serverless-binary-size.yml

name: "Serverless Binary Size"

on:
  pull_request:

env:
  SIZE_ALLOWANCE: fromJSON(1000000)  # 1 MB

jobs:
  comment:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout datadog-agent repository
        uses: actions/checkout@v3
        with:
          path: go/src/github.com/DataDog/datadog-agent

      - name: Checkout datadog-agent base branch
        run: |
          cd go/src/github.com/DataDog/datadog-agent
          git fetch origin $GITHUB_BASE_REF --depth 1
          git checkout $GITHUB_BASE_REF

      - name: Checkout the datadog-lambda-extension repository
        uses: actions/checkout@v3
        with:
          repository: DataDog/datadog-lambda-extension
          path: go/src/github.com/DataDog/datadog-lambda-extension

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v2

      - name: Previous binary size and dependencies
        id: previous
        run: |
          cd go/src/github.com/DataDog/datadog-lambda-extension

          OUTPUT=$(./scripts/visualize_size.sh size)
          echo "binary size before merging this pull request is $OUTPUT"
          echo "result=$OUTPUT" >> $GITHUB_OUTPUT

          echo "deps<<EOF" >> $GITHUB_OUTPUT
          ./scripts/visualize_size.sh list_symbols | awk '{print $2}' | head -n 100 >> $GITHUB_OUTPUT
          echo "EOF" >> $GITHUB_OUTPUT

      - name: Checkout datadog-agent pr branch
        run: |
          cd go/src/github.com/DataDog/datadog-agent
          git fetch origin $GITHUB_SHA --depth 1
          git checkout $GITHUB_SHA

      - name: Current binary size and dependencies
        id: current
        run: |
          cd go/src/github.com/DataDog/datadog-lambda-extension

          OUTPUT=$(./scripts/visualize_size.sh size)
          echo "binary size after merging this pull request will be $OUTPUT"
          echo "result=$OUTPUT" >> $GITHUB_OUTPUT

          echo "deps<<EOF" >> $GITHUB_OUTPUT
          ./scripts/visualize_size.sh list_symbols | awk '{print $2}' | head -n 100 >> $GITHUB_OUTPUT
          echo "EOF" >> $GITHUB_OUTPUT

      - name: Compare sizes
        id: compare
        run: |
          OUTPUT=$(( ${{ steps.current.outputs.result }} - ${{ steps.previous.outputs.result }} ))
          echo "diff=$OUTPUT" >> $GITHUB_OUTPUT

          OUTPUT=$(( $OUTPUT / 100000 ))
          echo "coldstart=$OUTPUT" >> $GITHUB_OUTPUT

      ### Steps below only run if size diff > SIZE_ALLOWANCE ###

      - name: Install graphviz
        uses: ts-graphviz/setup-graphviz@v1
        if: steps.compare.outputs.diff > env.SIZE_ALLOWANCE

      - name: Install digraph
        if: steps.compare.outputs.diff > env.SIZE_ALLOWANCE
        run: |
          GOPATH=$(pwd)/go go install golang.org/x/tools/cmd/digraph@latest

      - name: List new dependencies
        id: deps
        if: steps.compare.outputs.diff > env.SIZE_ALLOWANCE
        run: |
          echo "deps<<EOF" >> $GITHUB_OUTPUT
          for dep in $(echo "${{ steps.current.outputs.deps }}"); do
            if ! echo "${{ steps.previous.outputs.deps }}" | grep -w -q "$dep"; then
              echo "$dep" >> $GITHUB_OUTPUT
            fi
          done
          echo "EOF" >> $GITHUB_OUTPUT

      - name: Create dependency graphs
        if: steps.compare.outputs.diff > env.SIZE_ALLOWANCE
        run: |
          export PATH=$(pwd)/go/bin:$PATH
          cd go/src/github.com/DataDog/datadog-lambda-extension
          mkdir graphs
          for dep in $(echo "${{ steps.deps.outputs.deps }}"); do
            PACKAGE=$dep ./scripts/visualize_size.sh graph
            mv .layers/output.svg graphs/$(echo $dep | tr '/' '-').svg
          done

      - name: Archive dependency graphs
        uses: actions/upload-artifact@v3
        if: steps.compare.outputs.diff > env.SIZE_ALLOWANCE
        with:
          name: dependency-graphs
          path: go/src/github.com/DataDog/datadog-lambda-extension/graphs

      - name: Post comment
        uses: marocchino/sticky-pull-request-comment@v2.5.0
        if: steps.compare.outputs.diff > env.SIZE_ALLOWANCE
        with:
          hide_and_recreate: true
          hide_classify: "RESOLVED"
          message: |
            :warning::rotating_light: Warning, this pull request increases the binary size of serverless extension by ${{ steps.compare.outputs.diff }} bytes. Each MB of binary size increase means about 10ms of additional cold start time, so this pull request would increase cold start time by ${{ steps.compare.outputs.coldstart }}ms.

            If you have questions, we are happy to help, come visit us in the [#serverless](https://dd.slack.com/archives/CBWDFKWV8) slack channel and provide a link to this comment.

            <details>
            <summary>Debug info</summary>

            These dependencies were added to the serverless extension by this pull request:

            ```
            ${{ steps.deps.outputs.deps }}
            ```

            View dependency graphs for each added dependency in the [artifacts section](https://github.com/DataDog/datadog-agent/actions/runs/${{ github.run_id }}#artifacts) of the github action.

            We suggest you consider adding the `!serverless` build tag to remove any new dependencies not needed in the serverless extension.
            </details>