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
206
207
208
209
210
211
212
|
// Copyright 2012 Rob Figueiredo. All rights reserved.
// Copyright 2014 The Gogs Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package cron
import (
"sort"
"time"
)
// Cron keeps track of any number of entries, invoking the associated func as
// specified by the schedule. It may be started, stopped, and the entries may
// be inspected while running.
type Cron struct {
entries []*Entry
stop chan struct{}
add chan *Entry
snapshot chan []*Entry
running bool
}
// Job is an interface for submitted cron jobs.
type Job interface {
Run()
}
// The Schedule describes a job's duty cycle.
type Schedule interface {
// Return the next activation time, later than the given time.
// Next is invoked initially, and then each time the job is run.
Next(time.Time) time.Time
}
// Entry consists of a schedule and the func to execute on that schedule.
type Entry struct {
Description string
Spec string
// The schedule on which this job should be run.
Schedule Schedule
// The next time the job will run. This is the zero time if Cron has not been
// started or this entry's schedule is unsatisfiable
Next time.Time
// The last time this job was run. This is the zero time if the job has never
// been run.
Prev time.Time
// The Job to run.
Job Job
ExecTimes int // Execute times count.
}
// byTime is a wrapper for sorting the entry array by time
// (with zero time at the end).
type byTime []*Entry
func (s byTime) Len() int { return len(s) }
func (s byTime) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s byTime) Less(i, j int) bool {
// Two zero times should return false.
// Otherwise, zero is "greater" than any other time.
// (To sort it at the end of the list.)
if s[i].Next.IsZero() {
return false
}
if s[j].Next.IsZero() {
return true
}
return s[i].Next.Before(s[j].Next)
}
// New returns a new Cron job runner.
func New() *Cron {
return &Cron{
entries: nil,
add: make(chan *Entry),
stop: make(chan struct{}),
snapshot: make(chan []*Entry),
running: false,
}
}
// A wrapper that turns a func() into a cron.Job
type FuncJob func()
func (f FuncJob) Run() { f() }
// AddFunc adds a func to the Cron to be run on the given schedule.
func (c *Cron) AddFunc(desc, spec string, cmd func()) (*Entry, error) {
return c.AddJob(desc, spec, FuncJob(cmd))
}
// AddFunc adds a Job to the Cron to be run on the given schedule.
func (c *Cron) AddJob(desc, spec string, cmd Job) (*Entry, error) {
schedule, err := Parse(spec)
if err != nil {
return nil, err
}
return c.Schedule(desc, spec, schedule, cmd), nil
}
// Schedule adds a Job to the Cron to be run on the given schedule.
func (c *Cron) Schedule(desc, spec string, schedule Schedule, cmd Job) *Entry {
entry := &Entry{
Description: desc,
Spec: spec,
Schedule: schedule,
Job: cmd,
}
if c.running {
c.add <- entry
} else {
c.entries = append(c.entries, entry)
}
return entry
}
// Entries returns a snapshot of the cron entries.
func (c *Cron) Entries() []*Entry {
if c.running {
c.snapshot <- nil
x := <-c.snapshot
return x
}
return c.entrySnapshot()
}
// Start the cron scheduler in its own go-routine.
func (c *Cron) Start() {
c.running = true
go c.run()
}
// Run the scheduler.. this is private just due to the need to synchronize
// access to the 'running' state variable.
func (c *Cron) run() {
// Figure out the next activation times for each entry.
now := time.Now().Local()
for _, entry := range c.entries {
entry.Next = entry.Schedule.Next(now)
}
for {
// Determine the next entry to run.
sort.Sort(byTime(c.entries))
var effective time.Time
if len(c.entries) == 0 || c.entries[0].Next.IsZero() {
// If there are no entries yet, just sleep - it still handles new entries
// and stop requests.
effective = now.AddDate(10, 0, 0)
} else {
effective = c.entries[0].Next
}
select {
case now = <-time.After(effective.Sub(now)):
// Run every entry whose next time was this effective time.
for _, e := range c.entries {
if e.Next != effective {
break
}
go e.Job.Run()
e.ExecTimes++
e.Prev = e.Next
e.Next = e.Schedule.Next(effective)
}
continue
case newEntry := <-c.add:
c.entries = append(c.entries, newEntry)
newEntry.Next = newEntry.Schedule.Next(now)
case <-c.snapshot:
c.snapshot <- c.entrySnapshot()
case <-c.stop:
return
}
// 'now' should be updated after newEntry and snapshot cases.
now = time.Now().Local()
}
}
// Stop the cron scheduler.
func (c *Cron) Stop() {
c.stop <- struct{}{}
c.running = false
}
// entrySnapshot returns a copy of the current cron entry list.
func (c *Cron) entrySnapshot() []*Entry {
entries := make([]*Entry, 0, len(c.entries))
for _, e := range c.entries {
entries = append(entries, &Entry{
Description: e.Description,
Spec: e.Spec,
Schedule: e.Schedule,
Next: e.Next,
Prev: e.Prev,
Job: e.Job,
ExecTimes: e.ExecTimes,
})
}
return entries
}
|
