easier for smaller vendors to give longer security support. There are a variety of open Android projects like LineageOS which give longer security support on a variety of phones. If you deliberately choose a phone that is likely to be well supported by projects like LineageOS (which pretty much means just Pixel phones) then you can expect to be able to actually use it when it is 10 years old. Compare this to the Samsung Galaxy S3 released in 2012 which was a massive improvement over the original Galaxy S (the S2 felt closer to the S than the S3). The Samsung Galaxy S4 released in 2013 was one of the first phones to have FullHD resolution which is high enough that most people can t easily recognise the benefits of higher resolution. It wasn t until 2015 that phones with 4G of RAM became common which is enough that for most phone use it s adequate today. Now that 16G of RAM is affordable in laptops running more secure OSs like Qubes is viable for more people. Even without Qubes, OS security has been improving a lot with better compiler features, new languages like Rust, and changes to software design and testing. Containers are being used more but we still aren t getting all the benefits of that. TPM has become usable in the last few years and we are only starting to take advantage of what it can offer. In 2012 BTRFS was still at an early stage of development and not many people wanted to use it in production, I was using it in production then and while I didn t lose any data from bugs I did have some downtime because of BTRFS issues. Now BTRFS is quite solid for server use. DDR4 was released in 2014 and gave significant improvements over DDR3 for performance and capacity. My home workstation now has 256G of DDR4 which wasn t particularly expensive while the previous biggest system I owned had 96G of DDR3 RAM. Now DDR5 is available to again increase performance and size while also making DDR4 cheap on the second hand market. This isn t a comprehensive list of all advances in the computer industry over the last 12 years or so, it s just some things that seem particularly noteworthy to me. Please comment about what you think are the most noteworthy advances I didn t mention.

9 July 2024

Simon Josefsson: Towards Idempotent Rebuilds?

After rebuilding all added/modified packages in Trisquel, I have been circling around the elephant in the room: 99% of the binary packages in Trisquel comes from Ubuntu, which to a large extent are built from Debian source packages. Is it possible to rebuild the official binary packages identically? Does anyone make an effort to do so? Does anyone care about going through the differences between the official package and a rebuilt version? Reproducible-build.org s effort to track reproducibility bugs in Debian (and other systems) is amazing. However as far as I know, they do not confirm or deny that their rebuilds match the official packages. In fact, typically their rebuilds do not match the official packages, even when they say the package is reproducible, which had me surprised at first. To understand why that happens, compare the buildinfo file for the official coreutils 9.1-1 from Debian bookworm with the buildinfo file for reproducible-build.org s build and you will see that the SHA256 checksum does not match, but still they declare it as a reproducible package. As far as I can tell of the situation, the purpose of their rebuilds are not to say anything about the official binary build, instead the purpose is to offer a QA service to maintainers by performing two builds of a package and declaring success if both builds match. I have felt that something is lacking, and months have passed and I haven t found any project that address the problem I am interested in. During my earlier work I created a project called debdistreproduce which performs rebuilds of the difference between two distributions in a GitLab pipeline, and display diffoscope output for further analysis. A couple of days ago I had the idea of rewriting it to perform rebuilds of a single distribution. A new project debdistrebuild was born and today I m happy to bless it as version 1.0 and to announces the project! Debdistrebuild has rebuilt the top-50 popcon packages from Debian bullseye, bookworm and trixie, on amd64 and arm64, as well as Ubuntu jammy and noble on amd64, see the summary status page for links. This is intended as a proof of concept, to allow people experiment with the concept of doing GitLab-based package rebuilds and analysis. Compare how Guix has the guix challenge command. Or I should say debdistrebuild has attempted to rebuild those distributions. The number of identically built packages are fairly low, so I didn t want to waste resources building the rest of the archive until I understand if the differences are due to consequences of my build environment (plain apt-get build-dep followed by dpkg-buildpackage in a fresh container), or due to some real difference. Summarizing the results, debdistrebuild is able to rebuild 34% of Debian bullseye on amd64, 36% of bookworm on amd64, 32% of bookworm on arm64. The results for trixie and Ubuntu are disappointing, below 10%. So what causes my rebuilds to be different from the official rebuilds? Some are trivial like the classical problem of varying build paths, resulting in a different NT_GNU_BUILD_ID causing a mismatch. Some are a bit strange, like a subtle difference in one of perl s headers file. Some are due to embedded version numbers from a build dependency. Several of the build logs and diffoscope outputs doesn t make sense, likely due to bugs in my build scripts, especially for Ubuntu which appears to strip translations and do other build variations that I don t do. In general, the classes of reproducibility problems are the expected. Some are assembler differences for GnuPG s gpgv-static, likely triggered by upload of a new version of gcc after the original package was built. There are at least two ways to resolve that problem: either use the same version of build dependencies that were used to produce the original build, or demand that all packages that are affected by a change in another package are rebuilt centrally until there are no more differences. The current design of debdistrebuild uses the latest version of a build dependency that is available in the distribution. We call this a idempotent rebuild . This is usually not how the binary packages were built originally, they are often built against earlier versions of their build dependency. That is the situation for most binary distributions. Instead of using the latest build dependency version, higher reproducability may be achieved by rebuilding using the same version of the build dependencies that were used during the original build. This requires parsing buildinfo files to find the right version of the build dependency to install. We believe doing so will lead to a higher number of reproducibly built packages. However it begs the question: can we rebuild that earlier version of the build dependency? This circles back to really old versions and bootstrappable builds eventually. While rebuilding old versions would be interesting on its own, we believe that is less helpful for trusting the latest version and improving a binary distribution: it is challenging to publish a new version of some old package that would fix a reproducibility bug in another package when used as a build dependency, and then rebuild the later packages with the modified earlier version. Those earlier packages were already published, and are part of history. It may be that ultimately it will no longer be possible to rebuild some package, because proper source code is missing (for packages using build dependencies that were never part of a release); hardware to build a package could be missing; or that the source code is no longer publicly distributable. I argue that getting to 100% idempotent rebuilds is an interesting goal on its own, and to reach it we need to start measure idempotent rebuild status. One could conceivable imagine a way to rebuild modified versions of earlier packages, and then rebuild later packages using the modified earlier packages as build dependencies, for the purpose of achieving higher level of reproducible rebuilds of the last version, and to reach for bootstrappability. However, it may be still be that this is insufficient to achieve idempotent rebuilds of the last versions. Idempotent rebuilds are different from a reproducible build (where we try to reproduce the build using the same inputs), and also to bootstrappable builds (in which all binaries are ultimately built from source code). Consider a cycle where package X influence the content of package Y, which in turn influence the content of package X. These cycles may involve several packages, and it is conceivable that a cycle could be circular and infinite. It may be difficult to identify these chains, and even more difficult to break them up, but this effort help identify where to start looking for them. Rebuilding packages using the same build dependency versions as were used during the original build, or rebuilding packages using a bootsrappable build process, both seem orthogonal to the idempotent rebuild problem. Our notion of rebuildability appears thus to be complementary to reproducible-builds.org s definition and bootstrappable.org s definition. Each to their own devices, and Happy Hacking! Addendum about terminology: With idempotent rebuild I am talking about a rebuild of the entire operating system, applied to itself. Compare how you build the latest version of the GNU C Compiler: it first builds itself using whatever system compiler is available (often an earlier version of gcc) which we call step 1. Then step 2 is to build a copy of itself using the compiler built in step 1. The final step 3 is to build another copy of itself using the compiler from step 2. Debian, Ubuntu etc are at step 1 in this process right now. The output of step 2 and step 3 ought to be bit-by-bit identical, or something is wrong. The comparison between step 2 and 3 is what I refer to with an idempotent rebuild. Of course, most packages aren t a compiler that can compile itself. However entire operating systems such as Trisquel, PureOS, Ubuntu or Debian are (hopefully) a self-contained system that ought to be able to rebuild itself to an identical copy. Or something is amiss. The reproducible build and bootstrappable build projects are about improve the quality of step 1. The property I am interested is the identical rebuild and comparison in step 2 and 3. I feel the word idempotent describes the property I m interested in well, but I realize there may be better ways to describe this. Ideas welcome!

Russ Allbery: Review: Raising Steam

Review: Raising Steam, by Terry Pratchett
Series: Discworld #40
Publisher: Anchor Books
Copyright: 2013
Printing: October 2014
ISBN: 0-8041-6920-9
Format: Trade paperback
Pages: 365
Raising Steam is the 40th Discworld novel and the third Moist von Lipwig novel, following Making Money. This is not a good place to start reading the series. Dick Simnel is a tinkerer from a line of tinkerers. He has been obsessed with mastering the power of steam since the age of ten, when his father died in a steam accident. That pursuit took him deeper into mathematics and precision, calculations and experiments, until he built Iron Girder: Discworld's first steam-powered locomotive. His early funding came from some convenient family pirate treasure, but turning his prototype into something more will require significantly more resources. That is how he ends up in the office of Harry King, Ankh-Morpork's sanitation magnate. Simnel's steam locomotive has the potential to solve some obvious logistical problems, such as getting fish from the docks of Quirm to the streets of Ankh-Morpork before it stops being vaguely edible. That's not what makes railways catch fire, however. As soon as Iron Girder is huffing and puffing its way around King's compound, it becomes the most popular attraction in the city. People stand in line for hours to ride it over and over again for reasons that they cannot entirely explain. There is something wild and uncontrollable going on. Vetinari is not sure he likes wild and uncontrollable, but he knows the lap into which such problems can be dumped: Moist von Lipwig, who is already getting bored with being a figurehead for the city's banking system. The setup for Raising Steam reminds me more of Moving Pictures than the other Moist von Lipwig novels. Simnel himself is a relentlessly practical engineer, but the trains themselves have tapped some sort of primal magic. Unlike Moving Pictures, Pratchett doesn't provide an explicit fantasy explanation involving intruding powers from another world. It might have been a more interesting book if he had. Instead, this book expects the reader to believe there is something inherently appealing and fascinating about trains, without providing much logic or underlying justification. I think some readers will be willing to go along with this, and others (myself included) will be left wishing the story had more world-building and fewer exclamation points. That's not the real problem with this book, though. Sadly, its true downfall is that Pratchett's writing ability had almost completely collapsed by the time he wrote it. As mentioned in my review of Snuff, we're now well into the period where Pratchett was suffering the effects of early-onset Alzheimer's. In that book, his health issues mostly affected the dialogue near the end of the novel. In this book, published two years later, it's pervasive and much worse. Here's a typical passage from early in the book:
It is said that a soft answer turneth away wrath, but this assertion has a lot to do with hope and was now turning out to be patently inaccurate, since even a well-spoken and thoughtful soft answer could actually drive the wrong kind of person into a state of fury if wrath was what they had in mind, and that was the state the elderly dwarf was now enjoying.
One of the best things about Discworld is Pratchett's ability to drop unexpected bits of wisdom in a sentence or two, or twist a verbal knife in an unexpected and surprising direction. Raising Steam still shows flashes of that ability, but it's buried in run-on sentences, drowned in cliches and repetition, and often left behind as the containing sentence meanders off into the weeds and sputters to a confused halt. The idea is still there; the delivery, sadly, is not. This is the first Discworld novel that I found mentally taxing to read. Sentences are often so overpacked that they require real effort to untangle, and the untangled meaning rarely feels worth the effort. The individual voice of the characters is almost gone. Vetinari's monologues, rather than being a rare event with dangerous layers, are frequent, rambling, and indecisive, often sounding like an entirely different character than the Vetinari we know. The constant repetition of the name any given character is speaking to was impossible for me to ignore. And the momentum of the story feels wrong; rather than constructing the events of the story in a way that sweeps the reader along, it felt like Pratchett was constantly pushing, trying to convince the reader that trains were the most exciting thing to ever happen to Discworld. The bones of a good story are here, including further development of dwarf politics from The Fifth Elephant and Thud! and the further fallout of the events of Snuff. There are also glimmers of Pratchett's typically sharp observations and turns of phrase that could have been unearthed and polished. But at the very least this book needed way more editing and a lot of rewriting. I suspect it could have dropped thirty pages just by tightening the dialogue and removing some of the repetition. I'm afraid I did not enjoy this. I am a bit of a hard sell for the magic fascination of trains I love trains, but my model railroad days are behind me and I'm now more interested in them as part of urban transportation policy. Previous Discworld books on technology and social systems did more of the work of drawing the reader in, providing character hooks and additional complexity, and building a firmer foundation than "trains are awesome." The main problem, though, was the quality of the writing, particularly when compared to the previous novels with the same characters. I dragged myself through this book out of a sense of completionism and obligation, and was relieved when I finished it. This is the first Discworld novel that I don't recommend. I think the only reason to read it is if you want to have read all of Discworld. Otherwise, consider stopping with Snuff and letting it be the send-off for the Ankh-Morpork characters. Followed by The Shepherd's Crown, a Tiffany Aching story and the last Discworld novel. Rating: 3 out of 10

8 July 2024

Thorsten Alteholz: My Debian Activities in June 2024

FTP master This month I accepted 270 and rejected 23 packages. The overall number of packages that got accepted was 279.

Debian LTS This was my hundred-twentieth month that I did some work for the Debian LTS initiative, started by Raphael Hertzog at Freexian. During my allocated time I uploaded or worked on: This month handling of the CVE of cups was a bit messy. After lifting the embargo of the CVE, a published patch did not work with all possible combinations of the configuration. In other words, in cases of having only one local domain socket configured, the cupsd did not start and failed with a strange error. Anyway, upstream published a new set of patches, which made cups work again. Unfortunately this happended just before the latest point release for Bullseye and Bookworm, so that the new packages did not make it into the release, but stopped in the corresponding p-u-queues: stable-p-u and old-p-u. I also continued to work on tiff and last but not least did a week of FD and attended the monthly LTS/ELTS meeting. Debian ELTS This month was the seventy-first ELTS month. During my allocated time I tried to upload a new version of cups for Jessie and Stretch. Unfortunately this was stopped due to an autopkgtest error, which I could not reproduce yet. I also wanted to finally upload a fixed version of exim4. Unfortunately this was stopped due to lots of CI-jobs for Buster. Updates for Buster are now also availble from ELTS, so some stuff had to prepared before the actual switch end of June. Additionally everything was delayed due to a crash of the CI worker. All in all this month was rather ill-fated. At least the exim4 upload will happen/already happened in July. I also continued to work on an update for libvirt, did a week of FD and attended the LTS/ELTS meeting. Debian Printing This month I uploaded new upstream or bugfix versions of: This work is generously funded by Freexian! Debian Astro This month I uploaded a new upstream or bugfix version of: All of those uploads are somehow related to /usr-move. Debian IoT This month I uploaded new upstream or bugfix versions of: Debian Mobcom The following packages have been prepared by the GSoC student Nathan: misc This month I uploaded new upstream or bugfix versions of: Here as well all uploads are somehow related to /usr-move

7 July 2024

Niels Thykier: Improving packaging file detection in Debian

Debian packaging consists of a directory (debian/) containing a number of "hard-coded" filenames such as debian/control, debian/changelog, debian/copyright. In addition to these, many packages will also use a number of optional files that are named via a pattern such as debian/ PACKAGE .install. At a high level the patterns looks deceptively simple. However, if you start working on trying to automatically classify files in debian/ (which could be helpful to tell the user they have a typo in the filename), you will quickly realize these patterns are not machine friendly at all for this purpose.
The patterns deconstructed To appreciate the problem fully, here is a primer on the pattern and all its issues. If you are already well-versed in these, you might want to skip the section. The most common patterns are debian/package.stem or debian/stem and usually the go to example is the install stem ( a concrete example being debian/debhelper.install). However, the full pattern consists of 4 parts where 3 of them are optional.
  • The package name followed by a period. Optional, but must be the first if present.
  • The name segment followed by a period. Optional, but must appear between the package name (if present) and the stem. If the package name is not present, then the name segment must be first.
  • The stem. Mandatory.
  • An architecture restriction prefixed by a period. Optional, must appear after the stem if present.
To visualize it with [foo] to mark optional parts, it looks like debian/[PACKAGE.][NAME.]STEM[.ARCH] Detecting whether a given file is in fact a packaging file now boils down to reverse engineering its name against this pattern. Again, so far, it might still look manageable. One major complication is that every part (except ARCH) can contain periods. So a trivial "split by period" is not going to cut it. As an example:
debian/g++-3.0.user.service
This example is deliberately crafted to be ambiguous and show this problem in its full glory. This file name can be in multiple ways:
  • Is the stem service or user.service? (both are known stems from dh_installsystemd and dh_installsystemduser respectively). In fact, it can be both at the same time with "clever" usage of --name=user passed to dh_installsystemd.
  • The g++-3.0 can be a package prefix or part of the name segment. Even if there is a g++-3.0 package in debian/control, then debhelper (until compat 15) will still happily match this file for the main package if you pass --name=g++-3.0 to the helper. Side bar: Woe is you if there is a g++-3 and a g++-3.0 package in debian/control, then we have multiple options for the package prefix! Though, I do not think that happens in practice.
Therefore, there are a lot of possible ways to split this filename that all matches the pattern but with vastly different meaning and consequences.
Making detection practical To make this detection practical, lets look at the first problems that we need to solve.
  1. We need the possible stems up front to have a chance at all. When multiple stems are an option, go for the longest match (that is, the one with most periods) since --name is rare and "code golfing" is even rarer.
  2. We can make the package prefix mandatory for files with the name segment. This way, the moment there is something before the stem, we know the package prefix will be part of it and can cut it. It does not solve the ambiguity if one package name is a prefix of another package name (from the same source), but it still a lot better. This made its way into debhelper compat 15 and now it is "just" a slow long way to a better future.
A simple solution to the first problem could be to have a static list of known stems. That will get you started but the debhelper eco-system strive on decentralization, so this feels like a mismatch. There is also a second problem with the static list. Namely, a given stem is only "valid" if the command in question is actually in use. Which means you now need to dumpster dive into the mess that is Turning-complete debhelper configuration file known as debian/rules to fully solve that. Thanks to the Turning-completeness, we will never get a perfect solution for a static analysis. Instead, it is time to back out and instead apply some simplifications. Here is a sample flow:
  1. Check whether the dh sequencer is used. If so, use some heuristics to figure out which addons are used.
  2. Delegate to dh_assistant to figure out which commands will be used and which debhelper config file stems it knows about. Here we need to know which sequences are in use from step one (if relevant). Combine this with any other sources for stems you have.
  3. Deconstruct all files in debian/ against the stems and known package names from debian/control. In theory, dumpster diving after --name options would be helpful here, but personally I skipped that part as I want to keep my debian/rules parsing to an absolute minimum.
With this logic, you can now:
  • Provide typo detection of the stem (debian/foo.intsall -> debian/foo.install) provided to have adequate handling of the corner cases (such as debian/*.conf not needing correction into debian/*.config)
  • Detect possible invalid package prefix (debian/foo.install without foo being a package). Note this has to be a weak warning unless the package is using debhelper compat 15 or you dumpster dived to validate that dh_install was not passed dh_install --name foo. Agreed, no one should do that, but they can and false positives are the worst kind of positives for a linting tool.
  • With some limitations, detect files used without the relevant command being active. As an example, the some integration modes of debputy removes dh_install, so a debian/foo.install would not be used.
  • Associate a given file with a given command to assist users with the documentation look up. Like debian/foo.user.service is related to dh_installsystemduser, so man dh_installsystemduser is a natural start for documentation.
I have added the logic for all these features in debputy though the documentation association is currently not in a user facing command. All the others are now diagnostics emitted by debputy in its editor support mode (debputy lsp server) or via debputy lint. In the editor mode, the diagnostics are currently associated with the package name in debian/control due to technical limitations of how the editor integration works. Some of these features will the latest version of debhelper (moving target at times). Check with debputy lsp features for the Extra dh support feature, which will be enabled if you got all you need. Note: The detection is currently (mostly) ignoring files with architecture restrictions. That might be lifted in the future. However, architecture restricted config files tend to be rare, so they were not a priority at this point. Additionally, debputy for technical reasons ignores stem typos with multiple matches. That sadly means that typos of debian/docs will often be unreported due to its proximity to debian/dirs and vice versa.
Diving a bit deeper on getting the stems To get the stems, debputy has 3 primary sources:
  1. Its own plugins can provide packager provided files. These are only relevant if the package is using debputy.
  2. It is als possible to provide a debputy plugin that identifies packaging files (either static or named ones). Though in practice, we probably do not want people to roll their own debputy plugin for this purpose, since the detection only works if the plugin is installed. I have used this mechanism to have debhelper provide a debhelper-documentation plugin to enrich the auto-detected data and we can assume most people interested in this feature would have debhelper installed.
  3. It asks dh_assistant list-guessed-dh-config-files for config files, which is covered below.
The dh_assistant command uses the same logic as dh to identify the active add-ons and loads them. From there, it scans all commands mentioned in the sequence for the PROMISE: DH NOOP WITHOUT ...-hint and a new INTROSPECTABLE: CONFIG-FILES ...-hint. When these hints reference a packaging file (as an example, via pkgfile(foo)) then dh_assistant records that as a known packaging file for that helper. Additionally, debhelper now also tracks commands that were removed from the sequence. Several of the dh_assistant subcommand now use this to enrich their (JSON) output with notes about these commands being known but not active.
The end result With all of this work, you now get:
$ apt satisfy 'dh-debputy (>= 0.1.43~), debhelper (>= 13.16~), python3-lsprotocol, python3-levenshtein'
# For demo purposes, pull two known repos (feel free to use your own packages here)
$ git clone https://salsa.debian.org/debian/debhelper.git -b debian/13.16
$ git clone https://salsa.debian.org/debian/debputy.git -b debian/0.1.43
$ cd debhelper
$ mv debian/debhelper.install debian/debhelper.intsall
$ debputy lint
warning: File: debian/debhelper.intsall:1:0:1:0: The file "debian/debhelper.intsall" is likely a typo of "debian/debhelper.install"
    File-level diagnostic
$ mv debian/debhelper.intsall debian/debhleper.install
$ debputy lint
warning: File: debian/debhleper.install:1:0:1:0: Possible typo in "debian/debhleper.install". Consider renaming the file to "debian/debhelper.debhleper.install" or "debian/debhelper.install" if it is intended for debhelper
    File-level diagnostic
$ cd ../debputy
$ touch debian/install
$ debputy lint --no-warn-about-check-manifest
warning: File: debian/install:1:0:1:0: The file debian/install is related to a command that is not active in the dh sequence with the current addons
    File-level diagnostic
As mentioned, you also get these diagnostics in the editor via the debputy lsp server feature. Here the diagnostics appear in debian/control over the package name for technical reasons. The editor side still needs a bit more work. Notably, changes to the filename is not triggered automatically and will first be caught on the next change to debian/control. Likewise, changes to debian/rules to add --with to dh might also have some limitations depending on the editor. Saving both files and then triggering an edit of debian/control seems to work reliable but ideally it should not be that involved. The debhelper side could also do with some work to remove the unnecessary support for the name segment with many file stems that do not need them and announce that to debputy. Anyhow, it is still a vast improvement over the status quo that was "Why is my file silently ignored!?".

4 July 2024

Arturo Borrero Gonz lez: Wikimedia Toolforge: migrating Kubernetes from PodSecurityPolicy to Kyverno

Le ch teau de Val re et le Haut de Cry en juillet 2022 Christian David, CC BY-SA 4.0, via Wikimedia Commons This post was originally published in the Wikimedia Tech blog, authored by Arturo Borrero Gonzalez. Summary: this article shares the experience and learnings of migrating away from Kubernetes PodSecurityPolicy into Kyverno in the Wikimedia Toolforge platform. Wikimedia Toolforge is a Platform-as-a-Service, built with Kubernetes, and maintained by the Wikimedia Cloud Services team (WMCS). It is completely free and open, and we welcome anyone to use it to build and host tools (bots, webservices, scheduled jobs, etc) in support of Wikimedia projects. We provide a set of platform-specific services, command line interfaces, and shortcuts to help in the task of setting up webservices, jobs, and stuff like building container images, or using databases. Using these interfaces makes the underlying Kubernetes system pretty much invisible to users. We also allow direct access to the Kubernetes API, and some advanced users do directly interact with it. Each account has a Kubernetes namespace where they can freely deploy their workloads. We have a number of controls in place to ensure performance, stability, and fairness of the system, including quotas, RBAC permissions, and up until recently PodSecurityPolicies (PSP). At the time of this writing, we had around 3.500 Toolforge tool accounts in the system. We early adopted PSP in 2019 as a way to make sure Pods had the correct runtime configuration. We needed Pods to stay within the safe boundaries of a set of pre-defined parameters. Back when we adopted PSP there was already the option to use 3rd party agents, like OpenPolicyAgent Gatekeeper, but we decided not to invest in them, and went with a native, built-in mechanism instead. In 2021 it was announced that the PSP mechanism would be deprecated, and removed in Kubernetes 1.25. Even though we had been warned years in advance, we did not prioritize the migration of PSP until we were in Kubernetes 1.24, and blocked, unable to upgrade forward without taking actions. The WMCS team explored different alternatives for this migration, but eventually we decided to go with Kyverno as a replacement for PSP. And so with that decision it began the journey described in this blog post. First, we needed a source code refactor for one of the key components of our Toolforge Kubernetes: maintain-kubeusers. This custom piece of software that we built in-house, contains the logic to fetch accounts from LDAP and do the necessary instrumentation on Kubernetes to accommodate each one: create namespace, RBAC, quota, a kubeconfig file, etc. With the refactor, we introduced a proper reconciliation loop, in a way that the software would have a notion of what needs to be done for each account, what would be missing, what to delete, upgrade, and so on. This would allow us to easily deploy new resources for each account, or iterate on their definitions. The initial version of the refactor had a number of problems, though. For one, the new version of maintain-kubeusers was doing more filesystem interaction than the previous version, resulting in a slow reconciliation loop over all the accounts. We used NFS as the underlying storage system for Toolforge, and it could be very slow because of reasons beyond this blog post. This was corrected in the next few days after the initial refactor rollout. A side note with an implementation detail: we stored a configmap on each account namespace with the state of each resource. Storing more state on this configmap was our solution to avoid additional NFS latency. I initially estimated this refactor would take me a week to complete, but unfortunately it took me around three weeks instead. Previous to the refactor, there were several manual steps and cleanups required to be done when updating the definition of a resource. The process is now automated, more robust, performant, efficient and clean. So in my opinion it was worth it, even if it took more time than expected. Then, we worked on the Kyverno policies themselves. Because we had a very particular PSP setting, in order to ease the transition, we tried to replicate their semantics on a 1:1 basis as much as possible. This involved things like transparent mutation of Pod resources, then validation. Additionally, we had one different PSP definition for each account, so we decided to create one different Kyverno namespaced policy resource for each account namespace remember, we had 3.5k accounts. We created a Kyverno policy template that we would then render and inject for each account. For developing and testing all this, maintain-kubeusers and the Kyverno bits, we had a project called lima-kilo, which was a local Kubernetes setup replicating production Toolforge. This was used by each engineer in their laptop as a common development environment. We had planned the migration from PSP to Kyverno policies in stages, like this:
  1. update our internal template generators to make Pod security settings explicit
  2. introduce Kyverno policies in Audit mode
  3. see how the cluster would behave with them, and if we had any offending resources reported by the new policies, and correct them
  4. modify Kyverno policies and set them in Enforce mode
  5. drop PSP
In stage 1, we updated things like the toolforge-jobs-framework and tools-webservice. In stage 2, when we deployed the 3.5k Kyverno policy resources, our production cluster died almost immediately. Surprise. All the monitoring went red, the Kubernetes apiserver became irresponsibe, and we were unable to perform any administrative actions in the Kubernetes control plane, or even the underlying virtual machines. All Toolforge users were impacted. This was a full scale outage that required the energy of the whole WMCS team to recover from. We temporarily disabled Kyverno until we could learn what had occurred. This incident happened despite having tested before in lima-kilo and in another pre-production cluster we had, called Toolsbeta. But we had not tested that many policy resources. Clearly, this was something scale-related. After the incident, I went on and created 3.5k Kyverno policy resources on lima-kilo, and indeed I was able to reproduce the outage. We took a number of measures, corrected a few errors in our infrastructure, reached out to the Kyverno upstream developers, asking for advice, and at the end we did the following to accommodate the setup to our needs: I have to admit, I was briefly tempted to drop Kyverno, and even stop pursuing using an external policy agent entirely, and write our own custom admission controller out of concerns over performance of this architecture. However, after applying all the measures listed above, the system became very stable, so we decided to move forward. The second attempt at deploying it all went through just fine. No outage this time When we were in stage 4 we detected another bug. We had been following the Kubernetes upstream documentation for setting securityContext to the right values. In particular, we were enforcing the procMount to be set to the default value, which per the docs it was DefaultProcMount . However, that string is the name of the internal variable in the source code, whereas the actual default value is the string Default . This caused pods to be rightfully rejected by Kyverno while we figured the problem. I sent a patch upstream to fix this problem. We finally had everything in place, reached stage 5, and we were able to disable PSP. We unloaded the PSP controller from the kubernetes apiserver, and deleted every individual PSP definition. Everything was very smooth in this last step of the migration. This whole PSP project, including the maintain-kubeusers refactor, the outage, and all the different migration stages took roughly three months to complete. For me there are a number of valuable reasons to learn from this project. For one, the scale is something to consider, and test, when evaluating a new architecture or software component. Not doing so can lead to service outages, or unexpectedly poor performances. This is in the first chapter of the SRE handbook, but we got a reminder the hard way This post was originally published in the Wikimedia Tech blog, authored by Arturo Borrero Gonzalez.

Samuel Henrique: Debian's curl now supports HTTP3

tl;dr Starting with curl 8.0.0-2, you can now use HTTP3.
curl --http3-only https://example.com
Or, if you would like to try it out in a container:
podman run debian:unstable apt install --update -y curl && curl --http3-only https://example.com
(in case you haven't noticed, apt now has the --update option for the upgrade and install commands, although not available on stable yet)

Availability
  • Debian unstable - Since 2024-07-02
  • Debian testing - Since 2024-07-18
  • Debian 12/bookworm backports - Expected by the end of August 2024.
  • Debian 12/bookworm - Due to the mechanisms we have in place to make sure Debian stable is in fact stable, we will never be able to ship this in the regular repository. Users can make use of the backports repositories instead.
  • Debian derivatives - Rolling releases will get it by the time it's on Debian testing (e.g.: Kali Linux). Stable derivatives only in their next major release.

The challenge HTTP3 is fresh new, well... not really, but at least fresh enough that I'm not aware of any other Linux distribution supporting it on curl, the reason is likely two-fold:
  1. OpenSSL is not there yet OpenSSL still doesn't have proper HTTP3 support, and given that OpenSSL is so widely used, almost every curl distributor/packager will build curl with it and thus changing the TLS backend to something else is risky. Unfortunately, proper support for the OpenSSL libcurl is unlikely to come anytime before the end of this year, the OpenSSL performance is not good enough yet as of version 3.3. Daniel Stenberg has written about the state of this multiple times, most recently at HTTP/3 in curl mid 2024, if you're interested, I suggest reading through his other posts as well. Some might have noticed that nginx does support HTTP3 through OpenSSL, although when you look closely, it's not exactly perfect:
    An SSL library that provides QUIC support is recommended to build nginx, such as BoringSSL, LibreSSL, or QuicTLS. Otherwise, the OpenSSL compatibility layer will be used that does not support early data.
    As you can see, they don't recommend using OpenSSL, and when doing so, you don't get complete support.

  2. HTTP3 support for GnuTLS/nghttp3/ngtcp2 is recent The non-experimental support arrived back in October 2023, and so that's when I started seriously planning for this. curl has been working on HTTP3 support for years, and so it did support other TLS backends before that, but out of them, the one most feasible for a distribution to ship would be GnuTLS, which gets HTTP3 support through ngctp2 and nghttp3.

How it was done The Debian curl package has historically shipped at least two variants of libcurl, an OpenSSL and a GnuTLS one. The OpenSSL libcurl can't support HTTP3 for the reasons explained above, but the GnuTLS libcurl can (with ngtcp2 and nghtp3). Debian packages can choose which version of libcurl to link against (without having to modify any upstream source code). Debian's "git" package being a famous example of a package that links against the GnuTLS libcurl. Enabling HTTP3 on curl was done in three steps:
  1. Make sure all required dependencies fulfill the minimum requirements.
  2. Enable HTTP3 for GnuTLS libcurl.
  3. Change the libcurl used by the curl CLI, from OpenSSL to GnuTLS.
curl's HTTP3 support requires a somewhat recent version of nghttp3 and updating that required a transition (due to the SONAME bump), while we've also had months of freeze for transitions due to the time_t transition. After the dependencies were in place, enabling HTTP3 for the GnuTLS libcurl was straightforward. Then, for the last part, we had to switch the TLS backend used by the curl CLI. Doing the swap is also quite easy on the packaging level, but we have to consider the chances of this change breaking our users' environments.

Ensuring there are no breakages The first thing to consider regarding breakages is that this change is not going to be pushed directly to the current Debian stable releases, it will be present in the next stable release (13/trixie) but the current one will stick to the version that's already shipped. Secondly, we have to consider the risk of losing the ability to use certain parameters from the curl CLI which could be limited to the OpenSSL backend. During curl-up 2024, the curl developers pointed out the existence of a page that lists the TLS related options and the backends they work with. Analysing that page, ignoring all of the options that are suffixed with "BLOB" (only pertinent to the library, not the CLI), the only one left which is attention worthy is CURLOPT_ECH.
This experimental feature requires a special build of OpenSSL, as ECH is not yet supported in OpenSSL releases. In contrast ECH is supported by the latest BoringSSL and wolfSSL releases.
As it turns out, Encrypted Client Hello is experimental and it's not supported by the vanilla OpenSSL. This was enough of an investigation for me to go ahead with the change. Noting that even in the worst case scenario (we find a horrible regression), we can rollback without having affected a single stable release. Now that the package is on Debian unstable, the CI tests (autopkgtest) of every package that depends on curl is currently running, the results are compared against the migration-reference (in this case, the curl CLI with OpenSSL, before the change). If everything goes right, curl with HTTP3 support will migrate to Debian testing in around 5 days. If we spot any issues, we'll have to solve them first and it's going to be hard to predict how long it takes, although it's fair to expect less than a month.

Feedback Feel free to join the Matrix room for the Debian curl maintainers:
https://matrix.to/#/#debian-curl-maintainers:matrix.org

Acknowledgements It took us a bit longer than expected to be able to enable HTTP3, nonetheless it's still early enough to be excited about. A lot of people were crucial to make this happen. I should recognize in the first place, obviously, the curl developers and the developers of the supporting libraries: GnuTLS, nghttp3, ngtcp2. Participating in the curl-up 2024 conference helped me get motivated to push this through, besides becoming aware of the right documentation to research for impact. On the Debian side, Sakirnth Nagarasa <sakirnth> was responsible for updating and taking care of the transition for nghttp3 and ngtcp2. Also on the Debian side, I've got loads of help and support from the co-maintainers of the curl package: Sergio Durigan Junior <sergiodj> and Carlos Henrique Lima Melara <charles>.

Changes since publication

2024-07-18
  • Update date of availability for Debian testing and expected date for bookworm backports.
  • We have historically spoken Portuguese in the room but we'll switch to English in case anyone joins.

3 July 2024

Samuel Henrique: Announcing wcurl: a curl wrapper to download files

tl;dr Whenever you need to download files through the terminal and don't feel like using wget:
wcurl example.com/filename.txt
Manpage:
https://manpages.debian.org/unstable/curl/wcurl.1.en.html

Availability (comes installed with the curl package):
  • Debian unstable - Since 2024-07-02
  • Debian testing - Since 2024-07-18
  • Debian 12/bookworm backports - Expected by the end of August 2024.
  • Debian 12/bookworm - Depends on whether Debian's release team will approve it, it could be available in the next point release.
  • Debian derivatives - Rolling releases will get it by the time it's on Debian testing (e.g.: Kali Linux). Stable derivatives only in their next major release.
If you don't want to wait for the package update to arrive, you can always copy the script and place it in your /usr/bin, the code is here:
https://github.com/Debian/wcurl/blob/main/wcurl
https://salsa.debian.org/debian/wcurl/-/blob/main/wcurl?ref_type=heads

Smoother CLI experience Starting with curl version 8.8.0-2, the Debian's curl package now ships a wcurl executable. wcurl is the solution for those who just need to download files without having to remember curl's parameters for things like automatically naming the files. Some people, myself included, would fall back to using wget whenever there was a need to download a file. Sometimes even installing wget just for that usecase. After all, it's easier to remember "apt install wget" rather than "curl -L -O -C - ...". wcurl consists of a simple shell script that provides sane defaults for the curl invocation, for when the use case is to just download files. By default, wcurl will:
  • Encode whitespaces in URLs;
  • Download multiple URLs in parallel if the installed curl's version is >= 7.66.0;
  • Follow redirects;
  • Automatically choose a filename as output;
  • Avoid overwriting files if the installed curl's version is >= 7.83.0 (--no-clobber);
  • Perform retries;
  • Set the downloaded file timestamp to the value provided by the server, if available;
  • Default to the protocol used as https if the URL doesn't contain any;
  • Disable curl's URL globbing parser so and [] characters in URLs are not treated specially.
Example to download a single file:
wcurl example.com/filename.txt
If you ever need to set a custom flag, you can make use of the --curl-options wcurl option, anything set there will be passed to the curl invocation. Just beware that if you need to set any custom flags, it's likely you will be better served by calling curl directly. The --curl-options option is there to allow for some flexibility in unforeseen circumstances.

The need for wcurl I've always felt a bit ashamed of not remembering curl's parameters for downloading a file and automatically naming it, having resorted to wget most of the times this was needed (even installing wget when it wasn't there, just for this). I've spoken to a few other experienced people I know and confirmed what could be obvious to others: a lot of people struggle with this. Recently, the curl project released the results of 2024's curl survey, which also showed this is as a much needed feature, just look at some of the answers:

Q: Which curl command line option do you think needs improvement and how?
-O, I really want wget like functionality where I don't have to specify the name
Downloading a file (like wget) could be improved - with automatic naming of the file
downloading files - wget is much cleaner
I wish the default behaviour when GETting a binary was to drop it on disk. That's the only reason 'wget foo.tgz" is still ingrained in my muscle memory .
Maybe have a way to download without specifying something in -o (the only reason i used wget still)
--remote-time should be default
--remote-name-all could really use a short flag

Q: If you miss support for something, tell us what!
"Write the data to the file named in the URL (or in redirects if I'm feeling daring), and timestamp the file to the last-modified-date". This is the main reason I'm still using wget.
I can finally feel less bad about falling back to wget due to not remembering the parameters I want.

Idealization vs. reality I don't believe curl will ever change its default behavior in such a way that would accommodate this need, as that would have a side-effect of breaking things which expect the current behavior (the blast radius is literally the solar system). This means a new executable needs to be shipped side-by-side with curl, an opportunity to start fresh and work with a more focused use case (to download files). Ideally, this new executable would be maintained by the curl project, make use of libcurl under-the-hood, and be available everywhere. Nobody wants to worry if their systems have the tool or not, it should always be there. Given I'm just a Debian Developer, with not as much free time as I wish, I've decided to write a simple shell script wrapper calling the curl CLI under-the-hood. wcurl will come installed with the curl package from now on, and I will check with the release team about shipping it on the current Debian stable as well. Shipping wcurl in other distros will be up to them (Debian-derivatives should pick it up automatically, though). We've tried to make it easy for anyone to ship this by using the curl license, keeping the script POSIX-compliant, and shipping a manpage. Maybe if there's enough interest across distributions, someone might sign up for implementing this in upstream curl and increase its reach. I would be happy with the curl project reusing the wcurl name when that happens. It's unlikely that wcurl would be shipped by curl upstream as it is, assuming they would prefer a solution that uses libcurl direclty (more similar to curl the CLI, to maintain). In the worst case, wcurl becomes a Debian-specific tool that only a few people are aware of, in the best case, it becomes the new go-to CLI tool for simply downloading files. I would be happy if at least someone other than me finds it useful.

Naming is hard When I started working on it, I was calling the new executable "curld" (stands for "curl download"), but then when discussing this in one of our weekly calls in the Debian Bras lia community, it was mentioned that this could be confused for a daemon. We then settled for the name "wcurl", suggested by Carlos Henrique Lima Melara <charles>. It doesn't really stand for anything, but it's very easy to remember. You know... "it's that wget alternative for when you want to use curl instead" :)

Feedback I'm hosting the code on Github and Debian's GitLab instance, feel free to open an issue to provide feedback.
https://salsa.debian.org/debian/wcurl
https://github.com/Debian/wcurl We also have a Matrix room for the Debian curl maintainers:
https://matrix.to/#/#debian-curl-maintainers:matrix.org

Acknowledgments The idea for wcurl came a few days before the curl-up conference 2024. I've been thinking a lot about developer productivity in the terminal lately, different tools and better defaults. Before curl-up, I was also thinking about packaging improvements for the curl package. I don't remember what exactly happened, but I likely had to download something and felt a bit ashamed of maintaining curl and not remembering the parameters to download files the way I wanted. I first discussed this idea in the conference, where I asked the participants about it and there were no concerns raised, and some people said I should give it a go. Participating in curl-up was a really great experience and I'm thankful for the interactions I've had there. On the Debian side, I've got reviews of the code and manpage by Sergio Durigan Junior <sergiodj>, Guilherme Puida Moreira <puida> and Carlos Henrique Lima Melara <charles>. Sergio ended up rewriting the tool to be POSIX-compliant (my version was written in bash), so he takes all the credit for the portability.

Changes since publication

2024-07-18
  • Update date of availability for Debian testing and expected date for bookworm backports.
  • Mention charles as the person who suggested "wcurl" as a name.
  • Update wcurl's -o/--opts options, it's now just --curl-options.
  • Remove mention of language spoken in the Matrix room, we are using English now.
  • Update list of features of wcurl.

2 July 2024

Mike Gabriel: Polis - a FLOSS Tool for Civic Participation -- Introduction (episode 1/5)

This is the first article of a 5-episode blog post series written by Guido Berh rster, member of staff at my company Fre(i)e Software GmbH. Thanks, Guido for being on the Polis project. Enjoy the read on the work Guido has been doing over the past months,
Mike
A team lead by Raoul Kramer/BetaBreak is currently adapting Polis for evaluation and testing by several Dutch provincial governments and central government ministries. Guido Berh rster (author of this article) who is an employee at Fre(i)e Software GmbH has been involved in this project as the main software developer. This series of blog posts describes how and why Polis was initially modified and adapted, what issues the team ran into and how this ultimately lead them to start a new Open Source project called Particiapp for accelerating the development of alternative Polis frontends compatible to but independent from the upstream project. Table of Contents of the Blog Post Series
  1. Introduction (this article)
  2. Initial evaluation and adaptation
  3. Issues extending Polis and adjusting our goals
  4. Creating (a) new frontend(s) for Polis
  5. Current status and roadmap
Polis - The Introduction What is Polis? Polis is a platform for participation which helps to gather, analyze and understand viewpoints of large groups of participants on complex issues. In practical terms participants take part in conversations on a predefined topic by voting on statements or submitting their own statements (referred to as comments in Polis) for others to vote on1. Through statistical analysis including machine learning participants are sorted into groups based on similarities in voting behavior. In addition, group-informed and overall consensus statements are identified and presented to participants in real-time. This allows for participants to react to and refine statements and either individually or through a predefined process to come to an overall consensus. Furthermore, the order in which statements are presented to participants is influenced by a complex weighting system based on a number of factors such as variance, recency, and frequency of skipping. This so called comment routing is intended to facilitate a meaningful contribution of participants without requiring them to vote on each of a potentially huge number of statements 2. Polis open-ended nature sets it apart from online surveys using pre-defined questions and allows its users to gather a more accurate picture of the public opinion. In contrast to a discussion forum or comment section where participants directly reply to each other, it discourages unproductive behavior such as provocations or personal attacks by not presenting statements in chronological order in combination with voting. Finally, its comment routing is intended to provide scalability towards a large number of participants which generate a potentially large number of statements. The project was developed and is maintained by The Computational Democracy Project, a USA-based non-profit organization which provides a hosted version and offers related services. It is also released as Open Source software under the AGPL 3.0 license. Polis has been used in a variety of different contexts as part of broader political processes facilitating broader political participation and opinion-forming, and gathering feedback and creative input. Use of Polis in Taiwan One prominent use case of Polis is its adoption as part of the vTaiwan participatory governance project. Established by the g0v civic tech community in the wake of the 2014 mass protests by the Sunflower movement, the vTaiwan project enables consultations on proposed legislation among a broad range of stakeholders including government ministries, lawmakers, experts, interest groups, civil society as well as the broader public. Although the resulting recommendations are non-binding, they exert pressure on the government to take action and recommendations have been adopted into legislation.345 vTaiwan uses Polis for large-scale online deliberations as part of a structured participation process. These deliberations take place after identifying and involving stakeholders and experts and providing through information about the topic at hand to the public. Citizens are then given the opportunity to vote on statements or provide alternative proposals which allows for the refinement of ideas and ideally leads to a consensus at the end. The results of these online deliberations are then curated, discussed in publicly broadcast face-to-face meetings which ultimately produce concrete policy recommendations. vTaiwan has in numerous cases given impulses resulting in government action and provided significant input e.g. on legislation regulating Uber or technological experiments by Fintech startups.35 See also
  1. https://compdemocracy.org/Polis/
  2. https://compdemocracy.org/comment-routing/
  3. https://info.vtaiwan.tw/
  4. https://www.theguardian.com/world/2020/sep/27/taiwan-civic-hackers-polis-consensus-social-media-platform
  5. https://www.technologyreview.com/2018/08/21/240284/the-simple-but-ingenious-system-taiwan-uses-to-crowdsource-its-laws/

1 July 2024

Russell Coker: VoLTE in Australia

Introduction In Australia the 3G mobile frequencies are to be reused so they are in the process of shutting down the 3G service. That means that everyone has to use VoLTE (Voice Over LTE) for phone calls (including emergency calls). The shutdown time varies by telco, Kogan Mobile (one of the better services which has good value for money and generally works well) shut down their 3G service in January. Aldi Mobile (another one of the good services which is slightly more expensive but has included free calls to most first-world countries and uses the largest phone network) will shut theirs down at the end of August. For background there s a Fosdem talk about OpenSIPS with VoLTE and VoNR [1], it s more complex than you want to know. Also VoNR (Voice over New Radio) is the standard for 5G voice and it s different from VoLTE and has a fallback to VoLTE. Another good lecture for background information is the Fosdem talk on VoLTE at the handset end [2]. The PinePhonePro In October 2023 I tried using my PinePhonePro as my main phone but that only lasted a few days due to problems with calls and poor battery life [3]. Since then I went back to the Huawei Mate 10 Pro that I bought refurbished in June 2019 for $389. So that has been my main phone for 5 years now, giving a cost of $1.50 per week. I had tried using a Huawei Nova 7i running Android without Google Play as an experiment but that had failed, I do many things that need Android apps [4]. I followed the PinePhone wiki to get my PinePhonePro working with VoLTE [5]. That worked fine for me, the only difference from the instructions is that I had to use device /dev/ttyUSB3 and that the modem kept resetting itself during the process and when that happened I had to kill minicom and start again. After changing the setting and saving it the PinePhonePro seemed to work well with VoLTE on a Kogan Mobile SIM (so definitely not using 3G). One issue I have found is that Plasma Mobile (my preferred FOSS phone GUI) appears to have a library issue that results in polling every 14ms even when the screen is locked [6]. If you have a few processes doing that (which means the most lightly used Plasma system) it really hurts battery use. The maintainer has quite reasonably deferred action on this bug report given the KDE 6 transition. Later on in the Trixie development cycle I hope to get this issue resolved, I don t expect it to suddenly make battery life good. But it might make battery life acceptable. I am now idly considering carrying around my PinePhonePro in a powered off state for situations where I might need to do high security operations (root logins to servers or online banking) but for which carrying a laptop isn t convenient. It will do well for the turn on, do 30 mins of work that needs security, and then turn off scenario. Huawei Mate 10 Pro and Redmi 9A The Huawei Mate 10 Pro has been my main phone for 5 years and it has worked well, so it would be ideal if it could do VoLTE as the PinePhonePro isn t ready yet. All the web pages I ve seen about the Mate 10 Pro say that it will either allow upgrading to a VoLTE configuration if run with the right SIM or only support it with the right SIM. I did a test with a Chinese SIM which gave an option of turning on VoLTE but didn t allow any firmware updates and the VoLTE option went away when I put an Australian SIM in. Some forum comments had led me to believe that it would either permanently enable VoLTE or allow upgrading the firmware to one that enables VoLTE if I used a Chinese SIM but that is not the case. I didn t expect a high probability of success but I had to give it a go as it s a nice phone. I did some tests on a Redmi 9A (a terrible phone that has really bad latency on the UI in spite of having reasonably good hardware). The one I tested on didn t have VoLTE enabled when I got it, to test that I used the code *#*#4636#*#* in the dialler to get the menu of SIM information and it showed that VoLTE was not provisioned. I then had to update to the latest release of Android for that phone and enter *#*#86583#*#* in the dialler to enable VoLTE, the message displayed after entering that magic number must end in DISABLE . I get the impression that the code in question makes the phone not check certain aspects of whether the carrier is good for VoLTE and just do it. So apparently Kogan Mobile somehow gives the Redmi 9A the impression that VoLTE isn t supported but if the phone just goes ahead and connects it will work. I don t plan to use a Redmi 9A myself as it s too slow, but I added it to my collection to offer to anyone else I know who needs a phone with VoLTE and doesn t use the phone seriously or to someone who needs a known good phone for testing things. Samsung Galaxy Note 9 I got some Samsung Galaxy Note 9 phones to run Droidian as an experiment [7]. But Droidian dropped support for the Note 9 and I couldn t figure out how to enable VoLTE via Droidian, which was very annoying after I had spent $109 on a test phone and $215 on a phone for real use (I have no plans to try Droidian again at this time). I tried installing LineageOS on one Note 9 [8] which was much easier than expected (especially after previously installing Droidian). But VoLTE wasn t an option. According to Reddit LineageOS doesn t support VoLTE on Samsung devices and you can use a magisk module or a VoLTE enabler module but those aren t supported by LineageOS either [9]. I downloaded an original image for the Note 9 from SamsMobile.com [10]. That image booted past the orange stage (where if you have problems then your phone is probably permanently useless) but didn t boot into the OS. A friend helped me out with that and it turned out that the Heimdal flash tool on Linux didn t do something it needed to do and that Odin on Windows was required. After using Odin everything was fine and I have a Note 9 with VoLTE running the latest Samsung firmware which is security patch level 1st July 2022!!! So I have a choice between using a Note 9 for data and SMS while running a current version of Lineage OS with all security fixes or running a Samsung image with no security updates for 2 years which supports phone calls. So based on this I have to recommend Pixel as the phone of choice, it has a decent level of support from Google and long term support from LineageOS. According to the LineageOS web site you can run the current version of Lineage on the original Pixel phone from 2016! Of course getting VoLTE to work on it might be another saga, but it would probably be easier to do with LineageOS on a Pixel than on a Samsung phone. Conclusion The operation of the Note 9 for me is decent now apart from the potential security issues. The same goes for selling one of the phones. The PinePhonePro still has potential to become my daily driver at some future time if I and others can optimise power use. Also a complicating factor is that I want to have both Jabber and Matrix be actually instant IM systems not IM with a 5 minute delay, so suspend mode isn t a good option. Pixel phones will be a much higher priority when looking at phones to buy in future. The older Pixel phones go for as little as $100 on eBay and can still run the latest LineageOS. VoLTE seems needlessly complicated.

Niels Thykier: Debian packaging with style black

When I started working on the language server for debputy, one of several reasons was about automatic applying a formatting style. Such that you would not have to remember to manually reformat the file. One of the problems with supporting automatic formatting is that no one agrees on the "one true style". To make this concrete, Johannes Schauer Marin Rodrigues did the numbers of which wrap-and-sort option that are most common in https://bugs.debian.org/895570#46. Unsurprising, we end up with 14-15 different styles with various degrees of popularity. To make matters worse, wrap-and-sort does not provide a way to declare "this package uses options -sat". So that begged the question, how would debputy know which style it should use when it was going to reformat file. After a couple of false-starts, Christian Hofstaedtler mentioned that we could just have a field in debian/control for supporting a "per-package" setting in responds to my concern about adding a new "per-package" config file. At first, I was not happy with it, because how would you specify all of these options in a field (in a decent manner)? But then I realized that one I do not want all these styles and that I could start simpler. The Python code formatter black is quite successful despite not having a lot of personalized style options. In fact, black makes a statement out of not allowing a lot of different styles. Combing that, the result was X-Style: black (to be added to the Source stanza of debian/control), which every possible reference to the black tool for how styling would work. Namely, you outsource the style management to the tool (debputy) and then start using your focus on something else than discussing styles. As with black, this packaging formatting style is going to be opinionated and it will evolve over time. At the starting point, it is similar to wrap-and-sort -sat for the deb822 files (debputy does not reformat other files at the moment). But as mentioned, it will likely evolve and possible diverge from wrap-and-sort over time. The choice of the starting point was based on the numbers posted by Johannes #895570. It was not my personal favorite but it seemed to have a majority and is also close to the one suggested by salsa pipeline maintainers. The delta being -kb which I had originally but removed in 0.1.34 at request of Otto Kek l inen after reviewing the numbers from Johannes one more time. To facilitate this new change, I uploaded debputy/0.1.30 (a while back) to Debian unstable with the following changes:
  • Support for the X-Style: black header.
  • When a style is defined, the debputy lsp server command will now automatically reformat deb822 files on save (if the editor supports it) or on explicit "reformat file" request from the editor (usually indirectly from the user).
  • New subcommand debputy reformat command that will reformat the files, when a style is defined.
  • A new pre-commit hook repo to run debputy lint and debputy reformat. These hooks are available from https://salsa.debian.org/debian/debputy-pre-commit-hooks version v0.1 and can be used with the pre-commit tool (from the package of same name).
The obvious omission is a salsa-pipeline feature for this. Otto has put that on to his personal todo list and I am looking forward to that.
Beyond black Another thing I dislike about our existing style tooling is that if you run wrap-and-sort without any arguments, you have a higher probability of "trashing" the style of the current package than getting the desired result. Part of this is because wrap-and-sort's defaults are out of sync with the usage (which is basically what https://bugs.debian.org/895570 is about). But I see another problem. The wrap-and-sort tool explicitly defined options to tweak the style but provided maintainers no way to record their preference in any machine readable way. The net result is that we have tons of diverging styles and that you (as a user of wrap-and-sort) have to manually tell wrap-and-sort which style you want every time you run the tool. In my opinion that is not playing to the strengths of neither human nor machine. Rather, it is playing to the weaknesses of the human if anything at all. But the salsa-CI pipeline people also ran into this issue and decided to work around this deficiency. To use wrap-and-sort in the salsa-CI pipeline, you have to set a variable to activate the job and another variable with the actual options you want. The salsa-CI pipeline is quite machine readable and wrap-and-sort is widely used. I had debputy reformat also check for the salsa-CI variables as a fallback. This fallback also works for the editor mode (debputy lsp server), so you might not even have to run debputy reformat. :) This was a deliberate trade-off. While I do not want all us to have all these options, I also want Debian packaging to be less painful and have fewer paper cuts. Having debputy go extra lengths to meet wrap-and-sort users where they are came out as the better solution for me. A nice side-effect of this trade-off is that debputy reformat now a good tool for drive-by contributors. You can safely run debputy reformat on any package and either it will apply the styling or it will back out and inform you that no obvious style was detected. In the latter case, you would have to fallback to manually deducing the style and applying it.
Differences to wrap-and-sort The debputy reformat has some limitations or known differences to wrap-and-sort. Notably, debputy reformat (nor debputy lsp server) will not invoke wrap-and-sort. Instead, debputy has its own reformatting engine that provides similar features. One reason for not running wrap-and-sort is that I want debputy reformat to match the style that debputy lsp server will give you. That way, you get consistent style across all debputy commands. Another reason is that it is important to me that reformatting is safe and does not change semantics. This leads to two regrettable known differences to the wrap-and-sort behavior due to safety in addition to one scope limitation in debputy:
  1. debputy will ignore requests to sort the stanzas when the "keep first" option is disabled (-b --no-keep-first). This combination is unsafe reformatting. I feel it was a mistake for wrap-and-sort to ever allow this but at least it is no longer the default (-b is now -bk by default). This will be less of a problem in debhelper-compat 15, since the concept of "main package" will disappear and all multi-binary source packages will be required to use debian/package.install rather than debian/install.
  2. debputy will not reorder the contents of debhelper packaging files such as debian/install. This is also an (theoretical) unsafe thing to do. While the average package will not experience issues with this, there are rare corner cases where the re-ordering can affect the end result. I happen to know this, because I ran into issues when trying to optimize dh_install in a way that assumed the order did not matter. Stuff broke and there is now special-case code in dh_install to back out of that optimization when that happens.
  3. debputy has a limited list of wrap-and-sort options it understands. Some options may cause debputy to back out and disable reformatting entirely with a remark that it cannot apply that style. If you run into a case of this, feel free to file a feature request to support it. I will not promise to support everything, but if it is safe and trivially doable with the engine already, then I probably will.
As stated, where debputy cannot implement the wrap-and-sort styles fully, then it will currently implement a subset that is safe if that can be identified or back out entirely of the formatting when it cannot. In all cases, debputy will not break the formatting if it is correct. It may just fail at correcting one aspect of the wrap-and-sort style if you happen to get it wrong. It is also important to remember that the prerequisite for debputy applying any wrap-and-sort style is that you have set the salsa-CI pipeline variables to trigger wrap-and-sort with the salsa-CI pipeline. So there is still a CI check before the merge that will run the wrap-and-sort in its full glory that provides the final safety net for you.
Just give me a style In conclusion, if you, like me, are more interested in getting a consistent style rather than discussing what that style should be, now you can get that with X-Style: black. You can also have your custom wrap-and-sort style be picked up automatically for drive-by contributors.
$ apt satisfy 'dh-debputy (>= 0.1.30), python3-lsprotocol'
# Add  X-Style: black  to  debian/control  for "just give me a style"
#
# OR, if there is a specific  wrap-and-sort  style for you then set
# SALSA_CI_DISABLE_WRAP_AND_SORT=no plus set relevant options in
# SALSA_CI_WRAP_AND_SORT_ARGS in debian/salsa-ci.yml (or .gitlab-ci.yml)
$ debputy reformat
It is sadly not yet in the salsa-ci pipeline. Otto is looking into that and hopefully we will have it soon. :) And if you find yourself often doing archive-wide contributions and is tired of having to reverse engineer package formatting styles, consider using debputy reformat or debputy lsp server. If you use debputy in this way, please consider providing feedback on what would help you.

Abhijith PA: A lazy local file sharing setup

At home, I have both a laptop and a *desktop PC. Most of my essential things, such as emails, repositories, password managers, contacts, and calendars are synced between the two devices. However, when I need to share some documents and I am lazy enough to go pick a flash drive, my only option is to push them to the Internet and download them on the other system, which is sitting at 20~ meters away. Typically, I do this either through email attachments or a matrix client. Occasionally, I think about setting up a network storage solution at home. But then I ask myself do I really need one. In my home network, I already have a Raspberry Pi running as my Wi-Fi router, doing DNS level ad blocking with Dnsmasq and DNS over TLS with stubby. Rpi has a 16GB memory card. I can mount RPi remote directory to both machines. I use pcmanfm as my file manager. It has the ability (like every other file managers) to mount remote storage over ssh. But one annoying thing is that whenever I open the mount directory, by default it shows the root file system of the remote device even when I explicitly mentioned the path. Then I discovered sshfs. I wrote the following script, which mount remote directory and open that in pcmanfm.
#!/bin/bash
LOCMOUNT="/home/user/Public"
sshfs raspberrypi:Public $LOCMOUNT
pcmanfm $MOUNT
I haven t enabled any encryption for the memory until now since other than some logs RPi wasn t writing anything to it. I set up fscrypt on Rpi storage now. And ta-da, a lazy person s local sharing solution. *Desktop - Well, technically it s an old laptop with a broken keyboard and trackpad, connected to a monitor, keyboard and mouse. I don t feel keeping it on a shelf.

30 June 2024

Joachim Breitner: Do surprises get larger?

The setup Imagine you are living on a riverbank. Every now and then, the river swells and you have high water. The first few times this may come as a surprise, but soon you learn that such floods are a recurring occurrence at that river, and you make suitable preparation. Let s say you feel well-prepared against any flood that is no higher than the highest one observed so far. The more floods you have seen, the higher that mark is, and the better prepared you are. But of course, eventually a higher flood will occur that surprises you. Of course such new record floods are happening rarer and rarer as you have seen more of them. I was wondering though: By how much do the new records exceed the previous high mark? Does this excess decrease or increase over time? A priori both could be. When the high mark is already rather high, maybe new record floods will just barley pass that mark? Or maybe, simply because new records are so rare events, when they do occur, they can be surprisingly bad? This post is a leisurely mathematical investigating of this question, which of course isn t restricted to high waters; it could be anything that produces a measurement repeatedly and (mostly) independently weather events, sport results, dice rolls. The answer of course depends on the distribution of results: How likely is each possible results.

Dice are simple With dice rolls the answer is rather simple. Let our measurement be how often you can roll a die until it shows a 6. This simple game we can repeat many times, and keep track of our record. Let s say the record happens to be 7 rolls. If in the next run we roll the die 7 times, and it still does not show a 6, then we know that we have broken the record, and every further roll increases by how much we beat the old record. But note that how often we will now roll the die is completely independent of what happened before! So for this game the answer is: The excess with which the record is broken is always the same. Mathematically speaking this is because the distribution of rolls until the die shows a 6 is memoryless. Such distributions are rather special, its essentially just the example we gave (a geometric distribution), or its continuous analogue (the exponential distributions, for example the time until a radioactive particle decays).

Mathematical formulation With this out of the way, let us look at some other distributions, and for that, introduce some mathematical notations. Let X be a random variable with probability density function (x) and cumulative distribution function (x), and a be the previous record. We are interested in the behavior of Y(a) = X a X > x i.e. by how much X exceeds a under the condition that it did exceed a. How does Y change as a increases? In particular, how does the expected value of the excess e(a) = E(Y(a)) change?

Uniform distribution If X is uniformly distributed between, say, 0 and 1, then a new record will appear uniformly distributed between a and 1, and as that range gets smaller, the excess must get smaller as well. More precisely, e(a) = E(X a X > a) = E(X X > a) a = (1 a)/2 This not very interesting linear line is plotted in blue in this diagram:
The expected record surpass for the uniform distribution The expected record surpass for the uniform distribution
The orange line with the logarithmic scale on the right tries to convey how unlikely it is to surpass the record value a: it shows how many attempts we expect before the record is broken. This can be calculated by n(a) = 1/(1 (a)).

Normal distribution For the normal distribution (with median 0 and standard derivation 1, to keep things simple), we can look up the expected value of the one-sided truncated normal distribution and obtain e(a) = E(X X > a) a = (a)/(1 (a)) a Now is this growing or shrinking? We can plot this an have a quick look:
The expected record surpass for the normal distribution The expected record surpass for the normal distribution
Indeed it is, too, a decreasing function! (As a sanity check we can see that e(0) = (2/ ), which is the expected value of the half-normal distribution, as it should.)

Could it be any different? This settles my question: It seems that each new surprisingly high water will tend to be less surprising than the previously assuming high waters were uniformly or normally distributed, which is unlikely to be helpful. This does raise the question, though, if there are probability distributions for which e(a) is be increasing? I can try to construct one, and because it s a bit easier, I ll consider a discrete distribution on the positive natural numbers, and consider at g(0) = E(X) and g(1) = E(X 1 X > 1). What does it take for g(1) > g(0)? Using E(X) = p + (1 p)E(X X > 1) for p = P(X = 1) we find that in order to have g(1) > g(0), we need E(X) > 1/p. This is plausible because we get equality when E(X) = 1/p, as it precisely the case for the geometric distribution. And it is also plausible that it helps if p is large (so that the next first record is likely just 1) and if, nevertheless, E(X) is large (so that if we do get an outcome other than 1, it s much larger). Starting with the geometric distribution, where P(X > n X n) = pn = p (the probability of again not rolling a six) is constant, it seems that these pn is increasing, we get the desired behavior. So let p1 < p2 < pn < be an increasing sequence of probabilities, and define X so that P(X = n) = p1 pn 1 (1 pn) (imagine the die wears off and the more often you roll it, the less likely it shows a 6). Then for this variation of the game, every new record tends to exceed the previous more than previous records. As the p increase, we get a flatter long end in the probability distribution.

Gamma distribution To get a nice plot, I ll take the intuition from this and turn to continuous distributions. The Wikipedia page for the exponential distribution says it is a special case of the gamma distribution, which has an additional shape parameter , and it seems that it could influence the shape of the distribution to be and make the probability distribution have a longer end. Let s play around with = 2 and = 0.5, 1 and 1.5:
The expected record surpass for the gamma distribution The expected record surpass for the gamma distribution
  • For = 1 (dotted) this should just be the exponential distribution, and we see that e(a) is flat, as predicted earlier.
  • For larger (dashed) the graph does not look much different from the one for the normal distribution not a surprise, as for , the gamma distribution turns into the normal distribution.
  • For smaller (solid) we get the desired effect: e(a) is increasing. This means that new records tend to break records more impressively.
The orange line shows that this comes at a cost: for a given old record a, new records are harder to come by with smaller .

Conclusion As usual, it all depends on the distribution. Otherwise, not much, it s late.

29 June 2024

Russ Allbery: Review: Bitter Angels

Review: Bitter Angels, by C.L. Anderson
Publisher: Ballantine Books
Copyright: 2009
ISBN: 0-553-59217-3
Format: Mass market
Pages: 438
Bitter Angels is a stand-alone science fiction novel. It won the Philip K. Dick award for best SF original paperback in 2010. C.L. Anderson is a pen name for Sarah Zettel. Terese was a Guardian, one of the agents of the Pax Solaris who find ways to keep the peace in troubled systems and high-stress situations with the help of an implanted Companion, an assistant AI. Forty years ago, on one of those missions, she was captured and her Companion was forcibly removed. She was rescued by her friend and mentor and retired afterwards, starting a new life and a new family, trying to leave the memories behind. Now, the woman who rescued her is dead. She was murdered on duty in the Erasmus system, a corporate hellhole that appears to be on the verge of exploding into a political hot spot. Bianca's last instructions asked for Terese to replace her. Terese's family is furious at her for even considering returning to the Guardians, but she can't say no. Duty, and Bianca's dying request, call too strongly. Amerand is Security on Dazzle, one of the Erasmus stations. He is one of the refugees from Oblivion, the station that the First Bloods who rule the system let die. He keeps his head above water and tries to protect his father and find his mother without doing anything that the ever-present Clerks might find concerning. Keeping an eye on newly-arriving Solaris saints is a typical assignment, since the First Bloods don't trust the meddling do-gooders. But something is not quite right, and a cryptic warning from his Clerk makes him even more suspicious. This is the second book by Sarah Zettel that I've read, and both of them have been tense, claustrophobic thrillers set in a world with harsh social inequality and little space for the characters to maneuver. In this case, the structure of her future universe reminded me a bit of Iain M. Banks's Culture, but with less advanced technology and only humans. The Pax Solaris has eliminated war within its borders and greatly extended lifespans. That peace is maintained by Guardians, who play a role similar to Special Circumstances but a bit more idealist and less lethal. They show up where there are problems and meddle, manipulating and pushing to try to defuse the problems before they reach the Pax Solaris. Like a Culture novel, nearly all of the action takes place outside the Pax Solaris in the Erasmus system. Erasmus is a corporate colony that has turned into a cross between a hereditary dictatorship and the Corporate Rim from Martha Wells's Murderbot series. Debt slavery is ubiquitous, economic inequality is inconceivably vast, and the Clerks are everywhere. Erasmus natives like Amerand have very little leeway and even fewer options. Survival is a matter of not drawing the attention of the wrong people. Terese and her fellow Guardians are appalled, but also keenly aware that destabilizing the local politics may make the situation even worse and get a lot of people killed. Bitter Angels is structured like a mystery: who killed Bianca, and what was her plan when she was killed? Unlike a lot of books of this type, the villains are not idiots and their plan is both satisfyingly complex and still depressingly relevant. I don't think I'm giving anything away by saying that I have read recent news articles about people with very similar plans, albeit involving less science-fiction technology. Anderson starts with a tense situation and increases the pressure relentlessly, leaving the heroes one step behind the villains for almost the entire novel. It is not happy or optimistic reading at times, the book is quite dark but it certainly was engrossing. The one world-building quibble that I had is that the Erasmus system is portrayed partly as a hydraulic empire, and while this is arguably feasible given that spaceship travel is strictly controlled, it seemed like a weird choice given the prevalence of water on the nearby moons. Water smuggling plays a significant role in the plot, and I wasn't entirely convinced of the politics and logistics behind it. If this sort of thing bugs you, there are some pieces that may require suspension of disbelief. Bitter Angels is the sort of tense thriller where catastrophe is barely avoided and the cost of victory is too high, so you will want to be in the mood for that before you dive in. But if that's what you're looking for, I thought Anderson delivered a complex and satisfying story. Content warning: major character suicide. Rating: 7 out of 10

24 June 2024

Dirk Eddelbuettel: x13binary 1.1.61 on CRAN: Maintenance

The x13binary team is thrilled to share the availability of Release 1.1.61 of the x13binary package providing the X-13ARIMA-SEATS program by the US Census Bureau which arrived on CRAN earlier today. This release brings two updates suggested by the tireless CRAN maintainers. Kurt Hornik suggested to now also ignore stderr when calling the x13 binary via system: it appears that builds under the new-ish and clang-based flang-new now emit on stderr even if Fortran-based binaries did not before. So we adjust. And Brian Ripley pointed out that our Makefile for creating the x13 binary was not quite as is should be, which we adjusted. And I just realized I should have named this 1.1.60-2 to follow the upstream convention but didn t. Next time. Courtesy of my CRANberries, there is also a diffstat report for this release showing changes to the previous release. If you like this or other open-source work I do, you can sponsor me at GitHub.

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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