Domain Reliability: Switch to BackoffEntry in Scheduler

components/domain_reliability/scheduler.cc

 // Copyright 2014 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.
 
 #include "components/domain_reliability/scheduler.h"
 
 #include <algorithm>
 
 #include "base/metrics/field_trial.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/values.h"
 #include "components/domain_reliability/config.h"
 #include "components/domain_reliability/util.h"
 
 namespace {
 
 const unsigned kInvalidCollectorIndex = static_cast<unsigned>(-1);
 
 const unsigned kDefaultMinimumUploadDelaySec = 60;
 const unsigned kDefaultMaximumUploadDelaySec = 300;
 const unsigned kDefaultUploadRetryIntervalSec = 60;
 
 const char* kMinimumUploadDelayFieldTrialName = "DomRel-MinimumUploadDelay";
 const char* kMaximumUploadDelayFieldTrialName = "DomRel-MaximumUploadDelay";
 const char* kUploadRetryIntervalFieldTrialName = "DomRel-UploadRetryInterval";
 
+// Fixed elements of backoff policy
+const double kMultiplyFactor = 2.0;
+const double kJitterFactor = 0.1;
+const int64 kMaximumBackoffMs = 60 * 1000 * 1000;
+
 unsigned GetUnsignedFieldTrialValueOrDefault(std::string field_trial_name,
                                              unsigned default_value) {
   if (!base::FieldTrialList::TrialExists(field_trial_name))
     return default_value;
 
   std::string group_name = base::FieldTrialList::FindFullName(field_trial_name);
   unsigned value;
   if (!base::StringToUint(group_name, &value)) {
     LOG(ERROR) << "Expected unsigned integer for field trial "
                << field_trial_name << " group name, but got \"" << group_name
@@ skipping 25 matching lines @@
 
   return params;
 }
 
 DomainReliabilityScheduler::DomainReliabilityScheduler(
     MockableTime* time,
     size_t num_collectors,
     const Params& params,
     const ScheduleUploadCallback& callback)
     : time_(time),
-      collectors_(num_collectors),
       params_(params),
       callback_(callback),
       upload_pending_(false),
       upload_scheduled_(false),
       upload_running_(false),
       collector_index_(kInvalidCollectorIndex),
       last_upload_finished_(false) {
+  backoff_policy_.num_errors_to_ignore = 0;
+  backoff_policy_.initial_delay_ms =
+      params.upload_retry_interval.InMilliseconds();
+  backoff_policy_.multiply_factor = kMultiplyFactor;
+  backoff_policy_.jitter_factor = kJitterFactor;
+  backoff_policy_.maximum_backoff_ms = kMaximumBackoffMs;
+  backoff_policy_.entry_lifetime_ms = 0;

[davidben, 2014/11/07 20:06:04]

Just to confirm, this bit is a no-op from patch set 1 since you never call
CanDiscard(), correct?

+  backoff_policy_.always_use_initial_delay = false;
+
+  for (size_t i = 0; i < num_collectors; ++i) {
+    collectors_.push_back(
+      new MockableTimeBackoffEntry(&backoff_policy_, time_));
+  }
 }
 
 DomainReliabilityScheduler::~DomainReliabilityScheduler() {}
 
 void DomainReliabilityScheduler::OnBeaconAdded() {
   if (!upload_pending_)
     first_beacon_time_ = time_->NowTicks();
   upload_pending_ = true;
   MaybeScheduleUpload();
 }
@@ skipping 19 matching lines @@
 }
 
 void DomainReliabilityScheduler::OnUploadComplete(bool success) {
   DCHECK(upload_running_);
   DCHECK_NE(kInvalidCollectorIndex, collector_index_);
   upload_running_ = false;
 
   VLOG(1) << "Upload to collector " << collector_index_
           << (success ? " succeeded." : " failed.");
 
-  CollectorState* collector = &collectors_[collector_index_];
+  net::BackoffEntry* backoff = collectors_[collector_index_];
   collector_index_ = kInvalidCollectorIndex;
+  backoff->InformOfRequest(success);
 
-  if (success) {
-    collector->failures = 0;
-  } else {
+  if (!success) {
     // Restore upload_pending_ and first_beacon_time_ to pre-upload state,
     // since upload failed.
     upload_pending_ = true;
     first_beacon_time_ = old_first_beacon_time_;
-
-    ++collector->failures;
   }
 
-  base::TimeTicks now = time_->NowTicks();
-  base::TimeDelta retry_interval = GetUploadRetryInterval(collector->failures);
-  collector->next_upload = now + retry_interval;
-
-  last_upload_end_time_ = now;
+  last_upload_end_time_ = time_->NowTicks();
   last_upload_success_ = success;
   last_upload_finished_ = true;
 
-  VLOG(1) << "Next upload to collector at least "
-          << retry_interval.InSeconds() << " seconds from now.";
-
   MaybeScheduleUpload();
 }
 
 base::Value* DomainReliabilityScheduler::GetWebUIData() const {
   base::TimeTicks now = time_->NowTicks();
 
   base::DictionaryValue* data = new base::DictionaryValue();
 
   data->SetBoolean("upload_pending", upload_pending_);
   data->SetBoolean("upload_scheduled", upload_scheduled_);
   data->SetBoolean("upload_running", upload_running_);
 
   data->SetInteger("scheduled_min", (scheduled_min_time_ - now).InSeconds());
   data->SetInteger("scheduled_max", (scheduled_max_time_ - now).InSeconds());
 
   data->SetInteger("collector_index", static_cast<int>(collector_index_));
 
   if (last_upload_finished_) {
     base::DictionaryValue* last = new base::DictionaryValue();
     last->SetInteger("start_time", (now - last_upload_start_time_).InSeconds());
     last->SetInteger("end_time", (now - last_upload_end_time_).InSeconds());
     last->SetInteger("collector_index",
         static_cast<int>(last_upload_collector_index_));
     last->SetBoolean("success", last_upload_success_);
     data->Set("last_upload", last);
   }
 
   base::ListValue* collectors = new base::ListValue();
   for (size_t i = 0; i < collectors_.size(); ++i) {
-    const CollectorState* state = &collectors_[i];
+    const net::BackoffEntry* backoff = collectors_[i];
     base::DictionaryValue* value = new base::DictionaryValue();
-    value->SetInteger("failures", state->failures);
-    value->SetInteger("next_upload", (state->next_upload - now).InSeconds());
+    value->SetInteger("failures", backoff->failure_count());
+    value->SetInteger("next_upload",
+        (backoff->GetReleaseTime() - now).InSeconds());
     collectors->Append(value);
   }
   data->Set("collectors", collectors);
 
   return data;
 }
 
-DomainReliabilityScheduler::CollectorState::CollectorState() : failures(0) {}
+void DomainReliabilityScheduler::MakeDeterministicForTesting() {
+  backoff_policy_.jitter_factor = 0.0;
+}
 
 void DomainReliabilityScheduler::MaybeScheduleUpload() {
   if (!upload_pending_ || upload_scheduled_ || upload_running_)
     return;
 
   upload_scheduled_ = true;
   old_first_beacon_time_ = first_beacon_time_;
 
   base::TimeTicks now = time_->NowTicks();
 
@@ skipping 26 matching lines @@
     base::TimeTicks now,
     base::TimeTicks* upload_time_out,
     size_t* collector_index_out) {
   DCHECK(upload_time_out);
   DCHECK(collector_index_out);
 
   base::TimeTicks min_time;
   size_t min_index = kInvalidCollectorIndex;
 
   for (size_t i = 0; i < collectors_.size(); ++i) {
-    CollectorState* collector = &collectors_[i];
+    net::BackoffEntry* backoff = collectors_[i];
     // If a collector is usable, use the first one in the list.
-    if (collector->failures == 0 || collector->next_upload <= now) {
+    if (!backoff->ShouldRejectRequest()) {
       min_time = now;
       min_index = i;
       break;
+    }
+
     // If not, keep track of which will be usable soonest:
-    } else if (min_index == kInvalidCollectorIndex ||
-        collector->next_upload < min_time) {
-      min_time = collector->next_upload;
+    base::TimeTicks time = backoff->GetReleaseTime();
+    if (min_index == kInvalidCollectorIndex || time < min_time) {
+      min_time = time;
       min_index = i;
     }
   }
 
   DCHECK_NE(kInvalidCollectorIndex, min_index);
   *upload_time_out = min_time;
   *collector_index_out = min_index;
 }
 
-base::TimeDelta DomainReliabilityScheduler::GetUploadRetryInterval(
-    unsigned failures) {
-  if (failures == 0)
-    return base::TimeDelta::FromSeconds(0);
-  else {
-    // Don't back off more than 64x the original delay.
-    if (failures > 7)
-      failures = 7;
-    return params_.upload_retry_interval * (1 << (failures - 1));
-  }
-}
-
 }  // namespace domain_reliability