Groovysh Server

Introduction

If you are familiar with groovy, you know what groovysh is. It's damn simple REPL (read, evaluate, print, loop) shell for evaluating groovy code. And groovy-shell-server is full featured groovy shell inside your application.

How many times you are in situation when all you need is to call some method inside your application, but the only way to do it is JMX or custom user interface (web page, for instance)? Groovy shell server allows you to run REPL shell inside your application and work with it like you are using groovysh.

Groovy shell server uses groovysh API inside, so all features of groovysh (autocompletion, history etc.) are supported.

Installation

Just drop all distributed jar files in your application classpath. In the moment it's the only option. In a future you will be able to use it as a regular maven dependency.

Using

In your application you should start GroovyShellService:

GroovyShellService service = new GroovyShellService();
service.setPort(6789);
service.setBindings(new HashMap<String, Object>() {{
	put("foo", obj1);
	put("bar", obj2);
}});
							
service.start();

And destroy it on application exit:

service.destroy();

Groovy shell server use custom client for connect to a server. After you download a package, you should unpack it and it's ready to go:

$ tar xvf groovy-shell-client-1.0.tar.gz 
x groovy-shell-client-1.0/lib/slf4j-api-1.6.1.jar
x groovy-shell-client-1.0/lib/jline-0.9.94.jar
x groovy-shell-client-1.0/lib/logback-classic-0.9.25.jar
x groovy-shell-client-1.0/lib/logback-core-0.9.25.jar
x groovy-shell-client-1.0/lib/groovy-shell-client-1.0.jar
x groovy-shell-client-1.0/bin/remote-groovysh
$ ./groovy-shell-client-1.0/bin/remote-groovysh localhost 6789
Groovy Shell (1.5.6, JVM: 19.1-b02-334)
Type 'help' or '\h' for help.
-------------------------------------------------------------------------------
groovy:000> (1..10).each { println "Kill all humans!" }
Kill all humans!
Kill all humans!
Kill all humans!
Kill all humans!
Kill all humans!
Kill all humans!
Kill all humans!
Kill all humans!
Kill all humans!
Kill all humans!
===> 1..10
groovy:000>

Build

Use maven-assembly plugin to build and create archive of groovy-shell-server:

mvn -f groovy-shell-server/pom.xml assembly:assembly

and groovy-shell-client:

mvn -f groovy-shell-client/pom.xml assembly:assembly

Archives will be placed in groovy-shell-server/target/ and groovy-shell-client/target/ respectively.

Simple run

In order to simple run applications you can use maven-exec plugin:

mvn -f groovy-shell-server/pom.xml exec:java -Dexec.mainClass=com.iterative.groovy.service.Main

and

mvn -f groovy-shell-client/pom.xml exec:java -Dexec.mainClass=com.farpost.groovy.shell.GroovyShellClient -Dexec.args="localhost 6789"

Management

What if a well-meaning developer fires up a remote shell and accidentally executes a script which hammers the server? Fortunately, each GroovyShellService instance registers itself with the default MBeanServer and provides a "killAllClients" operation to kill any open client sockets and stop the associated client threads. Thus you can connect with jconsole or your favorite JMX frontend to resolve this issue if it arises.