§Deploying to Heroku

Heroku is a cloud application platform – a new way of building and deploying web apps.

§Add the Procfile　

Heroku requires a special file in the application root called Procfile. Create a simple text file with the following content:

web: target/start -Dhttp.port=${PORT} ${JAVA_OPTS}

§Store your application in git

Just create a git repository for your application:

$ git init
$ git add .
$ git commit -m "init"

§Create a new application on Heroku

Note that you need an Heroku account, and to install the heroku gem.

$ heroku create --stack cedar
Creating warm-frost-1289... done, stack is cedar
http://warm-1289.herokuapp.com/ | [email protected]:warm-1289.git
Git remote heroku added

§Deploy your application

To deploy your application on Heroku, just use git to push it into the heroku remote repository:

$ git push heroku master
Counting objects: 34, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (20/20), done.
Writing objects: 100% (34/34), 35.45 KiB, done.
Total 34 (delta 0), reused 0 (delta 0)

-----> Heroku receiving push
-----> Scala app detected
-----> Building app with sbt v0.11.0
-----> Running: sbt clean compile stage
       ...
-----> Discovering process types
       Procfile declares types -> web
-----> Compiled slug size is 46.3MB
-----> Launching... done, v5
       http://8044.herokuapp.com deployed to Heroku

To [email protected]:floating-lightning-8044.git
* [new branch]      master -> master

Heroku will run sbt clean compile stage to prepare your application. On the first deployment, all dependencies will be downloaded, which takes a while to complete (but will be cached for future deployments).

§Check that your application has been deployed

Now, let’s check the state of the application’s processes:

$ heroku ps
Process       State               Command
------------  ------------------  ----------------------
web.1         up for 10s          target/start 

The web process is up. Review the logs for more information:

$ heroku logs
2011-08-18T00:13:41+00:00 heroku[web.1]: Starting process with command `target/start`
2011-08-18T00:14:18+00:00 app[web.1]: Starting on port:28328
2011-08-18T00:14:18+00:00 app[web.1]: Started.
2011-08-18T00:14:19+00:00 heroku[web.1]: State changed from starting to up
...

Looks good. We can now visit the app with heroku open.

§Running play commands remotely

Cedar allows you to launch a REPL process attached to your local terminal for experimenting in your application’s environment:

$ heroku run sbt play
Running sbt play attached to terminal... up, run.2
[info] Loading global plugins from /app/.sbt_home/.sbt/plugins
[info] Updating {file:/app/.sbt_home/.sbt/plugins/}default-0f55ac...
[info] Set current project to My first application (in build file:/app/)
       _            _ 
 _ __ | | __ _ _  _| |
| '_ \| |/ _' | || |_|
|  __/|_|\____|\__ (_)
|_|            |__/ 
             
play! 2.0-beta, http://www.playframework.org

> Type "help" or "license" for more information.
> Type "exit" or use Ctrl+D to leave this console.

[My first application] $