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
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
/**
* 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 <string>
#include <vector>
#include "mongo/base/status.h"
#include "mongo/base/status_with.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/client/fetcher.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/repl/base_cloner.h"
#include "mongo/db/repl/collection_cloner.h"
#include "mongo/db/repl/database_cloner.h"
#include "mongo/executor/task_executor.h"
#include "mongo/stdx/condition_variable.h"
#include "mongo/stdx/mutex.h"
#include "mongo/util/concurrency/thread_pool.h"
#include "mongo/util/net/hostandport.h"
namespace mongo {
namespace repl {
/**
* Clones all databases.
*/
class DatabasesCloner {
public:
struct Stats {
size_t databasesCloned{0};
std::vector<DatabaseCloner::Stats> databaseStats;
std::string toString() const;
BSONObj toBSON() const;
void append(BSONObjBuilder* builder) const;
};
using IncludeDbFilterFn = stdx::function<bool(const BSONObj& dbInfo)>;
using OnFinishFn = stdx::function<void(const Status&)>;
using StartCollectionClonerFn = DatabaseCloner::StartCollectionClonerFn;
using ScheduleDbWorkFn = stdx::function<StatusWith<executor::TaskExecutor::CallbackHandle>(
executor::TaskExecutor::CallbackFn)>;
DatabasesCloner(StorageInterface* si,
executor::TaskExecutor* exec,
ThreadPool* dbWorkThreadPool,
HostAndPort source,
IncludeDbFilterFn includeDbPred,
OnFinishFn finishFn);
~DatabasesCloner();
Status startup() noexcept;
bool isActive();
void join();
void shutdown();
DatabasesCloner::Stats getStats() const;
/**
* Returns the status after completion. If multiple error occur, only one is recorded/returned.
*
* NOTE: A value of ErrorCodes::NotYetInitialized is the default until started.
*/
Status getStatus();
std::string toString() const;
/**
* Overrides how executor schedules database work.
*
* For testing only.
*/
void setScheduleDbWorkFn_forTest(const ScheduleDbWorkFn& scheduleDbWorkFn);
/**
* Overrides how executor starts a collection cloner.
*
* For testing only.
*/
void setStartCollectionClonerFn(const StartCollectionClonerFn& startCollectionCloner);
/**
* Calls DatabasesCloner::_setAdminAsFirst.
* For testing only.
*/
void setAdminAsFirst_forTest(std::vector<BSONElement>& dbsArray);
/**
* Calls DatabasesCloner::_parseListDatabasesResponse.
* For testing only.
*/
StatusWith<std::vector<BSONElement>> parseListDatabasesResponse_forTest(BSONObj dbResponse);
private:
bool _isActive_inlock() const;
/**
* Returns a copy of the database cloners.
*/
std::vector<std::shared_ptr<DatabaseCloner>> _getDatabaseCloners() const;
/**
* Returns scheduler for listDatabases (null if not created).
*/
RemoteCommandRetryScheduler* _getListDatabasesScheduler() const;
/**
* Setting the status to not-OK will stop the process
*/
void _setStatus_inlock(Status s);
/** Will fail the cloner, call the completion function, and become inactive. */
void _fail_inlock(stdx::unique_lock<stdx::mutex>* lk, Status s);
/** Will call the completion function, and become inactive. */
void _succeed_inlock(stdx::unique_lock<stdx::mutex>* lk);
/** Called each time a database clone is finished */
void _onEachDBCloneFinish(const Status& status, const std::string& name);
// Callbacks
void _onListDatabaseFinish(const executor::TaskExecutor::RemoteCommandCallbackArgs& cbd);
/**
* Takes a vector of BSONElements and scans for an element that contains a 'name' field with the
* value 'admin'. If found, the element is swapped with the first element in the vector.
* Otherwise, return.
*
* Used to parse the BSONResponse returned by listDatabases.
*/
void _setAdminAsFirst(std::vector<BSONElement>& dbsArray);
/**
* Takes a 'listDatabases' command response and parses the response into a
* vector of BSON elements.
*
* If the input response is malformed, Status ErrorCodes::BadValue will be returned.
*/
StatusWith<std::vector<BSONElement>> _parseListDatabasesResponse(BSONObj dbResponse);
//
// All member variables are labeled with one of the following codes indicating the
// synchronization rules for accessing them.
//
// (R) Read-only in concurrent operation; no synchronization required.
// (M) Reads and writes guarded by _mutex
// (S) Self-synchronizing; access in any way from any context.
//
mutable stdx::mutex _mutex; // (S)
Status _status{ErrorCodes::NotYetInitialized, ""}; // (M) If it is not OK, we stop everything.
executor::TaskExecutor* _exec; // (R) executor to schedule things with
ThreadPool* _dbWorkThreadPool; // (R) db worker thread pool for collection cloning.
const HostAndPort _source; // (R) The source to use.
ScheduleDbWorkFn _scheduleDbWorkFn; // (M)
StartCollectionClonerFn _startCollectionClonerFn; // (M)
const IncludeDbFilterFn _includeDbFn; // (R) function which decides which dbs are cloned.
OnFinishFn _finishFn; // (M) function called when finished.
StorageInterface* _storage; // (R)
std::unique_ptr<RemoteCommandRetryScheduler> _listDBsScheduler; // (M) scheduler for listDBs.
std::vector<std::shared_ptr<DatabaseCloner>> _databaseCloners; // (M) database cloners by name
Stats _stats; // (M)
// State transitions:
// PreStart --> Running --> ShuttingDown --> Complete
// It is possible to skip intermediate states. For example,
// Calling shutdown() when the cloner has not started will transition from PreStart directly
// to Complete.
enum class State { kPreStart, kRunning, kShuttingDown, kComplete };
State _state = State::kPreStart;
};
} // namespace repl
} // namespace mongo
|