Hey all, I’ve seen a few posts on this mailing list and in the JRuby JIRA looking for gem management strategies that don’t rely on a local installation of JRuby and locally installed gems in a deployed Java + JRuby application.
The application model I am looking at is a Java application built by Maven that embeds JRuby scripts that have gem dependencies. I'd like to support a deployment model that doesn't require a local install of JRuby and the required gems. The primary issue appears to be that Ruby and RubyGems are heavily file system dependent so are not friendly to having resources loaded from the classpath. jruby-complete takes care of providing the JRuby and the core Ruby dependencies with a strategy where core Ruby libraries are extracted at runtime to the file system from the jar. I have been experimenting with a similar strategy for managing gem dependencies and have a working implementation that I’d like to float out here for comment. It goes something like this: Package [name]-[version].gem files in the Java application classpath. Either at application startup or on demand (by modifying Kernel::gem) find the desired gem if it is not already installed by scanning the root of the classpath, ala Spring’s PathMatchingResourcePatternResolver (http://static.springframework.org/spring/docs/2.0.x/api/org/springframework/core/io/support/PathMatchingResourcePatternResolver.html). Extract and install the gem into an application-specific GEM_HOME using Gem::Installer. Done. This enables packaging and deploying gems as jars (the .gem file in the root of a jar) and managing these dependencies with Maven, including transitive dependencies among gems. Goldspike (Rails on Tomcat) uses a similar strategy by bundling expanded gems in WEB-INF and setting GEM_HOME to that location. I have a version of this working that first extracts the .gem file to file system from the classpath by reading from a classpath resource InputStream. I noticed that Gem::Format has a method for reading from an IO stream (Gem::Format.from_io). It would be great to skip the intermediate extraction step by using this method. I ran into trouble figuring out how to use the InputStream from the classloader as an IO object in Ruby. I tried creating an org.jruby.RubyIO object from the InputStream but get an error when calling Gem::Format.from_io with the created object: /lib/ruby/site_ruby/1.8/rubygems/package.rb:411:in `new': Illegal seek (Errno::ESPIPE) Comments on the overall strategy? If desired by others I’ll definitely share the end result. Suggestions on the IO issue? Thanks, Alon -- View this message in context: http://www.nabble.com/Proposal-for-managing-gem-dependencies-in-a-Java-%2B-JRuby-application-tf4946209.html#a14161350 Sent from the JRuby - Dev mailing list archive at Nabble.com. --------------------------------------------------------------------- To unsubscribe from this list please visit: http://xircles.codehaus.org/manage_email
