network_event_log.h revision 3551c9c881056c480085172ff9840cab31610854 
1// Copyright (c) 2012 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 CHROMEOS_NETWORK_NETWORK_EVENT_LOG_H_
6#define CHROMEOS_NETWORK_NETWORK_EVENT_LOG_H_
7
8#include <deque>
9#include <string>
10
11#include "base/basictypes.h"
12#include "base/strings/stringprintf.h"
13#include "base/time/time.h"
14#include "chromeos/chromeos_export.h"
15
16namespace base {
17class Value;
18}
19
20namespace chromeos {
21
22// Namespace for functions for logging network events.
23namespace network_event_log {
24
25// Used to determine which order to output event entries in GetAsString.
26enum StringOrder {
27  OLDEST_FIRST,
28  NEWEST_FIRST
29};
30
31// Used to set the detail level for logging.
32enum LogLevel {
33  LOG_LEVEL_ERROR = 0,
34  LOG_LEVEL_USER = 1,
35  LOG_LEVEL_EVENT = 2,
36  LOG_LEVEL_DEBUG = 3
37};
38
39// Default log level.
40CHROMEOS_EXPORT extern const LogLevel kDefaultLogLevel;
41
42// Initializes / shuts down network event logging. Calling Initialize more than
43// once will reset the log.
44CHROMEOS_EXPORT void Initialize();
45CHROMEOS_EXPORT void Shutdown();
46
47// Returns true if network event logging has been initialized.
48CHROMEOS_EXPORT bool IsInitialized();
49
50namespace internal {
51
52// Gets the maximum number of log entries.
53CHROMEOS_EXPORT size_t GetMaxLogEntries();
54
55// Sets the maximum number of entries to something other than the default. If
56// |max_entries| is less than the current maximum number of entries, this will
57// delete any existing entries in excess of |max_entries|.
58CHROMEOS_EXPORT void SetMaxLogEntries(size_t max_entries);
59
60// Adds an entry to the event log at level specified by |log_level|.
61// A maximum number of events are recorded after which new events replace
62// old ones. Error events are prioritized such that error events will only be
63// deleted if more than least half of the entries are errors (at which point
64// the oldest error entry will be replaced). Does nothing unless Initialize()
65// has been called. NOTE: Generally use NET_LOG instead.
66CHROMEOS_EXPORT void AddEntry(const char* file,
67                              int file_line,
68                              LogLevel log_level,
69                              const std::string& event,
70                              const std::string& description);
71
72}  // namespace internal
73
74// Outputs the log to a formatted string.
75// |order| determines which order to output the events.
76// |format| is a string that determines which elements to show. Elements
77// must be comma-separated, e.g. "time,desc".
78// Note: order of the format strings does not affect the output.
79//  "time" - Include a timestamp.
80//  "file" - Include file and line number.
81//  "desc" - Include the description.
82//  "html" - Include html tags.
83//  "json" - Return as JSON format
84// Only events with |log_level| <= |max_level| are included in the output.
85// If |max_events| > 0, limits how many events are output.
86// If |json| is specified, returns a JSON list of dictionaries containing time,
87// level, file, event, and description.
88CHROMEOS_EXPORT std::string GetAsString(StringOrder order,
89                                        const std::string& format,
90                                        LogLevel max_level,
91                                        size_t max_events);
92
93// Helper function for displaying a value as a string.
94CHROMEOS_EXPORT std::string ValueAsString(const base::Value& value);
95
96// Errors
97#define NET_LOG_ERROR(event, desc) NET_LOG_LEVEL(                       \
98    ::chromeos::network_event_log::LOG_LEVEL_ERROR, event, desc)
99
100// Chrome initiated events, e.g. connection requests, scan requests,
101// configuration removal (either from the UI or from ONC policy application).
102#define NET_LOG_USER(event, desc) NET_LOG_LEVEL(                        \
103    ::chromeos::network_event_log::LOG_LEVEL_USER, event, desc)
104
105// Important events, e.g. state updates
106#define NET_LOG_EVENT(event, desc) NET_LOG_LEVEL(                       \
107    ::chromeos::network_event_log::LOG_LEVEL_EVENT, event, desc)
108
109// Non-essential debugging events
110#define NET_LOG_DEBUG(event, desc) NET_LOG_LEVEL(                       \
111    ::chromeos::network_event_log::LOG_LEVEL_DEBUG, event, desc)
112
113// Macro to include file and line number info in the event log.
114#define NET_LOG_LEVEL(log_level, event, description)            \
115  ::chromeos::network_event_log::internal::AddEntry(            \
116      __FILE__, __LINE__, log_level, event, description)
117
118}  // namespace network_event_log
119
120}  // namespace chromeos
121
122#endif  // CHROMEOS_NETWORK_NETWORK_EVENT_LOG_H_
123