[client-sync] Report latest sync activity

Summary:
Add infrastructure to report and retrieve the latest sync activity, and
start reporting when we download a message or detect that a folder
has no new messages. This will be used to detect if the sync loop is
stuck. Part of T7681.

Test Plan: manual, specs

Reviewers: evan, mark, juan

Reviewed By: juan

Differential Revision: https://phab.nylas.com/D4261

packages/client-sync/src/local-api/routes/health.es6

@@ -0,0 +1,52 @@
+const Joi = require('joi');
+const {getLastSyncActivityForAccount, getLastSyncActivity} = require('../../shared/sync-activity').default
+
+module.exports = (server) => {
+  server.route({
+    method: 'GET',
+    path: '/health',
+    config: {
+      description: 'Returns information about the last recorded sync activity for all accounts',
+      tags: ['health'],
+    },
+    handler: (request, reply) => {
+      let response;
+      try {
+        response = getLastSyncActivity()
+        response = JSON.stringify(response)
+        reply(response)
+      } catch (err) {
+        const context = response ? "" : "Could not retrieve last sync activity"
+        request.logger.error(err, context)
+        reply(err)
+      }
+    },
+  })
+
+  server.route({
+    method: 'GET',
+    path: '/health/{accountId}',
+    config: {
+      description: 'Returns information about the last recorded sync activity for the specified account',
+      tags: ['health'],
+      validate: {
+        params: {
+          accountId: Joi.string(),
+        },
+      },
+    },
+    handler: (request, reply) => {
+      let response;
+      try {
+        const {accountId} = request.params
+        response = getLastSyncActivityForAccount(accountId)
+        response = JSON.stringify(response)
+        reply(response)
+      } catch (err) {
+        const context = response ? "" : "Could not retrieve last sync activity"
+        request.logger.error(err, context)
+        reply(err)
+      }
+    },
+  })
+};

packages/client-sync/src/local-sync-worker/sync-tasks/fetch-messages-in-folder.imap.es6

@@ -3,6 +3,7 @@ const {IMAPConnection} = require('isomorphic-core');
 const {Capabilities} = IMAPConnection;
 const SyncTask = require('./sync-task')
 const MessageProcessor = require('../../message-processor')
+const {reportSyncActivity} = require('../../shared/sync-activity').default
 
 const MessageFlagAttributes = ['id', 'threadId', 'folderImapUID', 'unread', 'starred', 'folderImapXGMLabels']
 const FETCH_ATTRIBUTES_BATCH_SIZE = 1000;
@@ -724,7 +725,9 @@ class FetchMessagesInFolderIMAP extends SyncTask {
     if (shouldFetchMessages) {
       yield this._fetchNextMessageBatch()
     } else {
-      this._logger.log(`🔚 📂 ${this._folder.name} has no new messages - skipping fetch messages`)
+      const activity = `🔚 📂 ${this._folder.name} has no new messages - skipping fetch messages`
+      this._logger.log(activity)
+      reportSyncActivity(this._db.accountId, activity)
     }
     if (shouldFetchAttributes) {
       yield this._fetchMessageAttributeChanges();

packages/client-sync/src/message-processor/index.js

@@ -9,6 +9,7 @@ const extractContacts = require('./extract-contacts');
 const {MessageFactory} = require('isomorphic-core');
 const LocalDatabaseConnector = require('../shared/local-database-connector');
 const {BatteryStatusManager} = require('nylas-exports');
+const {reportSyncActivity} = require('../shared/sync-activity');
 
 const MAX_QUEUE_LENGTH = 500
 const MAX_CPU_USE_ON_AC = 1.0;
@@ -153,8 +154,9 @@ class MessageProcessor {
         await folder.updateSyncState({oldestProcessedDate: justProcessedDate})
       }
 
-
-      logger.log(`🔃 ✉️ (${folder.name}) "${messageValues.subject}" - ${messageValues.date}`)
+      const activity = `🔃 ✉️ (${folder.name}) "${messageValues.subject}" - ${messageValues.date}`
+      logger.log(activity)
+      reportSyncActivity(accountId, activity)
       return processedMessage
     } catch (err) {
       await this._onError({imapMessage, desiredParts, folder, err, logger});

packages/client-sync/src/shared/sync-activity.es6

@@ -0,0 +1,29 @@
+class SyncActivity {
+  constructor() {
+    // Keyed by accountId, each value is structured like
+    // {
+    //   time: 1490293620249,
+    //   activity: (whatever was passed in, usually a string)
+    // }
+    this._lastActivityByAccountId = {}
+  }
+
+  reportSyncActivity = (accountId, activity) => {
+    if (!this._lastActivityByAccountId[accountId]) {
+      this._lastActivityByAccountId[accountId] = {};
+    }
+    const lastActivity = this._lastActivityByAccountId[accountId]
+    lastActivity.time = Date.now();
+    lastActivity.activity = activity;
+  }
+
+  getLastSyncActivityForAccount = (accountId) => {
+    return this._lastActivityByAccountId[accountId]
+  }
+
+  getLastSyncActivity = () => {
+    return this._lastActivityByAccountId
+  }
+}
+
+export default new SyncActivity()