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JobQueue

JobQueue

A JobQueue is used to process Jobs. A job is added to the queue via the .add() method, and the configured JobQueueStrategy will check for new jobs and process each according to the defined process function.

Note: JobQueue instances should not be directly instantiated. Rather, the JobQueueService createQueue() method should be used (see that service for example usage).

Signature
class JobQueue<Data extends JobData<Data> = object> {
name: string
started: boolean
constructor(options: CreateQueueOptions<Data>, jobQueueStrategy: JobQueueStrategy, jobBufferService: JobBufferService)
add(data: Data, options?: JobOptions<Data>) => Promise<SubscribableJob<Data>>;
}

name

property
string

started

property
boolean

constructor

method
(options: CreateQueueOptions<Data>, jobQueueStrategy: JobQueueStrategy, jobBufferService: JobBufferService) => JobQueue

add

method
(data: Data, options?: JobOptions<Data>) => Promise<SubscribableJob<Data>>

Adds a new Job to the queue. The resolved SubscribableJob allows the calling code to subscribe to updates to the Job:

Example

const job = await this.myQueue.add({ intervalMs, shouldFail }, { retries: 2 });
return job.updates().pipe(
map(update => {
// The returned Observable will emit a value for every update to the job
// such as when the `progress` or `status` value changes.
Logger.info(`Job ${update.id}: progress: ${update.progress}`);
if (update.state === JobState.COMPLETED) {
Logger.info(`COMPLETED ${update.id}: ${update.result}`);
}
return update.result;
}),
catchError(err => of(err.message)),
);

Alternatively, if you aren't interested in the intermediate progress changes, you can convert to a Promise like this:

Example

const job = await this.myQueue.add({ intervalMs, shouldFail }, { retries: 2 });
return job.updates().toPromise()
.then(update => update.result),
.catch(err => err.message);