I am interested in hearing more! What do you think about the
feasibility of making gems run entirely from within the archive? There
are two possible approaches: make JRuby's imply of File work against
URL based resources (hard); or make RubyGems itself be archive-aware.
Either way I am interested on seeing what you have!
- Charlie
On Dec 4, 2007, at 16:47, Alon Salant <[EMAIL PROTECTED]> wrote:
Hey all,
I’ve seen a few posts on this mailing list and in the JRuby JIRA loo
king 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 floa
t 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 definite
ly share
the end result.
Suggestions on the IO issue?
Thanks,
Alon
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