58 lines
2.4 KiB
Markdown
58 lines
2.4 KiB
Markdown
# Dockron
|
|
|
|
Simple scheduling for short-running Docker containers
|
|
|
|
## Usage
|
|
|
|
Dockron requires access to the Docker, so it may need to be run as root, or, if in a Docker container, need the socket mapped as a volume.
|
|
|
|
### Running Dockron
|
|
|
|
As simple as:
|
|
|
|
dockron
|
|
|
|
It will then run in the foreground, periodically checking Docker for containers with labels containing a cron schedule.
|
|
|
|
By default, Dockron will periodically poll Docker for new containers or schedule changes every minute. You can specify an interval by using the `-watch` flag.
|
|
|
|
### Running with Docker
|
|
|
|
Dockron is also available as a Docker image. The multi-arch repo can be found at [IamTheFij/dockron](https://hub.docker.com/r/iamthefij/dockron)
|
|
|
|
From either an `amd64`, `arm`, or `arm64` machine, you can run Dockron using:
|
|
|
|
docker run -v /var/run/docker.sock:/var/run/docker.sock:ro iamthefij/dockron -watch
|
|
|
|
### Scheduling a container
|
|
|
|
First, be sure your container is something that is not long running and will actually exit when complete. This is for batch runs and not keeping a service running. Docker should be able to do that on it's own with a restart policy.
|
|
|
|
Create your container and add a label in the form `'dockron.schedule=* * * * *'`, where the value is a valid cron expression (See the section [Cron Expression Formatting](#cron-expression-formatting)).
|
|
|
|
Dockron will now start that container peridically on the schedule.
|
|
|
|
### Cron Expression Formatting
|
|
|
|
For more information on the cron expression parsing, see the docs for [robfig/cron](https://godoc.org/github.com/robfig/cron).
|
|
|
|
## Caveats
|
|
|
|
Dockron is quite simple right now. It does not yet:
|
|
|
|
* Issue any retries
|
|
* Cancel hanging jobs
|
|
|
|
I intend to keep it simple as well. It will likely never:
|
|
|
|
* Provide any kind of alerting (check out [Minitor](https://git.iamthefij.com/IamTheFij/minitor))
|
|
* Handle job dependencies
|
|
|
|
Either use a separate tool in conjunction with Dockron, or use a more robust scheduler like Tron, or Chronos.
|
|
|
|
## Building
|
|
|
|
If you have go on your machine, you can simply use `make build` or `make run` to build and test Dockron. If you don't have go but you do have Docker, you can still build docker images using the provide multi-stage Dockerfile! You can kick that off with `make docker-staged-build`
|
|
|
|
There is also an example `docker-compose.yml` that will use the multi-stage build to ensure an easy sample. This can be run with `make docker-example`.
|