Implement UMA log throttling for cellular connections

components/metrics/data_use_tracker.cc

Index: components/metrics/data_use_tracker.cc
diff --git a/components/metrics/data_use_tracker.cc b/components/metrics/data_use_tracker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a74bdf117eb795ede47e563f9b67f5cfed8d321a
--- /dev/null
+++ b/components/metrics/data_use_tracker.cc
@@ -0,0 +1,205 @@
+// Copyright 2016 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/metrics/data_use_tracker.h"
+
+#include <string>
+
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/stringprintf.h"
+#include "components/metrics/metrics_pref_names.h"
+#include "components/prefs/scoped_user_pref_update.h"
+#include "components/variations/variations_associated_data.h"
+
+namespace metrics {
+
+namespace {
+
+// This function is for forwarding metrics usage pref changes to the appropriate
+// callback on the appropriate thread.
+// TODO(gayane): Reduce the frequency of posting tasks from IO to UI thread.
+void UpdateMetricsUsagePrefs(
+    const UpdateUsagePrefCallbackType& update_on_ui_callback,
+    scoped_refptr<base::SequencedTaskRunner> ui_task_runner,
+    const std::string& service_name,
+    int message_size,
+    bool is_cellular) {
+  ui_task_runner->PostTask(
+      FROM_HERE, base::Bind(update_on_ui_callback, service_name, message_size,
+                            is_cellular));
+}
+
+}  // namespace
+
+DataUseTracker::DataUseTracker(PrefService* local_state)
+    : local_state_(local_state), weak_ptr_factory_(this) {}
+
+DataUseTracker::~DataUseTracker() {}
+
+// static
+scoped_ptr<DataUseTracker> DataUseTracker::Create(PrefService* local_state) {
+  scoped_ptr<DataUseTracker> data_use_tracker;
+  if (variations::GetVariationParamValue("UMA_EnableCellularLogUpload",
+                                         "Uma_Quota") != "" &&
+      variations::GetVariationParamValue("UMA_EnableCellularLogUpload",
+                                         "Uma_Ratio") != "") {
+    data_use_tracker.reset(new DataUseTracker(local_state));
+  }
+  return data_use_tracker;
+}
+
+// static
+void DataUseTracker::RegisterPrefs(PrefRegistrySimple* registry) {
+  registry->RegisterDictionaryPref(metrics::prefs::kUserCellDataUse);
+  registry->RegisterDictionaryPref(metrics::prefs::kUmaCellDataUse);
+}
+
+UpdateUsagePrefCallbackType DataUseTracker::GetDataUseForwardingCallback(
+    scoped_refptr<base::SequencedTaskRunner> ui_task_runner) {
+  DCHECK(ui_task_runner->RunsTasksOnCurrentThread());
+
+  return base::Bind(
+      &UpdateMetricsUsagePrefs,
+      base::Bind(&DataUseTracker::UpdateMetricsUsagePrefsOnUIThread,
+                 weak_ptr_factory_.GetWeakPtr()),
+      ui_task_runner);
+}
+
+bool DataUseTracker::ShouldUploadLogOnCellular(int log_bytes) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  RemoveExpiredEntries();
+
+  int uma_weekly_quota_bytes;
+  if (!GetUmaWeeklyQuota(&uma_weekly_quota_bytes))
+    return true;
+
+  int uma_total_data_use = ComputeTotalDataUse(prefs::kUmaCellDataUse);
+  int new_uma_total_data_use = log_bytes + uma_total_data_use;
+  // If the new log doesn't increase the total UMA traffic to be above the
+  // allowed quota then the log should be uploaded.
+  if (new_uma_total_data_use <= uma_weekly_quota_bytes)
+    return true;
+
+  double uma_ratio;
+  if (!GetUmaRatio(&uma_ratio))
+    return true;
+
+  int user_total_data_use = ComputeTotalDataUse(prefs::kUserCellDataUse);
+  // If after adding the new log the uma ratio is still under the allowed ratio
+  // then the log should be uploaded and vice versa.
+  return new_uma_total_data_use /
+             static_cast<double>(log_bytes + user_total_data_use) <=
+         uma_ratio;
+}
+
+void DataUseTracker::UpdateMetricsUsagePrefsOnUIThread(
+    const std::string& service_name,
+    int message_size,
+    bool is_celllular) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (!is_celllular)
+    return;
+
+  UpdateUsagePref(prefs::kUserCellDataUse, message_size);
+  if (service_name == "UMA")
+    UpdateUsagePref(prefs::kUmaCellDataUse, message_size);
+}
+
+void DataUseTracker::UpdateUsagePref(const std::string& pref_name,
+                                     int message_size) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  DictionaryPrefUpdate pref_updater(local_state_, pref_name);
+  int todays_traffic = 0;
+  std::string todays_key = GetCurrentMeasurementDateAsString();
+
+  const base::DictionaryValue* user_pref_dict =
+      local_state_->GetDictionary(pref_name);
+  user_pref_dict->GetInteger(todays_key, &todays_traffic);
+  pref_updater->SetInteger(todays_key, todays_traffic + message_size);
+}
+
+void DataUseTracker::RemoveExpiredEntries() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  RemoveExpiredEntriesForPref(prefs::kUmaCellDataUse);
+  RemoveExpiredEntriesForPref(prefs::kUserCellDataUse);
+}
+
+void DataUseTracker::RemoveExpiredEntriesForPref(const std::string& pref_name) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  const base::DictionaryValue* user_pref_dict =
+      local_state_->GetDictionary(pref_name);
+  const base::Time current_date = GetCurrentMeasurementDate();
+  const base::Time week_ago = current_date - base::TimeDelta::FromDays(7);
+
+  base::DictionaryValue user_pref_new_dict;
+  for (base::DictionaryValue::Iterator it(*user_pref_dict); !it.IsAtEnd();
+       it.Advance()) {
+    base::Time key_date;
+    base::Time::FromUTCString(it.key().c_str(), &key_date);
+    if (key_date > week_ago)
+      user_pref_new_dict.Set(it.key(), it.value().CreateDeepCopy());
+  }
+  local_state_->Set(pref_name, user_pref_new_dict);
+}
+
+// Note: We compute total data use regardless of what is the current date. In
+// scenario when user travels back in time zone and current date becomes earlier
+// than latest registered date in perf, we still count that in total use as user
+// actually used that data.
+int DataUseTracker::ComputeTotalDataUse(const std::string& pref_name) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  int total_data_use = 0;
+  const base::DictionaryValue* pref_dict =
+      local_state_->GetDictionary(pref_name);
+  for (base::DictionaryValue::Iterator it(*pref_dict); !it.IsAtEnd();
+       it.Advance()) {
+    int value = 0;
+    it.value().GetAsInteger(&value);
+    total_data_use += value;
+  }
+  return total_data_use;
+}
+
+bool DataUseTracker::GetUmaWeeklyQuota(int* uma_weekly_quota_bytes) const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  std::string param_value_str = variations::GetVariationParamValue(
+      "UMA_EnableCellularLogUpload", "Uma_Quota");
+  if (param_value_str.empty())
+    return false;
+
+  base::StringToInt(param_value_str, uma_weekly_quota_bytes);
+  return true;
+}
+
+bool DataUseTracker::GetUmaRatio(double* ratio) const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  std::string param_value_str = variations::GetVariationParamValue(
+      "UMA_EnableCellularLogUpload", "Uma_Ratio");
+  if (param_value_str.empty())
+    return false;
+  base::StringToDouble(param_value_str, ratio);
+  return true;
+}
+
+base::Time DataUseTracker::GetCurrentMeasurementDate() const {
+  return base::Time::Now().LocalMidnight();
+}
+
+std::string DataUseTracker::GetCurrentMeasurementDateAsString() const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  base::Time::Exploded today_exploded;
+  GetCurrentMeasurementDate().LocalExplode(&today_exploded);
+  return base::StringPrintf("%04d-%02d-%02d", today_exploded.year,
+                            today_exploded.month, today_exploded.day_of_month);
+}
+
+}  // namespace metrics