diff options
Diffstat (limited to 'src/content/tils/2020/11/12')
| -rw-r--r-- | src/content/tils/2020/11/12/diy-nix-bash-ci.adoc | 45 | ||||
| -rw-r--r-- | src/content/tils/2020/11/12/git-bisect-automation.adoc | 23 | ||||
| -rw-r--r-- | src/content/tils/2020/11/12/useful-bashvars.adoc | 56 |
3 files changed, 43 insertions, 81 deletions
diff --git a/src/content/tils/2020/11/12/diy-nix-bash-ci.adoc b/src/content/tils/2020/11/12/diy-nix-bash-ci.adoc index 3336482..73919d5 100644 --- a/src/content/tils/2020/11/12/diy-nix-bash-ci.adoc +++ b/src/content/tils/2020/11/12/diy-nix-bash-ci.adoc @@ -1,27 +1,17 @@ ---- += DIY bare bones CI server with Bash and Nix -title: DIY bare bones CI server with Bash and Nix - -date: 2020-11-12 3 - -layout: post - -lang: en - -ref: diy-bare-bones-ci-server-with-bash-and-nix - -eu_categories: ci - ---- +:post-receive: https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks +:example-project: https://euandreh.xyz/remembering/ci.html With a server with Nix installed (no need for NixOS), you can leverage its build -isolation for running CI jobs by adding a [post-receive][post-receive] Git hook +isolation for running CI jobs by adding a {post-receive}[post-receive] Git hook to the server. In most of my project I like to keep a `test` attribute which runs the test with -`nix-build -A test`. This way, a post-receive hook could look like: +`nix-build -A test`. This way, a post-receive hook could look like: -```shell +[source,shell] +---- #!/usr/bin/env bash set -Eeuo pipefail set -x @@ -42,33 +32,30 @@ finish() { trap finish EXIT nix-build -A test -``` +---- -We initially (lines #5 to #8) create a log file, named after *when* the run is -running and for *which* commit it is running for. The `exec` and `tee` combo -allows the output of the script to go both to `stdout` *and* the log file. This +We initially (lines #5 to #8) create a log file, named after _when_ the run is +running and for _which_ commit it is running for. The `exec` and `tee` combo +allows the output of the script to go both to `stdout` _and_ the log file. This makes the logs output show up when you do a `git push`. Lines #10 to #13 create a fresh clone of the repository and line #20 runs the test command. After using a similar post-receive hook for a while, I now even generate a -simple HTML file to make the logs available ([example project][ci-logs]) +simple HTML file to make the logs available ({example-project}[example project]) through the browser. -[post-receive]: https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks -[ci-logs]: https://euandreh.xyz/remembering/ci.html - -## Upsides +== Upsides No vendor lock-in, as all you need is a server with Nix installed. And if you pin the Nixpkgs version you're using, this very simple setup yields extremely sandboxed runs on a very hermetic environment. -## Downsides +== Downsides Besides the many missing shiny features of this very simplistic CI, `nix-build` -can be very resource intensive. Specifically, it consumes too much memory. So if -it has to download too many things, or the build closure gets too big, the +can be very resource intensive. Specifically, it consumes too much memory. So +if it has to download too many things, or the build closure gets too big, the server might very well run out of memory. diff --git a/src/content/tils/2020/11/12/git-bisect-automation.adoc b/src/content/tils/2020/11/12/git-bisect-automation.adoc index 9c34b2a..c70bb2d 100644 --- a/src/content/tils/2020/11/12/git-bisect-automation.adoc +++ b/src/content/tils/2020/11/12/git-bisect-automation.adoc @@ -1,18 +1,4 @@ ---- - -title: Git bisect automation - -date: 2020-11-12 2 - -layout: post - -lang: en - -ref: git-bisect-automation - -eu_categories: git - ---- += Git bisect automation It is good to have an standardized way to run builds and tests on the repository of a project, so that you can find when a bug was introduced by using @@ -22,14 +8,15 @@ I've already been in the situation when a bug was introduced and I didn't know how it even was occurring, and running Git bisect over hundreds of commits to pinpoint the failing commit was very empowering: -``` +.... $ GOOD_COMMIT_SHA=e1fd0a817d192c5a5df72dd7422e36558fa78e46 $ git bisect start HEAD $GOOD_COMMIT_SHA $ git bisect run sn -c './build.sh && ./run-failing-case.sh' -``` +.... Git will than do a binary search between the commits, and run the commands you provide it with to find the failing commit. Instead of being afraid of doing a bisect, you should instead leverage it, and -make Git help you dig through the history of the repository to find the bad code. +make Git help you dig through the history of the repository to find the bad +code. diff --git a/src/content/tils/2020/11/12/useful-bashvars.adoc b/src/content/tils/2020/11/12/useful-bashvars.adoc index 33a072e..5061b64 100644 --- a/src/content/tils/2020/11/12/useful-bashvars.adoc +++ b/src/content/tils/2020/11/12/useful-bashvars.adoc @@ -1,59 +1,49 @@ ---- += Useful Bash variables -title: Useful Bash variables +:bash: https://www.gnu.org/software/bash/ +:bash-bang-bang: https://www.gnu.org/software/bash/manual/bash.html#Event-Designators +:bash-dollar-underscore: https://www.gnu.org/software/bash/manual/bash.html#Special-Parameters -date: 2020-11-12 1 +{bash}[GNU Bash] has a few two letter variables that may be useful when typing +on the terminal. -layout: post +== `!!`: the text of the last command -lang: en - -ref: useful-bash-variables - -eu_categories: shell - ---- - -[GNU Bash][gnu-bash] has a few two letter variables that may be useful when -typing on the terminal. - -[gnu-bash]: https://www.gnu.org/software/bash/ - -## `!!`: the text of the last command - -The [`!!` variable][previous-command] refers to the previous command, and I find +The {bash-bang-bang}[`!!` variable] refers to the previous command, and I find useful when following chains for symlinks: -[previous-command]: https://www.gnu.org/software/bash/manual/bash.html#Event-Designators - -```shell +[source,shell] +---- $ which git /run/current-system/sw/bin/git $ readlink $(!!) readlink $(which git) /nix/store/5bgr1xpm4m0r72h9049jbbhagxdyrnyb-git-2.28.0/bin/git -``` +---- It is also useful when you forget to prefix `sudo` to a command that requires it: -```shell +[source,shell] +---- $ requires-sudo.sh requires-sudo.sh: Permission denied $ sudo !! sudo ./requires-sudo.sh # all good -``` +---- Bash prints the command expansion before executing it, so it is better for you to follow along what it is doing. -## `$_`: most recent parameter +== `$_`: most recent parameter -The [`$_` variable][recent-parameter] will give you the most recent parameter -you provided to a previous argument, which can save you typing sometimes: +The {bash-dollar-underscore}[`$_` variable] will give you the most recent +parameter you provided to a previous argument, which can save you typing +sometimes: -```shell +[source,shell] +---- # instead of... $ mkdir -p a/b/c/d/ $ cd a/b/c/d/ @@ -61,11 +51,9 @@ $ cd a/b/c/d/ # ...you can: $ mkdir -p a/b/c/d/ $ cd $_ -``` - -[recent-parameter]: https://www.gnu.org/software/bash/manual/bash.html#Special-Parameters +---- -## Conclusion +== Conclusion I wouldn't use those in a script, as it would make the script terser to read, I find those useful shortcut that are handy when writing at the interactive |