chore(web): adjust assets cache control policy

Author: gribnoysup

packages/compass-web/scripts/upload.mts

@@ -54,11 +54,12 @@ const s3Client = new S3({
   credentials: getCredentials(),
 });
 
-const CACHE_MAX_AGE = 5 * 1000 * 60; // 5mins
+const IMMUTABLE_CACHE_MAX_AGE = 1000 * 60 * 60 * 24 * 7; // a week
 
 for (const file of artifacts) {
   const filePath = path.join(DIST_DIR, file);
-  // NB: important that upload root directory is always `compass/`
+  // TODO(SRE-4971): while we're uploading to the downloads bucket, the object
+  // key always needs to start with `compass/`
   const objectKey = `compass/web/${HEAD}/${file}`;
 
   console.log(
@@ -85,7 +86,9 @@ for (const file of artifacts) {
     ContentType: contentTypeForExt[path.extname(file)],
     ContentEncoding: 'br',
     ContentLength: compressedFileContent.byteLength,
-    CacheControl: `public, max-age=${CACHE_MAX_AGE}, must-revalidate`,
+    // Assets stored under the commit hash never change after upload, so the
+    // cache-control setting for them can be quite generous
+    CacheControl: `public, max-age=${IMMUTABLE_CACHE_MAX_AGE}, immutable`,
   });
 
   console.log('Successfully uploaded %s (ETag: %s)', file, res.ETag);