better reporting of sync error when "sync now"

public/javascripts/sync.js

@@ -8,12 +8,16 @@ function syncNow() {
             if (result.success) {
                 status.checkStatus();
 
-                message("Sync triggered.");
+                message("Sync finished successfully.");
             }
             else {
-                error("Sync failed");
+                if (result.message.length > 50) {
+                    result.message = result.message.substr(0, 50);
+                }
+
+                error("Sync failed: " + result.message);
             }
         },
-        error: () => error("Sync failed")
+        error: () => error("Sync failed for unknown reason.")
     });
 }

routes/api/sync.js

@@ -8,11 +8,7 @@ const sql = require('../../services/sql');
 const options = require('../../services/options');
 
 router.post('/now', auth.checkApiAuth, async (req, res, next) => {
-    await sync.sync();
-
-    res.send({
-        success: true
-    });
+    res.send(await sync.sync());
 });
 
 router.get('/changed', auth.checkApiAuth, async (req, res, next) => {

services/sync.js

@@ -195,7 +195,10 @@ async function sync() {
     if (syncInProgress) {
         logSyncError("Sync already in progress");
 
-        return;
+        return {
+            success: false,
+            message: "Sync already in progress"
+        };
     }
 
     syncInProgress = true;
@@ -204,7 +207,10 @@ async function sync() {
         if (!await migration.isDbUpToDate()) {
             logSyncError("DB not up to date");
 
-            return;
+            return {
+                success: false,
+                message: "DB not up to date"
+            };
         }
 
         const syncContext = await login();
@@ -214,9 +220,18 @@ async function sync() {
         await pullSync(syncContext);
 
         await pushSync(syncContext);
+
+        return {
+            success: true
+        };
     }
     catch (e) {
         logSync("sync failed: " + e.stack);
+
+        return {
+            success: false,
+            message: e.message
+        }
     }
     finally {
         syncInProgress = false;