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
|
/**
* 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 <functional>
#include <memory>
#include <string>
#include <boost/optional.hpp>
#include "mongo/platform/mutex.h"
#include "mongo/util/time_support.h"
namespace mongo {
class Client;
class PeriodicJobAnchor;
/**
* An interface for objects that run work items at specified intervals. Each individually scheduled
* job will be called in series.
*
* Implementations may use whatever internal threading and eventing
* model they wish. Implementations may choose when to stop running
* scheduled jobs (for example, some implementations may stop running
* when the server is in global shutdown).
*
* The runner will create client objects that it passes to jobs to use.
*/
class PeriodicRunner {
public:
using Job = std::function<void(Client* client)>;
using JobAnchor = PeriodicJobAnchor;
struct PeriodicJob {
PeriodicJob(std::string name, Job callable, Milliseconds period, bool isKillableByStepdown)
: name(std::move(name)),
job(std::move(callable)),
interval(period),
isKillableByStepdown(isKillableByStepdown) {}
/**
* name of the job
*/
std::string name;
/**
* A task to be run at regular intervals by the runner.
*/
Job job;
/**
* An interval at which the job should be run.
*/
Milliseconds interval;
/**
* Whether this job is killable during stepdown.
*/
bool isKillableByStepdown;
};
/**
* A ControllableJob allows a user to reschedule the execution of a Job
*/
class ControllableJob {
public:
virtual ~ControllableJob() = default;
/**
* Starts running the job
*/
virtual void start() = 0;
/**
* Pauses the job temporarily so that it does not execute until
* unpaused
*/
virtual void pause() = 0;
/**
* Resumes a paused job so that it continues executing each interval
*/
virtual void resume() = 0;
/**
* Stops the job, this function blocks until the job is stopped
* Safe to invalidate the job callable after calling this.
*/
virtual void stop() = 0;
/**
* Returns the current period for the job
*/
virtual Milliseconds getPeriod() = 0;
/**
* Updates the period of the job. This takes effect immediately by altering the current
* scheduling of the task. I.e. if more than ms have passed since the last execution of the
* job, it is run immediately. Otherwise the scheduling is adjusted forward or back by
* abs(new - old).
*/
virtual void setPeriod(Milliseconds ms) = 0;
};
virtual ~PeriodicRunner();
/**
* Creates a new job and adds it to the runner, but does not schedule it.
* The caller is responsible for calling 'start' on the resulting handle in
* order to begin the job running. This API should be used when the caller
* is interested in observing and controlling the job execution state.
*/
virtual JobAnchor makeJob(PeriodicJob job) = 0;
};
/**
* A PeriodicJobAnchor allows the holder to control the scheduling of a job for the lifetime of the
* anchor. When an anchor is destructed, it stops its underlying job.
*
* The underlying weak_ptr for this class is not synchronized. In essence, treat use of this class
* as if it were a raw pointer to a ControllableJob.
*
* Each wrapped PeriodicRunner::ControllableJob function on this object throws
* if the underlying job is gone (e.g. in shutdown).
*/
class [[nodiscard]] PeriodicJobAnchor {
public:
using Job = PeriodicRunner::ControllableJob;
public:
// Note that this constructor is only intended for use with PeriodicRunner::makeJob()
explicit PeriodicJobAnchor(std::shared_ptr<Job> handle);
PeriodicJobAnchor() = default;
PeriodicJobAnchor(PeriodicJobAnchor&&) = default;
PeriodicJobAnchor& operator=(PeriodicJobAnchor&&) = default;
PeriodicJobAnchor(const PeriodicJobAnchor&) = delete;
PeriodicJobAnchor& operator=(const PeriodicJobAnchor&) = delete;
~PeriodicJobAnchor();
void start();
void pause();
void resume();
void stop();
void setPeriod(Milliseconds ms);
Milliseconds getPeriod();
/**
* Abandon responsibility for scheduling the execution of this job
*
* This effectively invalidates the anchor.
*/
void detach();
/**
* Returns if this PeriodicJobAnchor is associated with a PeriodicRunner::ControllableJob
*
* This function is useful to see if a PeriodicJobAnchor is initialized. It does not necessarily
* inform whether a PeriodicJobAnchor will throw from a control function above.
*/
bool isValid() const noexcept;
explicit operator bool() const noexcept {
return isValid();
}
private:
std::shared_ptr<Job> _handle;
};
} // namespace mongo
|
