| // 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. |
| |
| #ifndef COMPONENTS_METRICS_FILE_METRICS_PROVIDER_H_ |
| #define COMPONENTS_METRICS_FILE_METRICS_PROVIDER_H_ |
| |
| #include <list> |
| #include <memory> |
| #include <string> |
| |
| #include "base/callback.h" |
| #include "base/files/file_path.h" |
| #include "base/gtest_prod_util.h" |
| #include "base/memory/weak_ptr.h" |
| #include "base/threading/thread_checker.h" |
| #include "base/time/time.h" |
| #include "components/metrics/metrics_provider.h" |
| |
| class PrefRegistrySimple; |
| class PrefService; |
| |
| namespace base { |
| class MemoryMappedFile; |
| class PersistentMemoryAllocator; |
| class TaskRunner; |
| } |
| |
| namespace metrics { |
| |
| // FileMetricsProvider gathers and logs histograms written to files on disk. |
| // Any number of files can be registered and will be polled once per upload |
| // cycle (at startup and periodically thereafter -- about every 30 minutes |
| // for desktop) for data to send. |
| class FileMetricsProvider : public MetricsProvider { |
| public: |
| enum SourceType { |
| // "Atomic" files are a collection of histograms that are written |
| // completely in a single atomic operation (typically a write followed |
| // by an atomic rename) and the file is never updated again except to |
| // be replaced by a completely new set of histograms. This is the only |
| // option that can be used if the file is not writeable by *this* |
| // process. Once the file has been read, an attempt will be made to |
| // delete it thus providing some measure of safety should different |
| // instantiations (such as by different users of a system-level install) |
| // try to read it. In case the delete operation fails, this class |
| // persistently tracks the last-modified time of the file so it will |
| // not be read a second time. |
| SOURCE_HISTOGRAMS_ATOMIC_FILE, |
| |
| // A directory of atomic PMA files. This handles a directory in which |
| // files of metrics are atomically added. Only files ending with ".pma" |
| // will be read. They are read according to their last-modified time and |
| // never read more that once (unless they change). Only one file will |
| // be read per reporting cycle. Filenames that start with a dot (.) or |
| // an underscore (_) are ignored so temporary files (perhaps created by |
| // the ImportantFileWriter) will not get read. Files that have been |
| // read will be attempted to be deleted; should those files not be |
| // deletable by this process, it is the reponsibility of the producer |
| // to keep the directory pruned in some manner. |
| SOURCE_HISTOGRAMS_ATOMIC_DIR, |
| |
| // "Active" files may be open by one or more other processes and updated |
| // at any time with new samples or new histograms. Such files may also be |
| // inactive for any period of time only to be opened again and have new |
| // data written to them. The file should probably never be deleted because |
| // there would be no guarantee that the data has been reported. |
| // TODO(bcwhite): Enable when read/write mem-mapped files are supported. |
| SOURCE_HISTOGRAMS_ACTIVE_FILE, |
| }; |
| |
| enum SourceAssociation { |
| // Associates the metrics in the file with the current run of the browser. |
| // The reporting will take place as part of the normal logging of |
| // histograms. |
| ASSOCIATE_CURRENT_RUN, |
| |
| // Associates the metrics in the file with the previous run of the browesr. |
| // The reporting will take place as part of the "stability" histograms. |
| // This is important when metrics are dumped as part of a crash of the |
| // previous run. This can only be used with FILE_HISTOGRAMS_ATOMIC. |
| ASSOCIATE_PREVIOUS_RUN, |
| }; |
| |
| FileMetricsProvider(const scoped_refptr<base::TaskRunner>& task_runner, |
| PrefService* local_state); |
| ~FileMetricsProvider() override; |
| |
| // Indicates a file or directory to be monitored and how the file or files |
| // within that directory are used. Because some metadata may need to persist |
| // across process restarts, preferences entries are used based on the |
| // |prefs_key| name. Call RegisterPrefs() with the same name to create the |
| // necessary keys in advance. Set |prefs_key| empty if no persistence is |
| // required. |
| void RegisterSource(const base::FilePath& path, |
| SourceType type, |
| SourceAssociation source_association, |
| const base::StringPiece prefs_key); |
| |
| // Registers all necessary preferences for maintaining persistent state |
| // about a monitored file across process restarts. The |prefs_key| is |
| // typically the filename. |
| static void RegisterPrefs(PrefRegistrySimple* prefs, |
| const base::StringPiece prefs_key); |
| |
| private: |
| friend class FileMetricsProviderTest; |
| |
| // The different results that can occur accessing a file. |
| enum AccessResult { |
| // File was successfully mapped. |
| ACCESS_RESULT_SUCCESS, |
| |
| // File does not exist. |
| ACCESS_RESULT_DOESNT_EXIST, |
| |
| // File exists but not modified since last read. |
| ACCESS_RESULT_NOT_MODIFIED, |
| |
| // File is not valid: is a directory or zero-size. |
| ACCESS_RESULT_INVALID_FILE, |
| |
| // System could not map file into memory. |
| ACCESS_RESULT_SYSTEM_MAP_FAILURE, |
| |
| // File had invalid contents. |
| ACCESS_RESULT_INVALID_CONTENTS, |
| |
| // File could not be opened. |
| ACCESS_RESULT_NO_OPEN, |
| |
| ACCESS_RESULT_MAX |
| }; |
| |
| // Information about sources being monitored; defined and used exclusively |
| // inside the .cc file. |
| struct SourceInfo; |
| using SourceInfoList = std::list<std::unique_ptr<SourceInfo>>; |
| |
| // Looks for the next file to read within a directory. Returns true if a |
| // file was found. This is part of CheckAndMapNewMetricSourcesOnTaskRunner |
| // and so runs on an thread capable of I/O. The |source| structure will |
| // be internally updated to indicate the next file to be read. |
| static bool LocateNextFileInDirectory(SourceInfo* source); |
| |
| // Checks a list of sources (on a task-runner allowed to do I/O) and merge |
| // any data found within them. |
| static void CheckAndMergeMetricSourcesOnTaskRunner(SourceInfoList* sources); |
| |
| // Checks a single source and maps it into memory. |
| static AccessResult CheckAndMapMetricSource(SourceInfo* source); |
| |
| // Merges all of the histograms from a |source| to the StatisticsRecorder. |
| static void MergeHistogramDeltasFromSource(SourceInfo* source); |
| |
| // Records all histograms from a given source via a snapshot-manager. |
| static void RecordHistogramSnapshotsFromSource( |
| base::HistogramSnapshotManager* snapshot_manager, |
| SourceInfo* source); |
| |
| // Creates a task to check all monitored sources for updates. |
| void ScheduleSourcesCheck(); |
| |
| // Takes a list of sources checked by an external task and determines what |
| // to do with each. |
| void RecordSourcesChecked(SourceInfoList* checked); |
| |
| // Schedules the deletion of a file in the background using the task-runner. |
| void DeleteFileAsync(const base::FilePath& path); |
| |
| // Updates the persistent state information to show a source as being read. |
| void RecordSourceAsRead(SourceInfo* source); |
| |
| // metrics::MetricsDataProvider: |
| void OnDidCreateMetricsLog() override; |
| bool HasInitialStabilityMetrics() override; |
| void MergeHistogramDeltas() override; |
| void RecordInitialHistogramSnapshots( |
| base::HistogramSnapshotManager* snapshot_manager) override; |
| |
| // A task-runner capable of performing I/O. |
| scoped_refptr<base::TaskRunner> task_runner_; |
| |
| // A list of sources not currently active that need to be checked for changes. |
| SourceInfoList sources_to_check_; |
| |
| // A list of currently active sources to be merged when required. |
| SourceInfoList sources_mapped_; |
| |
| // A list of sources for a previous run. These are held separately because |
| // they are not subject to the periodic background checking that handles |
| // metrics for the current run. |
| SourceInfoList sources_for_previous_run_; |
| |
| // The preferences-service used to store persistent state about sources. |
| PrefService* pref_service_; |
| |
| base::ThreadChecker thread_checker_; |
| base::WeakPtrFactory<FileMetricsProvider> weak_factory_; |
| |
| DISALLOW_COPY_AND_ASSIGN(FileMetricsProvider); |
| }; |
| |
| } // namespace metrics |
| |
| #endif // COMPONENTS_METRICS_FILE_METRICS_PROVIDER_H_ |