Named jobs in NestJS - Step-by-Step Execution

Concept Flow - Named jobs

Define Named Job

↓

Add Job to Queue with Name

↓

Worker Listens for Named Job

↓

Job Executes

↓

Job Completes or Fails

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Result or Retry Handling

This flow shows how a named job is defined, added to a queue, processed by a worker, and then completed or retried.

Execution Sample

NestJS

import { Processor, Process } from '@nestjs/bull';
import { Job } from 'bull';

@Processor('email')
export class EmailProcessor {
  @Process('send-welcome')
  async handleSendWelcome(job: Job) {
    console.log(`Sending welcome email to ${job.data.email}`);
  }
}

This code defines a named job 'send-welcome' inside an 'email' queue and processes it by logging the email address.

Execution Table

Step	Action	Job Name	Job Data	Worker Response	Output
1	Define processor and named job	send-welcome	N/A	Ready to process	No output
2	Add job to queue	send-welcome	{"email":"[e-mail]"}	Job queued	No output
3	Worker picks job	send-welcome	{"email":"[e-mail]"}	Job started	No output
4	Execute job handler	send-welcome	{"email":"[e-mail]"}	Processing	Logs: Sending welcome email to [e-mail]
5	Job completes	send-welcome	{"email":"[e-mail]"}	Job done	No output

💡 Job completes successfully after processing the named job 'send-welcome'.

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	Final
job.name	undefined	send-welcome	send-welcome	send-welcome	send-welcome
job.data.email	undefined	[e-mail]	[e-mail]	[e-mail]	[e-mail]
worker.status	idle	idle	processing	processing	idle

Key Moments - 2 Insights

Why does the worker only process jobs with the specific name 'send-welcome'?

Because the @Process decorator specifies the job name 'send-welcome', the worker listens only for jobs with that name as shown in execution_table step 3.

What happens if a job with a different name is added to the queue?

The worker will ignore it since it only processes 'send-welcome' jobs, so no handler runs for other names, as implied by the variable_tracker showing worker.status stays idle for other names.

Visual Quiz - 3 Questions

Look at the execution table, what is the job name when the worker starts processing?

A send-welcome

B email

C handleSendWelcome

D undefined

💡 Hint

Check the 'Job Name' column at Step 3 in the execution_table.

At which step does the console log output appear?

A Step 2

B Step 4

C Step 3

D Step 5

💡 Hint

Look at the 'Output' column in the execution_table for the log message.

If the job data email changed to '[e-mail]', what would change in the variable_tracker?

A worker.status would stay 'idle' throughout

B job.name would change to '[e-mail]'

C job.data.email would show '[e-mail]' after Step 2

D No changes in variable_tracker

💡 Hint

Refer to the 'job.data.email' row in variable_tracker and imagine the new email value.

Concept Snapshot

Named jobs in NestJS Bull queues let you label jobs with a string name.
Use @Process('job-name') to handle specific jobs.
Add jobs with queue.add('job-name', data).
Workers listen only for their named jobs.
This helps organize and separate job logic clearly.

Full Transcript

In NestJS, named jobs allow you to assign a specific name to each job type in a queue. You define a processor class with @Processor('queue-name') and use @Process('job-name') to handle jobs with that name. When you add a job to the queue with queue.add('job-name', data), the worker listens for jobs matching that name and runs the handler. The execution flow starts with defining the job, adding it to the queue, the worker picking it up, executing the handler, and completing the job. Variables like job.name and job.data track the job's identity and data throughout. This approach helps keep job processing organized and clear.