build: implement a Commit Queue in Actions

This is a (still experimental) implementation of a Commit Queue on
GitHub Actions, using labels and the scheduler event to land Pull
Requests. It uses `node-core-utils` to validate Pull Requests and to
prepare the commit message, and then it uses a GitHub personal token to
push changes back to the repository. If the Queue fails to land a Pull
Request, that PR will be removed from the queue and the
`node-core-utils` output will be pasted in the Pull Request.

An overview of the implementation is provided in
doc/guides/commit-queue.md, as well as current limitations.

Ref: https://github.com/mmarchini-oss/automated-merge-test
Ref: https://github.com/nodejs/build/issues/2201

PR-URL: https://github.com/nodejs/node/pull/34112
Refs: https://github.com/mmarchini-oss/automated-merge-test
Refs: https://github.com/nodejs/build/issues/2201
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Shelley Vohr <codebytere@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>

tools/actions/commit-queue.sh

@@ -0,0 +1,85 @@
+#!/bin/bash
+
+set -xe
+
+OWNER=$1
+REPOSITORY=$2
+GITHUB_TOKEN=$3
+shift 3
+
+API_URL=https://api.github.com
+COMMIT_QUEUE_LABEL='commit-queue'
+COMMIT_QUEUE_FAILED_LABEL='commit-queue-failed'
+
+function issueUrl() {
+  echo "$API_URL/repos/${OWNER}/${REPOSITORY}/issues/${1}"
+}
+
+function labelsUrl() {
+  echo "$(issueUrl "${1}")/labels"
+}
+
+function commentsUrl() {
+  echo "$(issueUrl "${1}")/comments"
+}
+
+function gitHubCurl() {
+  url=$1
+  method=$2
+  shift 2
+
+  curl -fsL --request "$method" \
+       --url "$url" \
+       --header "authorization: Bearer ${GITHUB_TOKEN}" \
+       --header 'content-type: application/json' "$@"
+}
+
+
+# TODO(mmarchini): should this be set with whoever added the label for each PR?
+git config --local user.email "github-bot@iojs.org"
+git config --local user.name "Node.js GitHub Bot"
+
+for pr in "$@"; do
+  # Skip PR if CI was requested
+  if gitHubCurl "$(labelsUrl "$pr")" GET | jq -e 'map(.name) | index("request-ci")'; then
+    echo "pr ${pr} skipped, waiting for CI to start"
+    continue
+  fi
+
+  # Skip PR if CI is still running
+  if ncu-ci url "https://github.com/${OWNER}/${REPOSITORY}/pull/${pr}" 2>&1 | grep "^Result *PENDING"; then
+    echo "pr ${pr} skipped, CI still running"
+    continue
+  fi
+
+  # Delete the commit queue label
+  gitHubCurl "$(labelsUrl "$pr")"/"$COMMIT_QUEUE_LABEL" DELETE
+
+  git node land --yes "$pr" >output 2>&1 || echo "Failed to land #${pr}"
+  # cat here otherwise we'll be supressing the output of git node land
+  cat output
+
+  # TODO(mmarchini): workaround for ncu not returning the expected status code,
+  # if the "Landed in..." message was not on the output we assume land failed
+  if ! tail -n 10 output | grep '. Post "Landed in .*/pull/'"${pr}"; then
+    gitHubCurl "$(labelsUrl "$pr")" POST --data '{"labels": ["'"${COMMIT_QUEUE_FAILED_LABEL}"'"]}'
+
+    jq -n --arg content "<details><summary>Commit Queue failed</summary><pre>$(cat output)</pre></details>" '{body: $content}' > output.json
+    cat output.json
+
+    gitHubCurl "$(commentsUrl "$pr")" POST --data @output.json
+
+    rm output output.json
+    # If `git node land --abort` fails, we're in unknown state. Better to stop
+    # the script here, current PR was removed from the queue so it shouldn't
+    # interfer again in the future
+    git node land --abort --yes
+  else
+    rm output
+    git push origin master
+
+    gitHubCurl "$(commentsUrl "$pr")" POST --data '{"body": "Landed in '"$(git rev-parse HEAD)"'"}'
+
+    gitHubCurl "$(issueUrl "$pr")" PATCH --data '{"state": "closed"}'
+  fi
+done