autodok

restart your containers with a new image

autodok provides an API to restart your running docker containers with a new image.
It is similar to watchtower, but it does not poll for new images - autodok only updates images & containers on-demand.

It is intended to be triggered by your CI pipeline, the recommended workflow is:

1. You push new code
2. This triggers your CI to build & push a new image
3. Your CI sends a POST request to autodok with the name of your running container and the new image:tag
4. autodok will download the new image and restart the container with the new image

How to

Setup

You can run autodok as a docker container with docker compose:

1. copy the included compose.yml to your server
2. make the service available by either uncommenting the port mapping or by exposing autodok via a reverse proxy of your choice (nginx, traefik, etc., recommended)
3. run docker compose up -d

You should check the logs (docker compose logs -f autodok) and copy the provided API key.

Usage

Manually

Trigger autodok manually by sending a POST request to /update, e.g. to restart the container foo with the image foo:latest:

curl -X POST "http://autodok.example.com/update" \
     -H "Authorization: $API_KEY" \
     -H "content-type: application/json" \
     -d '{"container": "foo", "image": "foo:latest"}'

CI

You can send requests to autodok however you like. Run a bash script, write a custom application, etc. An example with github actions could look like this:

  - name: trigger autodok deployment
    uses: fjogeleit/http-request-action@v1
    with:
      url: 'http://autodok.example.com/update'
      timeout: 300000
      method: 'POST'
      customHeaders: '{"Content-Type": "application/json", "Authorization": "${{ secrets.AUTODOK_API_KEY }}"}'
      data: '{"container": "foo", "image": "foo:latest"}'

For this to work you need to add a new secret (settings / secrets / actions / repository secrets) named AUTODOK_API_KEY that is set to the correct value.

API

Some endpoints in autodok require authorization. You have to send an Authorization header with the provided API key. The key will be logged each time when you start autodok, and you can always read it from ./data/api_key.

Endpoints

autodok exposes two endpoints:

GET /health

This is a simple healthcheck that returns 200 OK if the docker daemon is reachable. It does not require authorization and is always available.

POST /update

This endpoint will check if a container with the provided name is running. If it is, it will download the provided image and restart the container with the new image and the same settings (volumes etc.) as before.
You have to send an Authorization header with the correct API key to use this endpoint.

The following fields are supported in the request body:

field	example	required	description
container	foo	yes	Name of a running container
image	foo:latest	yes	Name and tag of an existing image

Examples

Healthcheck

curl -X GET "http://autodok.example.com/health"

Update container elasticsearch with new image docker.elastic.co/elasticsearch/elasticsearch:8.8.0

curl -X POST "http://autodok.example.com/update" \
     -H "Authorization: $API_KEY" \
     -H "content-type: application/json" \
     -d '{"container": "elasticsearch", "image": "docker.elastic.co/elasticsearch/elasticsearch:8.8.0"}'

# response:
{"message":"Container 'elasticsearch' restarted with new image 'docker.elastic.co/elasticsearch/elasticsearch:8.8.0'"}

FAQ & possible issues

Request timeouts

Requests to POST /update might timeout depending on your setup. Please keep in mind that downloading and restarting a big docker image might take a few minutes - your timeout settings have to respect this. Remember to set timeouts for your proxy server and for the client that executes the request, e.g. the used github action.

Using a private registry

You can download images from private registries by providing a standard docker config.json. Uncomment the volume in compose.yml and adjust the path to your config.json. autodok will then use your existing credentials whenever needed.

Restarting multiple containers at once

If you want to restart multiple containers you have to execute multiple requests, each containing the respective container name.

License

MIT