chore(release-check): add retries (#19336)

The `find-latest-release` script occasionally times out on PR builds.

Add sleeps and retries. The retries are pretty hefty because the API
limits are quite low. We can't just toss a GitHub Token in there, as
anyone who submits a PR would have access to it. This is the cheapest
fix for now.


----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

scripts/find-latest-release.js

@@ -16,9 +16,33 @@ async function main(matchRange) {
     throw new Error(`Not a valid range: ${matchRange}`);
   }
 
-  const { stdout, error } = cp.spawnSync('curl', ['https://api.github.com/repos/aws/aws-cdk/releases?per_page=100'], { maxBuffer: 10_000_000 });
-  if (error) { throw error; }
-  const releases = JSON.parse(stdout);
+  let releases;
+  for (let attempt = 0; attempt < 10; attempt++) {
+    const { stdout, error } = cp.spawnSync('curl', ['https://api.github.com/repos/aws/aws-cdk/releases?per_page=100'], { maxBuffer: 10_000_000 });
+    if (error) { throw error; }
+
+    const response = JSON.parse(stdout);
+    if (response.message) {
+      // This is actually an error response. Only recover from throttling errors.
+      if (!response.message.includes('API rate limit')) {
+        throw new Error(response.message);
+      }
+
+      // 60 requests/hour, so we need to sleep for a full minute to get any kind of response
+      const sleepTime = Math.floor(Math.random() * 60 * Math.pow(2, attempt));
+      console.log('Sleeping for', sleepTime, 'seconds');
+      await sleep(sleepTime * 1000);
+      continue;
+    }
+
+    releases = response;
+    break;
+  }
+  if (!releases) {
+    throw new Error('Retries exhaused');
+  }
+
+
   const versions = releases.map(r => r.name.replace(/^v/, '')); // v1.2.3 -> 1.2.3
 
   const sat = semver.maxSatisfying(versions, range);
@@ -28,7 +52,11 @@ async function main(matchRange) {
   console.log(sat);
 }
 
+function sleep(ms) {
+  return new Promise(ok => setTimeout(ok, ms));
+}
+
 main(process.argv[2]).catch(e => {
   console.error(e);
   process.exitCode = 1;
-});
+});