shellbro/clojure

Container image for everyday Clojure.

Why this image?

This is stock Clojure container image with minor tweaks and opinions:

1. It targets OpenJDK 11 and is based on Debian 10 (Buster).

2. Contains tools.deps as a tool of choice for dependency managment.

3. Uses non-root user by default. UID and GID can be both customized with Docker build args if you wish but Docker Hub hook sets it to sensible defaults (1000:1000). Thanks to this it is easy to share host directory $HOME/.m2 with container and download dependencies only once without permission issues.

4. Implements rlwrap workaround in such a way that you can call clj or clojure command passing any arguments. For example, to start a REPL with clojure.java-time dependency available use -Sdeps argument accordingly:

   $ sudo docker run --rm -it --detach-keys=ctrl-@\
                     -v "$HOME/.m2:/home/app-user/.m2"\
                     shellbro/clojure clj -Sdeps\
                     '{:deps {clojure.java-time {:mvn/version "0.3.2"}}}'
   

5. It is strictly versioned. Every image tag has a Unix time suffix indicating its release time.

Ad hoc containerized Clojure REPL

To have your Clojure REPL always at hand add the following function to your .bashrc file. This function takes your EDN deps as an argument and makes sure you didn't forget important docker run options for REPL to be fully working (like --detach-keys without which docker will intercept readline keybiding Ctrl-p).

function repl {
  sudo docker run --rm -it --detach-keys=ctrl-@\
                  -v "$HOME/.m2:/home/app-user/.m2"\
                  shellbro/clojure clj -Sdeps "{:deps ${1:-{}}}"
}

This time, to quickly spawn your Clojure REPL with clojure.java-time dependency just run:

$ repl '{clojure.java-time {:mvn/version "0.3.2"}}'
user=> (require '[java-time :as t])
nil
user=> (t/as (t/local-date) :year)
2020

Note that when using repl function :deps level is already in place for user convenience.