1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
|
/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include <list>
#include <memory>
#include <string>
#include "mongo/logger/appender.h"
#include "mongo/logv2/log_severity.h"
namespace mongo::logger {
/**
* Logging domain for events of type E.
*
* A logging domain consists of a set of Appenders.
*
* TODO: The severity doesn't seem to apply for auditing, maybe it only belongs on the
* MessageLogManager? We don't really have multiple tunable logging domains, right now. Other
* than the global domain, shouldLog doesn't matter.
*
* Usage: Configure the log domain in a single threaded context, using attachAppender,
* detachAppender and clearAppenders(). The domain takes ownership of any attached appender,
* returning an AppenderHandle for each attached appender. That handle may be used later to
* detach the appender, causing the domain to release ownership of it. Mostly, this
* attach/detach behavior is useful in testing, since you do not want to change the appenders of
* a domain that is currently receiving append() calls.
*
* Once you've configured the domain, call append() from potentially many threads, to add log
* messages.
*/
template <typename E>
class LogDomain {
using Event = E;
using AppenderList = std::list<std::unique_ptr<Appender<Event>>>;
using AppendersIter = typename AppenderList::iterator;
public:
/**
* Opaque handle returned by attachAppender(), which can be subsequently passed to
* detachAppender() to detach an appender from an instance of LogDomain.
*/
class AppenderHandle {
private:
friend class LogDomain;
explicit AppenderHandle(AppendersIter iter) : _iter{iter} {}
AppendersIter _iter;
};
LogDomain() = default;
~LogDomain() = default;
LogDomain(const LogDomain&) = delete;
LogDomain& operator=(const LogDomain&) = delete;
/**
* Receives an event for logging, calling append(event) on all attached appenders.
*
* If any appender fails, the behavior is determined by the abortOnFailure flag:
* *If abortOnFailure is set, ::abort() is immediately called.
* *If abortOnFailure is not set, the error is returned and no further appenders are called.
*/
Status append(const Event& event) {
for (auto& appender : _appenders) {
if (Status status = appender->append(event); !status.isOK()) {
if (_abortOnFailure) {
::abort();
}
return status;
}
}
return Status::OK();
}
/**
* Gets the state of the abortOnFailure flag.
*/
bool getAbortOnFailure() const {
return _abortOnFailure;
}
/**
* Sets the state of the abortOnFailure flag.
*/
void setAbortOnFailure(bool abortOnFailure) {
_abortOnFailure = abortOnFailure;
}
/**
* Attaches `appender`. Returns a handle for use with `detachAppender`.
*/
AppenderHandle attachAppender(std::unique_ptr<Appender<Event>> appender) {
return AppenderHandle(_appenders.insert(_appenders.end(), std::move(appender)));
}
/**
* Detaches the appender referenced by `handle`, returning it.
*/
std::unique_ptr<Appender<Event>> detachAppender(AppenderHandle handle) {
auto result = std::move(*handle._iter);
_appenders.erase(handle._iter);
return result;
}
/**
* Destroy all attached appenders, invalidating all handles.
*/
void clearAppenders() {
_appenders.clear();
}
private:
AppenderList _appenders;
bool _abortOnFailure = false;
};
} // namespace mongo::logger
|
