java/src/main/com/google/appengine/api/taskqueue/QueueStatistics.java

   1 // Copyright 2012 Google Inc. All rights reserved.
   2 package com.google.appengine.api.taskqueue;
   3
   4 import com.google.appengine.api.taskqueue.TaskQueuePb.TaskQueueFetchQueueStatsRequest;
   5 import com.google.appengine.api.taskqueue.TaskQueuePb.TaskQueueFetchQueueStatsResponse;
   6 import com.google.appengine.api.taskqueue.TaskQueuePb.TaskQueueScannerQueueInfo;
   7 import com.google.apphosting.api.ApiProxy.ApiConfig;
   8
   9 import java.util.ArrayList;
  10 import java.util.List;
  11 import java.util.concurrent.Future;
  12
  13 /**
  14  * {@link QueueStatistics} allow observation of the rate that tasks on a given
  15  * queue are being executed. Note that statistics provided are only approximate,
  16  * and some statistics may be delayed or transiently unavailable.
  17  *
  18  */
  19 public final class QueueStatistics {
  20   private final String queueName;
  21   private final int numTasks;
  22   private final Long oldestEtaUsec;
  23   private final long executedLastMinute;
  24   private final long executedLastHour;
  25   private final int requestsInFlight;
  26   private final double enforcedRate;
  27
  28   /**
  29    * Constructs QueueStatistics data object.
  30    * @throws IllegalArgumentException Complete queue statistics were not provided.
  31    */
  32   QueueStatistics(String queueName, TaskQueueFetchQueueStatsResponse.QueueStats stats) {
  33     this.queueName = queueName;
  34     this.numTasks = stats.getNumTasks();
  35     if (stats.getOldestEtaUsec() != -1) {
  36       this.oldestEtaUsec = stats.getOldestEtaUsec();
  37     } else {
  38       this.oldestEtaUsec = null;
  39     }
  40
  41     if (stats.hasScannerInfo()) {
  42       TaskQueueScannerQueueInfo scannerInfo = stats.getScannerInfo();
  43
  44       this.executedLastMinute = scannerInfo.getExecutedLastMinute();
  45       this.executedLastHour = scannerInfo.getExecutedLastHour();
  46       if (scannerInfo.hasRequestsInFlight()) {
  47         this.requestsInFlight = scannerInfo.getRequestsInFlight();
  48       } else {
  49         throw new IllegalArgumentException("Queue statistics not supplied");
  50       }
  51       if (scannerInfo.hasEnforcedRate()) {
  52         this.enforcedRate = scannerInfo.getEnforcedRate();
  53       } else {
  54         throw new IllegalArgumentException("Queue statistics not supplied");
  55       }
  56     } else {
  57       throw new IllegalArgumentException("Queue statistics not supplied");
  58     }
  59   }
  60
  61   /**
  62    * @return The name of the {@link Queue}.
  63    */
  64   public String getQueueName() {
  65     return queueName;
  66   }
  67
  68   /**
  69    * @return The approximate number of non-completed tasks in the queue.
  70    */
  71   public int getNumTasks() {
  72     return numTasks;
  73   }
  74
  75   /**
  76    * Returns a recent estimate of the eta of the oldest non-completed task in the queue.
  77    * @return The eta of the oldest non-completed task for the queue, or
  78    * {@code null} if there were no non-completed tasks found in the queue.
  79    */
  80   public Long getOldestEtaUsec() {
  81     return oldestEtaUsec;
  82   }
  83
  84   /**
  85    * @return The number of tasks executed in the last minute.
  86    */
  87   public long getExecutedLastMinute() {
  88     return executedLastMinute;
  89   }
  90
  91   /**
  92    * @return The number of tasks executed in the last hour.
  93    */
  94   long getExecutedLastHour() {
  95     return executedLastHour;
  96   }
  97
  98   /**
  99    * The number of requests that the queue has sent but not yet received a
 100    * reply for.
 101    * @return The number of tasks currently in flight.
 102    */
 103   public int getRequestsInFlight() {
 104     return requestsInFlight;
 105   }
 106
 107   /**
 108    * Returns the maximum number of tasks per second being run by this queue.
 109    * @return The enforced rate in tasks per second.
 110    */
 111   public double getEnforcedRate() {
 112     return enforcedRate;
 113   }
 114
 115   /**
 116    * See {@link Queue#fetchStatistics()}.
 117    */
 118   static Future<List<QueueStatistics>> fetchForQueuesAsync(
 119       final List<Queue> queues, QueueApiHelper helper, double deadlineInSeconds) {
 120     TaskQueueFetchQueueStatsRequest statsRequest = new TaskQueueFetchQueueStatsRequest();
 121
 122     for (Queue queue : queues) {
 123       statsRequest.addQueueName(queue.getQueueName());
 124     }
 125
 126     statsRequest.setMaxNumTasks(0);
 127
 128     ApiConfig apiConfig = new ApiConfig();
 129     apiConfig.setDeadlineInSeconds(deadlineInSeconds);
 130
 131     Future<TaskQueueFetchQueueStatsResponse> responseFuture = helper.makeAsyncCall(
 132         "FetchQueueStats", statsRequest, new TaskQueueFetchQueueStatsResponse(), apiConfig);
 133     return new FutureAdapter<TaskQueueFetchQueueStatsResponse,
 134                              List<QueueStatistics>>(responseFuture) {
 135       @Override
 136       protected List<QueueStatistics> wrap(TaskQueueFetchQueueStatsResponse statsResponse) {
 137         if (statsResponse.queueStatsSize() != queues.size()) {
 138           throw new QueueFailureException("Unable to obtain queue statistics");
 139         }
 140
 141         List<QueueStatistics> resultList = new ArrayList<QueueStatistics>();
 142         for (int i = 0; i < statsResponse.queueStatsSize(); ++i) {
 143           TaskQueueFetchQueueStatsResponse.QueueStats stats = statsResponse.getQueueStats(i);
 144
 145           if (!stats.hasScannerInfo()) {
 146             throw new TransientFailureException("Queue statistics temporarily unavailable");
 147           }
 148           TaskQueueScannerQueueInfo scannerInfo = stats.getScannerInfo();
 149           if (!scannerInfo.hasRequestsInFlight()) {
 150             throw new TransientFailureException("Queue statistics temporarily unavailable");
 151           }
 152           if (!scannerInfo.hasEnforcedRate()) {
 153             throw new TransientFailureException("Queue statistics temporarily unavailable");
 154           }
 155
 156           resultList.add(new QueueStatistics(queues.get(i).getQueueName(), stats));
 157         }
 158         return resultList;
 159       }
 160     };
 161   }
 162 }