Support printing environment variables in --help

[buremba]

It would be great if we can print the environment variables for arguments when --help is enabled. Ideally, it can be configurable in CliktHelpFormatter.

[ajalt]

Can you give me an example of the output you're asking for?

[buremba]

Here is how it looks like:

Usage: commands serve [OPTIONS]

  Spins up an HTTP server serving your datasets

Options:
  --profile TEXT                   Some description.

If we have PROFILE environment variable attached to the argument, maybe something like this would make sense:

Usage: commands serve [OPTIONS]

  Spins up an HTTP server serving your datasets

Options:
  --profile TEXT                   Some description.          PROFILE

or maybe this one:

Usage: commands serve [OPTIONS]

  Spins up an HTTP server serving your datasets

Options:
  --profile TEXT                   Some description.     
  PROFILE

What do you think?

[ajalt]

Are you asking for the values of the environment variables, or the names of the variables i.e. the values you pass to envvar when creating the option?

[buremba]

@ajalt , not sure if I understood the question. The feature request is for printing environment variables activated via envvar when we run program --help.
If you're asking whether we should print the value of the environment variables in --help, that would be a great addition as well.

[ajalt]

I'm not sure what you mean by activated.

If you have an option val opt by option(envvar="FOO"), are you asking for FOO to show up in the help output?

[buremba]

That's correct. :)