Self-cloning JRuby and RubyGems in a Jar

Posted by Nick Sieger Fri, 12 Jan 2007 04:27:07 GMT

As part of some work I’m doing to make JRuby more portable and easier to run standalone without all the $JRUBY_HOME launcher scripts, it’s now easier than ever to get up and running with JRuby, or to launch in your build scripts or IDE in a platform-neutral way. (Note: as of this writing, this feature is in 0.9.3 jruby-complete snapshots older than 2007/01/11 only.)

Here, give it a try:

IRB in a jar

$ curl -o jruby-complete.jar
$ java -jar jruby-complete.jar --command irb

RubyGems in a jar

RubyGems needs a place to unpack and run gems, so JRuby currently will hide all that away from you in ~/.jruby. (Also, unfortunately we exceed Java’s default memory size when downloading the RubyGems index file, so you’ll have to add the -Xmx256m argument for now to avoid an out of memory condition.)

$ java -Xmx256m -jar jruby-complete.jar --command gem install tattle -y --no-rdoc --no-ri
creating /Users/nicksieger/.jruby/bin/gem
... more files extracted ...
copying /Users/nicksieger/jruby-complete.jar to /Users/nicksieger/.jruby/lib
Bulk updating Gem source index for:
Successfully installed tattle-1.0.1
Successfully installed hoe-1.1.7
Successfully installed rubyforge-0.4.0
Successfully installed rake-0.7.1

You can still have JRuby unpack to a shared directory if you like, and use the regular shell scripts for launching JRuby. In this case, JRuby is actually replicating itself into the directory you choose. Simply add the bin subdirectory to your $PATH, and continue to use JRuby just as you would a regular Ruby installation.

$ sudo java -jar jruby-complete.jar --command extract /opt/local/jruby
creating /opt/local/jruby/bin/gem
... more files extracted ...
copying /Users/nicksieger/jruby-complete.jar to /opt/local/jruby/lib
$ PATH=/opt/local/jruby/bin:$PATH
$ which gem
$ jirb


The --command argument is not limited to just gem and irb. Once you’ve installed any gem that has an accompanying executable script, you can simply pass that argument as the --command:

$ java -jar jruby-complete.jar --command tattle report
ruby_install_name, jruby
LIBRUBY, jruby
target, java
arch, java
host_vendor, Apple Computer, Inc.
key, b1bd5eaf4254d9874ca297995b906be6f4975d395dd0136432f859c62a33cc8c
host_os, Mac OS X
ruby_version, 1.8.5
build, java
target_cpu, i386
prefix, /Users/nicksieger/.jruby
report_time, Thu Jan 11 22:21:57 CST 2007
rubygems_version, 0.9.0
host_cpu, i386
SHELL, /bin/sh
$ java -jar jruby-complete.jar --command tattle
Posting information to Tattle server.  Thanks!

And lo and behold, there’s a ruby_install_name of java at the new Gem Tattle homepage!

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  1. Avatar said about 10 hours later:

    I really like playing with the “complete” jar version of jruby, Thanks man.

    How do I tell it that my “.jruby” directory is not under my user account. I’ve set the environment variable JRUBY_HOME to where I’d like to go, but no dice.

  2. Avatar Nick said about 11 hours later:

    I commented on this in the JIRA issue. Basically, you need to pass -Djruby.home=/custom/path on the command line.

    java -Djruby.home=/custom/path -jar jruby-complete.jar ...


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