components/rappor/rappor_service.cc

   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 #include "components/rappor/rappor_service.h"
   6
   7 #include "base/base64.h"
   8 #include "base/metrics/field_trial.h"
   9 #include "base/prefs/pref_registry_simple.h"
  10 #include "base/prefs/pref_service.h"
  11 #include "base/rand_util.h"
  12 #include "base/stl_util.h"
  13 #include "base/time/time.h"
  14 #include "components/metrics/metrics_hashes.h"
  15 #include "components/rappor/log_uploader.h"
  16 #include "components/rappor/proto/rappor_metric.pb.h"
  17 #include "components/rappor/rappor_metric.h"
  18 #include "components/rappor/rappor_pref_names.h"
  19 #include "components/variations/variations_associated_data.h"
  20
  21 namespace rappor {
  22
  23 namespace {
  24
  25 // Seconds before the initial log is generated.
  26 const int kInitialLogIntervalSeconds = 15;
  27 // Interval between ongoing logs.
  28 const int kLogIntervalSeconds = 30 * 60;
  29
  30 const char kMimeType[] = "application/vnd.chrome.rappor";
  31
  32 const char kRapporDailyEventHistogram[] = "Rappor.DailyEvent.IntervalType";
  33
  34 // Constants for the RAPPOR rollout field trial.
  35 const char kRapporRolloutFieldTrialName[] = "RapporRollout";
  36
  37 // Constant for the finch parameter name for the server URL
  38 const char kRapporRolloutServerUrlParam[] = "ServerUrl";
  39
  40 // The rappor server's URL.
  41 const char kDefaultServerUrl[] = "https://clients4.google.com/rappor";
  42
  43 GURL GetServerUrl() {
  44   std::string server_url = variations::GetVariationParamValue(
  45       kRapporRolloutFieldTrialName,
  46       kRapporRolloutServerUrlParam);
  47   if (!server_url.empty())
  48     return GURL(server_url);
  49   else
  50     return GURL(kDefaultServerUrl);
  51 }
  52
  53 const RapporParameters kRapporParametersForType[NUM_RAPPOR_TYPES] = {
  54     // ETLD_PLUS_ONE_RAPPOR_TYPE
  55     {128 /* Num cohorts */,
  56      16 /* Bloom filter size bytes */,
  57      2 /* Bloom filter hash count */,
  58      rappor::PROBABILITY_50 /* Fake data probability */,
  59      rappor::PROBABILITY_50 /* Fake one probability */,
  60      rappor::PROBABILITY_75 /* One coin probability */,
  61      rappor::PROBABILITY_25 /* Zero coin probability */,
  62      FINE_LEVEL /* Reporting level */},
  63     // COARSE_RAPPOR_TYPE
  64     {128 /* Num cohorts */,
  65      1 /* Bloom filter size bytes */,
  66      2 /* Bloom filter hash count */,
  67      rappor::PROBABILITY_50 /* Fake data probability */,
  68      rappor::PROBABILITY_50 /* Fake one probability */,
  69      rappor::PROBABILITY_75 /* One coin probability */,
  70      rappor::PROBABILITY_25 /* Zero coin probability */,
  71      COARSE_LEVEL /* Reporting level */},
  72 };
  73
  74 }  // namespace
  75
  76 RapporService::RapporService(
  77     PrefService* pref_service,
  78     const base::Callback<bool(void)> is_incognito_callback)
  79     : pref_service_(pref_service),
  80       is_incognito_callback_(is_incognito_callback),
  81       cohort_(-1),
  82       daily_event_(pref_service,
  83                    prefs::kRapporLastDailySample,
  84                    kRapporDailyEventHistogram),
  85       reporting_level_(REPORTING_DISABLED) {
  86 }
  87
  88 RapporService::~RapporService() {
  89   STLDeleteValues(&metrics_map_);
  90 }
  91
  92 void RapporService::AddDailyObserver(
  93     scoped_ptr<metrics::DailyEvent::Observer> observer) {
  94   daily_event_.AddObserver(observer.Pass());
  95 }
  96
  97 void RapporService::Start(net::URLRequestContextGetter* request_context,
  98                           bool metrics_enabled) {
  99   const GURL server_url = GetServerUrl();
 100   if (!server_url.is_valid()) {
 101     DVLOG(1) << server_url.spec() << " is invalid. "
 102              << "RapporService not started.";
 103     return;
 104   }
 105   // TODO(holte): Consider moving this logic once we've determined the
 106   // conditions for COARSE metrics.
 107   ReportingLevel reporting_level = metrics_enabled ?
 108                                    FINE_LEVEL : REPORTING_DISABLED;
 109   DVLOG(1) << "RapporService reporting_level_? " << reporting_level;
 110   if (reporting_level <= REPORTING_DISABLED)
 111     return;
 112   DVLOG(1) << "RapporService started. Reporting to " << server_url.spec();
 113   DCHECK(!uploader_);
 114   Initialize(LoadCohort(), LoadSecret(), reporting_level);
 115   uploader_.reset(new LogUploader(server_url, kMimeType, request_context));
 116   log_rotation_timer_.Start(
 117       FROM_HERE,
 118       base::TimeDelta::FromSeconds(kInitialLogIntervalSeconds),
 119       this,
 120       &RapporService::OnLogInterval);
 121 }
 122
 123 void RapporService::Initialize(int32_t cohort,
 124                                const std::string& secret,
 125                                const ReportingLevel& reporting_level) {
 126   DCHECK(!IsInitialized());
 127   DCHECK(secret_.empty());
 128   cohort_ = cohort;
 129   secret_ = secret;
 130   reporting_level_ = reporting_level;
 131 }
 132
 133 void RapporService::OnLogInterval() {
 134   DCHECK(uploader_);
 135   DVLOG(2) << "RapporService::OnLogInterval";
 136   daily_event_.CheckInterval();
 137   RapporReports reports;
 138   if (ExportMetrics(&reports)) {
 139     std::string log_text;
 140     bool success = reports.SerializeToString(&log_text);
 141     DCHECK(success);
 142     DVLOG(1) << "RapporService sending a report of "
 143              << reports.report_size() << " value(s).";
 144     uploader_->QueueLog(log_text);
 145   }
 146   log_rotation_timer_.Start(FROM_HERE,
 147                             base::TimeDelta::FromSeconds(kLogIntervalSeconds),
 148                             this,
 149                             &RapporService::OnLogInterval);
 150 }
 151
 152 // static
 153 void RapporService::RegisterPrefs(PrefRegistrySimple* registry) {
 154   registry->RegisterStringPref(prefs::kRapporSecret, std::string());
 155   registry->RegisterIntegerPref(prefs::kRapporCohortDeprecated, -1);
 156   registry->RegisterIntegerPref(prefs::kRapporCohortSeed, -1);
 157   metrics::DailyEvent::RegisterPref(registry,
 158                                        prefs::kRapporLastDailySample);
 159 }
 160
 161 int32_t RapporService::LoadCohort() {
 162   // Ignore and delete old cohort parameter.
 163   pref_service_->ClearPref(prefs::kRapporCohortDeprecated);
 164
 165   int32_t cohort = pref_service_->GetInteger(prefs::kRapporCohortSeed);
 166   // If the user is already assigned to a valid cohort, we're done.
 167   if (cohort >= 0 && cohort < RapporParameters::kMaxCohorts)
 168     return cohort;
 169
 170   // This is the first time the client has started the service (or their
 171   // preferences were corrupted).  Randomly assign them to a cohort.
 172   cohort = base::RandGenerator(RapporParameters::kMaxCohorts);
 173   DVLOG(2) << "Selected a new Rappor cohort: " << cohort;
 174   pref_service_->SetInteger(prefs::kRapporCohortSeed, cohort);
 175   return cohort;
 176 }
 177
 178 std::string RapporService::LoadSecret() {
 179   std::string secret;
 180   std::string secret_base64 = pref_service_->GetString(prefs::kRapporSecret);
 181   if (!secret_base64.empty()) {
 182     bool decoded = base::Base64Decode(secret_base64, &secret);
 183     if (decoded && secret_.size() == HmacByteVectorGenerator::kEntropyInputSize)
 184       return secret;
 185     // If the preference fails to decode, or is the wrong size, it must be
 186     // corrupt, so continue as though it didn't exist yet and generate a new
 187     // one.
 188   }
 189
 190   DVLOG(2) << "Generated a new Rappor secret.";
 191   secret = HmacByteVectorGenerator::GenerateEntropyInput();
 192   base::Base64Encode(secret, &secret_base64);
 193   pref_service_->SetString(prefs::kRapporSecret, secret_base64);
 194   return secret;
 195 }
 196
 197 bool RapporService::ExportMetrics(RapporReports* reports) {
 198   if (metrics_map_.empty()) {
 199     DVLOG(2) << "metrics_map_ is empty.";
 200     return false;
 201   }
 202
 203   DCHECK_GE(cohort_, 0);
 204   reports->set_cohort(cohort_);
 205
 206   for (std::map<std::string, RapporMetric*>::const_iterator it =
 207            metrics_map_.begin();
 208        it != metrics_map_.end();
 209        ++it) {
 210     const RapporMetric* metric = it->second;
 211     RapporReports::Report* report = reports->add_report();
 212     report->set_name_hash(metrics::HashMetricName(it->first));
 213     ByteVector bytes = metric->GetReport(secret_);
 214     report->set_bits(std::string(bytes.begin(), bytes.end()));
 215   }
 216   STLDeleteValues(&metrics_map_);
 217   return true;
 218 }
 219
 220 bool RapporService::IsInitialized() const {
 221   return cohort_ >= 0;
 222 }
 223
 224 void RapporService::RecordSample(const std::string& metric_name,
 225                                  RapporType type,
 226                                  const std::string& sample) {
 227   // Ignore the sample if the service hasn't started yet.
 228   if (!IsInitialized())
 229     return;
 230   DCHECK_LT(type, NUM_RAPPOR_TYPES);
 231   const RapporParameters& parameters = kRapporParametersForType[type];
 232   DVLOG(2) << "Recording sample \"" << sample
 233            << "\" for metric \"" << metric_name
 234            << "\" of type: " << type;
 235   RecordSampleInternal(metric_name, parameters, sample);
 236 }
 237
 238 void RapporService::RecordSampleInternal(const std::string& metric_name,
 239                                          const RapporParameters& parameters,
 240                                          const std::string& sample) {
 241   DCHECK(IsInitialized());
 242   if (is_incognito_callback_.Run()) {
 243     DVLOG(2) << "Metric not logged due to incognito mode.";
 244     return;
 245   }
 246   // Skip this metric if it's reporting level is less than the enabled
 247   // reporting level.
 248   if (reporting_level_ < parameters.reporting_level) {
 249     DVLOG(2) << "Metric not logged due to reporting_level "
 250              << reporting_level_ << " < " << parameters.reporting_level;
 251     return;
 252   }
 253   RapporMetric* metric = LookUpMetric(metric_name, parameters);
 254   metric->AddSample(sample);
 255 }
 256
 257 RapporMetric* RapporService::LookUpMetric(const std::string& metric_name,
 258                                           const RapporParameters& parameters) {
 259   DCHECK(IsInitialized());
 260   std::map<std::string, RapporMetric*>::const_iterator it =
 261       metrics_map_.find(metric_name);
 262   if (it != metrics_map_.end()) {
 263     RapporMetric* metric = it->second;
 264     DCHECK_EQ(parameters.ToString(), metric->parameters().ToString());
 265     return metric;
 266   }
 267
 268   RapporMetric* new_metric = new RapporMetric(metric_name, parameters, cohort_);
 269   metrics_map_[metric_name] = new_metric;
 270   return new_metric;
 271 }
 272
 273 }  // namespace rappor