LogDog: Handle archive failures.

appengine/logdog/coordinator/backend/archiveCron.go

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package backend
 
 import (
         "fmt"
         "net/http"
         "time"
@@ skipping 100 matching lines @@
 
         queueName, err := archiveTaskQueueName(cfg)
         if err != nil {
                 log.Errorf(c, "Failed to get task queue name.")
                 return err
         }
 
         now := clock.Now(c).UTC()
         q := ds.NewQuery("LogStream")
 
+        // TODO(dnj): Next schema migration, remove this State constraint in favor
+        // of equality filters on _Terminated and ArchiveState.
+        // It is necessary for now since otherwise, *all* archived streams will match
+        // this query!
         var threshold time.Duration
         if complete {
                 threshold = cfg.GetCoordinator().ArchiveDelay.Duration()
                 q = q.Eq("State", coordinator.LSTerminated)
         } else {
                 threshold = cfg.GetCoordinator().ArchiveDelayMax.Duration()
                 q = q.Eq("State", coordinator.LSPending)
         }
         q = q.Lte("Updated", now.Add(-threshold))
 
@@ skipping 84 matching lines @@
         // Dispatch any remaining enqueued tasks.
         if err := addAndMaybeDispatchTasks(nil); err != nil {
                 return err
         }
 
         log.Fields{
                 "scheduledTaskCount": totalScheduledTasks,
         }.Debugf(c, "Archive sweep completed successfully.")
         return nil
 }