build: auto start Jenkins CI via PR labels

Add an Action that will find every PR with the `request-ci` label and
will start a Jenkins CI for each of these Pull Requests. The scheduler
event is used to circumvent GitHub Actions limitations on Pull Requests
from forks (where secrets are not accessible and the GITHUB_TOKEN is
read-only).

If the Action fails to start a CI, it will add a `request-ci-failed`
label and will leave a comment with the error message from NCU.

Fixes: https://github.com/nodejs/github-bot/issues/234

PR-URL: https://github.com/nodejs/node/pull/34089
Reviewed-By: Christian Clauss <cclauss@me.com>

.github/workflows/auto-start-ci.yml

@@ -0,0 +1,65 @@
+---
+name: Auto Start CI
+
+on:
+  push:
+  schedule:
+    # `schedule` event is used instead of `pull_request` because when a
+    # `pull_requesst` event is triggered on a PR from a fork, GITHUB_TOKEN will
+    # be read-only, and the Action won't have access to any other repository
+    # secrets, which it needs to access Jenkins API. Runs every five minutes
+    # (fastest the scheduler can run). Five minutes is optimistic, it can take
+    # longer to run.
+    - cron: "*/5 * * * *"
+
+jobs:
+  commitQueue:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@master
+
+      # Install dependencies
+      - name: Install jq
+        run: sudo apt-get install jq -y
+      - name: Install Node.js
+        uses: actions/setup-node@v2-beta
+        with:
+          node-version: '12'
+      - name: Install node-core-utils
+        run: npm install -g node-core-utils
+
+      - name: Set variables
+        run: |
+          echo "::set-env name=REPOSITORY::$(echo ${{ github.repository }} | cut -d/ -f2)"
+          echo "::set-env name=OWNER::${{ github.repository_owner }}"
+
+      # Get Pull Requests
+      - name: Get Pull Requests
+        uses: octokit/graphql-action@v2.x
+        id: get_prs_for_ci
+        with:
+          query: |
+            query prs($owner:String!, $repo:String!) {
+              repository(owner:$owner, name:$repo) {
+                pullRequests(labels: ["request-ci"], states: OPEN, last: 100) {
+                  nodes {
+                    number
+                  }
+                }
+              }
+            }
+          owner: ${{ env.OWNER }}
+          repo: ${{ env.REPOSITORY }}
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Setup node-core-utils
+        run: |
+          ncu-config set username ${{ secrets.JENKINS_USER }}
+          ncu-config set token none
+          ncu-config set jenkins_token ${{ secrets.JENKINS_TOKEN }}
+          ncu-config set owner ${{ env.OWNER }}
+          ncu-config set repo ${{ env.REPOSITORY }}
+
+      - name: Start CI
+        run: ./tools/start-ci.sh ${{ secrets.GITHUB_TOKEN }} ${{ env.OWNER }} ${{ env.REPOSITORY }} $(echo '${{ steps.get_prs_for_ci.outputs.data }}' | jq '.repository.pullRequests.nodes | map(.number) | .[]')

tools/actions/start-ci.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+
+set -xe
+
+GITHUB_TOKEN=$1
+OWNER=$2
+REPOSITORY=$3
+API_URL=https://api.github.com
+REQUEST_CI_LABEL='request-ci'
+REQUEST_CI_FAILED_LABEL='request-ci-failed'
+shift 3
+
+function issueUrl() {
+  echo "$API_URL/repos/${OWNER}/${REPOSITORY}/issues/${1}"
+}
+
+function labelsUrl() {
+  echo "$(issueUrl "${1}")/labels"
+}
+
+function commentsUrl() {
+  echo "$(issueUrl "${1}")/comments"
+}
+
+for pr in "$@"; do
+  curl -sL --request DELETE \
+       --url "$(labelsUrl "$pr")"/"$REQUEST_CI_LABEL" \
+       --header "authorization: Bearer ${GITHUB_TOKEN}" \
+       --header 'content-type: application/json'
+
+  ci_started=yes
+  rm -f output;
+  ncu-ci run "$pr" >output 2>&1 || ci_started=no
+
+  if [ "$ci_started" == "no" ]; then
+    # Do we need to reset?
+    curl -sL --request PUT \
+       --url "$(labelsUrl "$pr")" \
+       --header "authorization: Bearer ${GITHUB_TOKEN}" \
+       --header 'content-type: application/json' \
+       --data '{"labels": ["'"${REQUEST_CI_FAILED_LABEL}"'"]}'
+
+    jq -n --arg content "<details><summary>Couldn't start CI</summary><pre>$(cat output)</pre></details>" '{body: $content}' > output.json
+
+    curl -sL --request POST \
+       --url "$(commentsUrl "$pr")" \
+       --header "authorization: Bearer ${GITHUB_TOKEN}" \
+       --header 'content-type: application/json' \
+       --data @output.json
+
+    rm output.json;
+  fi
+done;