From 0b3e3d2f39587fb0a5e4792fe2f2abc1bd2bb86c Mon Sep 17 00:00:00 2001
From: Karim Hamidou <khamidou@gmail.com>
Date: Tue, 3 Jan 2017 16:03:27 -0800
Subject: [PATCH] Make K2 recover from connectivity losses.

Summary: I've found a pretty annoying bug --- N1 would stop syncing all accounts after the Internet connection dropped. It seems that deep inside node-imap or NodeJS itself, connections aren't timing out the right way. To work around this, this diff unilaterally restarts the sync every `nextSyncIn` milliseconds.

Test Plan: Tested manually by cutting internet access and checking that K2 recovered.

Reviewers: evan, juan

Reviewed By: evan

Differential Revision: https://phab.nylas.com/D3573
---
 packages/isomorphic-core/src/imap-connection.js          | 2 ++
 packages/local-sync/src/local-sync-worker/sync-worker.js | 5 +++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/packages/isomorphic-core/src/imap-connection.js b/packages/isomorphic-core/src/imap-connection.js
index ac64d3286..1b9cc456e 100644
--- a/packages/isomorphic-core/src/imap-connection.js
+++ b/packages/isomorphic-core/src/imap-connection.js
@@ -21,6 +21,7 @@ const Capabilities = {
 }
 
 const ONE_HOUR_SECS = 60 * 60;
+const SOCKET_TIMEOUT_SECS = 60;
 
 class IMAPConnection extends EventEmitter {
 
@@ -81,6 +82,7 @@ class IMAPConnection extends EventEmitter {
       user: this._settings.imap_username,
       password: this._settings.imap_password,
       tls: this._settings.ssl_required,
+      socketTimeout: SOCKET_TIMEOUT_SECS,
     }
 
     // This account uses XOAuth2, and we have the client_id + refresh token
diff --git a/packages/local-sync/src/local-sync-worker/sync-worker.js b/packages/local-sync/src/local-sync-worker/sync-worker.js
index 73ba62722..6904b7954 100644
--- a/packages/local-sync/src/local-sync-worker/sync-worker.js
+++ b/packages/local-sync/src/local-sync-worker/sync-worker.js
@@ -286,8 +286,6 @@ class SyncWorker {
     }
 
     this._syncStart = Date.now()
-    clearTimeout(this._syncTimer);
-    this._syncTimer = null;
     this._interrupted = false
     this._syncAttemptsWhileInProgress = 0
     this._syncInProgress = true
@@ -306,7 +304,9 @@ class SyncWorker {
     try {
       await this._account.update({syncError: null});
       await this.ensureConnection();
+
       await this.runNewSyncbackTasks();
+
       await this._conn.runOperation(new FetchFolderList(this._account, this._logger));
 
       // TODO prioritize syncing all of inbox first if there's a ton of folders (e.g. imap
@@ -435,6 +435,7 @@ class SyncWorker {
     console.log(`🔃 🔜 in ${nextSyncIn}ms`)
 
     this._syncTimer = setTimeout(() => {
+      this.closeConnection();
       this.syncNow({reason});
     }, nextSyncIn);
   }