chrome/browser/chromeos/external_metrics.h

   1 // Copyright (c) 2010 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 #ifndef CHROME_BROWSER_CHROMEOS_EXTERNAL_METRICS_H_
   6 #define CHROME_BROWSER_CHROMEOS_EXTERNAL_METRICS_H_
   7
   8 #include <string>
   9
  10 #include "base/compiler_specific.h"
  11 #include "base/gtest_prod_util.h"
  12 #include "base/memory/ref_counted.h"
  13
  14 namespace metrics {
  15 class MetricSample;
  16 }  // namespace metrics
  17
  18 namespace chromeos {
  19
  20 // ExternalMetrics is a service that Chrome offers to Chrome OS to upload
  21 // metrics to the UMA server on its behalf.  Chrome periodically reads the
  22 // content of a well-know file, and parses it into name-value pairs, each
  23 // representing a Chrome OS metrics event. The events are logged using the
  24 // normal UMA mechanism. The file is then truncated to zero size. Chrome uses
  25 // flock() to synchronize accesses to the file.
  26 class ExternalMetrics : public base::RefCountedThreadSafe<ExternalMetrics> {
  27  public:
  28   ExternalMetrics();
  29
  30   // Begins the external data collection.  This service is started and stopped
  31   // by the chrome metrics service.  Calls to RecordAction originate in the
  32   // blocking pool but are executed in the UI thread.
  33   void Start();
  34
  35   // Creates an ExternalMetrics instance reading from |filename| for testing
  36   // purpose.
  37   static scoped_refptr<ExternalMetrics> CreateForTesting(
  38       const std::string& filename);
  39
  40  private:
  41   friend class base::RefCountedThreadSafe<ExternalMetrics>;
  42   friend class ExternalMetricsTest;
  43
  44   FRIEND_TEST_ALL_PREFIXES(ExternalMetricsTest, CanReceiveHistogram);
  45   FRIEND_TEST_ALL_PREFIXES(ExternalMetricsTest, HandleMissingFile);
  46   FRIEND_TEST_ALL_PREFIXES(ExternalMetricsTest,
  47                            IncorrectHistogramsAreDiscarded);
  48
  49   // The max length of a message (name-value pair, plus header)
  50   static const int kMetricsMessageMaxLength = 1024;  // be generous
  51
  52   ~ExternalMetrics();
  53
  54   // Passes an action event to the UMA service on the UI thread.
  55   void RecordActionUI(const std::string& action_string);
  56
  57   // Passes an action event to the UMA service.
  58   void RecordAction(const std::string& action_name);
  59
  60   // Records an external crash of the given string description to
  61   // UMA service on the UI thread.
  62   void RecordCrashUI(const std::string& crash_kind);
  63
  64   // Records an external crash of the given string description.
  65   void RecordCrash(const std::string& crash_kind);
  66
  67   // Records an histogram. |sample| is expected to be an histogram.
  68   void RecordHistogram(const metrics::MetricSample& sample);
  69
  70   // Records a sparse histogram. |sample| is expected to be a sparse histogram.
  71   void RecordSparseHistogram(const metrics::MetricSample& sample);
  72
  73   // Records a linear histogram. |sample| is expected to be a linear histogram.
  74   void RecordLinearHistogram(const metrics::MetricSample& sample);
  75
  76   // Collects external events from metrics log file.  This is run at periodic
  77   // intervals.
  78   //
  79   // Returns the number of events collected.
  80   int CollectEvents();
  81
  82   // Calls CollectEvents and reschedules a future collection.
  83   void CollectEventsAndReschedule();
  84
  85   // Schedules a metrics event collection in the future.
  86   void ScheduleCollector();
  87
  88   // File used by libmetrics to send metrics to Chrome.
  89   std::string uma_events_file_;
  90
  91   DISALLOW_COPY_AND_ASSIGN(ExternalMetrics);
  92 };
  93
  94 }  // namespace chromeos
  95
  96 #endif  // CHROME_BROWSER_CHROMEOS_EXTERNAL_METRICS_H_