Load bundle dependencies from a global executable - ruby

Good evening,
I did a gem which contains executables which are called globally.
cd my_exec_gem
bundle install --deployment
gem build my_exec.gemspec
gem install my_exec-1.0.gem
my_exec <arguments>
My question is, what is the best way to execute my_exec with the version of the gems which have been installed in the my_exec_gem/vendor directory? How to adapt the gem path at the moment of the execution?
I want to keep the gems of the application isolated from the gems of the systen. (That's why there is --deployment)
Thank you!

The solution seems to be to use --binstubs to generate relative executables which change the ruby environment to run using the specified gems.

Related

Can't install gem using Bundler's Rakefile install task when developing a custom gem

I'm developing a couple of private gems and I think I don't understand correctly the PATH/GEM_PATH and/or Bundler/RVM installation flow, would love if someone could chip in.
I have a repository with two gems (A & B for simplicity sake). I've developed the gems using the scaffolding + following the guidelines provided by this bundler tutorial.
Thanks to the Bundler project I have a few Rakefile tasks like rake build, rake install, rake install:local and rake release. Because of the private nature of these gems I can't release them to RubyGems (and we haven't looked into hosting our rubygems).
My machines are using RVM to manage ruby versions and Bundler version 1.15.1
What I want to do: Assuming a new machine/developer trying out the project, ideally we would cd into each of the subfolders (currently 2, gem A and gem B), run rake install and after that we should have the gems available system wide for the current user.
What is happening: The gems are built and work properly, but they are only available inside the subfolder of each gem i.e. gem A is only available inside the subfolder A and gem B is only available inside subfolder B.
What I've tried: So, after rake build/install/install:local a new .gem file is generated under pkg. I've tried to manually install the "compiled" file using gem install pkg/A.gem, gem install --local pkg/A.gem and gem install --local --user-install pkg/A.gem without success. (there are plenty of SO questions/answers about this)
I believe this has something to do with the PATH variables, but like I said before I don't fully understand the way they are managed. I get the following results from these commands:
# Our gem
> gem which A
/home/ubuntu/.rvm/gems/ruby-2.4.0/gems/A-0.1.8/lib/A.rb
# Pry, available globally
> gem which pry
/home/ubuntu/.rvm/gems/ruby-2.4.0/gems/pry-0.11.1/lib/pry.rb
I've been lost and frustrated for far too long now, any help is appreciated. Also open to hear suggestions of better private gem installation flows :)
Yes, it has something to do with your PATH variables. Your installation seems to be good.
I advise you to first affirm your gems installation path with:
echo $GEM_HOME
The double check your PATH to ensure its present and also confirm that the GEM home is also where the gem got installed into from the rake install
echo $PATH
If not, put it in your path and you should be fine with something like this:
echo PATH=$PATH:$GEM_HOME >> ~/.bashrc
source ~/.bashrc
Build your gem as per that guide you linked. You should end up with a gem file. Distribute this as you see fit (I use rsync/crontab to download newer gem versions but anything goes). User can install the gem as follows:
gem install --user-install /path/to/your/file.gem
This will install the gem in the user's ~/.gem/ruby/<version>/gems/<your-gem-name> directory.
Tried it with an empty gem (foodie, as in that example guide) and it works fine. But if you don't specify the --user-install parameter it will try to install in the system ruby dir (/usr/lib/ruby/gems...)

Is there a preferred tool to edit Gemfiles?

I have a project that depends on Ruby to do something. I need to tell these people to install bundler, create a Gemfile (or update an existing one) and then run bundler install.
To be very clear, these people do not care about Ruby, they don't know what Ruby is and they don't need to know what Ruby is.
Currently my documentation is:
Run this command in terminal:
gem install bundler
Create a new file name Gemfile and add these contents:
source 'https://rubygems.org'
gem 'lightning_sites'
Or if there is already a Gemfile then edit that file and add the line gem 'lightning_sites' at the bottom.
Go back to the terminal and run:
bundle install --path vendor/bundle
I would like to replace the documentation for step 2 and preferable replace it with a command line. Is there a tool that ships by default with Ruby or bundler that accomplishes this?
If you want to avoid bundler you need to force-bundle all your dependencies inside your application. This is only really practical if none of your dependencies have compiled extensions, so if they're all pure Ruby you'll be able to do it.
What you end up doing is a bundle install --path gems/ for example, then package up everything including that directory as a deployable application. You may want to make a script that performs this step and creates a .zip file of the final result for distribution purposes.
This is a heavy-handed approach, so it's best to do this only if absolutely necessary.
You don't have to use Bundler to install gems, Ruby provides the gem command for installing gems individually.
You could simply run: gem install lightning_sites --install-dir lightning_sites and in whatever Ruby script is using the gem, programatically modify your GEM_PATH using Gem.paths before the require statement to include that install directory.

How to put Ruby dependencies in local project folder

Is there a way to put a ruby gem dependencies inside the project root folder ( in vendor directory or something similar ) ?
Run bundle package to cache gems to ./vendor/cache. As the docs point out, bundler will still look for platform-specific gems on rubygems.org. If you have control over the platforms (e.g. same development and deployment platforms), then you can use bundle install --local in addition to bundle package. You may also want to consider a command like bundle install --path vendor/bundle in this case.
Just generate gemfile with proper app dependencies, place it into the root of your app, and use bunlder to keep depencencies up-to-date. Since by default all gem will be placed into system folders, I strongly recommend you to use rvm or rbenv utilities to use for purpose of gem keeping.

Using Bundler in deployment

Pretty fundamental question but I'm trying to understand how best to use Bundler in a deployment situation.
I'm working on a Sinatra application that has about 20 dependent gems. During development, I'm using RVM with a custom gemset for the application, and I run bundle install to update the gemset in accordance with the gemfile.
When it comes to deployment (manually for now, so I can understand how it all works before using a tool like capistrano), I need to do bundle install --development right? This downloads the gems and places them in vendor/bundle.
My question is what else do I need to do? I'm using Unicorn on the server - do I just bundle exec unicorn ... and everything just works? (i.e. bundler finds the vendor directory and uses the gems from there?)
Should unicorn be a vendored gem in the application or a separate 'system' gem on the server that all applications share?
You need --deployment key, not --development: http://gembundler.com/man/bundle-install.1.html#DEPLOYMENT-MODE
On first run bundler creates config in .bundle directory. You can check it by running bundle config or just cat .bundle/config in project's directory. So bundle exec unicorn is enough since bundler knows where gems are installed. On development machine you can also install gems to arbitrary directory using --path key. For more details see manpage for bundle install (link above or bundle help install).

How to use bundler gem binaries in path

I just started using bundler for gem packaging in vendor/. The problem is with certain gems (like rspec and cucumber) that have binaries. The binary path that is under my_app/vendor/gems/ruby/1.8/...cucumber-0.6.2/bin/ is not in my path, therefore when I go to run cucumber i get command cannot be found.
What is the easiest way to execute the bundled gem binaries from within the app rather than adding a large number of folders to my path?
Thanks
Newer version of bundler have an "exec" action. So for cucumber it would be:
bundle exec cucumber
OK, so symlinking was in fact a daft idea. This question did get me thinking though, and I found this: http://litanyagainstfear.com/blog/2009/10/14/gem-bundler-is-the-future/
Bundler will also dump gem executables in your Rails.root/bin directory. This means you can then use bin/rake, for example.
so, from the Rails root, does bin/cucumber work?

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