Scalatra on Heroku

_README.md

Scalatra on Heroku

This is pretty easy to get up and running. Only thing you really need to do is start jetty directly, and add a script to execute this. You don't want to have to rely on SBT to start your application.

Easiest way to do this is create a Main method to start jetty. See JettyLauncher.scala - save this in your src/main/scala dir, setting the filter to your applications filter. Then use Typesafe's start script plugin to generate a script to start the app.

To enable the plugin, add the following to project/plugins/build.sbt

resolvers += {
    val typesafeRepoUrl = new java.net.URL("http://repo.typesafe.com/typesafe/ivy-snapshots")
    val pattern = Patterns(false, "[organisation]/[module]/[sbtversion]/[revision]/[type]s/[module](-[classifier])-[revision].[ext]")
    Resolver.url("Typesafe Ivy Snapshot Repository", typesafeRepoUrl)(pattern)
}

libraryDependencies <<= (libraryDependencies, sbtVersion) { (deps, version) =>
    deps :+ ("com.typesafe.startscript" %% "xsbt-start-script-plugin" % "0.1-SNAPSHOT" extra("sbtversion" -> version))
}

And the following to your build.sbt

import com.typesafe.startscript.StartScriptPlugin

seq(StartScriptPlugin.startScriptForClassesSettings: _*)

Once this is done, you are ready to deploy to Heroku. Create a Procfile in the root if your project containing

web: target/start

Commit your changes to git and make sure you have the heroku gem installed. You can then create and push the app.

heroku create appname --stack cedar
git push heroku master

JettyLauncher.scala

/*
 * Starts jetty for scalatra programatically
 *
 * Replace YourApplicationEndpointFilter with the filter in your application
 */
import org.eclipse.jetty.server.Server
import org.eclipse.jetty.servlet.{DefaultServlet, ServletContextHandler}

object JettyLauncher {
  def main(args: Array[String]) {
    val port = if(System.getenv("PORT") != null) System.getenv("PORT").toInt else 8080

    val server = new Server(port)
    val context = new ServletContextHandler(server, "/", ServletContextHandler.SESSIONS)

    context.addFilter(classOf[YourApplicationEndpointFilter], "/*", 0)
    context.addServlet(classOf[DefaultServlet], "/");
    context.setResourceBase("src/main/webapp")

    server.start
    server.join
  }

}