Web services, workers and cron jobs
Choose how a service runs, as a web service on a port, a worker in the background, or a cron job on a UTC schedule.
Every service has a Runs as setting that you choose when you add it. A web service listens on a port and gets an HTTPS address, a worker runs continuously without a port, and a cron job starts on a schedule, runs to completion and stops until the next run.
| Runs as | Port and address | Start command | Counts as an active service |
|---|---|---|---|
| Web service | Yes, with an address on apps.dekka.cloud |
Optional | Yes |
| Worker | No | Required | Yes |
| Cron job | No | Required | No |
In the API these are the resource kinds application, worker and scheduled_job. All three build and deploy the same way, from GitHub or an image, and all three can connect to databases and buckets.
Run a web service
A web service must listen on 0.0.0.0 on its port, which Dekka also passes to it as PORT. Dekka sends traffic to a new release only after its health check path returns a 2xx, and it is the only kind that can have custom domains and HTTP request logs.
Run a worker
Choose Worker for queue consumers and other processes that run without serving HTTP, and give it a start command such as node worker.js or celery -A app worker. A worker is restarted according to its restart policy.
Schedule a cron job
Choose Cron job, give it a start command and a schedule in five fields: minute, hour, day of month, month and day of week. Schedules run in UTC, and Ghana keeps UTC all year, so 0 2 * * * runs at 02:00 in Accra every day.
| Schedule | Runs |
|---|---|
*/15 * * * * |
Every 15 minutes |
0 2 * * * |
02:00 every day |
30 8 * * MON-FRI |
08:30 on weekdays |
0 0 1 * * |
Midnight on the first of each month |
Each field takes *, a number, a range such as 1-5, a step such as */10 or 0-30/5, and lists separated by commas. Months accept JAN to DEC, and days of the week accept SUN to SAT, where 0 and 7 both mean Sunday. When both the day of month and the day of week are restricted, a day matches if either one does. The dashboard describes a schedule in words as you type it, the API returns the next five run times as next_runs, and Dekka refuses a schedule that can never run, such as 0 0 31 2 *.
See and start cron job runs
Select a cron job on the canvas and open Runs to see each run with its status, exit code and output, newest first. Run now starts one straight away with the job's start command. A run moves from queued to running and ends succeeded, failed or cancelled, and a scheduled time that arrives while the previous run is still going is recorded as skipped rather than starting a second copy.
curl -X POST https://api.dekka.cloud/v1/resources/$JOB_ID/runs \
-H "Authorization: Bearer $DEKKA_API_KEY"A job that hasn't been deployed yet answers 409 job_not_deployed, and one whose last run is still going answers 409 run_in_progress.
Change how a service runs
Setting a cron schedule in a worker's or web service's settings turns it into a cron job, and clearing the schedule turns it back into a web service if it has a port or a worker if it doesn't. A web service with custom domains has to lose them before it can become a cron job.