Ghost/ghost/job-manager/lib/job-manager.js

129 lines
3.9 KiB
JavaScript

const path = require('path');
const fastq = require('fastq');
const later = require('@breejs/later');
const Bree = require('bree');
const pWaitFor = require('p-wait-for');
const errors = require('@tryghost/errors');
const isCronExpression = require('./is-cron-expression');
const assembleBreeJob = require('./assemble-bree-job');
const worker = async (task, callback) => {
try {
let result = await task();
callback(null, result);
} catch (error) {
callback(error);
}
};
const handler = (error, result) => {
if (error) {
// TODO: this handler should not be throwing as this blocks the queue
// throw error;
}
// Can potentially standardise the result here
return result;
};
class JobManager {
constructor(logging) {
this.queue = fastq(this, worker, 1);
this.bree = new Bree({
root: false, // set this to `false` to prevent requiring a root directory of jobs
hasSeconds: true, // precission is needed to avoid task ovelaps after immidiate execution
outputWorkerMetadata: true,
logger: logging
});
this.logging = logging;
}
/**
* Adds job to queue in current even loop
*
* @param {Function|String} job - function or path to a module defining a job
* @param {Object} [data] - data to be passed into the job
*/
addJob(job, data) {
this.logging.info('Adding one off job to the queue');
this.queue.push(async () => {
try {
if (typeof job === 'function') {
await job(data);
} else {
await require(job)(data);
}
} catch (err) {
// NOTE: each job should be written in a safe way and handle all errors internally
// if the error is caught here jobs implementaton should be changed
this.logging.error(new errors.IgnitionError({
level: 'critical',
errorType: 'UnhandledJobError',
message: 'Processed job threw an unhandled error',
context: (typeof job === 'function') ? 'function' : job,
err
}));
throw err;
}
}, handler);
}
/**
* Schedules recuring job offloaded to per-job event-loop (thread or a process)
*
* @param {String} when - cron or human readable schedule format
* @param {Function|String} job - function or path to a module defining a job
* @param {Object} [data] - data to be passed into the job
* @param {String} [name] - job name
*/
scheduleJob(when, job, data, name) {
let schedule;
if (!name) {
if (typeof job === 'string') {
name = path.parse(job).name;
} else {
throw new Error('Name parameter should be present if job is a function');
}
}
schedule = later.parse.text(when);
if (isCronExpression(when)) {
schedule = later.parse.cron(when);
}
if ((schedule.error && schedule.error !== -1) || schedule.schedules.length === 0) {
throw new Error('Invalid schedule format');
}
this.logging.info(`Scheduling job. Next run on: ${later.schedule(schedule).next()}`);
const breeJob = assembleBreeJob(when, job, data, name);
this.bree.add(breeJob);
return this.bree.start(name);
}
/**
* @param {import('p-wait-for').Options} [options]
*/
async shutdown(options) {
await this.bree.stop();
if (this.queue.idle()) {
return;
}
this.logging.warn('Waiting for busy job queue');
await pWaitFor(() => this.queue.idle() === true, options);
this.logging.warn('Job queue finished');
}
}
module.exports = JobManager;