cpython-wasm.yml

name: "Build"

on:
  push:
    branches:
      - main
  pull_request:
    branches:
      - main
    types:
      - opened
      - synchronize
      - reopened
  workflow_dispatch:
    inputs:
      cpython_ref:
        required: true
        default: "main"
        description: "Ref of CPython to build"
      deploy_channel:
        required: true
        default: "stable"
        description: "Where to publish the site (manual runs)"
        type: choice
        options:
          - stable
# Maybe rebuild evrery now and again?
#  schedule:
#    - cron: ""

permissions: {}

concurrency:
  group: cpython-wasm
  cancel-in-progress: false

jobs:
  get-emscripten-version:
    name: "Read pinned Emscripten/Node versions from CPython"
    runs-on: ubuntu-latest
    outputs:
      emscripten_version: ${{ steps.versions.outputs.emscripten_version }}
      node_version: ${{ steps.versions.outputs.node_version }}
      cpython_ref: ${{ steps.ref.outputs.cpython_ref }}
      deploy_channel: ${{ steps.channel.outputs.deploy_channel }}
      deploy_destination: ${{ steps.channel.outputs.deploy_destination }}
    steps:
      - name: "Resolve cpython ref"
        id: ref
        env:
          REF_INPUT: ${{ inputs.cpython_ref }}
        run: |
          ref="${REF_INPUT:-main}"
          echo "cpython_ref=$ref" >> "$GITHUB_OUTPUT"
      - name: "Resolve deploy channel"
        id: channel
        env:
          CHANNEL_INPUT: ${{ inputs.deploy_channel }}
          EVENT_NAME: ${{ github.event_name }}
          PR_NUMBER: ${{ github.event.pull_request.number }}
        run: |
          if [ "$EVENT_NAME" = "push" ]; then
            channel="stable"
            destination=""
          elif [ "$EVENT_NAME" = "pull_request" ]; then
            channel="preview"
            destination="pr-${PR_NUMBER}"
          else
            channel="${CHANNEL_INPUT:-stable}"
            destination=""
          fi
          echo "deploy_channel=$channel" >> "$GITHUB_OUTPUT"
          echo "deploy_destination=$destination" >> "$GITHUB_OUTPUT"
      - name: "Checkout cpython @ ${{ steps.ref.outputs.cpython_ref }}"
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          repository: "python/cpython"
          ref: ${{ steps.ref.outputs.cpython_ref }}
          persist-credentials: false
      - name: "Install Python"
        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
        with:
          python-version: "3.x"
      - name: "Read config.toml"
        id: versions
        shell: python
        run: |
          import os, tomllib
          from pathlib import Path
          cfg = tomllib.loads(Path("Platforms/emscripten/config.toml").read_text())
          with open(os.environ["GITHUB_OUTPUT"], "a") as f:
              f.write(f"emscripten_version={cfg['emscripten-version']}\n")
              f.write(f"node_version={cfg['node-version']}\n")

  build:
    name: "Cross-compile CPython to wasm32-emscripten"
    needs: get-emscripten-version
    runs-on: ubuntu-latest
    timeout-minutes: 120
    env:
      CPYTHON_REF: ${{ needs.get-emscripten-version.outputs.cpython_ref }}
    defaults:
      run:
        working-directory: cpython
    steps:
      - name: "Checkout codoscope"
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          path: codoscope
          persist-credentials: false

      - name: "Checkout cpython@${{ env.CPYTHON_REF }}"
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          repository: "python/cpython"
          ref: ${{ env.CPYTHON_REF }}
          path: cpython
          persist-credentials: false

      - name: "Install build Python"
        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
        with:
          python-version: "3"

      - name: "Install Node"
        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
        with:
          node-version: ${{ needs.get-emscripten-version.outputs.node_version }}

      - name: "Install Emscripten SDK ${{ needs.get-emscripten-version.outputs.emscripten_version }}"
        uses: mymindstorm/setup-emsdk@6ab9eb1bda2574c4ddb79809fc9247783eaf9021 # v14
        with:
          version: ${{ needs.get-emscripten-version.outputs.emscripten_version }}
          actions-cache-folder: emsdk-cache

      - name: "Build"
        run: python3 Tools/wasm/emscripten build --quiet

      - name: "Stage site"
        working-directory: ${{ github.workspace }}
        run: |
          mkdir _site
          cp -a cpython/cross-build/wasm32-emscripten/build/python/web_example/. _site/
          rm _site/server.py
          cp codoscope/web/index.html _site/index.html
          cp codoscope/web/driver.py  _site/driver.py
          if [ -f codoscope/web/python.worker.mjs ]; then
            cp codoscope/web/python.worker.mjs _site/python.worker.mjs
          fi

      - name: "Add Pages bits"
        shell: bash
        working-directory: ${{ github.workspace }}/_site
        run: |
          set -euo pipefail
          # GitHub Pages cannot set COOP/COEP headers, but the Emscripten
          # thingy needs SharedArrayBuffer. coi-serviceworker installs
          # those headers client-side (which costs us one automatic reload).
          # The <script src="coi-serviceworker.js"> tag lives in web/index.html.
          curl -fsSL -o coi-serviceworker.js \
            https://cdn.jsdelivr.net/gh/gzuidhof/coi-serviceworker@7b1d2a092d0d2dd2b7270b6f12f13605de26f214/coi-serviceworker.min.js

      - name: "Upload site artifact"
        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
        with:
          name: site
          path: _site
          if-no-files-found: error
          retention-days: 7
          include-hidden-files: true

  deploy:
    name: "Publish site"
    needs: [get-emscripten-version, build]
    runs-on: ubuntu-latest
    if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository
    permissions:
      contents: write
      pull-requests: write
    env:
      DEPLOY_CHANNEL: ${{ needs.get-emscripten-version.outputs.deploy_channel }}
      DEPLOY_DESTINATION: ${{ needs.get-emscripten-version.outputs.deploy_destination }}
    steps:
      - name: "Checkout"
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          persist-credentials: true

      - name: "Download site artifact"
        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4
        with:
          name: site
          path: site

      - name: "Deploy PR preview site"
        if: env.DEPLOY_CHANNEL == 'preview'
        uses: peaceiris/actions-gh-pages@e9c66a37f080288a11235e32cbe2dc5fb3a679cc # v4
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          publish_dir: ./site
          publish_branch: gh-pages
          destination_dir: ${{ env.DEPLOY_DESTINATION }}
          keep_files: true
          force_orphan: false
          commit_message: "Publish PR preview #${{ github.event.pull_request.number }}"

      - name: "Deploy stable site to gh-pages root"
        if: env.DEPLOY_CHANNEL == 'stable'
        uses: peaceiris/actions-gh-pages@e9c66a37f080288a11235e32cbe2dc5fb3a679cc # v4
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          publish_dir: ./site
          publish_branch: gh-pages
          keep_files: true
          force_orphan: false
          commit_message: "Publish site from main (cpython@${{ needs.get-emscripten-version.outputs.cpython_ref || 'main' }})"

      - name: "Comment PR preview URL"
        if: env.DEPLOY_CHANNEL == 'preview'
        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
        with:
          script: |
            const owner = context.repo.owner;
            const repo = context.repo.repo;
            const previewUrl = `https://${owner}.github.io/${repo}/${process.env.DEPLOY_DESTINATION}/`;
            await github.rest.issues.createComment({
              owner,
              repo,
              issue_number: context.issue.number,
              body: `Preview deployed: ${previewUrl}`,
            });