From 7029653c0086cd185fbd5b749d1b0f52fd0274a6 Mon Sep 17 00:00:00 2001
From: Juan Tejada <juans.tejada@gmail.com>
Date: Tue, 31 Jan 2017 10:29:57 -0800
Subject: [PATCH] [local-sync] Retry syncback tasks that throw retryable errors

Summary:
This will prevent us from showing error messages to the user when we
can automatically recover from the error

Test Plan: manual-- throw error from syncback task, check expected results

Reviewers: evan, mark, spang

Reviewed By: spang

Differential Revision: https://phab.nylas.com/D3812
---
 .../syncback-task-helpers.es6                 | 23 +++++++++++++++----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/packages/local-sync/src/local-sync-worker/syncback-task-helpers.es6 b/packages/local-sync/src/local-sync-worker/syncback-task-helpers.es6
index 0e1f71ab8..1c9bde346 100644
--- a/packages/local-sync/src/local-sync-worker/syncback-task-helpers.es6
+++ b/packages/local-sync/src/local-sync-worker/syncback-task-helpers.es6
@@ -1,5 +1,7 @@
+const {IMAPErrors} = require('isomorphic-core')
 const SyncbackTaskFactory = require('./syncback-task-factory');
 
+const MAX_TASK_RETRIES = 2
 
 // TODO NOTE! These are the tasks we exclude from the sync loop. This should be
 // refactored later.
@@ -118,11 +120,22 @@ export async function runSyncbackTask({task, runTask} = {}) {
     syncbackRequest.status = "INPROGRESS";
     await syncbackRequest.save();
 
-    // TODO `runTask` is a hack to allow tasks to be executed outside the
-    // context of an imap connection, specifically to allow running send tasks
-    // outside of the sync loop. This should be solved in a better way or
-    // probably refactored when we implement the sync scheduler
-    const responseJSON = await runTask(task)
+    let responseJSON;
+    for (let numTries = 0; numTries <= MAX_TASK_RETRIES; numTries++) {
+      try {
+        // TODO `runTask` is a hack to allow tasks to be executed outside the
+        // context of an imap connection, specifically to allow running send tasks
+        // outside of the sync loop. This should be solved in a better way or
+        // probably refactored when we implement the sync scheduler
+        responseJSON = await runTask(task)
+        break;
+      } catch (err) {
+        if (!(err instanceof IMAPErrors.RetryableError) || numTries >= MAX_TASK_RETRIES) {
+          throw err
+        }
+      }
+    }
+
     syncbackRequest.status = "SUCCEEDED";
     syncbackRequest.responseJSON = responseJSON || {};
     const after = new Date();