Run gem from local source code - ruby

I am currently working on developing a gem and I would like to be able to run that gem from command line and point it to my local source. Previously I've done this in rails by specifying the path in the gem file but now I would like to run the gem on a non rails app. So I would like to know how to call the gem from command line and specify that I want to use the source code in a certain directory.
For example can I cd into the directory that I want to run it on and do something like: ruby my_gem --path=~/code/mygem
Also do I have to build them gem or can I run it from source without building it?

From the root directory of your gem, try this to execute lib/MyGem.rb:
ruby -Ilib lib/MyGem.rb
or test your gem interactive:
irb -Ilib
> require 'mygem'
true

Related

Ruby script cannot load a gem installed via bundler

I am trying to include the ruby-mysql gem in my ruby script. I have installed the gem using bundler but when I run bundle exec ./mysql_connector, I receive the error ./mysql_connector:4:in ``require': cannot load such file -- ruby-mysql (LoadError). Can you please help me troubleshoot what the problem is?
What I did
Installed rails in my home directory.
I do not have root access to the server so I have installed rails in my local directory by following the instructions here:
http://www.r-bloggers.com/installing-ruby-on-linux-as-a-user-other-than-root/
Created a directory for my application.
My application resides in my home directory in a folder called connector. It has a Gemfile that looks like this:
source 'https://rubygems.org'
gem 'ruby-mysql'
Call bundle install.
Using ruby-mysql 2.9.14
Using bundler 1.11.2
Bundle complete! 1 Gemfile dependency, 2 gems now installed.
Bundled gems are installed into ./vendor/bundle.
Add dependencies to my script. My script is in connector/mysql_connector and it reads:
#!/home/dcox/bin/ruby
require 'rubygems'
require 'bundler/setup'
require 'ruby-mysql'
Make script executable. I saw that you need to run bundle exec using an executable file, so I followed the instructions here to make my script executable: http://commandercoriander.net/blog/2013/02/16/making-a-ruby-script-executable/
Run the script. I execute using bundle exec mysql_connector and see:
/home/dcox/bin/mysql_connector:4:in `require': cannot load such file -- ruby-mysql (LoadError)
from /home/dcox/bin/mysql_connector:4:in `<main>'
Is it the $LOAD_PATH? After searching around for answers, I discovered a lot of SO answers as well as a blog post (https://codedecoder.wordpress.com/2013/09/23/require-and-load-in-ruby-loaderror-cannot-load-such-file/) that seem to suggest the problem is that the gem is not installed in a directory on the $LOAD_PATH. Here is what I see when I run $LOAD_PATH from IRB:
irb(main):002:0> $LOAD_PATH
=> ["/home/dcox/lib/ruby/site_ruby/2.1.0",
"/home/dcox/lib/ruby/site_ruby/2.1.0/x86_64-linux",
"/home/dcox/lib/ruby/site_ruby", "/home/dcox/lib/ruby/vendor_ruby/2.1.0",
"/home/dcox/lib/ruby/vendor_ruby/2.1.0/x86_64-linux",
"/home/dcox/lib/ruby/vendor_ruby", "/home/dcox/lib/ruby/2.1.0",
"/home/dcox/lib/ruby/2.1.0/x86_64-linux"]
Next I checked to see the location of ruby-mysql:
dcox#analytics1:~/connector$ bundle show ruby-mysql
/data/home/dcox/connector/vendor/bundle/ruby/2.1.0/gems/ruby-mysql-2.9.14
Obviously my connector/vendor/bundle path is not on the $LOAD_PATH. I could add it, but I have a feeling I am missing something simple here because bundler is supposed to work as long as you follow the instructions, right?
Any advice or help is very much appreciated! Thanks!!
If you just want to require this specific gem, require 'mysql' should work (e.g., https://github.com/tmtm/ruby-mysql/blob/master/test/test_mysql.rb#L10).
Your file should call Bundler.setup http://bundler.io/bundler_setup.html
Better yet, if you instead call Bundler.require(:default) it will setup and require all the gems in your Gemfile for you.

How to pick gems from a specific directory

I forked a gem I use a lot in order to code some enhancements on it. I want it to be installed in a subfolder called ~/codebase/ruby, where I keep all my Ruby projects, arranged in subdirectories.
To do that, I built and installed the gem with the following commands:
gem build my_gem.gemspec
gem install mygem-x.x.gem -i./mygem
mygem is installed in ~/codebase/ruby/mygem. I can't get my client code (which is in another directory) to grab mygem from there.
I've tried all of the following without success:
Running ruby with argument -I<path_to_mygem>.
Adding <path_to_mygem> to PATH.
Putting :gempath: <path_to_mygem> into ~/.gemrc.
I know I could put the gem in ~/.gem/ruby/<version> (since it appears in gem env) and that would probably work, but that would break my existing directory structure of Ruby code, forcing me to code in a different directory only for mygem, which is something I want to avoid unless it's the only option.
Thoughts?
Hopefully you are using Bundler to load the required gems. Then you just specify the path to the gem file in your Gemfile:
gem 'my_gem', :path => '~/codebase/ruby/mygem'

Using rspec with a local gem

I am using a local gem (on my machine) with another application that is a command line app.
I have something like this in the gemfile to refer to the local gem:
gem 'mygem', :path => '/Users/devmachine/Projects/mygem'
When I run bundle console I am able to use the gem and all is well. However, whenever I run my test suite (rspec) I get the following message:
ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mygem (LoadError)
I'm confused. Any ideas?
You need to run:
bundle exec rspec
If you are not using the bundle evironment rspec won't know what you put in your Gemfile and just use the Gems it finds installed.

How to contribute to a Ruby Gem

I am trying to contribute to a Ruby gem and I don't understand how to test a local gem without using a globally installed gem.
The gem I want to contribute to is a command line interface gem. I clone the gem into a directory then cd into that directory. However, when I run commands in the terminal when I'm in the cloned project directory it still uses the global gem. I've even run
gem uninstall gemname
then while inside the newly cloned gem directory I redo
gem install gemname.
No matter what changes I make to the gem, I can't see the results or what my contributions are doing because it's always running the global gem.
When I do try to type a command line command that is supposed to interact with the gem while in the cloned gem directory I get:
-bash: ~/.gem/ruby/2.1.0/bin/githubrepo: No such file or directory
I've done a ton of research but I'm just not getting it. Help?
gem install gemname will look for a .gem file in the current directory. If not found it will look for it on the web.
gem install --local /path/to/your/gemname.gem will allow you to target a particular directory. You may need to gem build gemname.gemspec first, so it has your changes.
Instead of doing this, I would write tests in the gem directory itself. It's likely that when running code in there, you can simply require 'gemname' in Ruby to get the gem functionality.
If it's a well-written gem, it should have tests already. They will most likely be in a directory called test or spec. Have a look at these tests and try to carry on in that style to test your changes. This will make your code changes far far more likely to be accepted as a pull request.

Why do I need bundle exec to require this rubygem?

I have a Rails app with some non-Rails-dependent files under `lib/services'. One of these files uses the Domainatrix gem.
require "domainatrix"
class SuggestionParser
# various suggestion parsing methods
end
I have an empty spec for this file under spec/lib.
require "services/suggestion_parser"
describe SuggestionParser do
end
Unfortunately, when I try to run that spec without bundle exec I hit an error:
$: rspec spec/lib/services/suggestion_parser_spec.rb
-> /Users/davidtuite/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:55:in `require': cannot load such file -- domainatrix (LoadError)
Every other spec and gem in my project will run without using bundle exec. Why do I need to prefix this one in order to get it to run?
For convenience, here's a link to the Domainatrix gemspec.
My guess would be that domainatrix is declared using the :path or :git options in the Gemfile, neither of which install the gem in a way that makes it accessible to rubygems.
This could be confirmed if you post the line for domainatrix from the Gemfile.
try running the following commands:
$ rvm get head && rvm reload
$ chmod +x $rvm_path/hooks/after_cd_bundler
$ bundle install --without production --binstubs=./bundler_stubs
This won't solve the specific problem with your gem, but it will take away the necessity to type in bundle exec every time you run your tests if you're using rvm.

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