Service Node disconnect processing

app/services/hive.js

@@ -7,6 +7,8 @@
 const mongoose = require('mongoose');
 
 const UserSubscription = mongoose.model('UserSubscription');
+const UserNotification = mongoose.model('UserSubscription');
+
 const KaleidoscopeEvent = mongoose.model('KaleidoscopeEvent');
 
 const slug = require('slug');
@@ -20,6 +22,25 @@ class HiveService extends SiteService {
     super(dtp, module.exports);
   }
 
+  async start ( ) {
+    const { oauth2: oauth2Service } = this.dtp.services;
+
+    this.eventHandlers = {
+      onOAuth2RemoveClient: this.onOAuth2RemoveClient.bind(this),
+    };
+
+    oauth2Service.on(oauth2Service.getEventName('client.remove'), this.eventHandlers.onOAuth2RemoveClient);
+  }
+
+  async stop ( ) {
+    const { oauth2: oauth2Service } = this.dtp.services;
+
+    oauth2Service.off(oauth2Service.getEventName('client.remove'), this.eventHandlers.onOAuth2RemoveClient);
+    delete this.eventHandlers.onOAuth2RemoveClient;
+
+    delete this.eventHandlers;
+  }
+
   async subscribe (user, client, emitterId) {
     await UserSubscription.updateOne(
       { user: user._id },
@@ -277,6 +298,27 @@ class HiveService extends SiteService {
       .lean();
     return { events, totalEventCount };
   }
+
+  /*
+   * OAuth2 event handlers
+   */
+
+  /**
+   * This event fires when an OAuth2Client is being disconnected and removed by a
+   * Core, or a client app is being removed from a Service Node. The Hive service
+   * will remove all KaleidoscopeEvent records created on behalf of the client.
+   * @param {OAuth2Client} client the client being removed
+   */
+  async onOAuth2RemoveClient (client) {
+    this.log.alert('removing KaleidoscopeEvent records from OAuth2Client', { clientId: client._id, domain: client.site.domain });
+    await KaleidoscopeEvent
+      .find({ 'source.client': client._id })
+      .cursor()
+      .eachAsync(async (event) => {
+        await UserNotification.deleteMany({ event: event._id });
+        await KaleidoscopeEvent.deleteOne({ _id: event._id });
+      }, 1);
+  }
 }
 
 module.exports = {