ANSI graphic codes and Python

I was browsing the Django source code and I saw this function:

def colorize(tex开发者_StackOverflow社区t='', opts=(), **kwargs):
    """
    Returns your text, enclosed in ANSI graphics codes.

    Depends on the keyword arguments 'fg' and 'bg', and the contents of
    the opts tuple/list.

    Returns the RESET code if no parameters are given.

    Valid colors:
    'black', 'red', 'green', 'yellow', 'blue', 'magenta', 'cyan', 'white'

    Valid options:
    'bold'
    'underscore'
    'blink'
    'reverse'
    'conceal'
    'noreset' - string will not be auto-terminated with the RESET code

    Examples:
    colorize('hello', fg='red', bg='blue', opts=('blink',))
    colorize()
    colorize('goodbye', opts=('underscore',))
    print colorize('first line', fg='red', opts=('noreset',))
    print 'this should be red too'
    print colorize('and so should this')
    print 'this should not be red'
    """
    code_list = []
    if text == '' and len(opts) == 1 and opts[0] == 'reset':
        return '\x1b[%sm' % RESET       
    for k, v in kwargs.iteritems(): 
        if k == 'fg':
            code_list.append(foreground[v]) 
        elif k == 'bg':
            code_list.append(background[v]) 
    for o in opts:
        if o in opt_dict:
            code_list.append(opt_dict[o])   
    if 'noreset' not in opts:
        text = text + '\x1b[%sm' % RESET
    return ('\x1b[%sm' % ';'.join(code_list)) + text

I removed it out of the context and placed in another file just to try it, the thing is that it doesn't seem to colour the text I pass it. It might be that I don't understand it correctly but isn't it supposed to just return the text surrounded with ANSI graphics codes which than the terminal will convert to actual colours.

I tried all the given examples of calling it, but it just returned the argument I specified as a text.

I'm using Ubuntu so I think the terminal should support colours.

It's that you have many terms undefined, because it relies on several variables defined outside of the function.

Instead just

import django.utils.termcolors as termcolors
red_hello = termcolors.colorize("Hello", fg='red') # '\x1b[31mHello\x1b[0m'
print red_hello

Or just also copy the first few lines of django/utils/termcolors.py specifically:

color_names = ('black', 'red', 'green', 'yellow', 'blue', 'magenta', 'cyan', 'white')
foreground = dict([(color_names[x], '3%s' % x) for x in range(8)])
background = dict([(color_names[x], '4%s' % x) for x in range(8)])
RESET = '0'

def colorize( ... ):
    ...
print colorize("Hello", fg='red') # '\x1b[31mHello\x1b[0m'

Also note:

>>> from django.utils.termcolors import colorize
>>> red_hello = colorize("Hello", fg="red")
>>> red_hello # by not printing; it will not appear red; special characters are escaped
'\x1b[31mHello\x1b[0m'
>>> print red_hello # by print it will appear red; special characters are not escaped
Hello