Add functions for monitoring backup status of db records

GitOrigin-RevId: f0d3564dfd3b38ef9ee451de866c0c05acd0cb20

services/history-v1/backupVerifier/ProjectMetrics.mjs

@@ -0,0 +1,35 @@
+import Metrics from '@overleaf/metrics'
+import { objectIdFromDate } from './utils.mjs'
+import { db } from '../storage/lib/mongodb.js'
+
+const projectsCollection = db.collection('projects')
+
+/**
+ *
+ * @param {Date} beforeTime
+ * @return {Promise<void>}
+ */
+export async function measurePendingChangesBeforeTime(beforeTime) {
+  const pendingChangeCount = await projectsCollection.countDocuments({
+    'overleaf.backup.pendingChangeAt': {
+      $lt: beforeTime,
+    },
+  })
+
+  Metrics.gauge('backup_verification_pending_changes', pendingChangeCount)
+}
+
+/**
+ *
+ * @param {number} graceSeconds - Number of seconds projects are allowed before they must be backed up.
+ * @return {Promise<void>}
+ */
+export async function measureNeverBackedUpProjects(graceSeconds) {
+  const now = new Date()
+  const startOfGracePeriod = new Date(now - graceSeconds * 1000)
+  const neverBackedUpCount = await projectsCollection.countDocuments({
+    'overleaf.backup.lastBackedUpVersion': null,
+    _id: { $lt: objectIdFromDate(startOfGracePeriod) },
+  })
+  Metrics.gauge('backup_verification_never_backed_up', neverBackedUpCount)
+}