codegen-preview.yml

name: codegen diff preview
# This job will generate a codegen output diff comparing the target base ref with current HEAD ref and push it to S3
# and comment on GitHub PR with a link to the HTML output.
on:
  pull_request:
    types:
      - opened
      - reopened
      - synchronize

permissions:
  id-token: write
  contents: read
  pull-requests: write

# Allow one instance of this workflow per pull request, and cancel older runs when new changes are pushed
concurrency:
  group: ci-codegen-diff-${{ github.ref }}
  cancel-in-progress: true

env:
  JAVA_VERSION: 17
  RUN: ${{ github.run_id }}-${{ github.run_number }}
  DIFF2HTML_VERSION: 5.2.5
  # Below is the set of services that are generated for codegen preview
  # These are carefully selected to exercise every Smithy protocol.
  #  - @awsJson1_0: dynamodb
  #  - @awsJson1_1: codebuild
  #  - @awsQuery: sts
  #  - @ec2Query: ec2
  #  - @restJson1: polly
  #  - @restXml: s3
  PREVIEW_SERVICES: +dynamodb,+codebuild,+sts,+ec2,+polly,+s3
  HEAD_BRANCH_NAME: __tmp-localonly-head
  BASE_BRANCH_NAME: __tmp-localonly-base

jobs:

  generate-codegen-diff:
    runs-on: ubuntu-latest
    name: Generate diff and upload to S3
    outputs:
      bot-message: ${{ steps.generate-diff.outputs.codegen-diff-msg }}
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
          path: 'aws-sdk-kotlin'
      - uses: actions/checkout@v4
        with:
          repository: 'awslabs/aws-kotlin-repo-tools'
          path: 'aws-kotlin-repo-tools'
      - uses: actions/checkout@v4
        with:
          repository: 'awslabs/smithy-kotlin'
          fetch-depth: 0
          path: 'smithy-kotlin'
      - name: Set up JDK
        uses: actions/setup-java@v3
        with:
          java-version: ${{ env.JAVA_VERSION }}
          distribution: 'corretto'
          cache: 'gradle'
      - name: Install deps and setup environment
        run: |
          npm install -g diff2html-cli@${{ env.DIFF2HTML_VERSION }}
          env | sort
          # store off a copy of head ref of ci.py, otherwise base ref generation will use a different version of this script
          CODEGEN_DIFF_REVISIONS=${{ runner.temp }}/codegen-diff-revisions.py
          cp $GITHUB_WORKSPACE/aws-sdk-kotlin/.github/scripts/codegen-diff-revisions.py $CODEGEN_DIFF_REVISIONS
          echo "CODEGEN_DIFF_REVISIONS=$CODEGEN_DIFF_REVISIONS" >> "$GITHUB_ENV"
          echo "REPO_TOOLS=$GITHUB_WORKSPACE/aws-kotlin-repo-tools" >> "$GITHUB_ENV"
          echo "SMITHY_KOTLIN_DIR=$GITHUB_WORKSPACE/smithy-kotlin" >> "$GITHUB_ENV"
          echo "SDK_DIR=$GITHUB_WORKSPACE/aws-sdk-kotlin" >> "$GITHUB_ENV"

      - name: Generate code for head ref
        run: |
          branch=$(python3 $REPO_TOOLS/scripts/ci.py get-branch $SDK_DIR)
          pushd $SMITHY_KOTLIN_DIR
          if git ls-remote --quiet --exit-code --heads origin refs/heads/$branch
          then
            echo "using smithy-kotlin branch $branch for head ref codegen"
          else
            # in the case of feature branches with tentacles we may or may not have a corresponding base ref in smithy-kotlin
            # if we do let's use that, otherwise fallback to main
            echo "$branch does not exist in smithy-kotlin, will attempt base ref $GITHUB_BASE_REF"
            branch=$GITHUB_BASE_REF
          fi
          python3 $REPO_TOOLS/scripts/ci.py -v set-branch --branch $branch
          popd
          pushd $SDK_DIR
          git checkout -b $HEAD_BRANCH_NAME
          $CODEGEN_DIFF_REVISIONS codegen --bootstrap ${{ env.PREVIEW_SERVICES }}
          popd

      - name: Generate code for base ref
        run: |
          branch=$GITHUB_BASE_REF
          echo "checkout smithy-kotlin at base ref: $branch"
          pushd $SMITHY_KOTLIN_DIR
          git switch -f main
          python3 $REPO_TOOLS/scripts/ci.py -v set-branch --branch $branch
          popd
          echo "resetting aws-sdk-kotlin"
          pushd $SDK_DIR
          git switch -f main
          python3 $REPO_TOOLS/scripts/ci.py -v set-branch --branch $branch 
          git checkout -b $BASE_BRANCH_NAME
          $CODEGEN_DIFF_REVISIONS codegen --bootstrap ${{ env.PREVIEW_SERVICES }}
          popd

      - name: Generate diffs
        id: generate-diff
        run: |
          pushd $SDK_DIR
          $CODEGEN_DIFF_REVISIONS \
            --head-sha ${{ github.event.pull_request.head.sha }} \
            generate-diffs \
            --base-sha ${{ github.event.pull_request.base.sha }} \
            $BASE_BRANCH_NAME $HEAD_BRANCH_NAME
          cat ./tmp-codegen-diff/bot-message
          {
            echo 'codegen-diff-msg<<DIFF_MSG_EOF'
            echo "$(cat ./tmp-codegen-diff/bot-message)"
            echo 'DIFF_MSG_EOF'
          } >> "$GITHUB_OUTPUT"
          echo $GITHUB_OUTPUT

      - name: Configure AWS Credentials
        uses: aws-actions/configure-aws-credentials@v2
        with:
          role-to-assume: ${{ secrets.CI_AWS_ROLE_ARN }}
          aws-region: us-west-2

      - name: Upload diff to S3
        run: |
          SDK_DIR=$GITHUB_WORKSPACE/aws-sdk-kotlin
          pushd $SDK_DIR
          if [[ -d ./tmp-codegen-diff/${{ github.event.pull_request.base.sha }} ]]; then
            aws s3 cp ./tmp-codegen-diff/${{ github.event.pull_request.base.sha }} \
                "s3://${{ secrets.CDN_S3_BUCKET_NAME }}/codegen-diff/${{ github.event.pull_request.base.sha }}" --recursive
          fi

  # TODO - generate doc preview for N services and upload and link as well
  post-bot-comment:
    name: Post bot comment
    runs-on: ubuntu-latest
    needs:
      - generate-codegen-diff
    steps:
      - name: Post bot comment
        uses: actions/github-script@v5
        with:
          script: |
            await github.rest.issues.createComment({
              issue_number: ${{ github.event.number }},
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: '${{ needs.generate-codegen-diff.outputs.bot-message }}\n\n'
            })