Setting environment variables in a ruby gem

Question

I'm making a simple RubyGem (no Rails) that uses the Mail gem to send out emails from the CLI. In order to configure the mailer I have to supply a password, which I want to store secretly in an ENV variable or something so that it's not public.

I tried to use Dotenv but found that after installing my newly built gem, it only works when I am running it from the project directory. If I try to run the gem from my home directory, the ENV variable is no longer accessible.

In the gemspec spec.files I made sure to include the .env file.

I don't think I'm understanding the actual process for loading variables into a RubyGem.

Answer 1

The fact that the correct behaviour depends on the current working directory at time of invocation suggests that this is a relative path issue. Since it works at least some of the time, your gemspec setup must be correct.

I haven't used Dotenv myself, but looking through the source suggests that giving an explicit path to your env file through Dotenv.load is the way forward.

Try using Dotenv.load(File.expand_path("../.env", __FILE__)) from bin/myapp, or adapt to your directory structure (assuming the env file is in Gem root).

A similar approach is discussed in this tutorial.

Answer 2

Dotenv is a tool used to ship your environment variables around to different execution environments (e.g. development, staging, production, etc.), and it's not really intended for usage within a gem. The reason this only works when you run the script within the project directory is because that's how Dotenv is designed to work.

Try using the ENV global variable instead (which just loads the environment variables from your machine), and instructing your users to set the environment on their own, rather than having a .env file within the gem. That should allow running the script from anywhere, assuming there are no other issues.