dalga

README

Dalga

Dalga is a job scheduler.

• Can schedule periodic or one-off jobs.
• Stores jobs in a MySQL table.
• Has an HTTP interface for scheduling and cancelling jobs.
• Makes a POST request to the endpoint defined in config on the job's execution time.

Install

$ go get github.com/cenkalti/dalga

Usage

Example config file is in the repository.

To create the table for storing jobs:

$ dalga -config dalga.ini -create-table

Then, run the server:

$ dalga -config dalga.ini

Schedule a new job to run every 60 seconds:

$ curl -i -X PUT 'http://127.0.0.1:34006/jobs/check_feed/1234?interval=60'
HTTP/1.1 201 Created
Content-Type: application/json; charset=utf-8
Date: Tue, 11 Nov 2014 22:10:40 GMT
Content-Length: 83

{"path":"check_feed","body":"1234","interval":60,"next_run":"2014-11-11T22:11:40Z"}

PUT always returns 201. If there is an existing job with path and body, it will be rescheduled.

There are 4 options that you cann pass to Schedule but not every combination is valid:

Param	Description	Type	Example
interval	Run job at intervals in seconds	Integer	60
first-run	Do not run job until this time	RFC3339 Timestamp	1985-04-12T23:20:50.52Z
one-off	Run job only once	Boolean	true, false, yes, no, on, off, 1, 0
immediate	Run job immediately as it is scheduled	Boolean	true, false, yes, no, on, off, 1, 0

60 seconds later, Dalga makes a POST to your endpoint defined in config:

Path: <config.baseurl>/<job.path>
Body: <job.body>

The endpoint must return 200 if the job is successful.

The endpoint may return 204 if job is invalid. In this case Dalga will remove the job from the table.

Anything other than 200 or 204 makes Dalga to retry the job indefinitely with an exponential backoff.

Get the status of a job:

$ curl -i -X GET 'http://127.0.0.1:34006/jobs/check_feed/1234'
HTTP/1.1 200 OK
Content-Type: application/json; charset=utf-8
Date: Tue, 11 Nov 2014 22:12:21 GMT
Content-Length: 83

{"path":"check_feed","body":"1234","interval":60,"next_run":"2014-11-11T22:12:41Z"}

GET may return 404 if job is not found.

Cancel previously scheduled job:

$ curl -i -X DELETE 'http://127.0.0.1:34006/jobs/check_feed/1234'
HTTP/1.1 204 No Content
Date: Tue, 11 Nov 2014 22:13:35 GMT

You may trigger a job manually by sending a POST request:

$ curl -i -X POST 'http://127.0.0.1:34006/jobs/check_feed/1234?interval=60'
HTTP/1.1 200 OK
Content-Type: application/json
Date: Fri, 14 Nov 2014 09:09:01 GMT
Content-Length: 83

{"path":"check_feed","body":"1234","interval":0,"next_run":"2014-11-14T09:09:01Z"}