make mozlog human readable

demozlog.py

!/usr/bin/env python

"""
This de-mozlogifies a log line by line to make it readable by humans. To use:

tail -f /path/to/mozlog.log | python demozlog.py

"""

import datetime
import json
import sys


SEVERITY = {
    2: 'CRITICAL',
    3: 'ERROR',
    4: 'WARNING',
    6: 'INFO',
    7: 'DEBUG',
}


def ts_to_str(ts):
    ts = float(ts) / 1e9
    return datetime.datetime.fromtimestamp(ts).isoformat()


while True:
    line = sys.stdin.readline()
    try:
        data = json.loads(line)
        print('%s  %s  %s: %s' % (ts_to_str(data['Timestamp']), SEVERITY[data['Severity']], data['Type'], data['Fields']['msg']))
        if data['Fields'].get('error'):
            print('%s %s' % (data['Fields']['error'], data['Fields']['traceback']))
    except Exception:
        if line:
            print('sputter %s' % line)