If you use docker.io (or any similar service) to
build your Docker containers, it may be possible that, once the new
image is generated, you want your Docker host to automatically pull it
and restart the container.
Docker.io gives you the possibility to set a web hook after a
successful build. Basically it does a POST on a defined URL and send
some informations in JSON format.
listens to these web hooks and can be configured to run a particular
script, given a specific hook. It's a very simple service I wrote using
Python/Flask. It's also my first Flask application, so if you want to
improve it, feel free to send me a pull request on GitHub.
Note: this is not the only existing service that is able to do this
task. I took inspiration from this
and I really tried to
customize https://github.com/cpuguy83/dockerhub-webhook-listener for
my own needs, but the problem is that dockerhub-webhook-listener is
not ready to be used as is (you have to customize it) and I'm not very
good with Golang (yet) to be able to do it in little time. This is
why I rewrote the service in Python (that is my daily language). I want
to thank Brian Goff for the idea and all
the people in #docker @ FreeNode for the support.
How to use docker-puller
Setting up the service should be quite easy. After you clone the
repository from https://github.com/glowdigitalmedia/docker-puller there
is a config.json file where you define the host, port, a
token and a list of hooks you want to react to. For example:
Create a bash script (in this case it was called hello.sh) and put
it under script folder and write the instructions to be executed to pull
the new image and restart the container (example):
docker pull andreagrandi/test:latest
docker stop test
docker rm test
docker run --name test -d -p 8000:80 andreagrandi/test:latest
Once configured, I suggest you to setup a Nginx entry (instructions
not covered here) that for example redirect
yourhost.com/dockerpuller to localhost:8000 (I would advise to
enable SSL too, or people could be able to sniff your token). The
service can be started with: "python app.py" (or you can setup a
At this point docker-puller is up and running. Go to docker.io
automatic build settings and setup a webhook like this:
Every time docker.io finishes building and pushing your image to the
docker registry, it will POST on that URL. docker-puller will catch
the POST, check for a valid token, get the hook name and will execute
the relative script.
That's all! I hope this very simple service can be useful to other
people and once again, if you want to improve it, I will be glad to
accept your pull requests on GitHub.