Please help to finish install rails on nixos.

Try rails -v give output error:

 [user]# rails -v
 /nix/store/vyqv3ffri4fbwwd173a4xj9fj3qmsq0b-rubygems-1.8.17/lib/rubygems/dependency.rb:247:in `to_specs': Could not find rack (>= 0) amongst [bigdecimal-1.1.0, io-console-0.3, json-1.7.3, json-1.5.4, minitest-2.5.1, rack-ssl-1.3.2, railties-3.2.6, rake-0.9.2.2, rdoc-3.12, rdoc-3.9.4] (Gem::LoadError)
    from /nix/store/vyqv3ffri4fbwwd173a4xj9fj3qmsq0b-rubygems-1.8.17/lib/rubygems/specification.rb:772:in `block in activate_dependencies'
    from /nix/store/vyqv3ffri4fbwwd173a4xj9fj3qmsq0b-rubygems-1.8.17/lib/rubygems/specification.rb:761:in `each'
    from /nix/store/vyqv3ffri4fbwwd173a4xj9fj3qmsq0b-rubygems-1.8.17/lib/rubygems/specification.rb:761:in `activate_dependencies'
    from /nix/store/vyqv3ffri4fbwwd173a4xj9fj3qmsq0b-rubygems-1.8.17/lib/rubygems/specification.rb:745:in `activate'
    from /nix/store/vyqv3ffri4fbwwd173a4xj9fj3qmsq0b-rubygems-1.8.17/lib/rubygems/specification.rb:775:in `block in activate_dependencies'
    from /nix/store/vyqv3ffri4fbwwd173a4xj9fj3qmsq0b-rubygems-1.8.17/lib/rubygems/specification.rb:761:in `each'
    from /nix/store/vyqv3ffri4fbwwd173a4xj9fj3qmsq0b-rubygems-1.8.17/lib/rubygems/specification.rb:761:in `activate_dependencies'
    from /nix/store/vyqv3ffri4fbwwd173a4xj9fj3qmsq0b-rubygems-1.8.17/lib/rubygems/specification.rb:745:in `activate'
    from /nix/store/vyqv3ffri4fbwwd173a4xj9fj3qmsq0b-rubygems-1.8.17/lib/rubygems.rb:1211:in `gem'
    from /nix/store/0iazqkijlf3cc095lflwqvdlmg0mc72a-ruby-railties-3.2.6/bin/.rails-wrapped:18:in `<main>'

[user1:/etc/nix]# gem -v
1.8.23

[user]# ruby -v
ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-linux]

[user]# nix-store --query --roots /nix/store/vyqv3ffri4fbwwd173a4xj9fj3qmsq0b-rubygems-1.8.17/
/nix/var/nix/profiles/system-175-link
/run/current-system

[user1:/etc/nix]# gem update
Updating installed gems
Updating json
ERROR:  While executing gem ... (Gem::FilePermissionError)
   You don't have write permissions into the /nix/store/ddgq0g99hrpfiwppgrd89qjv2pzpm9qj-ruby-1.9.3-p194/lib/ruby/gems/1.9.1 directory.

[user# grep -i ruby /etc/nixos/configuration.nix
ruby
rubyLibs.bundler
rubyLibs.rack
rubyLibs.rake
rubyLibs.nix
rubyLibs.rails

Questions:

• why path ‘rubygem-1.8.17’ is alive for current system? (Rubygem must include itself as integrated part ruby from version 1.9)

• If rubygem-1.8.17 is valid presence in current system, then how to manual manage dependencies via edit gems.specs ?

• How to run ‘gem update’, if /nix/store is protected by system ?

Submitted by Vyacheslav Perestoronin on 25 August 2012 at 21:00