Colorised JSON log watcher with a tag manager.

logger.py

import time
import json

BLACK, RED, GREEN, YELLOW, BLUE, MAGENTA, CYAN, WHITE = range(8)

RESET = '\033[0m'


def termcolor(fg=None, bg=None):
    codes = []
    if fg is not None:
        codes.append('3%d' % fg)
    if bg is not None:
        codes.append('10%d' % bg)
    return '\033[%sm' % ';'.join(codes) if codes else ''


def colorize(message, fg=None, bg=None):
    return termcolor(fg, bg) + message + RESET


file = open('./dipify-auth.log')
while 1:
    where = file.tell()
    line = file.readline()
    if not line:
        time.sleep(1)
        file.seek(where)
    else:
        try:
            line = json.loads(line)
            level = line['level']
            try:
                tag = line['tag']
                if level == 'info':
                    print colorize(tag, fg=BLUE) + ' ' + colorize(level, fg=GREEN) + ' ' + line['message']
                elif level == 'warn':
                    print colorize(tag, fb=BLUE) + ' ' + colorize(level, fg=YELLOW) + ' ' + line['message']
                elif level == 'error':
                    print colorize(tag, fg=BLUE) + ' ' + colorize(level, fg=RED) + ' ' + line['message']
            except KeyError:
                if level == 'info':
                    print colorize(level, fg=GREEN) + ' ' + line['message']
                elif level == 'warn':
                    print colorize(level, fg=YELLOW) + ' ' + line['message']
                elif level == 'error':
                    print colorize(level, fg=RED) + ' ' + line['message']
                pass
        except ValueError:
            pass