Nailgun

This page describes how to speed up execution of DSpace command-line scripts (class launcher) using Nailgun by Martian Software, Inc.

The reason why even the simplest DSpace command-line scripts usually take several seconds to run is because the Java class launcher has to create a new JVM instance every time it's run. Nailgun has a client/server architecture and implements a very lightweight JVM in the server part, which keeps running as a service and therefore doesn't have to be started up every time. You then use the command line nailgun client (ng) to connect to it to launch a class, which is considerably faster than starting up the JVM.

1. Download and build the nailgun client and server (this assumes that dspace is installed in /dspace, that you have gcc installed and that you can run binaries from ~/bin):

   git clone git://github.com/martylamb/nailgun.git
   cd nailgun
   mvn clean install
   cp nailgun-server/target/nailgun-server-0.9.2-SNAPSHOT.jar /dspace/webapps/xmlui/WEB-INF/lib/
   cd nailgun-client
   gcc ng.c -o ng
   cp ng ~/bin
   # exit your shell and launch it again

2. Start the nailgun server and add DSpace to its classpath:

   java -classpath /dspace/lib/nailgun-server-0.9.2-SNAPSHOT.jar com.martiansoftware.nailgun.NGServer &
   ng ng-cp /dspace/lib/*.jar /dspace/config

3. Run the client:

   # instead of this:
   /dspace/bin/dspace
   # use this:
   ng org.dspace.app.launcher.ScriptLauncher
    
   # Example. Instead of 
   /dspace/bin/dspace update-discovery-index
   # use this
   ng org.dspace.app.launcher.ScriptLauncher update-discovery-index

4. After you're finished running multiple invocations of the DSpace command-line scripts, you can stop the Nailgun server:

   ng ng-stop