JRuby on Rails: A Taste of Honey (for the Enterprise)

Charles Nutter, Thomas Enebo

Session Link

Status

• Most Rails apps will now work on JRuby
• Most pure Ruby Gems work: Redcloth, etc
• Rails commands work
• Ruby DB MySQL adapter works (others close)
• Extensions that work: Mongrel, OpenSSL, YAML, RMagickJr

Advantages of JRuby

• Supports Java Unicode strings, Ruby and Java strings go back and forth safely
• JRuby supports Ruby's Thread. Same as a system thread so can spin off threads easily. Can pool threads.
• Access Java libraries
• JDBC drivers with JNDI connection pooling
• Supports more databases than Rails, but most still don't pass all tests
• Can be faster than Ruby (after warmup)

Disadvantages of JRuby

• Doesn't support SQLITE3?
• PostgreSQL still fails some tests
• Oracle, DB2 and MSSQL still not working
• Native extensions (C extensions) not supported, but people can port them or call to equivalent Java library
• RMagick not supported (but they are working on it)
• Command line likely slower (because of JVM warmup)
• Migrations don't work on all DBs

Building, Running, Deploying

• Install JRuby from tar
• Add to path
• Install with jruby -S gem install rails -y
• Install other stuff
• Can run with native DB, to install JDBC modify environment.rb
• Run as normal
• However using Mongrel means that each one needs JVM too, so it takes a lot memory

Deploy to App Server

• Install goldspide plugin
• jruby -S rake war:standalone:create
• Deploy to glassfish or tomcat
• Can run GlassFish as a gem (Alpha)