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
|
import { AsyncQueue, forever, queue } from 'async'
import * as Sequelize from 'sequelize'
import { database as db } from '../../initializers/database'
import {
JOBS_FETCHING_INTERVAL,
JOBS_FETCH_LIMIT_PER_CYCLE,
JOB_STATES
} from '../../initializers'
import { logger } from '../../helpers'
import { JobInstance } from '../../models'
import { JobHandler, jobHandlers } from './handlers'
type JobQueueCallback = (err: Error) => void
class JobScheduler {
private static instance: JobScheduler
private constructor () { }
static get Instance () {
return this.instance || (this.instance = new this())
}
activate () {
const limit = JOBS_FETCH_LIMIT_PER_CYCLE
logger.info('Jobs scheduler activated.')
const jobsQueue = queue<JobInstance, JobQueueCallback>(this.processJob.bind(this))
// Finish processing jobs from a previous start
const state = JOB_STATES.PROCESSING
db.Job.listWithLimit(limit, state)
.then(jobs => {
this.enqueueJobs(jobsQueue, jobs)
forever(
next => {
if (jobsQueue.length() !== 0) {
// Finish processing the queue first
return setTimeout(next, JOBS_FETCHING_INTERVAL)
}
const state = JOB_STATES.PENDING
db.Job.listWithLimit(limit, state)
.then(jobs => {
this.enqueueJobs(jobsQueue, jobs)
// Optimization: we could use "drain" from queue object
return setTimeout(next, JOBS_FETCHING_INTERVAL)
})
.catch(err => logger.error('Cannot list pending jobs.', err))
},
err => logger.error('Error in job scheduler queue.', err)
)
})
.catch(err => logger.error('Cannot list pending jobs.', err))
}
createJob (transaction: Sequelize.Transaction, handlerName: string, handlerInputData: object) {
const createQuery = {
state: JOB_STATES.PENDING,
handlerName,
handlerInputData
}
const options = { transaction }
return db.Job.create(createQuery, options)
}
private enqueueJobs (jobsQueue: AsyncQueue<JobInstance>, jobs: JobInstance[]) {
jobs.forEach(job => jobsQueue.push(job))
}
private processJob (job: JobInstance, callback: (err: Error) => void) {
const jobHandler = jobHandlers[job.handlerName]
if (jobHandler === undefined) {
logger.error('Unknown job handler for job %s.', job.handlerName)
return callback(null)
}
logger.info('Processing job %d with handler %s.', job.id, job.handlerName)
job.state = JOB_STATES.PROCESSING
return job.save()
.then(() => {
return jobHandler.process(job.handlerInputData)
})
.then(
result => {
return this.onJobSuccess(jobHandler, job, result)
},
err => {
logger.error('Error in job handler %s.', job.handlerName, err)
return this.onJobError(jobHandler, job, err)
}
)
.then(() => callback(null))
.catch(err => {
this.cannotSaveJobError(err)
return callback(err)
})
}
private onJobError (jobHandler: JobHandler<any>, job: JobInstance, err: Error) {
job.state = JOB_STATES.ERROR
return job.save()
.then(() => jobHandler.onError(err, job.id))
.catch(err => this.cannotSaveJobError(err))
}
private onJobSuccess (jobHandler: JobHandler<any>, job: JobInstance, jobResult: any) {
job.state = JOB_STATES.SUCCESS
return job.save()
.then(() => jobHandler.onSuccess(job.id, jobResult))
.catch(err => this.cannotSaveJobError(err))
}
private cannotSaveJobError (err: Error) {
logger.error('Cannot save new job state.', err)
}
}
// ---------------------------------------------------------------------------
export {
JobScheduler
}
|
