benchmark.yml

name: Benchmark

on:
  push:
    branches: [ main ]
    paths:
      - '**.go'
      - 'src/**'
      - 'Cargo.toml'
      - 'Cargo.lock'
      - '.github/workflows/benchmark.yml'
      - '.github/actions/**'
  pull_request:
    branches: [ main ]
    paths:
      - '**.go'
      - 'src/**'
      - 'Cargo.toml'
      - 'Cargo.lock'
      - '.github/workflows/benchmark.yml'
      - '.github/actions/**'
  workflow_dispatch:

permissions:
  contents: write
  deployments: write
  pull-requests: write

jobs:
  benchmark:
    name: Run Go benchmarks
    runs-on: ubuntu-latest

    steps:
    - name: Checkout code
      uses: actions/checkout@v4

    - name: Set up Go
      uses: actions/setup-go@v5
      with:
        go-version: '1.24'

    - name: Setup Rust
      uses: ./.github/actions/setup-rust

    - name: Build Rust library
      run: cargo build --release --locked

    - name: Run benchmarks
      run: |
        set -o pipefail
        export TOKENIZERS_LIB_PATH="${{ github.workspace }}/target/release/libtokenizers.so"
        go test -bench=. -benchmem -count=5 ./... | tee benchmark_output.txt

    - name: Store benchmark result
      uses: benchmark-action/github-action-benchmark@v1
      with:
        name: Go Benchmark
        tool: 'go'
        output-file-path: benchmark_output.txt
        github-token: ${{ secrets.GITHUB_TOKEN }}
        auto-push: true
        alert-threshold: '120%'
        comment-on-alert: true
        fail-on-alert: false
        alert-comment-cc-users: '@tazarov'
        summary-always: true

    - name: Upload benchmark results
      if: github.event_name == 'push' && github.ref == 'refs/heads/main'
      uses: actions/upload-artifact@v4
      with:
        name: benchmark-results
        path: benchmark_output.txt
        retention-days: 30

  benchmark-compare:
    name: Compare benchmarks (PR)
    if: github.event_name == 'pull_request'
    runs-on: ubuntu-latest

    steps:
    - name: Checkout PR code
      uses: actions/checkout@v4

    - name: Set up Go
      uses: actions/setup-go@v5
      with:
        go-version: '1.24'

    - name: Setup Rust
      uses: ./.github/actions/setup-rust

    - name: Install benchstat
      run: go install golang.org/x/perf/cmd/benchstat@latest

    - name: Build Rust library
      run: cargo build --release --locked

    - name: Run benchmarks on PR branch
      run: |
        export TOKENIZERS_LIB_PATH="${{ github.workspace }}/target/release/libtokenizers.so"
        go test -bench=. -benchmem -count=5 ./... > pr_bench.txt

    - name: Checkout base branch
      uses: actions/checkout@v4
      with:
        ref: ${{ github.base_ref }}
        path: base

    - name: Build base branch
      working-directory: base
      run: cargo build --release

    - name: Run benchmarks on base branch
      working-directory: base
      continue-on-error: true
      run: |
        export TOKENIZERS_LIB_PATH="${{ github.workspace }}/base/target/release/libtokenizers.so"
        go test -bench=. -benchmem -count=5 ./... > ../base_bench.txt || echo "No benchmarks found in base branch" > ../base_bench.txt

    - name: Compare benchmarks
      run: |
        echo "## Benchmark Comparison" > benchmark_comment.md
        echo "" >> benchmark_comment.md
        echo "\`\`\`" >> benchmark_comment.md
        benchstat base_bench.txt pr_bench.txt >> benchmark_comment.md || true
        echo "\`\`\`" >> benchmark_comment.md
        cat benchmark_comment.md

    - name: Comment PR with benchmark results
      if: github.event_name == 'pull_request'
      uses: actions/github-script@v7
      with:
        github-token: ${{secrets.GITHUB_TOKEN}}
        script: |
          const fs = require('fs');
          const comment = fs.readFileSync('benchmark_comment.md', 'utf8');

          const issue_number = context.issue.number;
          const owner = context.repo.owner;
          const repo = context.repo.repo;

          // Find and update existing comment or create new one
          const { data: comments } = await github.rest.issues.listComments({
            owner,
            repo,
            issue_number,
          });

          const botComment = comments.find(comment =>
            comment.user.type === 'Bot' &&
            comment.body.includes('## Benchmark Comparison')
          );

          if (botComment) {
            await github.rest.issues.updateComment({
              owner,
              repo,
              comment_id: botComment.id,
              body: comment
            });
          } else {
            await github.rest.issues.createComment({
              owner,
              repo,
              issue_number,
              body: comment
            });
          }