Iterate archive query alongside task queue.

appengine/logdog/coordinator/backend/backend.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 (
         "github.com/julienschmidt/httprouter"
         "github.com/luci/luci-go/appengine/gaemiddleware"
         "github.com/luci/luci-go/appengine/logdog/coordinator"
         "github.com/luci/luci-go/server/middleware"
 )
 
+const (
+        // defaultMultiTaskBatchSize is the default value for Backend's
+        // multiTaskBatchSize parameter.
+        defaultMultiTaskBatchSize = 100
+)
+
 // Backend is the base struct for all Backend handlers. It is mostly used to
 // configure testing parameters.
 type Backend struct {
         // multiTaskBatchSize is the number of batch tasks to create at a time.
         multiTaskBatchSize int
 
         // s is the backing Coordinator service base.
         s coordinator.Service
 }
 
+func (b *Backend) getMultiTaskBatchSize() int {
+        if v := b.multiTaskBatchSize; v > 0 {
+                return v
+        }
+        return defaultMultiTaskBatchSize
+}
+
 // InstallHandlers installs handlers for the Backend.
 func (b *Backend) InstallHandlers(r *httprouter.Router, h middleware.Base) {
         r.GET("/archive/cron/terminal", h(gaemiddleware.RequireCron(b.HandleArchiveCron)))
         r.GET("/archive/cron/nonterminal", h(gaemiddleware.RequireCron(b.HandleArchiveCronNT)))
         r.GET("/archive/cron/purge", h(b.HandleArchiveCronPurge))
 }