Throttle email notifications upon updating document frequently (#4026)

* feat: add needed columns for throttling notifs

* feat: update model

* feat: deliver only one notif in a 12 hour window

* fix: address review comments

* prevent retry if notification update fails
* fix type compatibility instead of circumventing it
* add index for emailedAt

* fix: add metadata attr to EmailProps

* chore: decouple metadata from EmailProps

* chore: add test

* chore: revert sending metadata in props

server/queues/processors/NotificationsProcessor.ts

@@ -1,3 +1,4 @@
+import { subHours } from "date-fns";
 import { uniqBy } from "lodash";
 import { Op } from "sequelize";
 import subscriptionCreator from "@server/commands/subscriptionCreator";
@@ -13,6 +14,7 @@ import {
   User,
   NotificationSetting,
   Subscription,
+  Notification,
 } from "@server/models";
 import {
   CollectionEvent,
@@ -72,16 +74,26 @@ export default class NotificationsProcessor extends BaseProcessor {
       const notify = await this.shouldNotify(document, recipient.user);
 
       if (notify) {
-        await DocumentNotificationEmail.schedule({
-          to: recipient.user.email,
-          eventName:
-            event.name === "documents.publish" ? "published" : "updated",
+        const notification = await Notification.create({
+          event: event.name,
+          userId: recipient.user.id,
+          actorId: document.updatedBy.id,
+          teamId: team.id,
           documentId: document.id,
-          teamUrl: team.url,
-          actorName: document.updatedBy.name,
-          collectionName: collection.name,
-          unsubscribeUrl: recipient.unsubscribeUrl,
         });
+        await DocumentNotificationEmail.schedule(
+          {
+            to: recipient.user.email,
+            eventName:
+              event.name === "documents.publish" ? "published" : "updated",
+            documentId: document.id,
+            teamUrl: team.url,
+            actorName: document.updatedBy.name,
+            collectionName: collection.name,
+            unsubscribeUrl: recipient.unsubscribeUrl,
+          },
+          { notificationId: notification.id }
+        );
       }
     }
   }
@@ -237,6 +249,23 @@ export default class NotificationsProcessor extends BaseProcessor {
       return false;
     }
 
+    // Deliver only a single notification in a 12 hour window
+    const notification = await Notification.findOne({
+      order: [["createdAt", "DESC"]],
+      where: {
+        userId: user.id,
+        documentId: document.id,
+        emailedAt: {
+          [Op.not]: null,
+          [Op.gte]: subHours(new Date(), 12),
+        },
+      },
+    });
+
+    if (notification) {
+      return false;
+    }
+
     // If this recipient has viewed the document since the last update was made
     // then we can avoid sending them a useless notification, yay.
     const view = await View.findOne({