[doc-updater] fix unbounded Redis key growth in project notifications cron (#35425)

* delete timestamp notification keys for solo projects
* add fallback 7d TTL for keys

GitOrigin-RevId: e0493e74b14b861863afc1d4ef5fa181432ad450

services/document-updater/app/js/RedisManager.js

@@ -16,6 +16,7 @@ const rclient = RedisWrapper.createClient(Settings.redis.documentupdater)
 // hold us up, and need to bail out quickly if there is a problem.
 const MAX_REDIS_REQUEST_LENGTH = 5000 // 5 seconds
 const PROJECT_BLOCK_TTL_SECS = 30
+const ONE_DAY_SECS = 24 * 60 * 60
 
 // Make times easy to read
 const minutes = 60 // seconds for Redis expire
@@ -575,6 +576,8 @@ const RedisManager = {
     await rclient.set(
       keys.projectNotificationTimestamp({ project_id: projectId }),
       timestamp,
+      'EX',
+      7 * ONE_DAY_SECS,
       'NX'
     )
   },

services/document-updater/scripts/project_notifications.mts

@@ -384,6 +384,9 @@ async function getProjectsToNotify(): Promise<{
         for (const c of candidates) {
           if (!projectsWithCollaborators.has(c.projectId)) {
             stats.skippedNoCollaborators++
+            if (!dryRun) {
+              await deleteProjectNotificationTimestamp(c.projectId, c.timestamp)
+            }
             continue
           }
           stats.matched++