Better progress text when waiting for other tasks

Fixes #630

src/apptaskmanager.js

@@ -22,6 +22,14 @@ let gPendingTasks = [ ];
 const TASK_CONCURRENCY = 3;
 const NOOP_CALLBACK = function (error) { if (error) debug(error); };
 
+function waitText(lockOperation) {
+    if (lockOperation === locker.OP_BOX_UPDATE) return 'Waiting for Cloudron to finish updating. See the Settings view';
+    if (lockOperation === locker.OP_PLATFORM_START) return 'Waiting for Cloudron to initialize';
+    if (lockOperation === locker.OP_FULL_BACKUP) return 'Wait for Cloudron to finish backup. See the Backups view';
+
+    return ''; // cannot happen
+}
+
 // callback is called when task is finished
 function scheduleTask(appId, taskId, callback) {
     assert.strictEqual(typeof appId, 'string');
@@ -34,6 +42,7 @@ function scheduleTask(appId, taskId, callback) {
 
     if (Object.keys(gActiveTasks).length >= TASK_CONCURRENCY) {
         debug(`Reached concurrency limit, queueing task id ${taskId}`);
+        tasks.update(taskId, { percent: 0, message: 'Waiting for other app tasks to complete' }, NOOP_CALLBACK);
         gPendingTasks.push({ appId, taskId, callback });
         return;
     }
@@ -41,7 +50,8 @@ function scheduleTask(appId, taskId, callback) {
     var lockError = locker.recursiveLock(locker.OP_APPTASK);
 
     if (lockError) {
-        debug(`Locked for another operation, queueing task id ${taskId}`);
+        debug(`Could not get lock. ${lockError.message}, queueing task id ${taskId}`);
+        tasks.update(taskId, { percent: 0, message: waitText(lockError.operation) }, NOOP_CALLBACK);
         gPendingTasks.push({ appId, taskId, callback });
         return;
     }