Quick tip here - you can write your Gemfile dependencies within your application file!
As a ruby/rails developer I’m used to Gemfile’s where I can specify which gems and versions I’m using within my project. But there can be cases when your application is so small that it would be cool if all the code could be placed in one file, not having two separate files: application & Gemfile.
1 2 3 4 5 6 7 8 9 10 #!/usr/bin/env ruby require 'bundler/inline' gemfile(true) do source 'https://rubygems.org' gem 'rainbow', '~> 2.2.1' end puts Rainbow("hola!").red.bright.underline
After that we can run our application with
ruby coloriz.rb. But probably it would be smarter to add execution permissions
and run it like normal unix application.
1 2 3 4 5 6 7 8 9 10 11 # set execute permissions chmod +x coloriz.rb # run our example application ./coloriz.rb Fetching gem metadata from https://rubygems.org/.. Fetching version metadata from https://rubygems.org/. Resolving dependencies... Installing rainbow 2.2.1 with native extensions Using bundler 1.14.5 hola!
And that’s it! Now your Gemfile is inline with your application code. When user will try to run application it will automatically check where all dependencies are in place and in case if not - install them.
At this momen I see only two caveats:
- every time when user will run application it will take some time to check dependencies
Gemfile.lockfile will be created - my suggestion would be to specify version number pretty close as with updates it could break your application
In case if there is no need for gem auto-install you can set
install parameter to
false or remove it from
#gemfile method call.
In such case it will only check for necessary gems in your system and if there will not be neede version you will receive an error, but overall
application start will be much more faster.
Could not find gem 'rainbow (~> 2.2.1)' in any of the gem sources listed in your Gemfile or available on this machine. (Bundler::GemNotFound)
Get source code:
git clone email@example.com:janis-vitols/examples.git --branch ruby/bundler/gemfile-inside-application --single-branch coloriz