components/domain_reliability/scheduler.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_DOMAIN_RELIABILITY_SCHEDULER_H_
   6 #define COMPONENTS_DOMAIN_RELIABILITY_SCHEDULER_H_
   7
   8 #include <vector>
   9
  10 #include "base/callback.h"
  11 #include "base/memory/scoped_vector.h"
  12 #include "base/time/time.h"
  13 #include "components/domain_reliability/domain_reliability_export.h"
  14 #include "components/domain_reliability/uploader.h"
  15 #include "net/base/backoff_entry.h"
  16
  17 namespace base {
  18 class Value;
  19 }  // namespace base
  20
  21 namespace domain_reliability {
  22
  23 class DomainReliabilityConfig;
  24 class MockableTime;
  25
  26 // Determines when an upload should be scheduled. A domain's config will
  27 // specify minimum and maximum upload delays; the minimum upload delay ensures
  28 // that Chrome will not send too many upload requests to a site by waiting at
  29 // least that long after the first beacon, while the maximum upload delay makes
  30 // sure the server receives the reports while they are still fresh.
  31 //
  32 // When everything is working fine, the scheduler will return precisely that
  33 // interval. If all uploaders have failed, then the beginning or ending points
  34 // of the interval may be pushed later to accomodate the retry with exponential
  35 // backoff.
  36 //
  37 // See dispatcher.h for an explanation of what happens with the scheduled
  38 // interval.
  39 class DOMAIN_RELIABILITY_EXPORT DomainReliabilityScheduler {
  40  public:
  41   typedef base::Callback<void(base::TimeDelta, base::TimeDelta)>
  42       ScheduleUploadCallback;
  43
  44   struct Params {
  45    public:
  46     base::TimeDelta minimum_upload_delay;
  47     base::TimeDelta maximum_upload_delay;
  48     base::TimeDelta upload_retry_interval;
  49
  50     static Params GetFromFieldTrialsOrDefaults();
  51   };
  52
  53   DomainReliabilityScheduler(MockableTime* time,
  54                              size_t num_collectors,
  55                              const Params& params,
  56                              const ScheduleUploadCallback& callback);
  57   ~DomainReliabilityScheduler();
  58
  59   // If there is no upload pending, schedules an upload based on the provided
  60   // parameters (some time between the minimum and maximum delay from now).
  61   // May call the ScheduleUploadCallback.
  62   void OnBeaconAdded();
  63
  64   // Returns which collector to use for an upload that is about to start. Must
  65   // be called exactly once during or after the ScheduleUploadCallback but
  66   // before OnUploadComplete is called. (Also records the upload start time for
  67   // future retries, if the upload ends up failing.)
  68   size_t OnUploadStart();
  69
  70   // Updates the scheduler state based on the result of an upload. Must be
  71   // called exactly once after |OnUploadStart|. |result| should be the result
  72   // passed to the upload callback by the Uploader.
  73   void OnUploadComplete(const DomainReliabilityUploader::UploadResult& result);
  74
  75   scoped_ptr<base::Value> GetWebUIData() const;
  76
  77   // Disables jitter in BackoffEntries to make scheduling deterministic for
  78   // unit tests.
  79   void MakeDeterministicForTesting();
  80
  81   // Gets the time of the first beacon that has not yet been successfully
  82   // uploaded.
  83   base::TimeTicks first_beacon_time() const { return first_beacon_time_; }
  84
  85   // Gets the time until the next upload attempt on the last collector used.
  86   // This will be 0 if the upload was a success; it does not take into account
  87   // minimum_upload_delay and maximum_upload_delay.
  88   base::TimeDelta last_collector_retry_delay() const {
  89     return last_collector_retry_delay_;
  90   }
  91
  92  private:
  93   void MaybeScheduleUpload();
  94
  95   void GetNextUploadTimeAndCollector(base::TimeTicks now,
  96                                      base::TimeTicks* upload_time_out,
  97                                      size_t* collector_index_out);
  98
  99   MockableTime* time_;
 100   Params params_;
 101   ScheduleUploadCallback callback_;
 102   net::BackoffEntry::Policy backoff_policy_;
 103   ScopedVector<net::BackoffEntry> collectors_;
 104
 105   // Whether there are beacons that have not yet been uploaded. Set when a
 106   // beacon arrives or an upload fails, and cleared when an upload starts.
 107   bool upload_pending_;
 108
 109   // Whether the scheduler has called the ScheduleUploadCallback to schedule
 110   // the next upload. Set when an upload is scheduled and cleared when the
 111   // upload starts.
 112   bool upload_scheduled_;
 113
 114   // Whether the last scheduled upload is in progress. Set when the upload
 115   // starts and cleared when the upload completes (successfully or not).
 116   bool upload_running_;
 117
 118   // Index of the collector selected for the next upload.  (Set in
 119   // |OnUploadStart| and cleared in |OnUploadComplete|.)
 120   size_t collector_index_;
 121
 122   // Time of the first beacon that was not included in the last successful
 123   // upload.
 124   base::TimeTicks first_beacon_time_;
 125
 126   // first_beacon_time_ saved during uploads.  Restored if upload fails.
 127   base::TimeTicks old_first_beacon_time_;
 128
 129   // Time until the next upload attempt on the last collector used. (Saved for
 130   // histograms in Context.)
 131   base::TimeDelta last_collector_retry_delay_;
 132
 133   // Extra bits to return in GetWebUIData.
 134   base::TimeTicks scheduled_min_time_;
 135   base::TimeTicks scheduled_max_time_;
 136   // Whether the other last_upload_* fields are populated.
 137   bool last_upload_finished_;
 138   base::TimeTicks last_upload_start_time_;
 139   base::TimeTicks last_upload_end_time_;
 140   size_t last_upload_collector_index_;
 141   bool last_upload_success_;
 142 };
 143
 144 }  // namespace domain_reliability
 145
 146 #endif  // COMPONENTS_DOMAIN_RELIABILITY_SCHEDULER_H_