Minimalist tool to search and list occurrences of unique exceptions in log files. The exceptions should be logged using the `exception` method.

logr.py

# -*- coding: utf-8 -*-
#
# logr.py is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as 
# published by the Free Software Foundation, either version 3 of the 
# License, or (at your option) any later version.
#
# logr.py is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with logr.py. If not, see <http://www.gnu.org/licenses/>.
#

"""
Minimalist tool to search and list occurrences of unique exceptions in log
files. The exceptions should be logged using the `exception` method.

Usage example::

    python logr.py /path/to/file.log

Sample output::

    Total 115432 line(s)
    Found 3 unique exception(s)...

    IOError 4 occurrence(s) at line(s):
        65227, 81122, 108628, 112905

    RuntimeError 5709 occurrence(s) at line(s):
        3, 16, 29, 42, 55, 68, 82, 95, 130, 143, 156, 169, 182, 195, 208, ...

    IntegrityError 1472 occurrence(s) at line(s):
        108, 247, 322, 382, 545, 594, 693, 715, 763, 796, 946, 982, 1133, 1168,
        1201, ...

"""

import argparse
import re
import textwrap


VERSION = '0.1'

BEGIN_TRACEBACK = re.compile(r'^Traceback \(most recent call last\)\:')

EXCEPTION_MESSAGE = re.compile(r'^(?P<exc_name>\w+)\:(?P<exc_message>.*)')


def logr_list_exceptions(filename, maxlines=0):

    exc_map = {}

    in_traceback = False
    traceback_line = 0
    
    with open(filename, 'rb') as fhandler:
    
        line_num = 0
        
        for line in fhandler:
        
            line_num += 1
            
            if BEGIN_TRACEBACK.match(line):
                in_traceback = True
                traceback_line = line_num
                
            if in_traceback:
                matcher = EXCEPTION_MESSAGE.match(line)
                if matcher is not None:
                    exc_name = matcher.group('exc_name')
                    exc_message = matcher.group('exc_message')
                    
                    if exc_name in exc_map:
                        data = exc_map[exc_name]
                        data['count'] += 1
                        data['lines'].append(traceback_line)
                    else:
                        data = {'count': 1, 'lines': [traceback_line,]}
                        exc_map[exc_name] = data
                    
                    in_traceback = False
                    traceback_line = 0
    
    print 'Total', line_num, 'line(s)'
                    
    if exc_map:
        print 'Found %d unique exception(s)...' % len(exc_map)
        print
        for exc_name, data in exc_map.iteritems():
            print exc_name, data['count'], 'occurrence(s) at line(s):'
            if maxlines > 0:
                lines = data['lines'][:maxlines]
            else:
                lines = data['lines']
            ellipses = ', ...' if len(lines) < len(data['lines']) else ''
            p = ', '.join([str(n) for n in lines]) + ellipses
            for line in textwrap.wrap(p, 75):
                print '   ', line
            print
    else:
        print 'No tracebacks found.'
                 

if __name__ == '__main__':

    version = '%%(prog)s %s' % VERSION

    parser = argparse.ArgumentParser(
            prog='logr',
            description='Search for exceptions in log files')
    
    parser.add_argument('filename', 
            help='The log file to search.')
            
    parser.add_argument('--version', action='version', version=version)
            
    parser.add_argument('-m', '--maxlines', type=int,
            default=15,
            action='store',
            help='Max line numbers to display (defaults to %(default)d, use 0 to display all)')
        
    args = parser.parse_args()

    logr_list_exceptions(args.filename, maxlines=args.maxlines)