Clojure is supported on Scalingo, you can deploy your apps

It uses Leiningen.

Note that you don’t have to do anything special to use this buildpack with Clojure apps on Scalingo; it will be used by default for all projects containing a project.clj file, though it may be an older revision than what you’re currently looking at.

Usage

Example usage for an app already stored in Git:

$ tree
|-- Procfile
|-- project.clj
|-- README
`-- src
    `-- sample
        `-- core.clj

$ scalingo create my-app

$ git push scalingo master
...
-----> Fetching custom buildpack
-----> Clojure app detected
-----> Installing Leiningen
       Downloading: leiningen-2.2.0-standalone.jar
       Writing: lein script
-----> Building with Leiningen
       Running: with-profile production compile :all
       Downloading: org/clojure/clojure/1.2.1/clojure-1.2.1.pom from central
       Downloading: org/clojure/clojure/1.2.1/clojure-1.2.1.jar from central
       Copying 1 file to /tmp/build_2e5yol0778bcw/lib
-----> Discovering process types
       Procfile declares types -> core
Build complete, shipping your container
Waiting for you application to boot
<-- https://my-app.osc-fr1.scalingo.io -->

The buildpack will detect your app as Clojure if it has a project.clj file in the root. If you use the clojure-maven-plugin, the standard Java buildpack should work instead.

Configuration

Leiningen 1.7.1 will be used by default, but if you have :min-lein-version "2.0.0" in project.clj (highly recommended) then the latest Leiningen 2.x release will be used instead.

Your Procfile should declare what process types which make up your app. Often in development Leiningen projects are launched using lein run -m my.project.namespace, but this is not recommended in production because it leaves Leiningen running in addition to your project’s process. It also uses profiles that are intended for development, which can let test libraries and test configuration sneak into production.

In order to ensure consistent builds, normally values set with scalingo env-set ... (other than LEIN_USERNAME, LEIN_PASSWORD, and LEIN_PASSPHRASE) will not be visible at compile time. To expose more to the compilation process, set a BUILD_CONFIG_ALLOWLIST config var containing a space-delimited list of config var names. Note that this can result in unpredictable behaviour since changing your app’s config does not result in a rebuild of your app. So it’s easy to get into a situation where your build is broken, but you don’t notice it until later when you push. For this reason it’s recommended to take care with this feature and always push after changing a allowlisted config value.

Choose JDK Version

Choosing the JDK version for Clojure is done the same way than for a simple Java application through the system.properties file.

See the Java documentation for more details.

Buildpack

More information at https://github.com/Scalingo/clojure-buildpack.