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1 | import { AsyncQueue, forever, queue } from 'async' | |
2 | import * as Sequelize from 'sequelize' | |
3 | import { JobCategory } from '../../../shared' | |
4 | import { logger } from '../../helpers' | |
5 | import { database as db, JOB_STATES, JOBS_FETCH_LIMIT_PER_CYCLE, JOBS_FETCHING_INTERVAL } from '../../initializers' | |
6 | import { JobInstance } from '../../models' | |
7 | ||
8 | export interface JobHandler<P, T> { | |
9 | process (data: object, jobId: number): Promise<T> | |
10 | onError (err: Error, jobId: number) | |
11 | onSuccess (jobId: number, jobResult: T, jobScheduler: JobScheduler<P, T>) | |
12 | } | |
13 | type JobQueueCallback = (err: Error) => void | |
14 | ||
15 | class JobScheduler<P, T> { | |
16 | ||
17 | constructor ( | |
18 | private jobCategory: JobCategory, | |
19 | private jobHandlers: { [ id: string ]: JobHandler<P, T> } | |
20 | ) {} | |
21 | ||
22 | async activate () { | |
23 | const limit = JOBS_FETCH_LIMIT_PER_CYCLE[this.jobCategory] | |
24 | ||
25 | logger.info('Jobs scheduler %s activated.', this.jobCategory) | |
26 | ||
27 | const jobsQueue = queue<JobInstance, JobQueueCallback>(this.processJob.bind(this)) | |
28 | ||
29 | // Finish processing jobs from a previous start | |
30 | const state = JOB_STATES.PROCESSING | |
31 | try { | |
32 | const jobs = await db.Job.listWithLimitByCategory(limit, state, this.jobCategory) | |
33 | ||
34 | this.enqueueJobs(jobsQueue, jobs) | |
35 | } catch (err) { | |
36 | logger.error('Cannot list pending jobs.', err) | |
37 | } | |
38 | ||
39 | forever( | |
40 | async next => { | |
41 | if (jobsQueue.length() !== 0) { | |
42 | // Finish processing the queue first | |
43 | return setTimeout(next, JOBS_FETCHING_INTERVAL) | |
44 | } | |
45 | ||
46 | const state = JOB_STATES.PENDING | |
47 | try { | |
48 | const jobs = await db.Job.listWithLimitByCategory(limit, state, this.jobCategory) | |
49 | ||
50 | this.enqueueJobs(jobsQueue, jobs) | |
51 | } catch (err) { | |
52 | logger.error('Cannot list pending jobs.', err) | |
53 | } | |
54 | ||
55 | // Optimization: we could use "drain" from queue object | |
56 | return setTimeout(next, JOBS_FETCHING_INTERVAL) | |
57 | }, | |
58 | ||
59 | err => logger.error('Error in job scheduler queue.', err) | |
60 | ) | |
61 | } | |
62 | ||
63 | createJob (transaction: Sequelize.Transaction, handlerName: string, handlerInputData: P) { | |
64 | const createQuery = { | |
65 | state: JOB_STATES.PENDING, | |
66 | category: this.jobCategory, | |
67 | handlerName, | |
68 | handlerInputData | |
69 | } | |
70 | ||
71 | const options = { transaction } | |
72 | ||
73 | return db.Job.create(createQuery, options) | |
74 | } | |
75 | ||
76 | private enqueueJobs (jobsQueue: AsyncQueue<JobInstance>, jobs: JobInstance[]) { | |
77 | jobs.forEach(job => jobsQueue.push(job)) | |
78 | } | |
79 | ||
80 | private async processJob (job: JobInstance, callback: (err: Error) => void) { | |
81 | const jobHandler = this.jobHandlers[job.handlerName] | |
82 | if (jobHandler === undefined) { | |
83 | logger.error('Unknown job handler for job %s.', job.handlerName) | |
84 | return callback(null) | |
85 | } | |
86 | ||
87 | logger.info('Processing job %d with handler %s.', job.id, job.handlerName) | |
88 | ||
89 | job.state = JOB_STATES.PROCESSING | |
90 | await job.save() | |
91 | ||
92 | try { | |
93 | const result: T = await jobHandler.process(job.handlerInputData, job.id) | |
94 | await this.onJobSuccess(jobHandler, job, result) | |
95 | } catch (err) { | |
96 | logger.error('Error in job handler %s.', job.handlerName, err) | |
97 | ||
98 | try { | |
99 | await this.onJobError(jobHandler, job, err) | |
100 | } catch (innerErr) { | |
101 | this.cannotSaveJobError(innerErr) | |
102 | return callback(innerErr) | |
103 | } | |
104 | } | |
105 | ||
106 | callback(null) | |
107 | } | |
108 | ||
109 | private async onJobError (jobHandler: JobHandler<P, T>, job: JobInstance, err: Error) { | |
110 | job.state = JOB_STATES.ERROR | |
111 | ||
112 | try { | |
113 | await job.save() | |
114 | await jobHandler.onError(err, job.id) | |
115 | } catch (err) { | |
116 | this.cannotSaveJobError(err) | |
117 | } | |
118 | } | |
119 | ||
120 | private async onJobSuccess (jobHandler: JobHandler<P, T>, job: JobInstance, jobResult: T) { | |
121 | job.state = JOB_STATES.SUCCESS | |
122 | ||
123 | try { | |
124 | await job.save() | |
125 | jobHandler.onSuccess(job.id, jobResult, this) | |
126 | } catch (err) { | |
127 | this.cannotSaveJobError(err) | |
128 | } | |
129 | } | |
130 | ||
131 | private cannotSaveJobError (err: Error) { | |
132 | logger.error('Cannot save new job state.', err) | |
133 | } | |
134 | } | |
135 | ||
136 | // --------------------------------------------------------------------------- | |
137 | ||
138 | export { | |
139 | JobScheduler | |
140 | } |