This is a Heroku buildpack for Clojure apps. It uses Leiningen.
Note that you don't have to do anything special to use this buildpack with Clojure apps on Heroku; it will be used by default for all projects containing a project.clj file, though it may be an older revision than current master.
This repository is made available so users can fork for their own needs and contribute patches back as well as for transparency.
Example usage for an app already stored in git:
$ tree
|-- Procfile
|-- project.clj
|-- README
`-- src
`-- sample
`-- core.clj
$ heroku create --stack cedar --buildpack http://github.com/heroku/heroku-buildpack-clojure.git
$ git push heroku master
...
-----> Heroku receiving push
-----> Fetching custom buildpack
-----> Clojure app detected
-----> Installing Leiningen
Downloading: leiningen-2.0.0-preview7-standalone.jar
Writing: lein script
-----> Building with Leiningen
Running: with-profile production do compile :all, clean-m2
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
-----> Compiled slug size is 10.0MB
-----> Launching... done, v4
http://gentle-water-8841.herokuapp.com deployed to Heroku
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. Leiningen 1.7.1 will be used by default, but if
you have :min-lein-version "2.0.0" in project.clj then Leiningen 2.x
will be used instead.
By default your project is built by running lein deps under
Leiningen 1.x and lein compile :all under Leiningen 2.x. To
customize this, check in a bin/build script into your project and it
will be run instead of invoking lein directly.
If you are using Leiningen 2.x, it's highly recommended that you use
the :production profile to avoid having tests and development
dependencies on your classpath in production. By default the
:production profile configures a mirror setting for faster
dependency fetching from S3; if you place a :production profile in
your project.clj you should do the same:
:production {:misc "configuration"
:mirrors {#"central|clojars"
"http://s3pository.herokuapp.com/clojure"}}You should reduce memory consumption by using the trampoline task in
your Procfile. This will cause Leiningen to calculate the classpath
and code to run for your project, then exit and execute your project's
JVM:
web: lein trampoline with-profile production run -m myapp.web
To change this buildpack, fork it on GitHub. Push up changes to your
fork, then create a test app with --buildpack YOUR_GITHUB_URL and
push to it. If you already have an existing app you may use
heroku config:add BUILDPACK_URL=YOUR_GITHUB_URL instead.
For example, you could adapt it to generate an uberjar at build time.
Open bin/compile in your editor, and replace the block labeled
"fetch deps with lein" with something like this:
echo "-----> Generating uberjar with Leiningen:"
echo " Running: LEIN_NO_DEV=y lein uberjar"
cd $BUILD_DIR
PATH=.lein/bin:/usr/local/bin:/usr/bin:/bin JAVA_OPTS="-Xmx500m -Duser.home=$BUILD_DIR" LEIN_NO_DEV=y lein uberjar 2>&1 | sed -u 's/^/ /'
if [ "${PIPESTATUS[*]}" != "0 0" ]; then
echo " ! Failed to create uberjar with Leiningen"
exit 1
fi
Commit and push the changes to your buildpack to your GitHub fork, then push your sample app to Heroku to test. The output should include:
-----> Generating uberjar with Leiningen:
If it's something other users would find useful, pull requests are welcome.
To see what the buildpack has produced, do heroku run bash and you
will be logged into an environment with your compiled app available.
From there you can explore the filesystem and run lein commands.