Sourcing and Setting Environment Variables in Ruby

I was looking for a simple way to source and set a bash environment variable from a file, in this specific instance, I can't be 100% sure that the any steps I take to ensure that the file itself is sourced on the host before Rails is started, nor can I impact the format of the file itself (e.g. changing it to YAML).

Here are the best options I've found.

File.readline

This is not the method I used, but it's useful. I would use this if I needed to set multiple variables from the source file.

# assumes the following format
#  NAME1=value1
#  NAME2=value2
File.readline "/my/rc_file" do |line|
    key, value = line.split "="
    ENV[key] = value
end

... or ...

# assumes the following format
#  export NAME1=value1
#  export NAME2=value2
#
# Note: I really don't like this for any situation 
# other then perhaps stand-alone scripting.
File.readline "/my/rc_file" do |line|
    line.gsub(/export /, "")
    key, value = line.split "="
    ENV[key] = value
end

Pure bash via backticks

This is the method I chose, as I only needed to set a single variable and knew the name of it. Additionally, I did it this way to ensure that the variable remained "nil" if the variable wasn't set for whatever reason.

unless ENV['KEY']
    my_key = `source /my/rc_file 2> /dev/null && echo $KEY`.chomp
    ENV['KEY'] = my_key unless my_key.empty? 
end

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