Wednesday, October 02, 2013

How to Install Play 2 War: The Bare Minimum

In this post, I'll show you how to install the Play 2 War extension. This article describes the installation and configuration procedure for Play 2.1.x applications.

From the author: 
This project is a module for Play framework 2 to package your apps into standard WAR packages. It can be used with Servlet 3.0 and 2.5 containers (Tomcat 6/7, Jetty 7/8/9, JBoss 5/6/7, ...)
Step 1: Add the Plugin to plugins.sbt

Navigate to \project and open the plugins.sbt file. Add the following line to the end of the file:

addSbtPlugin("com.github.play2war" % "play2-war-plugin" % "1.0")

Note: Be sure to include an empty line between this line and the previous addSbtPlugin statement.

Step 2: Add Play2War keys to Build.scala

In the same folder as plugins.sbt, you'll find the file Build.scala. Open this file and follow the template below for modifying it. Items in bold are the new lines that were added. Items in italics are items that can be modified to suit your application's needs.

import sbt._
import Keys._
import play.Project._
import com.github.play2war.plugin._

object ApplicationBuild extends Build {

  val appName         = "your_app_name"
  val appVersion      = "1.0-SNAPSHOT"

  val appDependencies = Seq(
    // Add your project dependencies here,
    javaCore,
    javaJdbc,
    javaEbean
  )

  val main = play.Project(appName, appVersion, appDependencies)
  .settings(Play2WarPlugin.play2WarSettings: _*).settings(
    // Add your own project settings here  
Play2WarKeys.servletVersion := "3.0"
  ).settings(
Play2WarKeys.targetName := Some("war_file_name")
  )


}

Tip: The full list of Play2WarKeys and their expected data types can be found here.

Step 3: Resolve Dependencies and Build the WAR

Open a command terminal and cd into your project's directory. Once there, run the following commands:

play
clean
dependencies
war

Once the war command has completed you can look in \target to see the generated WAR file. You can then take this file and deploy it to your servlet container of choice.

Why Would I Want to Use This Plugin?

That's a great question especially seeing that Play comes with its own high performance web server built in. My answer to that question is if you work in a Windows-centric environment like mine, you become acquainted with the "shortcomings" of the Play framework when it comes to production deployment in a Windows environment. Unlike Linux where you can easily set your application to run as a service in the background on startup, Windows forces you to resort to all sorts of .bat magic that leaves you with a bunch of command line windows popping up and having to stay open for the duration of the application's life.

So for a cleaner, less cluttered production server that other members of your team can appreciate, I recommend using a Servlet container like Tomcat that can be installed as Windows service and set to run on startup. No more .bat magic and no more freaking out when the server admin says he restarted the server a couple hours ago and now the folks in HR can't access the employee registration application.

Closing Remarks

In all, the installation of this extension was easy once you figured out how to switch mental context to deal with the different syntaxes for each file that has to be manipulated. I find that in some cases the author of the documentation could have gone into a little more detail in addressing the little gotchas with each file type. For example the need for an empty space between lines in the plugins.sbt file. Thankfully the Play command was smart enough to point this out to me when I tried to start the application and it was an easy fix.

That being said, though the installation of this particular plugin was not all that difficult, I would still like to see some more abstraction in the plugin installation process. I think the guys over at +Typesafe could take a very interesting page out of the Rails book in this regard.

That's it for now. I hope this article was useful.


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