Parallel GH actions workflow for Nixpkgs eval

Motivated by ofborg struggling [1] and its evaluations taking too long,
inspired by Jörg's initial PR [2]
and Adam's previous attempt to parallelise Nixpkgs evaluation [3],
this PR contains initial work to relief ofborg from its evaluation duty
by using GitHub Actions to evaluate Nixpkgs.

For now this doesn't take care of all of what ofborg does, such as
requesting appropriate reviewers or labeling mass rebuilds, but this can
be follow-up work.

[1]: https://discourse.nixos.org/t/infrastructure-announcement-the-future-of-ofborg-your-help-needed/56025?u=infinisil
[2]: https://github.com/NixOS/nixpkgs/pull/352808
[3]: https://github.com/NixOS/nixpkgs/pull/269403

Co-Authored-By: Jörg Thalheim <joerg@thalheim.io>
Co-Authored-By: Adam Joseph <adam@westernsemico.com>
This commit is contained in:
Silvan Mosberger 2024-11-14 23:14:20 +01:00
parent 72f462bdba
commit fbbe972898
11 changed files with 489 additions and 76 deletions

139
.github/workflows/eval.yml vendored Normal file
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@ -0,0 +1,139 @@
name: Eval
on: pull_request_target
permissions:
contents: read
jobs:
attrs:
name: Attributes
runs-on: ubuntu-latest
outputs:
mergedSha: ${{ steps.merged.outputs.mergedSha }}
systems: ${{ steps.systems.outputs.systems }}
steps:
# Important: Because of `pull_request_target`, this doesn't check out the PR,
# but rather the base branch of the PR, which is needed so we don't run untrusted code
- name: Check out the ci directory of the base branch
uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
with:
path: base
sparse-checkout: ci
- name: Check if the PR can be merged and get the test merge commit
id: merged
env:
GH_TOKEN: ${{ github.token }}
run: |
if mergedSha=$(base/ci/get-merge-commit.sh ${{ github.repository }} ${{ github.event.number }}); then
echo "Checking the merge commit $mergedSha"
echo "mergedSha=$mergedSha" >> "$GITHUB_OUTPUT"
else
# Skipping so that no notifications are sent
echo "Skipping the rest..."
fi
rm -rf base
- name: Check out the PR at the test merge commit
uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
# Add this to _all_ subsequent steps to skip them
if: steps.merged.outputs.mergedSha
with:
ref: ${{ env.mergedSha }}
path: nixpkgs
- name: Install Nix
uses: cachix/install-nix-action@08dcb3a5e62fa31e2da3d490afc4176ef55ecd72 # v30
if: steps.merged.outputs.mergedSha
- name: Evaluate the list of all attributes and get the systems matrix
id: systems
if: steps.merged.outputs.mergedSha
run: |
nix-build nixpkgs/ci -A eval.attrpathsSuperset
echo "systems=$(<result/systems.json)" >> "$GITHUB_OUTPUT"
- name: Upload the list of all attributes
uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4.4.3
if: steps.merged.outputs.mergedSha
with:
name: paths
path: result/*
outpaths:
name: Outpaths
runs-on: ubuntu-latest
needs: attrs
# Skip this and future steps if the PR can't be merged
if: needs.attrs.outputs.mergedSha
strategy:
matrix:
system: ${{ fromJSON(needs.attrs.outputs.systems) }}
steps:
- name: Download the list of all attributes
uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
with:
name: paths
path: paths
- name: Check out the PR at the test merge commit
uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
with:
ref: ${{ needs.attrs.outputs.mergedSha }}
path: nixpkgs
- name: Install Nix
uses: cachix/install-nix-action@08dcb3a5e62fa31e2da3d490afc4176ef55ecd72 # v30
- name: Evaluate the ${{ matrix.system }} output paths for all derivation attributes
run: |
nix-build nixpkgs/ci -A eval.singleSystem \
--argstr evalSystem ${{ matrix.system }} \
--arg attrpathFile ./paths/paths.json \
--arg chunkSize 10000
# If it uses too much memory, slightly decrease chunkSize
- name: Upload the output paths and eval stats
uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4.4.3
if: needs.attrs.outputs.mergedSha
with:
name: intermediate-${{ matrix.system }}
path: result/*
process:
name: Process
runs-on: ubuntu-latest
needs: outpaths
steps:
- name: Download output paths and eval stats for all systems
uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
with:
pattern: intermediate-*
path: intermediate
- name: Check out the PR at the test merge commit
uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
with:
ref: ${{ needs.attrs.outputs.mergedSha }}
path: nixpkgs
- name: Install Nix
uses: cachix/install-nix-action@08dcb3a5e62fa31e2da3d490afc4176ef55ecd72 # v30
- name: Combine all output paths and eval stats
run: |
nix-build nixpkgs/ci -A eval.combine \
--arg resultsDir ./intermediate
- name: Upload the combined results
uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4.4.3
with:
name: result
path: result/*
# TODO: Run this workflow also on `push` (on at least the main development branches)
# Then add an extra step here that waits for the base branch (not the merge base, because that could be very different)
# to have completed the eval, then use
# gh api --method GET /repos/NixOS/nixpkgs/actions/workflows/eval.yml/runs -f head_sha=<BASE>
# and follow it to the artifact results, where you can then download the outpaths.json from the base branch
# That can then be used to compare the number of changed paths, get evaluation stats and ping appropriate reviewers

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@ -26,4 +26,5 @@ in
inherit pkgs;
requestReviews = pkgs.callPackage ./request-reviews { };
codeownersValidator = pkgs.callPackage ./codeowners-validator { };
eval = pkgs.callPackage ./eval { };
}

19
ci/eval/README.md Normal file
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@ -0,0 +1,19 @@
# Nixpkgs CI evaluation
The code in this directory is used by the [eval.yml](../../.github/workflows/eval.yml) GitHub Actions workflow to evaluate the majority of Nixpkgs for all PRs, effectively making sure that when the development branches are processed by Hydra, no evaluation failures are encountered.
Furthermore it also allows local evaluation using
```
nix-build ci -A eval.full \
--max-jobs 4
--cores 2
--arg chunkSize 10000
```
- `--max-jobs`: The maximum number of derivations to run at the same time. Only each [supported system](../supportedSystems.nix) gets a separate derivation, so it doesn't make sense to set this higher than that number.
- `--cores`: The number of cores to use for each job. Recommended to set this to the amount of cores on your system divided by `--max-jobs`.
- `chunkSize`: The number of attributes that are evaluated simultaneously on a single core. Lowering this decreases memory usage at the cost of increased evaluation time. If this is too high, there won't be enough chunks to process them in parallel, and will also increase evaluation time.
A good default is to set `chunkSize` to 10000, which leads to about 3.6GB max memory usage per core, so suitable for fully utilising machines with 4 cores and 16GB memory, 8 cores and 32GB memory or 16 cores and 64GB memory.
Note that 16GB memory is the recommended minimum, while with less than 8GB memory evaluation time suffers greatly.

273
ci/eval/default.nix Normal file
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{
lib,
runCommand,
writeShellScript,
linkFarm,
time,
procps,
nix,
jq,
sta,
}:
let
nixpkgs =
with lib.fileset;
toSource {
root = ../..;
fileset = unions (
map (lib.path.append ../..) [
"default.nix"
"doc"
"lib"
"maintainers"
"nixos"
"pkgs"
".version"
"ci/supportedSystems.nix"
]
);
};
supportedSystems = import ../supportedSystems.nix;
attrpathsSuperset =
runCommand "attrpaths-superset.json"
{
src = nixpkgs;
nativeBuildInputs = [
nix
time
];
env.supportedSystems = builtins.toJSON supportedSystems;
passAsFile = [ "supportedSystems" ];
}
''
export NIX_STATE_DIR=$(mktemp -d)
mkdir $out
export GC_INITIAL_HEAP_SIZE=4g
command time -v \
nix-instantiate --eval --strict --json --show-trace \
$src/pkgs/top-level/release-attrpaths-superset.nix -A paths \
--arg enableWarnings false > $out/paths.json
mv "$supportedSystemsPath" $out/systems.json
'';
singleSystem =
{
# The system to evaluate.
# Note that this is intentionally not called `system`,
# because `--argstr system` would only be passed to the ci/default.nix file!
evalSystem,
# The path to the `paths.json` file from `attrpathsSuperset`
attrpathFile,
# The number of attributes per chunk, see ./README.md for more info.
chunkSize,
checkMeta ? true,
includeBroken ? true,
# Whether to just evaluate a single chunk for quick testing
quickTest ? false,
}:
let
singleChunk = writeShellScript "single-chunk" ''
set -euo pipefail
chunkSize=$1
myChunk=$2
system=$3
outputDir=$4
export NIX_SHOW_STATS=1
export NIX_SHOW_STATS_PATH="$outputDir/stats/$myChunk"
echo "Chunk $myChunk on $system start"
set +e
command time -f "Chunk $myChunk on $system done [%MKB max resident, %Es elapsed] %C" \
nix-env -f "${nixpkgs}/pkgs/top-level/release-attrpaths-parallel.nix" \
--query --available \
--no-name --attr-path --out-path \
--show-trace \
--arg chunkSize "$chunkSize" \
--arg myChunk "$myChunk" \
--arg attrpathFile "${attrpathFile}" \
--arg systems "[ \"$system\" ]" \
--arg checkMeta ${lib.boolToString checkMeta} \
--arg includeBroken ${lib.boolToString includeBroken} \
> "$outputDir/result/$myChunk"
exitCode=$?
set -e
if (( exitCode != 0 )); then
echo "Evaluation failed with exit code $exitCode"
# This immediately halts all xargs processes
kill $PPID
fi
'';
in
runCommand "nixpkgs-eval-${evalSystem}"
{
nativeBuildInputs = [
nix
time
procps
jq
];
env = {
inherit evalSystem chunkSize;
};
}
''
export NIX_STATE_DIR=$(mktemp -d)
nix-store --init
echo "System: $evalSystem"
cores=$NIX_BUILD_CORES
echo "Cores: $cores"
attrCount=$(jq length "${attrpathFile}")
echo "Attribute count: $attrCount"
echo "Chunk size: $chunkSize"
# Same as `attrCount / chunkSize` but rounded up
chunkCount=$(( (attrCount - 1) / chunkSize + 1 ))
echo "Chunk count: $chunkCount"
mkdir $out
# Record and print stats on free memory and swap in the background
(
while true; do
availMemory=$(free -b | grep Mem | awk '{print $7}')
freeSwap=$(free -b | grep Swap | awk '{print $4}')
echo "Available memory: $(( availMemory / 1024 / 1024 )) MiB, free swap: $(( freeSwap / 1024 / 1024 )) MiB"
if [[ ! -f "$out/min-avail-memory" ]] || (( availMemory < $(<$out/min-avail-memory) )); then
echo "$availMemory" > $out/min-avail-memory
fi
if [[ ! -f $out/min-free-swap ]] || (( availMemory < $(<$out/min-free-swap) )); then
echo "$freeSwap" > $out/min-free-swap
fi
sleep 4
done
) &
seq_end=$(( chunkCount - 1 ))
${lib.optionalString quickTest ''
seq_end=0
''}
chunkOutputDir=$(mktemp -d)
mkdir "$chunkOutputDir"/{result,stats}
seq -w 0 "$seq_end" |
command time -f "%e" -o "$out/total-time" \
xargs -I{} -P"$cores" \
${singleChunk} "$chunkSize" {} "$evalSystem" "$chunkOutputDir"
if (( chunkSize * chunkCount != attrCount )); then
# A final incomplete chunk would mess up the stats, don't include it
rm "$chunkOutputDir"/stats/"$seq_end"
fi
# Make sure the glob doesn't break when there's no files
shopt -s nullglob
cat "$chunkOutputDir"/result/* > $out/paths
cat "$chunkOutputDir"/stats/* > $out/stats.jsonstream
'';
combine =
{
resultsDir,
}:
runCommand "combined-result"
{
nativeBuildInputs = [
jq
sta
];
}
''
mkdir -p $out
# Transform output paths to JSON
cat ${resultsDir}/*/paths |
jq --sort-keys --raw-input --slurp '
split("\n") |
map(select(. != "") | split(" ") | map(select(. != ""))) |
map(
{
key: .[0],
value: .[1] | split(";") | map(split("=") |
if length == 1 then
{ key: "out", value: .[0] }
else
{ key: .[0], value: .[1] }
end) | from_entries}
) | from_entries
' > $out/outpaths.json
# Computes min, mean, error, etc. for a list of values and outputs a JSON from that
statistics() {
local stat=$1
sta --transpose |
jq --raw-input --argjson stat "$stat" -n '
[
inputs |
split("\t") |
{ key: .[0], value: (.[1] | fromjson) }
] |
from_entries |
{
key: ($stat | join(".")),
value: .
}'
}
# Gets all available number stats (without .sizes because those are constant and not interesting)
readarray -t stats < <(jq -cs '.[0] | del(.sizes) | paths(type == "number")' ${resultsDir}/*/stats.jsonstream)
# Combines the statistics from all evaluations
{
echo "{ \"key\": \"minAvailMemory\", \"value\": $(cat ${resultsDir}/*/min-avail-memory | sta --brief --min) }"
echo "{ \"key\": \"minFreeSwap\", \"value\": $(cat ${resultsDir}/*/min-free-swap | sta --brief --min) }"
cat ${resultsDir}/*/total-time | statistics '["totalTime"]'
for stat in "''${stats[@]}"; do
cat ${resultsDir}/*/stats.jsonstream |
jq --argjson stat "$stat" 'getpath($stat)' |
statistics "$stat"
done
} |
jq -s from_entries > $out/stats.json
'';
full =
{
# Whether to evaluate just a single system, by default all are evaluated
evalSystem ? if quickTest then "x86_64-linux" else null,
# The number of attributes per chunk, see ./README.md for more info.
chunkSize,
quickTest ? false,
}:
let
systems = if evalSystem == null then supportedSystems else [ evalSystem ];
results = linkFarm "results" (
map (evalSystem: {
name = evalSystem;
path = singleSystem {
inherit quickTest evalSystem chunkSize;
attrpathFile = attrpathsSuperset + "/paths.json";
};
}) systems
);
in
combine {
resultsDir = results;
};
in
{
inherit
attrpathsSuperset
singleSystem
combine
# The above three are used by separate VMs in a GitHub workflow,
# while the below is intended for testing on a single local machine
full
;
}

6
ci/supportedSystems.nix Normal file
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@ -0,0 +1,6 @@
[
"aarch64-linux"
"aarch64-darwin"
"x86_64-linux"
"x86_64-darwin"
]

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@ -14,19 +14,5 @@ let
in
pkgs.symlinkJoin {
name = "nixpkgs-lib-tests";
paths = map testWithNix nixVersions ++
#
# TEMPORARY MIGRATION MECHANISM
#
# This comment and the expression which follows it should be
# removed as part of resolving this issue:
#
# https://github.com/NixOS/nixpkgs/issues/272591
#
[(import ../../pkgs/test/release {
inherit pkgs lib nix;
})]
;
paths = map testWithNix nixVersions;
}

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@ -1,52 +0,0 @@
# Adapted from lib/tests/release.nix
{ pkgs-path ? ../../..
, pkgs ? import pkgs-path {}
, lib ? pkgs.lib
, nix ? pkgs.nix
}:
#
# This verifies that release-attrpaths-superset.nix does not encounter
# infinite recursion or non-tryEval-able failures.
#
pkgs.runCommand "all-attrs-eval-under-tryEval" {
nativeBuildInputs = [
nix
pkgs.gitMinimal
] ++ lib.optional pkgs.stdenv.hostPlatform.isLinux pkgs.inotify-tools;
strictDeps = true;
src = with lib.fileset; toSource {
root = pkgs-path;
fileset = unions [
../../../default.nix
../../../doc
../../../lib
../../../maintainers
../../../nixos
../../../pkgs
../../../.version
];
};
}
''
datadir="${nix}/share"
export TEST_ROOT=$(pwd)/test-tmp
export HOME=$(mktemp -d)
export NIX_BUILD_HOOK=
export NIX_CONF_DIR=$TEST_ROOT/etc
export NIX_LOCALSTATE_DIR=$TEST_ROOT/var
export NIX_LOG_DIR=$TEST_ROOT/var/log/nix
export NIX_STATE_DIR=$TEST_ROOT/var/nix
export NIX_STORE_DIR=$TEST_ROOT/store
export PAGER=cat
cacheDir=$TEST_ROOT/binary-cache
nix-store --init
echo "Running pkgs/top-level/release-attrpaths-superset.nix"
nix-instantiate --eval --strict --json $src/pkgs/top-level/release-attrpaths-superset.nix -A names > /dev/null
mkdir $out
echo success > $out/${nix.version}
''

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@ -0,0 +1,47 @@
# This file works in tandem with ../../ci/eval/default.nix
# It turns ./release-outpaths.nix into chunks of a fixed size
{
lib ? import ../../lib,
path ? ../..,
# The file containing all available attribute paths, which are split into chunks here
attrpathFile,
chunkSize,
myChunk,
checkMeta,
includeBroken,
systems,
}:
let
attrpaths = lib.importJSON attrpathFile;
myAttrpaths = lib.sublist (chunkSize * myChunk) chunkSize attrpaths;
unfiltered = import ./release-outpaths.nix {
inherit path;
inherit checkMeta includeBroken systems;
};
# Turns the unfiltered recursive attribute set into one that is limited to myAttrpaths
filtered =
let
recurse =
index: paths: attrs:
lib.mapAttrs (
name: values:
if attrs ? ${name} then
if lib.any (value: lib.length value <= index + 1) values then
attrs.${name}
else
recurse (index + 1) values attrs.${name}
# Make sure nix-env recurses as well
// {
recurseForDerivations = true;
}
else
null
) (lib.groupBy (a: lib.elemAt a index) paths);
in
recurse 0 myAttrpaths unfiltered;
in
filtered

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@ -9,7 +9,7 @@
$ hydra-eval-jobs -I . pkgs/top-level/release-haskell.nix
*/
{ supportedSystems ? [ "x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ] }:
{ supportedSystems ? import ../../ci/supportedSystems.nix }:
let

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@ -12,13 +12,7 @@
, attrNamesOnly ? false
# Set this to `null` to build for builtins.currentSystem only
, systems ? [
"aarch64-linux"
"aarch64-darwin"
#"i686-linux" # !!!
"x86_64-linux"
"x86_64-darwin"
]
, systems ? import ../../ci/supportedSystems.nix
}:
let
lib = import (path + "/lib");

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@ -12,7 +12,7 @@
, system ? builtins.currentSystem
, officialRelease ? false
# The platform doubles for which we build Nixpkgs.
, supportedSystems ? [ "x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ]
, supportedSystems ? import ../../ci/supportedSystems.nix
# The platform triples for which we build bootstrap tools.
, bootstrapConfigs ? [
"aarch64-apple-darwin"