Scheduled Task

Schedules recurring tasks while managing on-demand executions and limiting simultaneous executions. Helpful for managing process-heavy tasks running in child processes.

Installation

npm install @cityssm/scheduled-task

Usage

Child Process

// childProcess.js

import { ScheduledTask } from '@cityssm/scheduled-task'

// Initialize task
const task = new ScheduledTask(
  childProcessTaskName,
  () => {
    /*
     * Process-heavy code running in the child process.
     */
  },
  {
    schedule: {
      second: 0,
      minute: 0,
      hour: 0,
      dayOfWeek: '*',
      month: '*',
      year: '*'
    },
    minimumIntervalMillis: 10 * 60 * 1000,
    startTask: true
  }
)

// Listen for message to run the task on demand.
process.on('message', (_message) => {
  void task.runTask()
})

Options

Option	Description	Default
schedule	The frequency the task should run. See node-schedule for acceptable schedule formats.	Midnight
lastRunMillis	The last time the task was executed. Helpful to avoid rerunning a task too soon after a restart.	0
minimumIntervalMillis	The minimum amount of time between executions. Helpful if the task can be run on demand.	0
startTask	Whether the task should be started immediately after initialization.	false

Application

// app.js

import { fork } from 'node:child_process'

const childProcess = fork('childProcess.js')

childProcess.send('Run the task on demand.')

Real World Example

This package was made for the City's FASTER Web Helper application. The application does a lot of background syncing work in child processes.