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
|
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())
}
async 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
try {
const jobs = await db.Job.listWithLimit(limit, state)
this.enqueueJobs(jobsQueue, jobs)
} catch (err) {
logger.error('Cannot list pending jobs.', err)
}
forever(
async next => {
if (jobsQueue.length() !== 0) {
// Finish processing the queue first
return setTimeout(next, JOBS_FETCHING_INTERVAL)
}
const state = JOB_STATES.PENDING
try {
const jobs = await db.Job.listWithLimit(limit, state)
this.enqueueJobs(jobsQueue, jobs)
} catch (err) {
logger.error('Cannot list pending jobs.', err)
}
// Optimization: we could use "drain" from queue object
return setTimeout(next, JOBS_FETCHING_INTERVAL)
},
err => logger.error('Error in job scheduler queue.', 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 async 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
await job.save()
try {
const result = await jobHandler.process(job.handlerInputData, job.id)
await this.onJobSuccess(jobHandler, job, result)
} catch (err) {
logger.error('Error in job handler %s.', job.handlerName, err)
try {
await this.onJobError(jobHandler, job, err)
} catch (innerErr) {
this.cannotSaveJobError(innerErr)
return callback(innerErr)
}
}
callback(null)
}
private async onJobError (jobHandler: JobHandler<any>, job: JobInstance, err: Error) {
job.state = JOB_STATES.ERROR
try {
await job.save()
await jobHandler.onError(err, job.id)
} catch (err) {
this.cannotSaveJobError(err)
}
}
private async onJobSuccess (jobHandler: JobHandler<any>, job: JobInstance, jobResult: any) {
job.state = JOB_STATES.SUCCESS
try {
await job.save()
jobHandler.onSuccess(job.id, jobResult)
} catch (err) {
this.cannotSaveJobError(err)
}
}
private cannotSaveJobError (err: Error) {
logger.error('Cannot save new job state.', err)
}
}
// ---------------------------------------------------------------------------
export {
JobScheduler
}
|
