components/metrics/structured/structured_metrics_provider.h - chromium/src - Git at Google

 // Copyright 2019 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.

 #ifndef COMPONENTS_METRICS_STRUCTURED_STRUCTURED_METRICS_PROVIDER_H_
 #define COMPONENTS_METRICS_STRUCTURED_STRUCTURED_METRICS_PROVIDER_H_

 #include <memory>

 #include "base/files/file_path.h"
 #include "base/memory/scoped_refptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "components/metrics/metrics_provider.h"
 #include "components/metrics/structured/event_base.h"
 #include "components/metrics/structured/key_data.h"
 #include "components/metrics/structured/recorder.h"
 #include "third_party/abseil-cpp/absl/types/optional.h"

 namespace metrics {
 namespace structured {

 class EventsProto;
 class ExternalMetrics;

 // StructuredMetricsProvider is responsible for filling out the
 // |structured_metrics_event| section of the UMA proto. This class should not be
 // instantiated except by the ChromeMetricsServiceClient. This class is not
 // thread safe and should only be called on the browser UI sequence, because
 // calls from the metrics service come on the UI sequence.
 //
 // Initialization of the StructuredMetricsProvider must wait until a profile is
 // added, because state is stored within the profile directory. Initialization
 // happens in several steps:
 //
 // 1. A StructuredMetricsProvider instance is constructed and owned by the
 //    MetricsService. It registers itself as an observer of
 //    metrics::structured::Recorder.
 //
 // 2. When a profile is added that is eligible for recording,
 //    ChromeMetricsServiceClient calls Recorder::ProfileAdded, which notifies
 //    this class.
 //
 // 3. This class then begins initialization by asynchronously reading keys and
 //    unsent logs from the cryptohome.
 //
 // 4. If the read succeeds, initialization is complete and this class starts
 //    accepting events to record.
 //
 // After initialization, this class accepts events to record from
 // StructuredMetricsProvider::OnRecord via Recorder::Record via
 // EventBase::Record. These events are not uploaded immediately, and are cached
 // in ready-to-upload form.
 //
 // On a call to ProvideCurrentSessionData, the cache of unsent logs is added to
 // a ChromeUserMetricsExtension for upload, and is then cleared.
 class StructuredMetricsProvider : public metrics::MetricsProvider,
                                   public Recorder::RecorderImpl {
  public:
   StructuredMetricsProvider();
   ~StructuredMetricsProvider() override;
   StructuredMetricsProvider(const StructuredMetricsProvider&) = delete;
   StructuredMetricsProvider& operator=(const StructuredMetricsProvider&) =
       delete;

  private:
   friend class Recorder;
   friend class StructuredMetricsProviderTest;

   // State machine for step 4 of initialization. These are stored in three files
   // that are asynchronously read from disk at startup. When all files have
   // been read, the provider has been initialized.
   enum class InitState {
     kUninitialized = 1,
     // Set after we observe the recorder, which happens on construction.
     kProfileAdded = 2,
     // Set after all key and event files are read from disk.
     kInitialized = 3,
   };

   void OnKeyDataInitialized();
   void OnRead(ReadStatus status);
   void OnWrite(WriteStatus status);
   void OnExternalMetricsCollected(const EventsProto& events);
   void Purge();

   // Recorder::RecorderImpl:
   void OnProfileAdded(const base::FilePath& profile_path) override;
   void OnRecord(const EventBase& event) override;
   void OnReportingStateChanged(bool enabled) override;
   absl::optional<int> LastKeyRotation(uint64_t project_name_hash) override;

   // metrics::MetricsProvider:
   void OnRecordingEnabled() override;
   void OnRecordingDisabled() override;
   void ProvideCurrentSessionData(
       metrics::ChromeUserMetricsExtension* uma_proto) override;
   bool HasIndependentMetrics() override;
   void ProvideIndependentMetrics(base::OnceCallback<void(bool)> done_callback,
                                  ChromeUserMetricsExtension* uma_proto,
                                  base::HistogramSnapshotManager*) override;

   void WriteNowForTest();
   void SetExternalMetricsDirForTest(const base::FilePath& dir);
   void SetDeviceKeyDataPathForTest(const base::FilePath& path);

   // Beyond this number of logging events between successive calls to
   // ProvideCurrentSessionData, we stop recording events.
   static int kMaxEventsPerUpload;

   // The path used to store per-profile keys. Relative to the user's
   // cryptohome. This file is created by chromium.
   static char kProfileKeyDataPath[];

   // The path used to store per-device keys. This file is created by tmpfiles.d
   // on start and has its permissions and ownership set such that it is writable
   // by chronos.
   static char kDeviceKeyDataPath[];

   // The directory used to store unsent logs. Relative to the user's cryptohome.
   // This file is created by chromium.
   static char kUnsentLogsPath[];

   // Whether the metrics provider has completed initialization. Initialization
   // occurs across OnProfileAdded and OnInitializationCompleted. No incoming
   // events are recorded until initialization has succeeded.
   //
   // Execution is:
   //  - A profile is added.
   //  - OnProfileAdded is called, which constructs |storage_| and
   //    asynchronously reads events and keys.
   //  - OnInitializationCompleted is called once reading from disk is complete,
   //    which sets |init_count_| to kInitialized.
   //
   // The metrics provider does not handle multiprofile: initialization happens
   // only once, for the first-logged-in account aka. primary user.
   //
   // After a profile is added, three files need to be read from disk:
   // per-profile keys, per-device keys, and unsent events. |init_count_| tracks
   // how many of these have been read and, when it reaches 3, we set
   // |init_state_| to kInitialized.
   InitState init_state_ = InitState::kUninitialized;
   int init_count_ = 0;
   static constexpr int kTargetInitCount = 3;

   // Tracks the recording state signalled to the metrics provider by
   // OnRecordingEnabled and OnRecordingDisabled. This is false until
   // OnRecordingEnabled is called, which sets it true if structured metrics'
   // feature flag is enabled.
   bool recording_enabled_ = false;

   // Set by OnReportingStateChanged if all keys and events should be deleted,
   // but the files backing that state haven't been initialized yet. If set,
   // state will be purged upon initialization.
   bool purge_state_on_init_ = false;

   // The last time we provided independent metrics.
   base::Time last_provided_independent_metrics_;

   // Periodically reports metrics from cros.
   std::unique_ptr<ExternalMetrics> external_metrics_;

   // On-device storage within the user's cryptohome for unsent logs.
   std::unique_ptr<PersistentProto<EventsProto>> events_;

   // Storage for all event's keys, and hashing logic for values. This stores
   // keys on disk. |profile_key_data_| stores keys for per-profile projects,
   // and |device_key_data_| stores keys for per-device projects.
   std::unique_ptr<KeyData> profile_key_data_;
   std::unique_ptr<KeyData> device_key_data_;

   // Used to override the otherwise hardcoded path for device keys in unit tests
   // only.
   absl::optional<base::FilePath> device_key_data_path_for_test_;

   base::WeakPtrFactory<StructuredMetricsProvider> weak_factory_{this};
 };

 }  // namespace structured
 }  // namespace metrics

 #endif  // COMPONENTS_METRICS_STRUCTURED_STRUCTURED_METRICS_PROVIDER_H_
	// Copyright 2019 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.

	#ifndef COMPONENTS_METRICS_STRUCTURED_STRUCTURED_METRICS_PROVIDER_H_
	#define COMPONENTS_METRICS_STRUCTURED_STRUCTURED_METRICS_PROVIDER_H_

	#include <memory>

	#include "base/files/file_path.h"
	#include "base/memory/scoped_refptr.h"
	#include "base/memory/weak_ptr.h"
	#include "base/time/time.h"
	#include "components/metrics/metrics_provider.h"
	#include "components/metrics/structured/event_base.h"
	#include "components/metrics/structured/key_data.h"
	#include "components/metrics/structured/recorder.h"
	#include "third_party/abseil-cpp/absl/types/optional.h"

	namespace metrics {
	namespace structured {

	class EventsProto;
	class ExternalMetrics;

	// StructuredMetricsProvider is responsible for filling out the
	// \|structured_metrics_event\| section of the UMA proto. This class should not be
	// instantiated except by the ChromeMetricsServiceClient. This class is not
	// thread safe and should only be called on the browser UI sequence, because
	// calls from the metrics service come on the UI sequence.
	//
	// Initialization of the StructuredMetricsProvider must wait until a profile is
	// added, because state is stored within the profile directory. Initialization
	// happens in several steps:
	//
	// 1. A StructuredMetricsProvider instance is constructed and owned by the
	// MetricsService. It registers itself as an observer of
	// metrics::structured::Recorder.
	//
	// 2. When a profile is added that is eligible for recording,
	// ChromeMetricsServiceClient calls Recorder::ProfileAdded, which notifies
	// this class.
	//
	// 3. This class then begins initialization by asynchronously reading keys and
	// unsent logs from the cryptohome.
	//
	// 4. If the read succeeds, initialization is complete and this class starts
	// accepting events to record.
	//
	// After initialization, this class accepts events to record from
	// StructuredMetricsProvider::OnRecord via Recorder::Record via
	// EventBase::Record. These events are not uploaded immediately, and are cached
	// in ready-to-upload form.
	//
	// On a call to ProvideCurrentSessionData, the cache of unsent logs is added to
	// a ChromeUserMetricsExtension for upload, and is then cleared.
	class StructuredMetricsProvider : public metrics::MetricsProvider,
	public Recorder::RecorderImpl {
	public:
	StructuredMetricsProvider();
	~StructuredMetricsProvider() override;
	StructuredMetricsProvider(const StructuredMetricsProvider&) = delete;
	StructuredMetricsProvider& operator=(const StructuredMetricsProvider&) =
	delete;

	private:
	friend class Recorder;
	friend class StructuredMetricsProviderTest;

	// State machine for step 4 of initialization. These are stored in three files
	// that are asynchronously read from disk at startup. When all files have
	// been read, the provider has been initialized.
	enum class InitState {
	kUninitialized = 1,
	// Set after we observe the recorder, which happens on construction.
	kProfileAdded = 2,
	// Set after all key and event files are read from disk.
	kInitialized = 3,
	};

	void OnKeyDataInitialized();
	void OnRead(ReadStatus status);
	void OnWrite(WriteStatus status);
	void OnExternalMetricsCollected(const EventsProto& events);
	void Purge();

	// Recorder::RecorderImpl:
	void OnProfileAdded(const base::FilePath& profile_path) override;
	void OnRecord(const EventBase& event) override;
	void OnReportingStateChanged(bool enabled) override;
	absl::optional<int> LastKeyRotation(uint64_t project_name_hash) override;

	// metrics::MetricsProvider:
	void OnRecordingEnabled() override;
	void OnRecordingDisabled() override;
	void ProvideCurrentSessionData(
	metrics::ChromeUserMetricsExtension* uma_proto) override;
	bool HasIndependentMetrics() override;
	void ProvideIndependentMetrics(base::OnceCallback<void(bool)> done_callback,
	ChromeUserMetricsExtension* uma_proto,
	base::HistogramSnapshotManager*) override;

	void WriteNowForTest();
	void SetExternalMetricsDirForTest(const base::FilePath& dir);
	void SetDeviceKeyDataPathForTest(const base::FilePath& path);

	// Beyond this number of logging events between successive calls to
	// ProvideCurrentSessionData, we stop recording events.
	static int kMaxEventsPerUpload;

	// The path used to store per-profile keys. Relative to the user's
	// cryptohome. This file is created by chromium.
	static char kProfileKeyDataPath[];

	// The path used to store per-device keys. This file is created by tmpfiles.d
	// on start and has its permissions and ownership set such that it is writable
	// by chronos.
	static char kDeviceKeyDataPath[];

	// The directory used to store unsent logs. Relative to the user's cryptohome.
	// This file is created by chromium.
	static char kUnsentLogsPath[];

	// Whether the metrics provider has completed initialization. Initialization
	// occurs across OnProfileAdded and OnInitializationCompleted. No incoming
	// events are recorded until initialization has succeeded.
	//
	// Execution is:
	// - A profile is added.
	// - OnProfileAdded is called, which constructs \|storage_\| and
	// asynchronously reads events and keys.
	// - OnInitializationCompleted is called once reading from disk is complete,
	// which sets \|init_count_\| to kInitialized.
	//
	// The metrics provider does not handle multiprofile: initialization happens
	// only once, for the first-logged-in account aka. primary user.
	//
	// After a profile is added, three files need to be read from disk:
	// per-profile keys, per-device keys, and unsent events. \|init_count_\| tracks
	// how many of these have been read and, when it reaches 3, we set
	// \|init_state_\| to kInitialized.
	InitState init_state_ = InitState::kUninitialized;
	int init_count_ = 0;
	static constexpr int kTargetInitCount = 3;

	// Tracks the recording state signalled to the metrics provider by
	// OnRecordingEnabled and OnRecordingDisabled. This is false until
	// OnRecordingEnabled is called, which sets it true if structured metrics'
	// feature flag is enabled.
	bool recording_enabled_ = false;

	// Set by OnReportingStateChanged if all keys and events should be deleted,
	// but the files backing that state haven't been initialized yet. If set,
	// state will be purged upon initialization.
	bool purge_state_on_init_ = false;

	// The last time we provided independent metrics.
	base::Time last_provided_independent_metrics_;

	// Periodically reports metrics from cros.
	std::unique_ptr<ExternalMetrics> external_metrics_;

	// On-device storage within the user's cryptohome for unsent logs.
	std::unique_ptr<PersistentProto<EventsProto>> events_;

	// Storage for all event's keys, and hashing logic for values. This stores
	// keys on disk. \|profile_key_data_\| stores keys for per-profile projects,
	// and \|device_key_data_\| stores keys for per-device projects.
	std::unique_ptr<KeyData> profile_key_data_;
	std::unique_ptr<KeyData> device_key_data_;

	// Used to override the otherwise hardcoded path for device keys in unit tests
	// only.
	absl::optional<base::FilePath> device_key_data_path_for_test_;

	base::WeakPtrFactory<StructuredMetricsProvider> weak_factory_{this};
	};

	} // namespace structured
	} // namespace metrics

	#endif // COMPONENTS_METRICS_STRUCTURED_STRUCTURED_METRICS_PROVIDER_H_