G. Ruby: sourcing and setting environment varibles

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

3 months ago  /  0 notes