Add buildbot blog post

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diff --git a/_posts/2023-07-23-reconfig-buildbot.md b/_posts/2023-07-23-reconfig-buildbot.md
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+---
+layout: post
+title: Reconfiguring Buildbot / Buildbot short intro
+date: 2023-07-23 14:49 +0200
+lang: en
+categories: tech
+---
+
+Recently, I started moving my repositories from [Gitea](https://gitea.io/)
+to [Gitolite](https://gitolite.com/). Main reason was that I forgot to
+regularly update my Gitea instance, it's a program that constantly runs
+in the background, and I wasn't using the Issues / Wiki / etc. features
+anyway. Technically, a very simple bare repo would do the trick as well,
+since I'm the only user. But why not try something out while I'm at it?
+
+(Gitea is a project / source management system, think of a self-hosted version
+of Github.  
+Gitolite is a small program that gets called when you
+`git fetch` or `git push` and determines if your ssh public key has
+the permissions to perform the operation. It manages the repositories
+and allows for pretty fine-grained access control.)
+
+Because I didn't look properly, I didn't find the `git_buildbot.py` script
+anymore. (It's in the
+[buildbot-contrib](https://github.com/buildbot/buildbot-contrib/blob/master/master/contrib/git_buildbot.py)
+repo btw). Also, it annoyed me that buildbot created a build for every
+single change (commit), even though I had the `collapseRequests`
+config option set to `True`. (Spoiler alert. Turns out I had
+the `treeStableTimer` of the `SingleBranchScheduler` set to `None`.)
+
+So I actually went through the documentation headings, noticed "Change Hooks" and
+thought "Oh, surely this is the solution!". I only enabled the `base`
+dialect and tried various curl requests, which resulted in changes being
+submitted, but no builds being triggered. Clarification set in when I re-read
+my `master.cfg` again and saw that the `SingleBranchScheduler` had
+a filter set to only build on the master branch. After facepalming at myself,
+the curl request
+
+    curl -v "http://localhost:8010/change_hook?comments=force_build&author=uvok&branch=master"
+
+indeed triggered a build! Since I don't care about the actual
+commit messages being shown in buildbot, this would be the perfect
+solution!
+
+However, at this point I also discovered that the `treeStableTimer` was
+set to `None` (see above), so I decided to keep using the provided
+`git_buildbot.py` script. - Even though that means I have to install
+`python3-twisted` globally on the system (since I don't wanna figure
+out how to activate a venv from a git hook).
+
+Anyway, here's a very simplified diagram of the buildbot architecture:
+
+![Buildbot architecture](/assets/buildbot.svg)
+
+Note that the [Buildbot documentation](https://docs.buildbot.net/latest/manual/introduction.html)
+has a far more detailed diagram.
+
+Morale of the story: Read the manual, even if it's frustrating if you just want to
+get a single small thing done. ;)
+
diff --git a/assets/buildbot.svg b/assets/buildbot.svg
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