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 // Constant for the finch parameter name for the server URL
41 const char kRapporRolloutRequireUmaParam[] = "RequireUma";
42
43 // The rappor server's URL.
44 const char kDefaultServerUrl[] = "https://clients4.google.com/rappor";
45
GetServerUrl(bool metrics_enabled)46 GURL GetServerUrl(bool metrics_enabled) {
47 bool require_uma = variations::GetVariationParamValue(
48 kRapporRolloutFieldTrialName,
49 kRapporRolloutRequireUmaParam) != "False";
50 if (!metrics_enabled && require_uma)
51 return GURL(); // Invalid URL disables Rappor.
52 std::string server_url = variations::GetVariationParamValue(
53 kRapporRolloutFieldTrialName,
54 kRapporRolloutServerUrlParam);
55 if (!server_url.empty())
56 return GURL(server_url);
57 else
58 return GURL(kDefaultServerUrl);
59 }
60
61 const RapporParameters kRapporParametersForType[NUM_RAPPOR_TYPES] = {
62 // ETLD_PLUS_ONE_RAPPOR_TYPE
63 {128 /* Num cohorts */,
64 16 /* Bloom filter size bytes */,
65 2 /* Bloom filter hash count */,
66 rappor::PROBABILITY_50 /* Fake data probability */,
67 rappor::PROBABILITY_50 /* Fake one probability */,
68 rappor::PROBABILITY_75 /* One coin probability */,
69 rappor::PROBABILITY_25 /* Zero coin probability */},
70 };
71
72 } // namespace
73
RapporService(PrefService * pref_service)74 RapporService::RapporService(PrefService* pref_service)
75 : pref_service_(pref_service),
76 cohort_(-1),
77 daily_event_(pref_service,
78 prefs::kRapporLastDailySample,
79 kRapporDailyEventHistogram) {
80 }
81
~RapporService()82 RapporService::~RapporService() {
83 STLDeleteValues(&metrics_map_);
84 }
85
AddDailyObserver(scoped_ptr<metrics::DailyEvent::Observer> observer)86 void RapporService::AddDailyObserver(
87 scoped_ptr<metrics::DailyEvent::Observer> observer) {
88 daily_event_.AddObserver(observer.Pass());
89 }
90
Start(net::URLRequestContextGetter * request_context,bool metrics_enabled)91 void RapporService::Start(net::URLRequestContextGetter* request_context,
92 bool metrics_enabled) {
93 const GURL server_url = GetServerUrl(metrics_enabled);
94 if (!server_url.is_valid()) {
95 DVLOG(1) << server_url.spec() << " is invalid. "
96 << "RapporService not started.";
97 return;
98 }
99 DVLOG(1) << "RapporService started. Reporting to " << server_url.spec();
100 DCHECK(!uploader_);
101 LoadSecret();
102 LoadCohort();
103 uploader_.reset(new LogUploader(server_url, kMimeType, request_context));
104 log_rotation_timer_.Start(
105 FROM_HERE,
106 base::TimeDelta::FromSeconds(kInitialLogIntervalSeconds),
107 this,
108 &RapporService::OnLogInterval);
109 }
110
OnLogInterval()111 void RapporService::OnLogInterval() {
112 DCHECK(uploader_);
113 DVLOG(2) << "RapporService::OnLogInterval";
114 daily_event_.CheckInterval();
115 RapporReports reports;
116 if (ExportMetrics(&reports)) {
117 std::string log_text;
118 bool success = reports.SerializeToString(&log_text);
119 DCHECK(success);
120 DVLOG(1) << "RapporService sending a report of "
121 << reports.report_size() << " value(s).";
122 uploader_->QueueLog(log_text);
123 }
124 log_rotation_timer_.Start(FROM_HERE,
125 base::TimeDelta::FromSeconds(kLogIntervalSeconds),
126 this,
127 &RapporService::OnLogInterval);
128 }
129
130 // static
RegisterPrefs(PrefRegistrySimple * registry)131 void RapporService::RegisterPrefs(PrefRegistrySimple* registry) {
132 registry->RegisterStringPref(prefs::kRapporSecret, std::string());
133 registry->RegisterIntegerPref(prefs::kRapporCohortDeprecated, -1);
134 registry->RegisterIntegerPref(prefs::kRapporCohortSeed, -1);
135 metrics::DailyEvent::RegisterPref(registry,
136 prefs::kRapporLastDailySample);
137 }
138
LoadCohort()139 void RapporService::LoadCohort() {
140 DCHECK(!IsInitialized());
141 // Ignore and delete old cohort parameter.
142 pref_service_->ClearPref(prefs::kRapporCohortDeprecated);
143
144 cohort_ = pref_service_->GetInteger(prefs::kRapporCohortSeed);
145 // If the user is already assigned to a valid cohort, we're done.
146 if (cohort_ >= 0 && cohort_ < RapporParameters::kMaxCohorts)
147 return;
148
149 // This is the first time the client has started the service (or their
150 // preferences were corrupted). Randomly assign them to a cohort.
151 cohort_ = base::RandGenerator(RapporParameters::kMaxCohorts);
152 DVLOG(2) << "Selected a new Rappor cohort: " << cohort_;
153 pref_service_->SetInteger(prefs::kRapporCohortSeed, cohort_);
154 }
155
LoadSecret()156 void RapporService::LoadSecret() {
157 DCHECK(secret_.empty());
158 std::string secret_base64 = pref_service_->GetString(prefs::kRapporSecret);
159 if (!secret_base64.empty()) {
160 bool decoded = base::Base64Decode(secret_base64, &secret_);
161 if (decoded && secret_.size() == HmacByteVectorGenerator::kEntropyInputSize)
162 return;
163 // If the preference fails to decode, or is the wrong size, it must be
164 // corrupt, so continue as though it didn't exist yet and generate a new
165 // one.
166 }
167
168 DVLOG(2) << "Generated a new Rappor secret.";
169 secret_ = HmacByteVectorGenerator::GenerateEntropyInput();
170 base::Base64Encode(secret_, &secret_base64);
171 pref_service_->SetString(prefs::kRapporSecret, secret_base64);
172 }
173
ExportMetrics(RapporReports * reports)174 bool RapporService::ExportMetrics(RapporReports* reports) {
175 if (metrics_map_.empty())
176 return false;
177
178 DCHECK_GE(cohort_, 0);
179 reports->set_cohort(cohort_);
180
181 for (std::map<std::string, RapporMetric*>::const_iterator it =
182 metrics_map_.begin();
183 it != metrics_map_.end();
184 ++it) {
185 const RapporMetric* metric = it->second;
186 RapporReports::Report* report = reports->add_report();
187 report->set_name_hash(metrics::HashMetricName(it->first));
188 ByteVector bytes = metric->GetReport(secret_);
189 report->set_bits(std::string(bytes.begin(), bytes.end()));
190 }
191 STLDeleteValues(&metrics_map_);
192 return true;
193 }
194
IsInitialized() const195 bool RapporService::IsInitialized() const {
196 return cohort_ >= 0;
197 }
198
RecordSample(const std::string & metric_name,RapporType type,const std::string & sample)199 void RapporService::RecordSample(const std::string& metric_name,
200 RapporType type,
201 const std::string& sample) {
202 // Ignore the sample if the service hasn't started yet.
203 if (!IsInitialized())
204 return;
205 DCHECK_LT(type, NUM_RAPPOR_TYPES);
206 DVLOG(2) << "Recording sample \"" << sample
207 << "\" for metric \"" << metric_name
208 << "\" of type: " << type;
209 RecordSampleInternal(metric_name, kRapporParametersForType[type], sample);
210 }
211
RecordSampleInternal(const std::string & metric_name,const RapporParameters & parameters,const std::string & sample)212 void RapporService::RecordSampleInternal(const std::string& metric_name,
213 const RapporParameters& parameters,
214 const std::string& sample) {
215 DCHECK(IsInitialized());
216 RapporMetric* metric = LookUpMetric(metric_name, parameters);
217 metric->AddSample(sample);
218 }
219
LookUpMetric(const std::string & metric_name,const RapporParameters & parameters)220 RapporMetric* RapporService::LookUpMetric(const std::string& metric_name,
221 const RapporParameters& parameters) {
222 DCHECK(IsInitialized());
223 std::map<std::string, RapporMetric*>::const_iterator it =
224 metrics_map_.find(metric_name);
225 if (it != metrics_map_.end()) {
226 RapporMetric* metric = it->second;
227 DCHECK_EQ(parameters.ToString(), metric->parameters().ToString());
228 return metric;
229 }
230
231 RapporMetric* new_metric = new RapporMetric(metric_name, parameters, cohort_);
232 metrics_map_[metric_name] = new_metric;
233 return new_metric;
234 }
235
236 } // namespace rappor
237