Prettify owncloud log and parses stack traces out of the message

ocformatlog.py

#!/usr/bin/python

import sys
import json

def expand_stack(data, count):

        # detect stack
        message = data['message']
        stack_start = message.find('[{');
        stack_end = message.rfind('}]');
        if stack_start < 0 or stack_end < 0:
                return data

        try:
                stack = json.loads(message[stack_start:stack_end + 2])
                data['message'] = message[0: stack_start] + "(see stack attribute)"
                data['stack'] = stack
        except:
                sys.stderr.write('Could not parse stack on line %i: %s' % (count, message))

        return data

def process_file(f):
        count = 1
        for line in f:
                try:
                        data = json.loads(line)
                        data = expand_stack(data, count)

                        print(json.dumps(data, indent=4))
                except:
                        sys.stderr.write('Could not parse line %i: %s' % (count, line))

                count = count + 1

if len(sys.argv) > 1:
        for file_name in sys.argv[1:]:
                with open(file_name) as f:
                        process_file(f)
else:
        process_file(sys.stdin)