Why the need for multiple $GEM_PATHS

[Luke Hamilton]

Hi all,

Can some tell me why we need a $GEM_PATH location per ruby versions when using tools like RVM & rbenv?

I would like to switch between rubies without always need to download the gem's a second time as I am currently working off a very poor internet connection.

Thanks!

Luke Hamilton

“When I let go of what I am, I become what I might be.” – Lao Tzu

[Bayu Aldi Yansyah]

tool like rbenv can set what ruby version should on your project/directory . i mean you can use diferent ruby version for different project/directory. for that, gems need match ruby version for execute on command line. i think is reason why gem location in each ruby version.

[Michał Papis]

also appeared in Ruby Parley - moved to https://github.com/rubygems/rubygems/pull/596

$GEM_HOME is a way of controlling rubygems gems install location:

* benefits: thanks to GEM_HOME you can install ruby as "root" and gems as users, or reinstall ruby without removing gems, it allows you to separate the ruby directory from gems direcotry, you can also maintain multiple sets of gems by manipulating GEM_HOME to different directories - this is how rvm gemsets work

* problems: the need to use different gem paths per ruby/version exist because some gems might require specific ruby version, compiled c-extensions or might include implementation specific code/libraries, they can not be mixed all together, but that's just few percent of gems - rest of them can be mixed in one directory and it is what I have implemented in the pull request mentioned above

Cheers,
Michal

[Rick]

You only need multiple copies of any gems that require a specific version to run with your current ruby.  GEM_PATH can include multiple directories just as the shell PATH does.  So if you're running two different ruby environments, RUBY_A and RUBY_B, you could use a GEM_PATH that looks like:

RUBY_A_GEM_PATH=a_gems_dir:common_dir
RUBY_B_GEM_PATH=b_gems_dir:common_dir

[Luke Hamilton]

I ended up switching from rbenv to chruby as its only keeps one GEM_PATH location per major version of rubies and not a new location for all the patch levels. And its much simpler too. :)

Kind regards,

Luke Hamilton

+61 0430223558

@lukekhamilton

“When I let go of what I am, I become what I might be.” – Lao Tzu

--
You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group.
To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-ta...@googlegroups.com.
To post to this group, send email to rubyonra...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/36844e66-425e-4b21-b5a9-e555483e9d7f%40googlegroups.com.

For more options, visit https://groups.google.com/groups/opt_out.