Simple merge queue (#22992)

.github/actions-scripts/update-merge-queue-branch.js

@@ -0,0 +1,124 @@
+#!/usr/bin/env node
+
+import { getOctokit } from '@actions/github'
+const token = process.env.GITHUB_TOKEN
+const github = getOctokit(token)
+
+// Mergeable status documentation here:
+// https://docs.github.com/en/graphql/reference/enums#mergestatestatus
+// https://docs.github.com/en/graphql/reference/enums#mergeablestate
+
+/* 
+  This script gets a list of automerge-enabled PRs and sorts them 
+  by priority. The PRs with the skip-to-front-of-merge-queue label
+  are prioritized first. The rest of the PRs are sorted by the date 
+  they were updated. This is basically a FIFO queue, while allowing 
+  writers the ability to skip the line when high-priority ships are
+  needed but a freeze isn't necessary.
+*/
+
+main()
+
+async function main() {
+  // Get a list of open PRs and order them from oldest to newest
+  const query = `query ($first: Int, $after: String, $firstLabels: Int) {
+    organization(login: "github") {
+      repository(name: "docs-internal") {
+        pullRequests(first: $first, after: $after, states: OPEN, orderBy: {field: UPDATED_AT, direction: ASC}) {
+          edges{
+            node {
+              number
+              url
+              updatedAt
+              mergeable
+              mergeStateStatus
+              autoMergeRequest {
+                enabledBy {
+                  login
+                }
+                enabledAt
+              }
+              labels (first:$firstLabels){
+                nodes {
+                  name
+                }
+              }
+            }
+          }
+          pageInfo {
+            hasNextPage
+            endCursor
+          }
+        }
+      }
+    }
+  }`
+
+  const queryVariables = {
+    first: 100,
+    after: null, // when pagination in null it will get first page
+    firstLabels: 100,
+    headers: {
+      // required for the mergeStateStatus enum
+      accept: 'application/vnd.github.merge-info-preview+json',
+    },
+  }
+  let hasNextPage = true
+  const autoMergeEnabledPRs = []
+
+  // we need to get all the paginated results in the case that
+  // there are more than 100 PRs
+  while (hasNextPage) {
+    const graph = await github.graphql(query, queryVariables)
+    const dataRoot = graph.organization.repository.pullRequests
+    const pullRequests = dataRoot.edges
+    // update pagination variables
+    hasNextPage = dataRoot.pageInfo.hasNextPage
+    // the endCursor is the start cursor for the next page
+    queryVariables.after = dataRoot.pageInfo.endCursor
+
+    const filteredPrs = pullRequests
+      // this simplifies the format received from the graphql query to
+      // remove the unnecessary nested objects
+      .map((pr) => {
+        // make the labels object just an array of the label names
+        const labelArray = pr.node.labels.nodes.map((label) => label.name)
+        pr.node.labels = labelArray
+        // return the pr object and ✂️ the node property
+        return pr.node
+      })
+      .filter((pr) => pr.autoMergeRequest !== null)
+      .filter((pr) => pr.mergeable === 'MERGEABLE')
+      // filter out prs that don't have a calculated mergeable state yet
+      .filter((pr) => pr.mergeStateStatus !== 'UNKNOWN')
+      // filter out prs that still need a review, have merge conflicts,
+      // or have failing ci tests
+      .filter((pr) => pr.mergeStateStatus !== 'BLOCKED')
+      // **NOTE**: In the future we may want to send slack message to initiators
+      // of PRs with the following merge states because these can happen after
+      // a PR is green and the automerge is enabled
+      .filter((pr) => pr.mergeStateStatus !== 'DIRTY')
+      .filter((pr) => pr.mergeStateStatus !== 'UNSTABLE')
+
+    autoMergeEnabledPRs.push(...filteredPrs)
+  }
+
+  // Get the list of prs with the skip label so they can
+  // be put at the beginning of the list
+  const prioritizedPrList = autoMergeEnabledPRs
+    .filter((pr) => pr.labels.includes('skip-to-front-of-merge-queue'))
+    .concat(autoMergeEnabledPRs.filter((pr) => !pr.labels.includes('skip-to-front-of-merge-queue')))
+
+  const nextInQueue = prioritizedPrList.shift()
+  // Update the branch for the next PR in the merge queue
+  github.rest.pulls.updateBranch({
+    owner: 'github',
+    repo: 'docs-internal',
+    pull_number: parseInt(nextInQueue.number),
+  })
+
+  console.log(`⏱ Total PRs in the merge queue: ${prioritizedPrList.length + 1}`)
+  console.log(`🚂 Updated branch for PR #${JSON.stringify(nextInQueue, null, 2)}`)
+  console.log(`🚏 Next up in the queue: `)
+  console.log(JSON.stringify(prioritizedPrList, null, 2))
+}

.github/allowed-actions.js

@@ -17,7 +17,6 @@ export default [
   'cschleiden/actions-linter@caffd707beda4fc6083926a3dff48444bc7c24aa', // uses github-actions-parser v0.23.0
   'dawidd6/action-delete-branch@47743101a121ad657031e6704086271ca81b1911', // v3.0.2
   'dawidd6/action-download-artifact@af92a8455a59214b7b932932f2662fdefbd78126', // v2.15.0
-  'docker://chinthakagodawita/autoupdate-action:v1',
   'dorny/paths-filter@eb75a1edc117d3756a18ef89958ee59f9500ba58',
   'trilom/file-changes-action@a6ca26c14274c33b15e6499323aac178af06ad4b', // v1.2.4
   'github/codeql-action/analyze@v1',

.github/workflows/autoupdate-branch.yml

@@ -1,20 +1,22 @@
 name: Autoupdate branch
 
-# **What it does**: Any pull requests with automerge will get main branch updates.
-# **Why we have it**: So we don't have to watch pull requests and click update branch 100x.
+# **What it does**: The next pull request in the merge queue will get its
+# branch updated with main. Only updating one branch ensures that pull requests
+# in the queue are merged sequentially.
+# **Why we have it**: So we don't have to watch pull requests and click
+# update branch 1000x.
 # **Who does it impact**: Our health.
-
 #
-# This workflow checks all open PRs targeting `main` as their base branch and
-# will attempt to update them if they have automerge.
-# It is triggered when a `push` event occurs ON the `main` branch (e.g. a PR
-# was merged or a force-push was done).
+# The merge queue consists of any pull requests with automerge enabled and
+# are mergeable. There is a label that can be used to skip to the front of
+# the queue (`skip-to-front-of-merge-queue`).
 #
-# It should work on all PRs created from source branches within the repo itself
-# but is unlikely to work for PRs created from forked repos.
+# This workflow is triggered when a `push` event occurs ON the `main` branch
+#  (e.g. a PR was merged or a force-push was done).
 #
-# It is still worthwhile to leave it enabled for the `docs` open source repo as
-# it should at least be running on `repo-sync` branch PRs.
+# This workflow runs on all PRs created from source branches within the
+# public and private docs repos but is won't work for PRs created from
+# forked repos.
 #
 
 on:
@@ -28,8 +30,7 @@ jobs:
     name: autoupdate
     runs-on: ubuntu-latest
     steps:
-      - uses: docker://chinthakagodawita/autoupdate-action:v1
+      - name: Update next PR in queue
         env:
-          GITHUB_TOKEN: ${{ secrets.OCTOMERGER_PAT_WITH_REPO_AND_WORKFLOW_SCOPE }}
-          PR_FILTER: auto_merge
-          MERGE_MSG: 'Autoupdate branch'
+          GITHUB_TOKEN: ${{ secrets.DOCUBOT_REPO_PAT }}
+        run: node .github/actions-scripts/update-merge-queue-branch.js