Docker CRON

docker-cron is a cron service for Docker containers.

Building your cron image

Create a Dockerfile with the following contents:

FROM rochacon/docker-cron

Now, create a folder jobs and place your jobs definitions in it. Here is a sample job definition:

// This is a simple Hello world job that will run every 10 seconds
{
    "Id": "docker-hello-world-cron-id",
    "Interval": "*/10 * * * * *",
    "Name": "docker-hello-world",
    "Container": {
        "Cmd": ["echo", "$DISCLAIMER"],
        "Image": "busybox",
        "Env": [
            "DISCLAIMER=Hello World"
        ]
    }
}

The Interval field must be the cron expression. Reference: http://godoc.org/github.com/robfig/cron#hdr-CRON_Expression_Format The Name field is optional and can be used to guarantee that only one instance of the job will run at a time. The Container field is the description of the container and may include these fields: http://godoc.org/github.com/fsouza/go-dockerclient#Config

Now build your cron image:

docker build -t my-docker-cron .

Running

Now that we built our cron image, let's run it. docker-cron uses the DOCKER_HOST environment variable to comunicate with your Docker instance and defaults to unix://var/run/docker.sock.

To run the docker-cron with a local Docker instance:

docker run -d --name docker-cron -v /var/run/docker.sock:/var/run/docker.sock:rw my-docker-cron

Or with a remote Docker instance:

docker run -d --name docker-cron -e DOCKER_HOST=tcp://remote-docker.domain:2375 my-docker-cron

⚠️ Currently TLS connection is not supported.

License

MIT