@mashroom/mashroom-background-jobs

Mashroom Background Jobs

Plugin for Mashroom Server, a Microfrontend Integration Platform.

This plugin adds a background job scheduler to the Mashroom Server that supports cron expressions. It is possible to add background jobs via service or as custom plugin.

If you don't provide a cron expression the job is only executed now (immediately), this is useful if you need some code that should be executed once during server startup.

This plugin also comes with an Admin UI extension (/mashroom/admin/ext/background-jobs) that can be used to check the jobs.

Usage

If node_modules/@mashroom is configured as plugin path just add @mashroom/mashroom-background-jobs as dependency.

After that you can use the service like this:

import type {MashroomBackgroundJobService} from '@mashroom/mashroom-background-jobs/type-definitions';

export default async (req: Request, res: Response) => {
    const backgroundJobsService: MashroomBackgroundJobService = req.pluginContext.services.backgroundJobs.service;

    backgroundJobsService.schedule('Test Job', '0/5 * * * *', () => {
       // Job implementation
    });

    // ...
}

**NOTE**: Despite its name a job is started in the main thread and therefore blocks the event loop. So, if you do CPU intensive work you need to spawn a [Worker Thread](https://nodejs.org/api/worker_threads.html) yourself.

Services

MashroomBackgroundJobService

The exposed service is accessible through pluginContext.services.backgroundJobs.service

Interface:

export interface MashroomBackgroundJobService {

    /**
     * Schedule a job.
     * If cronSchedule is not defined the job is executed once (immediately).
     * Throws an error if the cron expression is invalid.
     */
    scheduleJob(name: string, cronSchedule: string | undefined | null, callback: MashroomBackgroundJobCallback): MashroomBackgroundJob;

    /**
     * Unschedule an existing job
     */
    unscheduleJob(name: string): void;

    readonly jobs: Readonly<Array<MashroomBackgroundJob>>;
}

Plugin Types

background-job

This plugin type allows it to schedule a background job.

To register your custom background-job plugin add this to package.json:

{
    "mashroom": {
        "plugins": [
            {
                "name": "My background job",
                "type": "background-job",
                "bootstrap": "./dist/mashroom-bootstrap.js",
                "defaultConfig": {
                   "cronSchedule": "0/1 * * * *",
                   "invokeImmediately": false,
                   "yourConfigProp": "whatever"
                }
            }
        ]
    }
}

• cronSchedule: The execution schedule for the job, must be a valid cron expression, see node-cron; if this is null or undefined the job is executed exactly one during startup.
• invokeImmediately: Optional hint that the job should additionally be invoked immediately (Default: false)

The bootstrap returns the job callback:

import type {MashroomBackgroundJobPluginBootstrapFunction} from '@mashroom/mashroom-background-jobs/type-definitions';

const bootstrap: MashroomBackgroundJobPluginBootstrapFunction = async (pluginName, pluginConfig, pluginContextHolder) => {
    const {yourConfigProp} = pluginConfig;
    return (pluginContect) => {
        // Job impl
    };
};

export default bootstrap;