#
msgid ""
msgstr ""

msgid "title: DIY bare bones CI server with Bash and Nix"
msgstr ""

msgid "date: 2020-11-12 3"
msgstr ""

msgid "layout: post"
msgstr ""

msgid "lang: en"
msgstr ""

msgid "ref: diy-bare-bones-ci-server-with-bash-and-nix"
msgstr ""

msgid ""
"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](https://git-"
"scm.com/book/en/v2/Customizing-Git-Git-Hooks) Git hook to the server."
msgstr ""

msgid ""
"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:"
msgstr ""

msgid ""
"#!/usr/bin/env bash\n"
"set -Eeuo pipefail\n"
"set -x\n"
"\n"
"LOGS_PREFIX=\"/data/static/ci-logs/libedn\"\n"
"mkdir -p \"$LOGS_DIR\"\n"
"LOGFILE=\"${LOGS_DIR}/$(date -Is)-$(git rev-parse master).log\"\n"
"exec &> >(tee -a \"${LOGFILE}\")\n"
"\n"
"unset GIT_DIR\n"
"CLONE=\"$(mktemp -d)\"\n"
"git clone . \"$CLONE\"\n"
"pushd \"$CLONE\"\n"
"\n"
"finish() {\n"
"  printf \"\\n\\n>>> exit status was %s\\n\" \"$?\"\n"
"}\n"
"trap finish EXIT\n"
"\n"
"nix-build -A test\n"
msgstr ""

msgid ""
"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`."
msgstr ""

msgid ""
"Lines #10 to #13 create a fresh clone of the repository and line #20 runs "
"the test command."
msgstr ""

msgid ""
"After using a similar post-receive hook for a while, I now even generate a "
"simple HTML file to make the [logs available](https://ci.euandreh.xyz/) "
"through the browser."
msgstr ""

msgid "Upsides"
msgstr ""

msgid "No vendor lock-in, as all you need is a server with Nix installed."
msgstr ""

msgid ""
"And if you pin the Nixpkgs version you're using, this very simple setup "
"yields extremely sandboxed runs on a very hermetic environment."
msgstr ""

msgid "Downsides"
msgstr ""

msgid ""
"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 server might very well run out of memory."
msgstr ""