| // Copyright (c) 2012 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 "chrome/browser/metrics/variations/variations_service.h" |
| |
| #include <set> |
| |
| #include "base/base64.h" |
| #include "base/build_time.h" |
| #include "base/command_line.h" |
| #include "base/memory/scoped_ptr.h" |
| #include "base/metrics/histogram.h" |
| #include "base/metrics/sparse_histogram.h" |
| #include "base/prefs/pref_registry_simple.h" |
| #include "base/prefs/pref_service.h" |
| #include "base/sha1.h" |
| #include "base/strings/string_number_conversions.h" |
| #include "base/version.h" |
| #include "chrome/browser/browser_process.h" |
| #include "chrome/browser/metrics/proto/trials_seed.pb.h" |
| #include "chrome/browser/metrics/variations/variations_seed_processor.h" |
| #include "chrome/browser/net/network_time_tracker.h" |
| #include "chrome/common/chrome_switches.h" |
| #include "chrome/common/metrics/variations/variations_util.h" |
| #include "chrome/common/pref_names.h" |
| #include "content/public/browser/browser_thread.h" |
| #include "content/public/common/url_fetcher.h" |
| #include "net/base/load_flags.h" |
| #include "net/base/net_errors.h" |
| #include "net/base/network_change_notifier.h" |
| #include "net/base/url_util.h" |
| #include "net/http/http_response_headers.h" |
| #include "net/http/http_status_code.h" |
| #include "net/http/http_util.h" |
| #include "net/url_request/url_fetcher.h" |
| #include "net/url_request/url_request_status.h" |
| #include "url/gurl.h" |
| |
| #if defined(OS_CHROMEOS) |
| #include "chrome/browser/chromeos/settings/cros_settings.h" |
| #endif |
| |
| namespace chrome_variations { |
| |
| namespace { |
| |
| // Default server of Variations seed info. |
| const char kDefaultVariationsServerURL[] = |
| "https://clients4.google.com/chrome-variations/seed"; |
| const int kMaxRetrySeedFetch = 5; |
| |
| // TODO(mad): To be removed when we stop updating the NetworkTimeTracker. |
| // For the HTTP date headers, the resolution of the server time is 1 second. |
| const int64 kServerTimeResolutionMs = 1000; |
| |
| // Wrapper around channel checking, used to enable channel mocking for |
| // testing. If the current browser channel is not UNKNOWN, this will return |
| // that channel value. Otherwise, if the fake channel flag is provided, this |
| // will return the fake channel. Failing that, this will return the UNKNOWN |
| // channel. |
| Study_Channel GetChannelForVariations() { |
| switch (chrome::VersionInfo::GetChannel()) { |
| case chrome::VersionInfo::CHANNEL_CANARY: |
| return Study_Channel_CANARY; |
| case chrome::VersionInfo::CHANNEL_DEV: |
| return Study_Channel_DEV; |
| case chrome::VersionInfo::CHANNEL_BETA: |
| return Study_Channel_BETA; |
| case chrome::VersionInfo::CHANNEL_STABLE: |
| return Study_Channel_STABLE; |
| case chrome::VersionInfo::CHANNEL_UNKNOWN: |
| break; |
| } |
| const std::string forced_channel = |
| CommandLine::ForCurrentProcess()->GetSwitchValueASCII( |
| switches::kFakeVariationsChannel); |
| if (forced_channel == "stable") |
| return Study_Channel_STABLE; |
| if (forced_channel == "beta") |
| return Study_Channel_BETA; |
| if (forced_channel == "dev") |
| return Study_Channel_DEV; |
| if (forced_channel == "canary") |
| return Study_Channel_CANARY; |
| DVLOG(1) << "Invalid channel provided: " << forced_channel; |
| return Study_Channel_UNKNOWN; |
| } |
| |
| // Returns a string that will be used for the value of the 'osname' URL param |
| // to the variations server. |
| std::string GetPlatformString() { |
| #if defined(OS_WIN) |
| return "win"; |
| #elif defined(OS_IOS) |
| return "ios"; |
| #elif defined(OS_MACOSX) |
| return "mac"; |
| #elif defined(OS_CHROMEOS) |
| return "chromeos"; |
| #elif defined(OS_ANDROID) |
| return "android"; |
| #elif defined(OS_LINUX) || defined(OS_BSD) || defined(OS_SOLARIS) |
| // Default BSD and SOLARIS to Linux to not break those builds, although these |
| // platforms are not officially supported by Chrome. |
| return "linux"; |
| #else |
| #error Unknown platform |
| #endif |
| } |
| |
| // Converts |date_time| in Study date format to base::Time. |
| base::Time ConvertStudyDateToBaseTime(int64 date_time) { |
| return base::Time::UnixEpoch() + base::TimeDelta::FromSeconds(date_time); |
| } |
| |
| // Gets the restrict parameter from |local_state| or from Chrome OS settings in |
| // the case of that platform. |
| std::string GetRestrictParameterPref(PrefService* local_state) { |
| std::string parameter; |
| #if defined(OS_CHROMEOS) |
| chromeos::CrosSettings::Get()->GetString( |
| chromeos::kVariationsRestrictParameter, ¶meter); |
| #else |
| if (local_state) |
| parameter = local_state->GetString(prefs::kVariationsRestrictParameter); |
| #endif |
| return parameter; |
| } |
| |
| // Computes a hash of the serialized variations seed data. |
| std::string HashSeed(const std::string& seed_data) { |
| const std::string sha1 = base::SHA1HashString(seed_data); |
| return base::HexEncode(sha1.data(), sha1.size()); |
| } |
| |
| enum ResourceRequestsAllowedState { |
| RESOURCE_REQUESTS_ALLOWED, |
| RESOURCE_REQUESTS_NOT_ALLOWED, |
| RESOURCE_REQUESTS_ALLOWED_NOTIFIED, |
| RESOURCE_REQUESTS_ALLOWED_ENUM_SIZE, |
| }; |
| |
| // Records UMA histogram with the current resource requests allowed state. |
| void RecordRequestsAllowedHistogram(ResourceRequestsAllowedState state) { |
| UMA_HISTOGRAM_ENUMERATION("Variations.ResourceRequestsAllowed", state, |
| RESOURCE_REQUESTS_ALLOWED_ENUM_SIZE); |
| } |
| |
| enum VariationSeedEmptyState { |
| VARIATIONS_SEED_NOT_EMPTY, |
| VARIATIONS_SEED_EMPTY, |
| VARIATIONS_SEED_CORRUPT, |
| VARIATIONS_SEED_EMPTY_ENUM_SIZE, |
| }; |
| |
| void RecordVariationSeedEmptyHistogram(VariationSeedEmptyState state) { |
| UMA_HISTOGRAM_ENUMERATION("Variations.SeedEmpty", state, |
| VARIATIONS_SEED_EMPTY_ENUM_SIZE); |
| } |
| |
| } // namespace |
| |
| VariationsService::VariationsService(PrefService* local_state) |
| : local_state_(local_state), |
| variations_server_url_(GetVariationsServerURL(local_state)), |
| create_trials_from_seed_called_(false), |
| initial_request_completed_(false), |
| resource_request_allowed_notifier_( |
| new ResourceRequestAllowedNotifier) { |
| resource_request_allowed_notifier_->Init(this); |
| } |
| |
| VariationsService::VariationsService(ResourceRequestAllowedNotifier* notifier, |
| PrefService* local_state) |
| : local_state_(local_state), |
| variations_server_url_(GetVariationsServerURL(NULL)), |
| create_trials_from_seed_called_(false), |
| initial_request_completed_(false), |
| resource_request_allowed_notifier_(notifier) { |
| resource_request_allowed_notifier_->Init(this); |
| } |
| |
| VariationsService::~VariationsService() { |
| } |
| |
| bool VariationsService::CreateTrialsFromSeed() { |
| create_trials_from_seed_called_ = true; |
| |
| TrialsSeed seed; |
| if (!LoadTrialsSeedFromPref(&seed)) |
| return false; |
| |
| const int64 date_value = local_state_->GetInt64(prefs::kVariationsSeedDate); |
| const base::Time seed_date = base::Time::FromInternalValue(date_value); |
| const base::Time build_time = base::GetBuildTime(); |
| // Use the build time for date checks if either the seed date is invalid or |
| // the build time is newer than the seed date. |
| base::Time reference_date = seed_date; |
| if (seed_date.is_null() || seed_date < build_time) |
| reference_date = build_time; |
| |
| const chrome::VersionInfo current_version_info; |
| if (!current_version_info.is_valid()) |
| return false; |
| |
| const base::Version current_version(current_version_info.Version()); |
| if (!current_version.IsValid()) |
| return false; |
| |
| VariationsSeedProcessor().CreateTrialsFromSeed( |
| seed, g_browser_process->GetApplicationLocale(), reference_date, |
| current_version, GetChannelForVariations()); |
| |
| // Log the "freshness" of the seed that was just used. The freshness is the |
| // time between the last successful seed download and now. |
| const int64 last_fetch_time_internal = |
| local_state_->GetInt64(prefs::kVariationsLastFetchTime); |
| if (last_fetch_time_internal) { |
| const base::Time now = base::Time::Now(); |
| const base::TimeDelta delta = |
| now - base::Time::FromInternalValue(last_fetch_time_internal); |
| // Log the value in number of minutes. |
| UMA_HISTOGRAM_CUSTOM_COUNTS("Variations.SeedFreshness", delta.InMinutes(), |
| 1, base::TimeDelta::FromDays(30).InMinutes(), 50); |
| } |
| |
| return true; |
| } |
| |
| void VariationsService::StartRepeatedVariationsSeedFetch() { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI)); |
| |
| // Check that |CreateTrialsFromSeed| was called, which is necessary to |
| // retrieve the serial number that will be sent to the server. |
| DCHECK(create_trials_from_seed_called_); |
| |
| DCHECK(!request_scheduler_.get()); |
| // Note that the act of instantiating the scheduler will start the fetch, if |
| // the scheduler deems appropriate. Using Unretained is fine here since the |
| // lifespan of request_scheduler_ is guaranteed to be shorter than that of |
| // this service. |
| request_scheduler_.reset(VariationsRequestScheduler::Create( |
| base::Bind(&VariationsService::FetchVariationsSeed, |
| base::Unretained(this)), local_state_)); |
| request_scheduler_->Start(); |
| } |
| |
| // static |
| GURL VariationsService::GetVariationsServerURL(PrefService* local_state) { |
| std::string server_url_string(CommandLine::ForCurrentProcess()-> |
| GetSwitchValueASCII(switches::kVariationsServerURL)); |
| if (server_url_string.empty()) |
| server_url_string = kDefaultVariationsServerURL; |
| GURL server_url = GURL(server_url_string); |
| |
| const std::string restrict_param = GetRestrictParameterPref(local_state); |
| if (!restrict_param.empty()) { |
| server_url = net::AppendOrReplaceQueryParameter(server_url, |
| "restrict", |
| restrict_param); |
| } |
| |
| server_url = net::AppendOrReplaceQueryParameter(server_url, "osname", |
| GetPlatformString()); |
| |
| DCHECK(server_url.is_valid()); |
| return server_url; |
| } |
| |
| #if defined(OS_WIN) |
| void VariationsService::StartGoogleUpdateRegistrySync() { |
| registry_syncer_.RequestRegistrySync(); |
| } |
| #endif |
| |
| void VariationsService::SetCreateTrialsFromSeedCalledForTesting(bool called) { |
| create_trials_from_seed_called_ = called; |
| } |
| |
| // static |
| std::string VariationsService::GetDefaultVariationsServerURLForTesting() { |
| return kDefaultVariationsServerURL; |
| } |
| |
| // static |
| void VariationsService::RegisterPrefs(PrefRegistrySimple* registry) { |
| registry->RegisterStringPref(prefs::kVariationsSeed, std::string()); |
| registry->RegisterStringPref(prefs::kVariationsSeedHash, std::string()); |
| registry->RegisterInt64Pref(prefs::kVariationsSeedDate, |
| base::Time().ToInternalValue()); |
| registry->RegisterInt64Pref(prefs::kVariationsLastFetchTime, 0); |
| registry->RegisterStringPref(prefs::kVariationsRestrictParameter, |
| std::string()); |
| } |
| |
| // static |
| VariationsService* VariationsService::Create(PrefService* local_state) { |
| #if !defined(GOOGLE_CHROME_BUILD) |
| // Unless the URL was provided, unsupported builds should return NULL to |
| // indicate that the service should not be used. |
| if (!CommandLine::ForCurrentProcess()->HasSwitch( |
| switches::kVariationsServerURL)) { |
| DVLOG(1) << "Not creating VariationsService in unofficial build without --" |
| << switches::kVariationsServerURL << " specified."; |
| return NULL; |
| } |
| #endif |
| return new VariationsService(local_state); |
| } |
| |
| void VariationsService::DoActualFetch() { |
| pending_seed_request_.reset(net::URLFetcher::Create( |
| 0, variations_server_url_, net::URLFetcher::GET, this)); |
| pending_seed_request_->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES | |
| net::LOAD_DO_NOT_SAVE_COOKIES); |
| pending_seed_request_->SetRequestContext( |
| g_browser_process->system_request_context()); |
| pending_seed_request_->SetMaxRetriesOn5xx(kMaxRetrySeedFetch); |
| if (!variations_serial_number_.empty()) { |
| pending_seed_request_->AddExtraRequestHeader("If-Match:" + |
| variations_serial_number_); |
| } |
| pending_seed_request_->Start(); |
| |
| const base::TimeTicks now = base::TimeTicks::Now(); |
| base::TimeDelta time_since_last_fetch; |
| // Record a time delta of 0 (default value) if there was no previous fetch. |
| if (!last_request_started_time_.is_null()) |
| time_since_last_fetch = now - last_request_started_time_; |
| UMA_HISTOGRAM_CUSTOM_COUNTS("Variations.TimeSinceLastFetchAttempt", |
| time_since_last_fetch.InMinutes(), 0, |
| base::TimeDelta::FromDays(7).InMinutes(), 50); |
| last_request_started_time_ = now; |
| } |
| |
| void VariationsService::FetchVariationsSeed() { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI)); |
| |
| if (!resource_request_allowed_notifier_->ResourceRequestsAllowed()) { |
| RecordRequestsAllowedHistogram(RESOURCE_REQUESTS_NOT_ALLOWED); |
| DVLOG(1) << "Resource requests were not allowed. Waiting for notification."; |
| return; |
| } |
| |
| RecordRequestsAllowedHistogram(RESOURCE_REQUESTS_ALLOWED); |
| DoActualFetch(); |
| } |
| |
| void VariationsService::OnURLFetchComplete(const net::URLFetcher* source) { |
| DCHECK_EQ(pending_seed_request_.get(), source); |
| |
| const bool is_first_request = !initial_request_completed_; |
| initial_request_completed_ = true; |
| |
| // The fetcher will be deleted when the request is handled. |
| scoped_ptr<const net::URLFetcher> request(pending_seed_request_.release()); |
| const net::URLRequestStatus& request_status = request->GetStatus(); |
| if (request_status.status() != net::URLRequestStatus::SUCCESS) { |
| UMA_HISTOGRAM_SPARSE_SLOWLY("Variations.FailedRequestErrorCode", |
| -request_status.error()); |
| DVLOG(1) << "Variations server request failed with error: " |
| << request_status.error() << ": " |
| << net::ErrorToString(request_status.error()); |
| // It's common for the very first fetch attempt to fail (e.g. the network |
| // may not yet be available). In such a case, try again soon, rather than |
| // waiting the full time interval. |
| if (is_first_request) |
| request_scheduler_->ScheduleFetchShortly(); |
| return; |
| } |
| |
| // Log the response code. |
| const int response_code = request->GetResponseCode(); |
| UMA_HISTOGRAM_SPARSE_SLOWLY("Variations.SeedFetchResponseCode", |
| response_code); |
| |
| const base::TimeDelta latency = |
| base::TimeTicks::Now() - last_request_started_time_; |
| |
| base::Time response_date; |
| if (response_code == net::HTTP_OK || |
| response_code == net::HTTP_NOT_MODIFIED) { |
| bool success = request->GetResponseHeaders()->GetDateValue(&response_date); |
| DCHECK(success || response_date.is_null()); |
| |
| if (!response_date.is_null()) { |
| NetworkTimeTracker::BuildNotifierUpdateCallback().Run( |
| response_date, |
| base::TimeDelta::FromMilliseconds(kServerTimeResolutionMs), |
| latency); |
| } |
| } |
| |
| if (response_code != net::HTTP_OK) { |
| DVLOG(1) << "Variations server request returned non-HTTP_OK response code: " |
| << response_code; |
| if (response_code == net::HTTP_NOT_MODIFIED) { |
| UMA_HISTOGRAM_MEDIUM_TIMES("Variations.FetchNotModifiedLatency", latency); |
| RecordLastFetchTime(); |
| } else { |
| UMA_HISTOGRAM_MEDIUM_TIMES("Variations.FetchOtherLatency", latency); |
| } |
| return; |
| } |
| UMA_HISTOGRAM_MEDIUM_TIMES("Variations.FetchSuccessLatency", latency); |
| |
| std::string seed_data; |
| bool success = request->GetResponseAsString(&seed_data); |
| DCHECK(success); |
| |
| StoreSeedData(seed_data, response_date); |
| } |
| |
| void VariationsService::OnResourceRequestsAllowed() { |
| // Note that this only attempts to fetch the seed at most once per period |
| // (kSeedFetchPeriodHours). This works because |
| // |resource_request_allowed_notifier_| only calls this method if an |
| // attempt was made earlier that fails (which implies that the period had |
| // elapsed). After a successful attempt is made, the notifier will know not |
| // to call this method again until another failed attempt occurs. |
| RecordRequestsAllowedHistogram(RESOURCE_REQUESTS_ALLOWED_NOTIFIED); |
| DVLOG(1) << "Retrying fetch."; |
| DoActualFetch(); |
| |
| // This service must have created a scheduler in order for this to be called. |
| DCHECK(request_scheduler_.get()); |
| request_scheduler_->Reset(); |
| } |
| |
| bool VariationsService::StoreSeedData(const std::string& seed_data, |
| const base::Time& seed_date) { |
| if (seed_data.empty()) { |
| VLOG(1) << "Variations Seed data from server is empty, rejecting the seed."; |
| return false; |
| } |
| |
| // Only store the seed data if it parses correctly. |
| TrialsSeed seed; |
| if (!seed.ParseFromString(seed_data)) { |
| VLOG(1) << "Variations Seed data from server is not in valid proto format, " |
| << "rejecting the seed."; |
| return false; |
| } |
| |
| std::string base64_seed_data; |
| if (!base::Base64Encode(seed_data, &base64_seed_data)) { |
| VLOG(1) << "Variations Seed data from server fails Base64Encode, rejecting " |
| << "the seed."; |
| return false; |
| } |
| |
| local_state_->SetString(prefs::kVariationsSeed, base64_seed_data); |
| local_state_->SetString(prefs::kVariationsSeedHash, HashSeed(seed_data)); |
| local_state_->SetInt64(prefs::kVariationsSeedDate, |
| seed_date.ToInternalValue()); |
| variations_serial_number_ = seed.serial_number(); |
| |
| RecordLastFetchTime(); |
| |
| return true; |
| } |
| |
| bool VariationsService::LoadTrialsSeedFromPref(TrialsSeed* seed) { |
| const std::string base64_seed_data = |
| local_state_->GetString(prefs::kVariationsSeed); |
| if (base64_seed_data.empty()) { |
| RecordVariationSeedEmptyHistogram(VARIATIONS_SEED_EMPTY); |
| return false; |
| } |
| |
| const std::string hash_from_pref = |
| local_state_->GetString(prefs::kVariationsSeedHash); |
| // If the decode process fails, assume the pref value is corrupt and clear it. |
| std::string seed_data; |
| if (!base::Base64Decode(base64_seed_data, &seed_data) || |
| (!hash_from_pref.empty() && HashSeed(seed_data) != hash_from_pref) || |
| !seed->ParseFromString(seed_data)) { |
| VLOG(1) << "Variations seed data in local pref is corrupt, clearing the " |
| << "pref."; |
| local_state_->ClearPref(prefs::kVariationsSeed); |
| local_state_->ClearPref(prefs::kVariationsSeedDate); |
| local_state_->ClearPref(prefs::kVariationsSeedHash); |
| RecordVariationSeedEmptyHistogram(VARIATIONS_SEED_CORRUPT); |
| return false; |
| } |
| variations_serial_number_ = seed->serial_number(); |
| RecordVariationSeedEmptyHistogram(VARIATIONS_SEED_NOT_EMPTY); |
| return true; |
| } |
| |
| void VariationsService::RecordLastFetchTime() { |
| // local_state_ is NULL in tests, so check it first. |
| if (local_state_) { |
| local_state_->SetInt64(prefs::kVariationsLastFetchTime, |
| base::Time::Now().ToInternalValue()); |
| } |
| } |
| |
| } // namespace chrome_variations |