workflows/labels: add bottleneck for throttling (#417512)

.github/workflows/labels.yml

@@ -39,7 +39,12 @@ jobs:
     if: github.event_name != 'schedule' || github.repository_owner == 'NixOS'
     steps:
       - name: Install dependencies
-        run: npm install @actions/artifact
+        run: npm install @actions/artifact bottleneck
+
+      - name: Log current API rate limits
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: gh api /rate_limit | jq
 
       - name: Labels from API data and Eval results
         uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
@@ -47,12 +52,41 @@ jobs:
           UPDATED_WITHIN: ${{ inputs.updatedWithin }}
         with:
           script: |
+            const Bottleneck = require('bottleneck')
             const path = require('node:path')
             const { DefaultArtifactClient } = require('@actions/artifact')
             const { readFile } = require('node:fs/promises')
 
             const artifactClient = new DefaultArtifactClient()
 
+            const stats = {
+              prs: 0,
+              requests: 0,
+              artifacts: 0
+            }
+
+            // Rate-Limiting and Throttling, see for details:
+            //   https://github.com/octokit/octokit.js/issues/1069#throttling
+            //   https://docs.github.com/en/rest/using-the-rest-api/best-practices-for-using-the-rest-api
+            const allLimits = new Bottleneck({
+              // Avoid concurrent requests
+              maxConcurrent: 1,
+              // Hourly limit is at 5000, but other jobs need some, too!
+              // https://docs.github.com/en/rest/using-the-rest-api/rate-limits-for-the-rest-api
+              reservoir: 1000,
+              reservoirRefreshAmount: 1000,
+              reservoirRefreshInterval: 60 * 60 * 1000
+            })
+            // Pause between mutative requests
+            const writeLimits = new Bottleneck({ minTime: 1000 }).chain(allLimits)
+            github.hook.wrap('request', async (request, options) => {
+              stats.requests++
+              if (['POST', 'PUT', 'PATCH', 'DELETE'].includes(options.method))
+                return writeLimits.schedule(request.bind(null, options))
+              else
+                return allLimits.schedule(request.bind(null, options))
+            })
+
             if (process.env.UPDATED_WITHIN && !/^\d+$/.test(process.env.UPDATED_WITHIN))
               throw new Error('Please enter "updated within" as integer in hours.')
 
@@ -90,7 +124,7 @@ jobs:
               base: context.payload.pull_request.base.ref
             }
 
-            await github.paginate(
+            const prs = await github.paginate(
               github.rest.pulls.list,
               {
                 ...context.repo,
@@ -99,12 +133,16 @@ jobs:
                 direction: 'desc',
                 ...prEventCondition
               },
-              async (response, done) => (await Promise.allSettled(response.data.map(async (pull_request) => {
+              (response, done) => response.data.map(async (pull_request) => {
                 try {
-                  const log = (k,v) => core.info(`PR #${pull_request.number} - ${k}: ${v}`)
+                  const log = (k,v,skip) => {
+                    core.info(`PR #${pull_request.number} - ${k}: ${v}` + (skip ? ' (skipped)' : ''))
+                    return skip
+                  }
 
-                  log('Last updated at', pull_request.updated_at)
-                  if (new Date(pull_request.updated_at) < cutoff) return done()
+                  if (log('Last updated at', pull_request.updated_at, new Date(pull_request.updated_at) < cutoff))
+                    return done()
+                  stats.prs++
                   log('URL', pull_request.html_url)
 
                   const run_id = (await github.rest.actions.listWorkflowRuns({
@@ -119,8 +157,8 @@ jobs:
 
                   // Newer PRs might not have run Eval to completion, yet. We can skip them, because this
                   // job will be run as part of that Eval run anyway.
-                  log('Last eval run', run_id ?? '<pending>')
-                  if (!run_id) return;
+                  if (log('Last eval run', run_id ?? '<pending>', !run_id))
+                    return;
 
                   const artifact = (await github.rest.actions.listWorkflowRunArtifacts({
                     ...context.repo,
@@ -132,8 +170,10 @@ jobs:
                   // actually download the artifact in the next step and avoid that race condition.
                   // Older PRs, where the workflow run was already eval.yml, but the artifact was not
                   // called "comparison", yet, will be skipped as well.
-                  log('Artifact expires at', artifact?.expires_at ?? '<not found>')
-                  if (new Date(artifact?.expires_at ?? 0) < new Date(new Date().getTime() + 60 * 1000)) return;
+                  const expired = new Date(artifact?.expires_at ?? 0) < new Date(new Date().getTime() + 60 * 1000)
+                  if (log('Artifact expires at', artifact?.expires_at ?? '<not found>', expired))
+                    return;
+                  stats.artifacts++
 
                   await artifactClient.downloadArtifact(artifact.id, {
                     findBy: {
@@ -195,10 +235,14 @@ jobs:
                 } catch (cause) {
                   throw new Error(`Labeling PR #${pull_request.number} failed.`, { cause })
                 }
-              })))
+              })
+            );
+
+            (await Promise.allSettled(prs.flat()))
               .filter(({ status }) => status == 'rejected')
               .map(({ reason }) => core.setFailed(`${reason.message}\n${reason.cause.stack}`))
-            )
+
+            core.notice(`Processed ${stats.prs} PRs, made ${stats.requests + stats.artifacts} API requests and downloaded ${stats.artifacts} artifacts.`)
 
       - uses: actions/labeler@8558fd74291d67161a8a78ce36a881fa63b766a9 # v5.0.0
         name: Labels from touched files