https://github.com/juliangruber/level-schedule

Durable job scheduler based on LevelDB
https://github.com/juliangruber/level-schedule

Last synced: 21 days ago
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Durable job scheduler based on LevelDB

• Host: GitHub
• URL: https://github.com/juliangruber/level-schedule
• Owner: juliangruber
• Created: 2013-04-01T13:46:54.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2016-11-28T17:32:36.000Z (almost 8 years ago)
• Last Synced: 2024-10-17T19:58:56.209Z (26 days ago)
• Language: JavaScript
• Size: 16.6 KB
• Stars: 38
• Watchers: 4
• Forks: 1
• Open Issues: 2
• Metadata Files:
  • Readme: README.md

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README

        
# level-schedule

Durable job scheduler based on [LevelDB](https://github.com/rvagg/node-levelup).

If the process is restarted it will transparently resume where it stopped.

[![Build Status](https://travis-ci.org/juliangruber/level-schedule.png?branch=master)](https://travis-ci.org/juliangruber/level-schedule)

## Usage

Print some JSON after 5s, even if the process restarts.

```js

var levelup = require('levelup');

var Schedule = require('level-schedule');

var db = levelup('./db');

Schedule(db)

  .job('print', function (payload) {

    console.log(payload);

  })

  .run('print', { some : 'json' }, Date.now() + 5000);

// => { some : 'json' }

```

## Periodic tasks

Run a task every 100ms. Always call `this.run` at the end of the task,

otherwise if the process crashes while running your task it will be

scheduled once too many.

```js

Schedule(db)

  .job('periodic', function () {

    console.log('doing some stuff...');

    this.run('periodic', Date.now() + 100)

  })

  .run('periodic', Date.now() + 100);

```

## Jobs

A job can be synchronous or asynchronous, just use the `done` argument when

defining an asynchronous job.

```js

Schedule(db)

  .job('sync', function (payload) {

    if (somethingBadHappend) {

      throw new Error();

    }

  })

  .job('async', function (payload, done) {

    // notice the 2nd argument

    doSomething(function (err) {

      done(err);

    });

  })

  .on('error', console.error)

  .run('sync')

  .run('async');

```

## API

### Schedule(db)

Setup `level-schedule` to use `db`.

### Schedule#job(name, fn)

Register a job with `name` and `fn`.

`fn` is called with 2 arguments:

* `payload` : The payload

* `done` : If the job performs async operations, call `done()` when done. If

an error occured you can pass that as an error argument to `done`.

### Schedule#run(job[, payload], timestamp)

Run `job` with `payload` at `timestamp`.

### Schedule#on('error', fn)

Call `fn` whenever an `Error` occurs. When no error listener has been

registered, errors will be thrown.

## Installation

With [npm](http://npmjs.org) do

```bash

$ npm install level-schedule

```

## License

(MIT)

Copyright (c) 2013 Julian Gruber <[email protected]>

Permission is hereby granted, free of charge, to any person obtaining a copy of

this software and associated documentation files (the "Software"), to deal in

the Software without restriction, including without limitation the rights to

use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies

of the Software, and to permit persons to whom the Software is furnished to do

so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all

copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

SOFTWARE.