Building a Ruby application with jruby-complete
Matt Fletcher - Atomic Object
JRuby
Ruby running on the JVM
jruby-complete
JRuby in a single jar file
who cares? why?
- control your Ruby runtime!
embed Ruby runtime
- no need to install Ruby
- control precisely what Ruby you're using (sort stability!)
constrained environment
- servers not under your control
- AIX, HPUX, Solaris, QNX, etc
Running jruby-complete directly
baseline
$ java -jar jruby-complete-1.4.0.jar
$ java -jar jruby-complete-1.4.0.jar -e "puts 'Ahoy'"
Ahoy
JVM heap and stack
$ java -Xmx500m -Xss1024k \
$ -jar jruby-complete-1.4.0.jar -e "puts 'Ahoy'"
Ahoy
irb
$ java -Xmx500m -Xss1024k \
$ -jar jruby-complete-1.4.0.jar -S jirb
irb(main):001:0> puts "Ahoy"
Ahoy
=> nil
Rakefile
JRUBY_COMPLETE = "jruby-complete-1.4.0.jar"
JRUBY = "java -Xmx500m -Xss1024k " \
"-jar #{JRUBY_COMPLETE}"Rakefile
namespace :jruby do
desc "Run JRuby help"
task :help do
sh %+#{JRUBY} --help+
end
desc "Run any command with JRuby"
task :run do
sh %+#{JRUBY} -e '#{ENV["cmd"]}'+
end
end$ rake jruby:run cmd='puts "Hello"'
Hello
Running an application and specs
lib/application_bootstrap.rb
puts 'Hello from application_bootstrap'Rakefile
task :run do
sh "#{JRUBY} lib/application_bootstrap.rb"
end$ rake run
java -Xmx500m -Xss1024k -jar jruby-complete-1.4.0.jar \
lib/application_bootstrap.rb
Hello from application_bootstrap
Ruby executables
- use -S to run commands in JRuby's bin directory
- For jruby-complete, this means the bin tucked inside the jar
- RSpec, Rake built into jruby-complete
- Other executables like jrubyc
Rakefile
namespace :spec do
desc "Run RSpec against a specific file"
task :run do
sh "#{JRUBY} -S spec -f specdoc " \
"#{ENV['spec']}"
end
endspec/unit/objectivism_spec.rb
describe "John Galt" do
it "doesn't tolerate logical fallacies" do
"A".should == "A"
end
end$ rake spec:run spec=spec/unit/objectivism_spec.rb
java -Xmx500m -Xss1024k -jar jruby-complete-1.4.0.jar \
-S spec -f specdoc spec/unit/objectivism_spec.rb
John Galt
- doesn't tolerate logical fallacies
Finished in 0.123 seconds
1 example, 0 failures
aliases and functions
- Some commands are getting cumbersome
- Your shell can help!
$ which sp
sp () {
rake spec:run spec=$@
}
$ sp spec/unit/objectivism_spec.rb
java -Xmx500m -Xss1024k -jar jruby-complete-1.4.0.jar \
-S spec -f specdoc spec/unit/objectivism_spec.rb
Compiling Ruby code
Rakefile
require "rake/clean"
namespace :jruby do
output_directory = "classes"
directory output_directory
CLEAN.include output_directory
desc "Compile Ruby files in lib"
task :compile => output_directory do
sh "#{JRUBY} -S jrubyc " \
"-p com/atomicobject " \
-t #{output_directory} lib"
end
end$ rake jruby:compile
java -Xmx500m -Xss1024k -jar jruby-complete-1.4.0.jar
-S jrubyc -p com/atomicobject -t classes lib
Compiling lib/application_bootstrap.rb to class
com/atomicobject/lib/application_bootstrap
Run it
$ rake jruby:run cmd='require \
$ "classes/com/atomicobject/lib/application_bootstrap"'
java -Xmx500m -Xss1024k -jar jruby-complete-1.4.0.jar ...
Hello from application_bootstrap
Conclusion
Further work
- Use JarJar Links to wrap jruby-complete, Ruby files, 3rd-party gems and jars into one file
- new CompoundJarClassLoader in JRuby - eliminates need for JarJar?
Additional resources
- This presentation: http://github.com/fletcherm/grruby-jruby-complete
- fletcherm-culerity: http://github.com/fletcherm/culerity
- Running a Ruby application with jruby-complete: http://spin.atomicobject.com/2010/02/01/running-a-ruby-application-with-jruby-complete
- Rolling a JRuby desktop application: http://spin.atomicobject.com/2008/07/02/rolling-a-jruby-desktop-application
- Ruby for desktop applications? Yes we can.: http://spin.atomicobject.com/2009/01/30/ruby-for-desktop-applications-yes-we-can