JRuby and JBang

[wfouche]

https://news.ycombinator.com/item?id=42487929

https://rockyj-blogs.web.app/2024/12/22/jruby-jbang.html

jruby/jruby#7964

[wfouche]

Initial attempt to run JRuby scripts using Jbang.

$ jbang run jruby_cli.java my_script.rb 1 2 3
Hello from JRuby!
Arguments received:
  Arg 0: 1
  Arg 1: 2
  Arg 2: 3

jruby_cli.java

///usr/bin/env jbang "$0" "$@" ; exit $?

//DEPS org.jruby:jruby-complete:9.4.13.0

import org.jruby.Main;

public class jruby_cli {
    public static void main(String[] javaArgs) {
        Main.main(javaArgs);
    }
}

my_script.rb

# my_script.rb
puts "Hello from JRuby!"
puts "Arguments received:"
ARGV.each_with_index do |arg, index|
  puts "  Arg #{index}: #{arg}"
end

if ARGV.empty?
  puts "No arguments provided to the Ruby script."
end

[quintesse]

Nice.

Btw, personally I would be much more inclined to try to add proper JRuby support to JBang (following the pattern of Jshell) than when we were talking about Python support. Mainly because the way to support JRuby seems obvious, there's one "official" way and if we do it that way we know we can support all JRuby scripts.

[wfouche]

JRuby already has a jbang-catalog repo:

• https://github.com/jruby/jbang-catalog

$ jbang run@jruby --version

Maven Jar dependencies are also supported:

• https://github.com/jruby/jar-dependencies/blob/master/example/example.gemspec

There does not seem to be any benefit to further integrate JRuby and JBang.

[quintesse]

You don't think jbang myapp.rb could be useful?

[wfouche]

If we build it, will it be used is what I was thinking when I looked at the JRuby examples.

The JRuby gem spec files already has version and maven dependency related information.

  s.required_ruby_version = '>= 2.6'

  # constrain the version of jar-dependencies itself
  s.add_runtime_dependency 'jar-dependencies', "~> #{version}"

  # the jar declarations
  s.requirements << 'jar org.bouncycastle:bcpkix-jdk15on, 1.49'
  s.requirements << 'jar org.bouncycastle:bcprov-jdk15on, 1.49'
  s.requirements << 'jar org.slf4j:slf4j-api, 1.7.7'

[wfouche]

JRuby just need better documentation, to describe its integration with Maven Central.

https://news.ycombinator.com/item?id=42487929

headius 6 months ago | parent | next [–]

We have all of the right tooling created to fetch jars from maven but no good tutorials on stitching it all together. Clearly that is step we should document better.
And for those following along, we keep the jbang configuration updated with every release so you know you're getting the most recent version.

[maxandersen]

If we build it, will it be used is what I was thinking when I looked at the JRuby examples.

The JRuby gem spec files already has version and maven dependency related information.

  s.required_ruby_version = '>= 2.6'



  # constrain the version of jar-dependencies itself

  s.add_runtime_dependency 'jar-dependencies', "~> #{version}"



  # the jar declarations

  s.requirements << 'jar org.bouncycastle:bcpkix-jdk15on, 1.49'

  s.requirements << 'jar org.bouncycastle:bcprov-jdk15on, 1.49'

  s.requirements << 'jar org.slf4j:slf4j-api, 1.7.7'

Got link to those examples?

I do think that having something working similar to jbang (all embedded) would be nice - same how for python would be nice but in python there is lot of fragmentation. Jruby is much more dominant / consistent.

But yes lets compare :)

[wfouche]

Got link to those examples?

See the examples folder at https://github.com/jruby/jar-dependencies

But yes lets compare :)

Good idea.