Search Results: "andrew"

11 September 2022

Andrew Cater: 202209110020 - Debian release day(s) - Cambridge - post 4

RattusRattus, Isy, smcv have all just left after a very long day. Steve is finishing up the final stages. The mayhem has quietened, the network cables are coiled, pretty much everything is tidied away. A new experience for two of us - I just hope it hasn't put them off too much.The IRC channels are quiet and we can put this one to bed after a good day's work well done.

10 September 2022

Andrew Cater: 202209102213 - Debian release day - Cambridge - post 3

Working a bit more slowly - coming to the end of the process. I've been wrestling with a couple of annoying old laptops and creating mayhem. The others are almost through the process - it's been a very long day, almost 12 hours now.As ever, it's good to be with people who appreciate this work - I'm also being menaced by a dog that wants fuss all the time. It certainly makes a difference to have fast connectivity and even faster remarks backwards and forwards.

Andrew Cater: 202209101602 Debian release day - Cambridge - post 2

Definitely settling into a rhythm - we've been joined by smcv in person (and bittin on line). Bullseye testing is now well beyond the standard image testing into the live images.Buster images are gradually being built so there's the added confusion of two sets of wiki editing, two sets of potential edit conflicts ...So six people in a small-ish sitting room, several with multiple laptops running several checks at once. It's all good, as ever.Dining room table has nine machines on it, three packet switches are fairly well full ...

Andrew Cater: 202209101115 Debian release day - Cambridge - Bullseye and Buster testing starting

And I'm over here with the Debian images/media release team in Cambridge.First time together in Cambridge for a long time: several of the usual suspects - RattusRattus, Sledge, Isy and myself. Also in the room are Kartik and egw - I think this is their first time.Chat is now physically in Sledge's sitting room as well as on IRC. The first couple of images are trickling in and tests are starting for Bullseye.
This is going to be a very long day - we've got full tests for Bullseye (Debian 11) and Buster (Debian 10) so double duty. This should be the last release for Buster since this has now passed to LTS.

28 August 2022

Andrew Cater: Debian Barbeque, Cambridge 2022

And here we are: second day of the barbeque in Cambridge. Lots of food - as always - some alcohol, some soft drinks, coffee.Lots of good friends, and banter and good natured argument. For a couple of folk, it's their first time here - but most people have known each other for years. Lots of reminiscing, some crochet from two of us. Multiple technical discussions weaving and overlapping
Not just meat and vegetarian options for food: a fresh loaf, gingerbread of various sorts, fresh Belgian-style waffles.I''m in the front room: four of us silently on laptops, one on a phone. Sounds of a loud game of Mao from the garden - all very normal for this time of year.Thanks to Jo and Steve, to all the cooks and folk sorting things out. One more night and I'll have done my first full BBQ here. Diet and slimming - what diet?

9 July 2022

Andrew Cater: 20220709 2100 UTC - Finished Debian media testing for the day

I've just finished my last test: Sledge is finishing his and will then push the release out. Today's been a bit slow and steady - but we've finally got there.Thanks, as ever, due to the release team for actually giving us an update, the press team for announcements - and, of course, the various sponsors, administrators and maintainers of Debian infrastructure like and the CD building machines.It's been a quiet release for the media team in terms of participation - we've not had our usual tester for debian-edu and it's been a bit subdued altogether.Not even as many blog posts as usual: I suppose I'll make up for it in August at the BBQ in Cambridge - if we don't all get another lockdown / COVID-19 variants / fuel prices at per litre to dissuade us.

Andrew Cater: Testing 11.4 Debian media images - almost finished - 20220709 1933 UTC

We're flagging a bit now, I think but close to the end. The standard Debian images caused no problems: Sledge and I are just finishing up the last few live images to test now.Thanks, as ever, to the crew: RattusRattus and Isy, Sledge struggling through feeling awful. No debian-edu testing today, unfortunately, but that almost never breaks anyway.Everyone's getting geared up for Kosovo - you'll see the other three there with any luck - and you'd catch all of us at the BBQ in Cambridge. It's going to be a hugely busy month and a bit for Steve and the others. :)

Andrew Cater: As has become traditional - blogging as part of the media release for Debian 11.4 - 202207091436 UTC

A lower profile release today: Sledge working in the background as affected by COVID. RattusRattus and Isy doing sterling service on the other side of Cambridge, /me over here.Testing on the standard install media is pretty much done: Isy, Andy and Sledge have moved on to testing the live images.Stupidly hot for UK - it's 28 degrees indoors with windows open.All good so far :)

6 June 2022

Reproducible Builds: Reproducible Builds in May 2022

Welcome to the May 2022 report from the Reproducible Builds project. In our reports we outline the most important things that we have been up to over the past month. As ever, if you are interested in contributing to the project, please visit our Contribute page on our website.

Repfix paper Zhilei Ren, Shiwei Sun, Jifeng Xuan, Xiaochen Li, Zhide Zhou and He Jiang have published an academic paper titled Automated Patching for Unreproducible Builds:
[..] fixing unreproducible build issues poses a set of challenges [..], among which we consider the localization granularity and the historical knowledge utilization as the most significant ones. To tackle these challenges, we propose a novel approach [called] RepFix that combines tracing-based fine-grained localization with history-based patch generation mechanisms.
The paper (PDF, 3.5MB) uses the Debian mylvmbackup package as an example to show how RepFix can automatically generate patches to make software build reproducibly. As it happens, Reiner Herrmann submitted a patch for the mylvmbackup package which has remained unapplied by the Debian package maintainer for over seven years, thus this paper inadvertently underscores that achieving reproducible builds will require both technical and social solutions.

Python variables Johannes Schauer discovered a fascinating bug where simply naming your Python variable _m led to unreproducible .pyc files. In particular, the types module in Python 3.10 requires the following patch to make it reproducible:
--- a/Lib/
+++ b/Lib/
@@ -37,8 +37,8 @@ _ag = _ag()
 AsyncGeneratorType = type(_ag)
 class _C:
-    def _m(self): pass
-MethodType = type(_C()._m)
+    def _b(self): pass
+MethodType = type(_C()._b)
Simply renaming the dummy method from _m to _b was enough to workaround the problem. Johannes bug report first led to a number of improvements in diffoscope to aid in dissecting .pyc files, but upstream identified this as caused by an issue surrounding interned strings and is being tracked in CPython bug #78274.

New SPDX team to incorporate build metadata in Software Bill of Materials SPDX, the open standard for Software Bill of Materials (SBOM), is continuously developed by a number of teams and committees. However, SPDX has welcomed a new addition; a team dedicated to enhancing metadata about software builds, complementing reproducible builds in creating a more secure software supply chain. The SPDX Builds Team has been working throughout May to define the universal primitives shared by all build systems, including the who, what, where and how of builds:
  • Who: the identity of the person or organisation that controls the build infrastructure.
  • What: the inputs and outputs of a given build, combining metadata about the build s configuration with an SBOM describing source code and dependencies.
  • Where: the software packages making up the build system, from build orchestration tools such as Woodpecker CI and Tekton to language-specific tools.
  • How: the invocation of a build, linking metadata of a build to the identity of the person or automation tool that initiated it.
The SPDX Builds Team expects to have a usable data model by September, ready for inclusion in the SPDX 3.0 standard. The team welcomes new contributors, inviting those interested in joining to introduce themselves on the SPDX-Tech mailing list.

Talks at Debian Reunion Hamburg Some of the Reproducible Builds team (Holger Levsen, Mattia Rizzolo, Roland Clobus, Philip Rinn, etc.) met in real life at the Debian Reunion Hamburg (official homepage). There were several informal discussions amongst them, as well as two talks related to reproducible builds. First, Holger Levsen gave a talk on the status of Reproducible Builds for bullseye and bookworm and beyond (WebM, 210MB): Secondly, Roland Clobus gave a talk called Reproducible builds as applied to non-compiler output (WebM, 115MB):

Supply-chain security attacks This was another bumper month for supply-chain attacks in package repositories. Early in the month, Lance R. Vick noticed that the maintainer of the NPM foreach package let their personal email domain expire, so they bought it and now controls foreach on NPM and the 36,826 projects that depend on it . Shortly afterwards, Drew DeVault published a related blog post titled When will we learn? that offers a brief timeline of major incidents in this area and, not uncontroversially, suggests that the correct way to ship packages is with your distribution s package manager .

Bootstrapping Bootstrapping is a process for building software tools progressively from a primitive compiler tool and source language up to a full Linux development environment with GCC, etc. This is important given the amount of trust we put in existing compiler binaries. This month, a bootstrappable mini-kernel was announced. Called boot2now, it comprises a series of compilers in the form of bootable machine images.

Google s new Assured Open Source Software service Google Cloud (the division responsible for the Google Compute Engine) announced a new Assured Open Source Software service. Noting the considerable 650% year-over-year increase in cyberattacks aimed at open source suppliers, the new service claims to enable enterprise and public sector users of open source software to easily incorporate the same OSS packages that Google uses into their own developer workflows . The announcement goes on to enumerate that packages curated by the new service would be:
  • Regularly scanned, analyzed, and fuzz-tested for vulnerabilities.
  • Have corresponding enriched metadata incorporating Container/Artifact Analysis data.
  • Are built with Cloud Build including evidence of verifiable SLSA-compliance
  • Are verifiably signed by Google.
  • Are distributed from an Artifact Registry secured and protected by Google.
(Full announcement)

A retrospective on the Rust programming language Andrew bunnie Huang published a long blog post this month promising a critical retrospective on the Rust programming language. Amongst many acute observations about the evolution of the language s syntax (etc.), the post beings to critique the languages approach to supply chain security ( Rust Has A Limited View of Supply Chain Security ) and reproducibility ( You Can t Reproduce Someone Else s Rust Build ):
There s some bugs open with the Rust maintainers to address reproducible builds, but with the number of issues they have to deal with in the language, I am not optimistic that this problem will be resolved anytime soon. Assuming the only driver of the unreproducibility is the inclusion of OS paths in the binary, one fix to this would be to re-configure our build system to run in some sort of a chroot environment or a virtual machine that fixes the paths in a way that almost anyone else could reproduce. I say almost anyone else because this fix would be OS-dependent, so we d be able to get reproducible builds under, for example, Linux, but it would not help Windows users where chroot environments are not a thing.
(Full post)

Reproducible Builds IRC meeting The minutes and logs from our May 2022 IRC meeting have been published. In case you missed this one, our next IRC meeting will take place on Tuesday 28th June at 15:00 UTC on #reproducible-builds on the OFTC network.

A new tool to improve supply-chain security in Arch Linux kpcyrd published yet another interesting tool related to reproducibility. Writing about the tool in a recent blog post, kpcyrd mentions that although many PKGBUILDs provide authentication in the context of signed Git tags (i.e. the ability to verify the Git tag was signed by one of the two trusted keys ), they do not support pinning, ie. that upstream could create a new signed Git tag with an identical name, and arbitrarily change the source code without the [maintainer] noticing . Conversely, other PKGBUILDs support pinning but not authentication. The new tool, auth-tarball-from-git, fixes both problems, as nearly outlined in kpcyrd s original blog post.

diffoscope diffoscope is our in-depth and content-aware diff utility. Not only can it locate and diagnose reproducibility issues, it can provide human-readable diffs from many kinds of binary formats. This month, Chris Lamb prepared and uploaded versions 212, 213 and 214 to Debian unstable. Chris also made the following changes:
  • New features:
    • Add support for extracting vmlinuz Linux kernel images. [ ]
    • Support both python-argcomplete 1.x and 2.x. [ ]
    • Strip sticky etc. from x.deb: sticky Debian binary package [ ]. [ ]
    • Integrate test coverage with GitLab s concept of artifacts. [ ][ ][ ]
  • Bug fixes:
    • Don t mask differences in .zip or .jar central directory extra fields. [ ]
    • Don t show a binary comparison of .zip or .jar files if we have observed at least one nested difference. [ ]
  • Codebase improvements:
    • Substantially update comment for our calls to zipinfo and zipinfo -v. [ ]
    • Use assert_diff in test_zip over calling get_data with a separate assert. [ ]
    • Don t call re.compile and then call .sub on the result; just call re.sub directly. [ ]
    • Clarify the comment around the difference between --usage and --help. [ ]
  • Testsuite improvements:
    • Test --help and --usage. [ ]
    • Test that --help includes the file formats. [ ]
Vagrant Cascadian added an external tool reference xb-tool for GNU Guix [ ] as well as updated the diffoscope package in GNU Guix itself [ ][ ][ ].

Distribution work In Debian, 41 reviews of Debian packages were added, 85 were updated and 13 were removed this month adding to our knowledge about identified issues. A number of issue types have been updated, including adding a new nondeterministic_ordering_in_deprecated_items_collected_by_doxygen toolchain issue [ ] as well as ones for mono_mastersummary_xml_files_inherit_filesystem_ordering [ ], extended_attributes_in_jar_file_created_without_manifest [ ] and apxs_captures_build_path [ ]. Vagrant Cascadian performed a rough check of the reproducibility of core package sets in GNU Guix, and in openSUSE, Bernhard M. Wiedemann posted his usual monthly reproducible builds status report.

Upstream patches The Reproducible Builds project detects, dissects and attempts to fix as many currently-unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of such patches, including:

Reproducible builds website Chris Lamb updated the main Reproducible Builds website and documentation in a number of small ways, but also prepared and published an interview with Jan Nieuwenhuizen about Bootstrappable Builds, GNU Mes and GNU Guix. [ ][ ][ ][ ] In addition, Tim Jones added a link to the Talos Linux project [ ] and billchenchina fixed a dead link [ ].

Testing framework The Reproducible Builds project runs a significant testing framework at, to check packages and other artifacts for reproducibility. This month, the following changes were made:
  • Holger Levsen:
    • Add support for detecting running kernels that require attention. [ ]
    • Temporarily configure a host to support performing Debian builds for packages that lack .buildinfo files. [ ]
    • Update generated webpages to clarify wishes for feedback. [ ]
    • Update copyright years on various scripts. [ ]
  • Mattia Rizzolo:
    • Provide a facility so that Debian Live image generation can copy a file remotely. [ ][ ][ ][ ]
  • Roland Clobus:
    • Add initial support for testing generated images with OpenQA. [ ]
And finally, as usual, node maintenance was also performed by Holger Levsen [ ][ ].

Misc news On our mailing list this month:

Contact 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:

27 March 2022

Andrew Cater: Imminent release for the media images for Debian 10.12 and 11.3 20220327 0010

OK - so it wasn't quite all done in one day - and since today is TZ change day in the UK, it might actually run into the TZ bump but I suspect that it will all be done very soon now. Very few glitches - everybody cheerful with what's been done.I did spot someone in IRC who had been reading the release notes - which is always much appreciated. Lots of security fixes overall in the last couple of months but just a fairly normal time, I think.Thanks to the team behind all of this: the ftpmasters, the press team and everyone else involved in making Debian more secure. This is the last blog for this one - there will be another point release along in about three months or so.

26 March 2022

Andrew Cater: Part way through testing Debian media images 20220326 1555UTC - Found a new useful utility

For various obscure reasons, I have a mirror of Debian in one room and the main laptop and so on I use in another. The mirror is connected to a fast Internet line - and has a 1Gb Ethernet cable into the back directly from the router, the laptop and everything else - not so much, everything is wired, but depends on a WiFi link across the property. One end is fast - one end runs like a snail.Steve suggested I use a different tool to make images directly on the mirror machine - jigit. Slightly less polished than jigdo but - if you're on the same machine - blazingly fast. I just used it to make the Blu-Ray sized .iso and was very pleasantly surprised. jigit-mkimage -j [jigdo file] -t [template file] -m Debian=[path to mirror of Debian] -o [output filename]
Another nice surprise for me - I have a horrible old Lenovo Ideapad. It's one of the Bay Trail Intel machines with a 32 bit UEFI and a 64 bit processor. I rescued it from the junk heap. Reinstalling it with an image today fixed an issue I had with slow boot and has turned it into an adequate machine for web browsing.All in all, I've done relatively few tests so far - but it's been a good day, as ever.More later.

Andrew Cater: Debian media team - testing and releasing Debian 11.3 - 20220326 1243UTC

And back to relative normality : the usual suspects are in Cambridge. It's a glorious day across the UK and we're spending it indoors with laptops :)We'll also be releasing a point release of Buster as a wrap up of recent changes.Debian 10 should move from full support to LTS on July August 14th - one year after the release of Debian 11 - and there will be a final point release of Buster somewhere around that point.
All seems to be behaving itself well.Thanks to all for the hard work that goes into preparing each release and especially the security fixes of which there seem to be loads lately.

Andrew Cater: Still testing Debian media images 20220326 2026UTC- almost finished 11.3 - Buster starting soon

And we're working through quite nicely.
It's been a long, long day so far and we're about 1/2 way through :)
Shout out to Isy, Sledge and RattusRattus in Cambridge and also smcv.Two releases in a day is a whole bunch :)

13 January 2022

Bits from Debian: New Debian Developers and Maintainers (November and December 2021)

The following contributors got their Debian Developer accounts in the last two months: The following contributors were added as Debian Maintainers in the last two months: Congratulations!

18 December 2021

Andrew Cater: Debian media team - testing and releasing Debian 11.2 20211218 2030

We've more or less finished the release of the Debian CD/DVD/Blu-Ray and other media for Bullseye 11.2 release. This is one of the (roughly) quarterly point releases and roll-up releases.Thanks firstly to the developers, users, helpers, bug filers who help to keep Debian moving and working and to the release team and press team who more or less finish their job before the media team start theirs.
Thanks to Sledge and RattusRattus and Isy in Cambridge and to Schweer who single-handedly clears all the Debian-edu testing. This release run seemed to be a bit more slick, a bit faster, a few fewer problems and it's always a joy to work with colleagues who are like family.The last couple of years have been more than a bit difficult: this (should) be more or less the last major action from the release team and others for 2021.I'm going to take the opportunity this gives me to wish all concerned with Debian (and every other Linux) the very best wishes for the year to come. Surely, it can only get better - eventually.

13 September 2021

Bits from Debian: New Debian Developers and Maintainers (July and August 2021)

The following contributors got their Debian Developer accounts in the last two months: The following contributors were added as Debian Maintainers in the last two months: Congratulations!

6 September 2021

Vincent Bernat: Switching to the i3 window manager

I have been using the awesome window manager for 10 years. It is a tiling window manager, configurable and extendable with the Lua language. Using a general-purpose programming language to configure every aspect is a double-edged sword. Due to laziness and the apparent difficulty of adapting my configuration about 3000 lines to newer releases, I was stuck with the 3.4 version, whose last release is from 2013. It was time for a rewrite. Instead, I have switched to the i3 window manager, lured by the possibility to migrate to Wayland and Sway later with minimal pain. Using an embedded interpreter for configuration is not as important to me as it was in the past: it brings both complexity and brittleness.
i3 dual screen setup
Dual screen desktop running i3, Emacs, some terminals, including a Quake console, Firefox, Polybar as the status bar, and Dunst as the notification daemon.
The window manager is only one part of a desktop environment. There are several options for the other components. I am also introducing them in this post.

i3: the window manager i3 aims to be a minimal tiling window manager. Its documentation can be read from top to bottom in less than an hour. i3 organize windows in a tree. Each non-leaf node contains one or several windows and has an orientation and a layout. This information arbitrates the window positions. i3 features three layouts: split, stacking, and tabbed. They are demonstrated in the below screenshot:
Example of layouts
Demonstration of the layouts available in i3. The main container is split horizontally. The first child is split vertically. The second one is tabbed. The last one is stacking.
Tree representation of the previous screenshot
Tree representation of the previous screenshot.
Most of the other tiling window managers, including the awesome window manager, use predefined layouts. They usually feature a large area for the main window and another area divided among the remaining windows. These layouts can be tuned a bit, but you mostly stick to a couple of them. When a new window is added, the behavior is quite predictable. Moreover, you can cycle through the various windows without thinking too much as they are ordered. i3 is more flexible with its ability to build any layout on the fly, it can feel quite overwhelming as you need to visualize the tree in your head. At first, it is not unusual to find yourself with a complex tree with many useless nested containers. Moreover, you have to navigate windows using directions. It takes some time to get used to. I set up a split layout for Emacs and a few terminals, but most of the other workspaces are using a tabbed layout. I don t use the stacking layout. You can find many scripts trying to emulate other tiling window managers but I did try to get my setup pristine of these tentatives and get a chance to familiarize myself. i3 can also save and restore layouts, which is quite a powerful feature. My configuration is quite similar to the default one and has less than 200 lines.

i3 companion: the missing bits i3 philosophy is to keep a minimal core and let the user implements missing features using the IPC protocol:
Do not add further complexity when it can be avoided. We are generally happy with the feature set of i3 and instead focus on fixing bugs and maintaining it for stability. New features will therefore only be considered if the benefit outweighs the additional complexity, and we encourage users to implement features using the IPC whenever possible. Introduction to the i3 window manager
While this is not as powerful as an embedded language, it is enough for many cases. Moreover, as high-level features may be opinionated, delegating them to small, loosely coupled pieces of code keeps them more maintainable. Libraries exist for this purpose in several languages. Users have published many scripts to extend i3: automatic layout and window promotion to mimic the behavior of other tiling window managers, window swallowing to put a new app on top of the terminal launching it, and cycling between windows with Alt+Tab. Instead of maintaining a script for each feature, I have centralized everything into a single Python process, i3-companion using asyncio and the i3ipc-python library. Each feature is self-contained into a function. It implements the following components:
make a workspace exclusive to an application
When a workspace contains Emacs or Firefox, I would like other applications to move to another workspace, except for the terminal which is allowed to intrude into any workspace. The workspace_exclusive() function monitors new windows and moves them if needed to an empty workspace or to one with the same application already running.
implement a Quake console
The quake_console() function implements a drop-down console available from any workspace. It can be toggled with Mod+ . This is implemented as a scratchpad window.
back and forth workspace switching on the same output
With the workspace back_and_forth command, we can ask i3 to switch to the previous workspace. However, this feature is not restricted to the current output. I prefer to have one keybinding to switch to the workspace on the next output and one keybinding to switch to the previous workspace on the same output. This behavior is implemented in the previous_workspace() function by keeping a per-output history of the focused workspaces.
create a new empty workspace or move a window to an empty workspace
To create a new empty workspace or move a window to an empty workspace, you have to locate a free slot and use workspace number 4 or move container to workspace number 4. The new_workspace() function finds a free number and use it as the target workspace.
restart some services on output change
When adding or removing an output, some actions need to be executed: refresh the wallpaper, restart some components unable to adapt their configuration on their own, etc. i3 triggers an event for this purpose. The output_update() function also takes an extra step to coalesce multiple consecutive events and to check if there is a real change with the low-level library xcffib.
I will detail the other features as this post goes on. On the technical side, each function is decorated with the events it should react to:
@on(CommandEvent("previous-workspace"), I3Event.WORKSPACE_FOCUS)
async def previous_workspace(i3, event):
    """Go to previous workspace on the same output."""
The CommandEvent() event class is my way to send a command to the companion, using either i3-msg -t send_tick or binding a key to a nop command. The latter is used to avoid spawning a shell and a i3-msg process just to send a message. The companion listens to binding events and checks if this is a nop command.
bindsym $mod+Tab nop "previous-workspace"
There are other decorators to avoid code duplication: @debounce() to coalesce multiple consecutive calls, @static() to define a static variable, and @retry() to retry a function on failure. The whole script is a bit more than 1000 lines. I think this is worth a read as I am quite happy with the result.

dunst: the notification daemon Unlike the awesome window manager, i3 does not come with a built-in notification system. Dunst is a lightweight notification daemon. I am running a modified version with HiDPI support for X11 and recursive icon lookup. The i3 companion has a helper function, notify(), to send notifications using DBus. container_info() and workspace_info() uses it to display information about the container or the tree for a workspace.
Notification showing i3 tree for a workspace
Notification showing i3 s tree for a workspace

polybar: the status bar i3 bundles i3bar, a versatile status bar, but I have opted for Polybar. A wrapper script runs one instance for each monitor. The first module is the built-in support for i3 workspaces. To not have to remember which application is running in a workspace, the i3 companion renames workspaces to include an icon for each application. This is done in the workspace_rename() function. The icons are from the Font Awesome project. I maintain a mapping between applications and icons. This is a bit cumbersome but it looks great.
i3 workspaces in Polybar
i3 workspaces in Polybar
For CPU, memory, brightness, battery, disk, and audio volume, I am relying on the built-in modules. Polybar s wrapper script generates the list of filesystems to monitor and they get only displayed when available space is low. The battery widget turns red and blinks slowly when running out of power. Check my Polybar configuration for more details.
Various modules for Polybar
Polybar displaying various information: CPU usage, memory usage, screen brightness, battery status, Bluetooth status (with a connected headset), network status (connected to a wireless network and to a VPN), notification status, and speaker volume.
For Bluetooh, network, and notification statuses, I am using Polybar s ipc module: the next version of Polybar can receive an arbitrary text on an IPC socket. The module is defined with a single hook to be executed at the start to restore the latest status.
type = custom/ipc
hook-0 = cat $XDG_RUNTIME_DIR/i3/network.txt 2> /dev/null
initial = 1
It can be updated with polybar-msg action "#network.send.XXXX". In the i3 companion, the @polybar() decorator takes the string returned by a function and pushes the update through the IPC socket. The i3 companion reacts to DBus signals to update the Bluetooth and network icons. The @on() decorator accepts a DBusSignal() object:
        signature="sa sv as",
        onlyif=lambda args: (
            args[0] == "org.bluez.Device1"
            and "Connected" in args[1]
            or args[0] == "org.bluez.Adapter1"
            and "Powered" in args[1]
async def bluetooth_status(i3, event, *args):
    """Update bluetooth status for Polybar."""
The middle of the bar is occupied by the date and a weather forecast. The latest also uses the IPC mechanism, but the source is a Python script triggered by a timer.
Date and weather in Polybar
Current date and weather forecast for the day in Polybar. The data is retrieved with the OpenWeather API.
I don t use the system tray integrated with Polybar. The embedded icons usually look horrible and they all behave differently. A few years back, Gnome has removed the system tray. Most of the problems are fixed by the DBus-based Status Notifier Item protocol also known as Application Indicators or Ayatana Indicators for GNOME. However, Polybar does not support this protocol. In the i3 companion, The implementation of Bluetooth and network icons, including displaying notifications on change, takes about 200 lines. I got to learn a bit about how DBus works and I get exactly the info I want.

picom: the compositor I like having slightly transparent backgrounds for terminals and to reduce the opacity of unfocused windows. This requires a compositor.1 picom is a lightweight compositor. It works well for me, but it may need some tweaking depending on your graphic card.2 Unlike the awesome window manager, i3 does not handle transparency, so the compositor needs to decide by itself the opacity of each window. Check my configuration for details.

systemd: the service manager I use systemd to start i3 and the various services around it. My xsession script only sets some environment variables and lets systemd handles everything else. Have a look at this article from Micha G ral for the rationale. Notably, each component can be easily restarted and their logs are not mangled inside the ~/.xsession-errors file.3 I am using a two-stage setup: i3.service depends on to start services before i3:
Description=X session
Then, i3 executes the second stage by invoking the
Description=i3 session
Have a look on my configuration files for more details.

rofi: the application launcher Rofi is an application launcher. Its appearance can be customized through a CSS-like language and it comes with several themes. Have a look at my configuration for mine.
Rofi as an application launcher
Rofi as an application launcher
It can also act as a generic menu application. I have a script to control a media player and another one to select the wifi network. It is quite a flexible application.
Rofi as a wifi network selector
Rofi to select a wireless network

xss-lock and i3lock: the screen locker i3lock is a simple screen locker. xss-lock invokes it reliably on inactivity or before a system suspend. For inactivity, it uses the XScreenSaver events. The delay is configured using the xset s command. The locker can be invoked immediately with xset s activate. X11 applications know how to prevent the screen saver from running. I have also developed a small dimmer application that is executed 20 seconds before the locker to give me a chance to move the mouse if I am not away.4 Have a look at my configuration script.
Demonstration of xss-lock, xss-dimmer and i3lock with a 4 speedup.

The remaining components
  • autorandr is a tool to detect the connected display, match them against a set of profiles, and configure them with xrandr.
  • inputplug executes a script for each new mouse and keyboard plugged. This is quite useful to load the appropriate the keyboard map. See my configuration.
  • xsettingsd provides settings to X11 applications, not unlike xrdb but it notifies applications for changes. The main use is to configure the Gtk and DPI settings. See my article on HiDPI support on Linux with X11.
  • Redshift adjusts the color temperature of the screen according to the time of day.
  • maim is a utility to take screenshots. I use Prt Scn to trigger a screenshot of a window or a specific area and Mod+Prt Scn to capture the whole desktop to a file. Check the helper script for details.
  • I have a collection of wallpapers I rotate every hour. A script selects them using advanced machine learning algorithms and stitches them together on multi-screen setups. The selected wallpaper is reused by i3lock.

  1. Apart from the eye candy, a compositor also helps to get tear-free video playbacks.
  2. My configuration works with both Haswell (2014) and Whiskey Lake (2018) Intel GPUs. It also works with AMD GPU based on the Polaris chipset (2017).
  3. You cannot manage two different displays this way e.g. :0 and :1. In the first implementation, I did try to parametrize each service with the associated display, but this is useless: there is only one DBus user session and many services rely on it. For example, you cannot run two notification daemons.
  4. I have only discovered later that XSecureLock ships such a dimmer with a similar implementation. But mine has a cool countdown!

30 August 2021

Andrew Cater: Oh, my goodness, where's the fantastic barbeque [OMGWTFBBQ 2021]

I'm guessing the last glasses will be through the dishwasher (again) and Pepper the dog can settle down without having to cope with so many people.For those who don't know - Steve and his wife Jo (Sledge and Randombird) hold a barbeque in their garden every August Bank Holiday weekend [UK Bank Holiday on the last Monday in August]. The barbeque is not small - it's the dominating feature in the suburban garden, brick built, with a dedication stone, lights, electricity. The garden is small, generally made smaller by forty or so Debian friends and allies standing and sitting around. People are talking, arguing, hugging people they've not seen for (literal) years and putting the world to rights. This is Debian central point - with large quantities of meat and salads, an amount of beer/alcohol and "Cambridge gin" and general goodwill. This year was more than usually atmospheric because for some of us it was the first time with a large group of people in a while. Side conversations abound: for me it was learning something about the high energy particle physics community, how to precision build helicopters, fly quadcopters and precision 3D print anything, the maths of Isy counting crochet stitches to sew together randomly sized squares ... and, of course, obligatory things like how random is random and what's good enough entropy. And a few sessions of the game of our leader.
This is also a place for stuff to get done: I was unashamedly using this to upgrade the storage in my laptop while there were sensible engineers around. A corner of the table, a RattusRattus and it was quickly sorted - then a discussion around the internals of Thinkpads as he took his apart. Then getting a full install - Gb Ethernet to the Debian mirror in the cupboard six feet away is faster bandwidth than a jumbo jet full of tapes. Then getting mail to work again - it's handy when the mailserver owner is next to you, having come in from the garden to help, and finally IRC. And not just me: "You need a GPG key signed - there's three DPLs here, there's a release manager - but you've just missed one of the DAMs." plus an in-depth GPG how-to session on the other side of the table.I was the luckiest one with the most comfortable bed in the house overnight but I couldn't stay for last night. Thanks once again to all involved but especially Steve and Jo who do this for the love of it, and the fun, and the community and the family. Oh, and thanks to Lenovo - not just for being a platinum sponsor of Debconf but also for providing the official laptop of this and most Debian occasions

28 August 2021

Andrew Cater: "If you do it twice, it's tradition" - says nattie

Thanks to all who've made Debconf 21 such a good place to be.

A song for Debconf21 ["What shall we do with the drunken sailor"]

What shall we do with the online Debconf?What shall we do with the online Debconf?What shall we do with the online Debconf?

Earl-y in the morning

Close it up as we agreed it

Save each script in case we need it

Work out how we best live-feed itNext year s Debconf s dawning

Next year s Kosovo and Pristina

This virtual Debconf needs no cleaner

Hope when COVID s gone we re keener

To meet up every morning

Thanks to the Debconf orga team

Thanks to those who Loopy meme

Things are not always as they seeem

In virtual Debconf s morning

Bullseye s out its share is rising

Debconf s fun and quite surprising

Linux 30 :)

Yours and my thing - Debian s 28

Thanks to all who video d sessions

Debconf T-shirts - prized possessions

Debcamp bug-fixed some regressions

Now onto next year!

A closing song for Debconf 21 [Frere Jacques/Brueder Martin]


Virtual DebConf s

Now all through

Closed for you

Kosovo is next year

See you in Pristina!!

DebConf 22

Twenty twenty-two

19 August 2021

Andrew Cater: Vanilla Debian on a Raspberry Pi 4 with UEFI

Thanks to the good folk who put the hard work into building a UEFI implementation for the Raspberry Pi 4 which "just works", allowing you to install Debian straightforwardly, and especially to Pete Batard who has written up the process and collected a zip file together.

Not quite so straightforward ...

I have an early model Raspberry Pi 4. I wanted to install Debian on an SSD connected via a cable to a USB3 port. It turned out that the version of the software in the EEPROM would not boot reliably so the first task was to update this with the latest stable EEPROM available from the Raspberry Pi downloads.

The easiest way to do this was to boot an SD card with Raspbian on. Once that was done, I had a Pi that would boot from an SSD.

Untar the files

A tarball of UEFI from Pete's Github repository at - latest is v 1.29 as at 20210814.

Plugging in the SSD to another machine to format the drive: msdos format, one ESP partition in FAT32 and marked bootable and the rest of the drive blank.

One aarch64 DVD image from the usual place.

Untar the UEFI tarball into the ESP partition you've just made

Plug the SSD into a USB3 port on the RPi using a USB -> SATA cable

Write the aarch image to a USB stick using dd and place that into one of the other USB ports. Add a keyboard.


Power up the RPi4, hit Esc and work your way through UEFI to select a boot device and go, save the settings and go.

The install is almost identical to any Debian d-i install.

There is a setting in UEFI to reclaim the 1G of memory that was masked out, there's a setting for control of the fan shim if you have that style of fan.

End result - happiness

Done the other day and sitting next to me on the desktop.