benchmark.yml

name: Benchmark

on:
  pull_request:
    branches: [master]
  workflow_dispatch:
    inputs:
      base:
        description: 'Ref to compare this branch against'
        default: master

permissions:
  contents: read

jobs:
  benchmark:
    timeout-minutes: 30
    runs-on: ubuntu-latest
    permissions:
      contents: read
      # the comment on the pull request. Read-only on a pull request from a fork, where the
      # job summary is the only output
      pull-requests: write
    env:
      # the PostgreSQL that comes with the runner image, over its unix socket: no container
      # and no TCP between the client and the server, so the numbers are the client's.
      # The role is named after the OS user, which is what peer authentication wants
      PGHOST: /var/run/postgresql
      PGDATABASE: benchmark
    steps:
      - name: Start PostgreSQL
        run: |
          sudo systemctl start postgresql.service
          sudo -u postgres createuser "$USER"
          sudo -u postgres createdb -O "$USER" benchmark
      - uses: actions/checkout@v4
        with:
          path: head
          persist-credentials: false
      - uses: actions/checkout@v4
        with:
          path: base
          ref: ${{ github.event.pull_request.base.sha || inputs.base }}
          persist-credentials: false
      - name: Setup node
        uses: actions/setup-node@v4
        with:
          node-version: 26
          cache: yarn
          cache-dependency-path: |
            head/yarn.lock
            base/yarn.lock
      - name: Build both arms
        run: |
          for arm in base head; do
            (cd $arm && yarn install --frozen-lockfile && yarn build)
          done
      - name: Run benchmark
        working-directory: head
        run: node benchmark/compare.js --base ../base --head . --rounds 4 --duration 3 --output ../benchmark_summary.md
      - name: Publish the summary
        run: cat benchmark_summary.md >> "$GITHUB_STEP_SUMMARY"
      - uses: actions/upload-artifact@v4
        with:
          name: benchmark-summary
          path: benchmark_summary.md
      - name: Comment on the pull request
        if: github.event_name == 'pull_request'
        continue-on-error: true
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs')
            const marker = '<!-- benchmark-comment -->'
            const body = fs.readFileSync('benchmark_summary.md', 'utf8')
            const issue_number = context.payload.pull_request.number
            const comments = await github.paginate(github.rest.issues.listComments, {
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number,
            })
            const existing = comments.find((c) => c.user?.type === 'Bot' && c.body?.includes(marker))
            if (existing) {
              await github.rest.issues.updateComment({ owner: context.repo.owner, repo: context.repo.repo, comment_id: existing.id, body })
            } else {
              await github.rest.issues.createComment({ owner: context.repo.owner, repo: context.repo.repo, issue_number, body })
            }