import logging
from logging.handlers import MemoryHandler
from collections import deque

logs = None
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')

def get_logs():
    return '\n'.join([formatter.format(x) for x in logs])

def setup_logger(capacity=300):
    global logs
    if logs: return

    # Setup default global logger
    logger = logging.getLogger()
    logger.setLevel(logging.INFO)
    logger.addHandler(logging.StreamHandler())

    # Create a memory handler with a deque as its buffer
    logs = deque(maxlen=capacity)
    memory_handler = MemoryHandler(capacity, flushLevel=logging.INFO)
    memory_handler.buffer = logs
    memory_handler.setFormatter(formatter)
    logger.addHandler(memory_handler)