loghandler.py

import time
import logging
import pprint
import random
from threading import Thread, Event

class lastPerThread(logging.Handler):
    """
    A log handler which keeps the last log message availble per thread
    """
    def __init__(self):
        """
        Initialize the handler, seutp our dict to hold messages
        """
        logging.Handler.__init__(self)
        self.lastMessages = {}
        self.level = logging.DEBUG


    def flush(self):
        """
        no-op
        """


    def emit(self, record):
        """
        Keep the lastMessage list up-to-date
        """
        try:
            self.lastMessages[record.thread] = record
        except (KeyboardInterrupt, SystemExit):
            raise
        except:
            self.handleError(record)


    def current(self):
        """
        Return all the latest logs per thread
        """
        return self.lastMessages

def logloop():
    while True:
        time.sleep(2)
        log.info('sleepy thread! ' + str(random.getrandbits(4)))

def logoutputter(handler):
    while True:
        time.sleep(5)
        logs = handler.current()
        for i, msg in logs.iteritems():
            print handler.format(msg)


logging.basicConfig(format='%(asctime)s [%(threadName)16s][%(module)14s][%(levelname)8s] %(message)s')
log = logging.getLogger()
log.setLevel(logging.DEBUG)

def main():

    handler = lastPerThread()
    handler.setFormatter(logging.Formatter('    %(asctime)s [%(threadName)16s][%(module)14s][%(levelname)8s] %(message)s'))
    log.addHandler(handler)

    t = Thread(target=logoutputter, name='logoutputter', args=(handler,))
    t.daemon = True
    t.start()

    t = Thread(target=logloop, name='logloop')
    t.daemon = True
    t.start()

    time.sleep(2)

    t = Thread(target=logloop, name='logloop2')
    t.daemon = True
    t.start()

    while True:
        time.sleep(2)
        log.info('sleepy main!')

if __name__ == '__main__':
    main()