Base layer for building time-based repetitive tasks
npm install repetitive-taskRepetitiveTask provides a base layer for building time-based repetitive tasks, such as background jobs that run forever.
Simple task that always runs
``js
const RepetitiveTask = require('repetitive-task')
class CpuMonitor extends RepetitiveTask {
_process (task) {
console.log(process.cpuUsage())
}
}
const monitor = new CpuMonitor(60 * 1000)
monitor.start()
`
Condition based task
`js
const irrigation = require('./irrigation')
const RepetitiveTask = require('repetitive-task')
class Gardener extends RepetitiveTask {
_getTask () {
return irrigation.getSoilMoisture()
.then((moistureLevel) => {
// Only water the garden if the moisture level is below 20%
if (moistureLevel < 20) {
return moistureLevel
}
return null
})
}
_process (moistureLevel) {
return irrigation.turnOnWater()
.then(() => {
return new Promise((resolve) => {
setTimeout(resolve, 5 60 1000)
})
})
.then(() => irrigation.turnOffWater())
}
}
const gardener = new Gardener(12 60 60 * 1000)
gardener.start()
`
Creates a new RepetitiveTask instance.
* interval (Number): The interval (in seconds) for the repetitive task.
_NOTE: Tasks don't run on a strict interval. The specified interval is actually the amount of time between the end of one run and the beginning of the next run. This ensures that a long running task will never result in multiple tasks running simultaneously._
Starts the repetitive task.
Stops the repetitive task. Stopping the task may be asynchronous since a task may be running at the time of the call. The promise will resolve when the task has completed.
In order for RepetitiveTask to be useful, you must extend it with your actual task. The following methods are available to customize the behavior of the task.
Creates a logger for the repetitive task.
The built-in logger writes JSON messages to stdout, but can be replaced with any logger that supports the following API:
* info([data], message)
*
The optional data parameter is an object with additional properties to include in the log.
Gets a task to work on. Depending on the type of task being performed, you may need to determine if there is a task to run at any given time. For example, you may need to pull an item off of a queue and process it. In this case, _getTask() should read from the queue and return the item, if any.
Returning a falsy value indicates that there is no task to perform right now.
Gets additional data to log about the task. The object returned from _getLogData() will be passed to the logger for the "processing task" message.
* task (Mixed): The task object returned from _getTask().
Processes the task. This is the main function for the repetitive task and is the only method that must be implemented for the task to run.
* task (Mixed): The task object returned from _getTask()`.
Copyright RepetitiveTask contributors.
Released under the terms of the ISC license.