How do I change the color of my Terminal.App when I log into my production remote on Heroku?

Question

I remember there was an article, or a few, going around about how the author changes the color of the terminal from green (for development) to red (for production) based on the SSH address.

But I am not sure how to replicate that with Heroku console.

Ideally, I would like for it to be say blue, when I do heroku console --remote staging and then red, when I do heroku console --remote production.

Any suggestions anyone ?

Answer 1

In any file that is loaded as part of the production environment (say, config/environments/production.rb), you can put:

if defined? IRB
  # whew!
  conf = IRB.conf[:PROMPT][IRB.conf[:PROMPT_MODE]]
  red = "\033[0;31m"
  reset = "\033[0m"
  conf[:PROMPT_S] = "#{red}>> #{reset}" # regular prompt
end

The crazy escape characters are ANSI color codes. The "\033" is an escape character, and the rest is a code for a particular color or effect. You can find a list of other colors and effects here. That IRB.conf hash is a global conf for IRB. You may want to set a few other keys on it - they're documented here.

If you're not using Rails (and hence don't necessarily have an environment file), you can always check the current environment by using ENV['RACK_ENV'], which should be set to 'production' on Heroku.

Answer 2

I do this by using the Marco Polo gem https://github.com/arches/marco-polo

You can then change your console prompt by setting the heroku config variable MARCO_POLO_APP_NAME. You can take advantage of escape codes to change the color. In my case, I set the production prompt to be white on a magenta background (hard to miss) using this control sequence for the value of MARCO_POLO_APP_NAME

[ESC][105;97;1mPRODUCTION[ESC][0m

Unfortunately, Stack Overflow won't let me post the escape character itself. You'll have to use Notepad++ and run a Regexp search and replace to replace [ESC] above with \x1B. Then you can copy and paste into the value of MARCO_POLO_APP_NAME in the Heroku console. I couldn't manage to set it at the command line.