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// Copyright 2010 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROME_BROWSER_ASH_EXTERNAL_METRICS_EXTERNAL_METRICS_H_
#define CHROME_BROWSER_ASH_EXTERNAL_METRICS_EXTERNAL_METRICS_H_
#include <string>
#include "base/gtest_prod_util.h"
#include "base/memory/ref_counted.h"
#include "base/time/time.h"
namespace metrics {
class MetricSample;
} // namespace metrics
namespace ash {
// ExternalMetrics is a service that Chrome offers to Chrome OS to upload
// metrics to the UMA server on its behalf. Chrome periodically reads the
// content of a well-know file, and parses it into name-value pairs, each
// representing a Chrome OS metrics event. The events are logged using the
// normal UMA mechanism. The file is then truncated to zero size. Chrome uses
// flock() to synchronize accesses to the file.
class ExternalMetrics : public base::RefCountedThreadSafe<ExternalMetrics> {
public:
// The file from which externally-reported metrics are read.
static constexpr char kEventsFilePath[] = "/var/lib/metrics/uma-events";
// The directory containing per-pid event files from which externally-reported
// metrics are read.
static constexpr char kEventsDirectoryPath[] =
"/var/lib/metrics/uma-events.d";
// This directory holds per-pid event files. These files contain metrics
// collected before the stateful partition is mounted. This is read
// by externally-reported metrics when the crash reporter is invoked with the
// FLAGS_early flag to capture early boot metrics.
static constexpr char kUmaEarlyMetricsDirectoryPath[] = "/run/early-metrics/";
ExternalMetrics();
ExternalMetrics(const ExternalMetrics&) = delete;
ExternalMetrics& operator=(const ExternalMetrics&) = delete;
// Returns the global singleton or null if it hasn't been created.
static ExternalMetrics* Get();
// Begins the external data collection. This service is started and stopped
// by the chrome metrics service. Calls to RecordAction originate in the
// blocking pool but are executed in the UI thread.
void Start();
// Creates an ExternalMetrics instance reading from |filename| and |dir| for
// testing purpose.
static scoped_refptr<ExternalMetrics> CreateForTesting(
const std::string& filename,
const std::string& uma_events_dir,
const std::string& uma_early_metrics_dir);
// Synchronously executes one collection run for testing purposes. Does not
// schedule any followup runs.
void CollectNowForTesting() { CollectEvents(); }
private:
friend class base::RefCountedThreadSafe<ExternalMetrics>;
friend class ExternalMetricsTest;
FRIEND_TEST_ALL_PREFIXES(ExternalMetricsTest, CustomInterval);
FRIEND_TEST_ALL_PREFIXES(ExternalMetricsTest, ProcessSamplesSuccessfully);
FRIEND_TEST_ALL_PREFIXES(ExternalMetricsTest, HandleMissingFile);
FRIEND_TEST_ALL_PREFIXES(ExternalMetricsTest, CanReceiveHistogram);
FRIEND_TEST_ALL_PREFIXES(ExternalMetricsTest,
CanReceiveHistogramFromPidFiles);
FRIEND_TEST_ALL_PREFIXES(ExternalMetricsTest,
CanReceiveMetricsFromEarlyMetricsDir);
FRIEND_TEST_ALL_PREFIXES(ExternalMetricsTest,
IncorrectHistogramsAreDiscarded);
// The max length of a message (name-value pair, plus header)
static const int kMetricsMessageMaxLength = 1024; // be generous
~ExternalMetrics();
// Passes an action event to the UMA service on the UI thread.
void RecordActionUI(const std::string& action_string, int num_samples);
// Passes an action event to the UMA service.
void RecordAction(const metrics::MetricSample& sample);
// Records an external crash of the given string description to
// UMA service on the UI thread.
void RecordCrashUI(const std::string& crash_kind, int num_samples);
// Records an external crash of the given string description.
void RecordCrash(const metrics::MetricSample& sample);
// Records an histogram. |sample| is expected to be an histogram.
void RecordHistogram(const metrics::MetricSample& sample);
// Records a sparse histogram. |sample| is expected to be a sparse histogram.
void RecordSparseHistogram(const metrics::MetricSample& sample);
// Records a linear histogram. |sample| is expected to be a linear histogram.
void RecordLinearHistogram(const metrics::MetricSample& sample);
// Returns the number of samples found in |samples|. |samples| is
// cleared at the end of the method. Used to process the samples in an event
// file.
int ProcessSamples(
std::vector<std::unique_ptr<metrics::MetricSample>>* samples);
// Collects external events from metrics log file. This is run at periodic
// intervals.
//
// Returns the number of events collected.
int CollectEvents();
// Calls CollectEvents and reschedules a future collection.
void CollectEventsAndReschedule();
// Schedules a metrics event collection in the future.
void ScheduleCollector();
// File used by libmetrics to send metrics to Chrome.
std::string uma_events_file_;
// Directory of per-pid event files used by libmetrics to send metrics to
// Chrome.
std::string uma_events_dir_;
// Directory of per-pid event files before stateful partition is mounted.
// Used by libmetrics to send metrics to Chrome.
std::string uma_early_metrics_dir_;
// Interval between metrics being read from our sources.
base::TimeDelta collection_interval_;
};
} // namespace ash
#endif // CHROME_BROWSER_ASH_EXTERNAL_METRICS_EXTERNAL_METRICS_H_
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