How To Install Grails on an Ubuntu 12.04 VPS
Grails is an open-source web development framework, based on the Groovy programming language (which runs on the Java platform).
Step One: Install JDK
Log in into your VPS (droplet), preferably via SSH. (You can follow this tutorial on how to configure SSH on your Droplet.) Then, in order to install OpenJDK, run the following command in the terminal:
sudo apt-get install openjdk-6-jdk
(We'll install version 6 of the OpenJDK for maximum compatibility with Grails.)
Then, the terminal will ask you for your root password. Enter it and confirm your installation by typing
y. Then, the JDK will begin downloading and installing.
Step Two: Install GVM (Groovy enVironment Manager)
GVM is a command-line tool for managing parallel version of different SDKs on Unix-based systems. You can even install multiple version of Groovy or Grails and switch between them very easily.
Before installing GVM, we need to install cURL on our system. Run:
sudo apt-get install curl
(Of course, type 'y' to confirm the installation.)
Now that we have cURL installed, we can go and install GVM.
In the bash terminal, execute the following command:
curl -s get.gvmtool.net | bash
When the installation ends, it will ask you to open a new terminal or type in a certain command. Type the command the installer gives you. It should be something like:
Step Three: Install Grails
Run the following command in order to install the latest Grails version currently available:
gvm install grails
(If you want to install a specific version of Grails, just add it in the line. For example:
gvm install grails 2.2.0)
After the installation finishes, it will ask you whether you want to set this version as the default one. You should enter
y to confirm.
Step Four: Test Your Installation
It's good practice to test if everything was installed as expected, so go ahead an create a new Grails project.
Run the following commands to create a new directory and a new application inside this directory.
mkdir projects cd projects grails create-app test
Then, enter the newly-created project directory and run it:
cd test grails run-app
grails run-app command is intelligent enough to know which application to run that's in the directory you're in.)
Note: It will install a couple of things before first running an application, so just wait until it's done.
http://DROPLET_IP:8080/test and you should be seeing the default Grails application.
You have successfully installed Grails for your development environment!
Note that the run-app command we used here should only be used in the development environment, as it doesn't scale well in production (and shouldn't). Real-world production deployments are done as WAR files and are executed by Apache Tomcat, for example. This files have many optimizations in them that aren't available in the run-app command.