For more information about this image and its history, please see the relevant manifest file (library/clojure) in the docker-library/official-images GitHub repo.
Clojure is a dialect of the Lisp programming language. It is a general-purpose programming language with an emphasis on functional programming. It runs on the Java Virtual Machine, Common Langauge Runtime, and JavaScript engines. Like other Lisps, Clojure treats code as data and has a macro system.
Since the most common way to use Clojure is in conjunction with Leiningen (lein), this image assumes that's how you'll be working. The most straightforward way to use this image is to add a Dockerfile to an existing Leiningen/Clojure project:
FROM clojure
COPY . /usr/src/app
WORKDIR /usr/src/app
CMD ["lein", "run"]
Then, run these commands to build and run the image:
docker build -t my-clojure-app .
docker run -it --rm --name my-running-app my-clojure-app
While the above is the most straightforward example of a Dockerfile, it does have some drawbacks. The lein run command will download your dependencies, compile the project, and then run it. That's a lot of work, all of which you may not want done every time you run the image. To get around this, you can download the dependencies and compile the project ahead of time. This will significantly reduce startup time when you run your image.
FROM clojure
RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app
COPY project.clj /usr/src/app/
RUN lein deps
COPY . /usr/src/app
RUN mv "$(lein uberjar | sed -n 's/^Created \(.*standalone\.jar\)/\1/p')" app-standalone.jar
CMD ["java", "-jar", "app-standalone.jar"]
Writing the Dockerfile this way will download the dependencies (and cache them, so they are only re-downloaded when the dependencies change) and then compile them into a standalone jar ahead of time rather than each time the image is run.
You can then build and run the image as above.
If you have an existing Lein/Clojure project, it's fairly straightforward to compile your project into a jar from a container:
docker run -it --rm -v "$PWD":/usr/src/app -w /usr/src/app clojure lein uberjar
This will build your project into a jar file located in your project's target/uberjar directory.
View license information for the software contained in this image.
This image is officially supported on Docker version 1.6.2.
Support for older versions (down to 1.0) is provided on a best-effort basis.
Documentation for this image is stored in the clojure/ directory of the docker-library/docs GitHub repo. Be sure to familiarize yourself with the repository's README.md file before attempting a pull request.
If you have any problems with or questions about this image, please contact us through a GitHub issue.
You can also reach many of the official image maintainers via the #docker-library IRC channel on Freenode.
You are invited to contribute new features, fixes, or updates, large or small; we are always thrilled to receive pull requests, and do our best to process them as fast as we can.
Before you start to code, we recommend discussing your plans through a GitHub issue, especially for more ambitious contributions. This gives other contributors a chance to point you in the right direction, give you feedback on your design, and help you find out if someone else is working on the same thing.