required_env_fetcher

In certain situations it makes sense to allow default values of environment variables that are otherwise required. For example, imagine we're precompiling assets as part of CI when we don't have access to some environment variables we require for the app be up and accepting requests, but aren't required for asset compilation. Using this library we can designate it safe to use default values in those situations.

Add this line to your application's Gemfile:

gem "required_env_fetcher"

And then execute:

$ bundle

Or install it yourself as:

$ gem install required_env_fetcher

When you have an environment variable that is required - perhaps with code like:

# in config/application.rb
module MyApp
  class Application < Rails::Application
    config.x.redis_url = ENV.fetch("REDIS_URL")
  end
end

When you run rails assets:precompile you'll always need to have a REDIS_URL set or else loading the application environment will fail. You can update your initializer to do something like:

config.x.redis_url = RequiredEnvFetcher.fetch("REDIS_URL")

Now you can run SKIP_REQUIRED_ENV_VAR_ENFORCEMENT=true rails assets:precompile and so long as none of your assets rely on the redis URL they will be able to compile.

If you need a specific default value (for example, if the value needs to be a valid URL) you can do:

config.x.redis_url = RequiredEnvFetcher.fetch("REDIS_URL", "http://example.com")

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install.

To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org .

Bug reports and pull requests are welcome on GitHub at https://github.com/ezcater/required_env_fetcher-ruby.

The gem is available as open source under the terms of the MIT License.