thread_grouped_logging.py

import logging
import time
import threading
from collections import defaultdict


def log_info(message,logger):
    logger.info(message)
    time.sleep(3)
    logger.info(message)


class TailLogHandler(logging.Handler):

    def __init__(self, log_queue):
        logging.Handler.__init__(self)
        self.log_queue = log_queue

    def emit(self, record):
        thread_name = threading.Thread.getName(threading.current_thread())
        self.log_queue[thread_name].append(self.format(record))


class TailoredLogger(object):

    def __init__(self):
        self._log_queue = defaultdict(list)
        self._log_handler = TailLogHandler(self._log_queue)

    def contents(self,thread):
        return self._log_queue[thread]
    
    def get_threads(self):
        return self._log_queue.keys()
    
    @property
    def log_handler(self):
        return self._log_handler



logger = logging.getLogger(__name__)

tail = TailoredLogger()

formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')

log_handler = tail.log_handler
log_handler.setFormatter(formatter)
logger.addHandler(log_handler)
logger.setLevel(logging.INFO)


threads = []
for i in range(10):
    t = threading.Thread(
        target=log_info, args=("Hello from thread {}".format(i),logger)
    )
    
    threads.append(t)

# Start the threads
for t in threads:
    t.start()

# Wait for the threads to complete
for t in threads:
    t.join()

for thread in tail.get_threads():
    print("\n".join(tail.contents(thread)))