uberimage

A Leiningen plugin to generate a docker image that runs a project's uberjar.

Requires leiningen 2.4.3 or later.

Usage

Put [com.palletops/uberimage "0.4.1"] into the :plugins vector of your :user profile.

$ lein uberimage

The plugin will run 'uberjar' on your project, generate the docker image with your uberjar in it, and report the uuid of the generated image.

Note that if you have not already pulled the base image (eg. with docker pull pallet/java), then it might take some while for the image generation to complete.

Running your container

Once the image is built, you can run it via docker with

docker run generated-image-uuid

By default your image doesn't have any ports mapped. If your service needs to open incoming ports, you need to bind the container port to a host port, running your container this way instead:

docker run generated-image-uuid -p 3000:8080

where the 3000 is the port where your service listens on the container, and the 8080 is the port you want your service to listen to on the host. Then, open your browser and type http://<docker-host-ip>:8080/... to access your service.

Configuration

The project.clj :uberimage key can be used to configure the image's CMD and to place extra files into the image.

:uberimage {:cmd ["/bin/dash" "/myrunscript" "param1" "param2"]
            :instructions ["RUN apt-get update && apt-get -y dist-upgrade"]
            :files {"myrunscript" "docker/myrunscript"}
            :tag "user/repo:tag"}

The :cmd value maps directly to a Dockerfile CMD statement

The :instructions value specifies a list of Dockerfile instructions to be inserted into the generated Dockerfile immediately after the FROM instruction at the start of the Dockerfile

The :files value is a map of additional files to be copied into the docker image. Keys are docker image target paths and values are lein project source paths.

The :tag value supplies a repository name (and optionally a tag) to be applied to the resulting image in case of success. If :project-version-tag is set to true, the Leiningen project version is used as the tag. In this case, the :tag value refers only to the repository name.

The :base-image value is used to specify the base image from which the project image is built (defaults to pallet/java).

Options

By default, the docker API is assumed to be on http://localhost:2375. You can override this by setting the the DOCKER_HOST environment variable, or using the -H option, e.g.

lein uberimage -H http://localhost:4243

If you have DOCKER_HOST set, but don't want that value used, override it with the DOCKER_ENDPOINT environment variable.

The base image used to construct the image can be specified using -b.

lein uberimage -b your-image-with-jvm

The repository name (and optionally a tag) to be applied to the resulting image in case of success can be specified using -t.

lein uberimage -t user/repo:tag

The Leiningen project version can be used as the image tag via the -p option.

lein uberimage -t user/repo -p

Limitations

Currently your project needs to build with lein uberjar (as lein uberimage invokes uberjar) and you must supply a :main so that the uberjar is executable via java -jar.

Depends on leiningen 2.4.3 or later.

Using a :target-path with a %s is it seems to break the plugin.

Requires docker api on a TCP socket (eg. for plain docker or on coreos). Other examples of enabling the API: on ubuntu.

TODO

Allow choice of running AOT's with -jar, or non AOT'd with clojure.main.

Allow choice of java runtime.

Use -p to push the resulting image to a repository.

License

Copyright © 2014 Hugo Duncan

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.