forked from semk/utils
/
prefork_server.py
184 lines (152 loc) · 5.77 KB
/
prefork_server.py
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#! /usr/bin/env python
#
# A simple python preforking server
#
# @author: Sreejith K
import os
import sys
import socket
import logging
import logging.handlers
import signal
import select
from multiprocessing import Process, Queue
from multiprocessing.reduction import reduce_handle, rebuild_handle
from curses.ascii import ctrl
log = logging.getLogger(__name__)
def setup_logging(path, level):
"""Setup application logging.
"""
log_handler = logging.handlers.RotatingFileHandler(path,
maxBytes=1024*1024,
backupCount=2)
root_logger = logging.getLogger('')
root_logger.setLevel(level)
format = '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
formatter = logging.Formatter(format)
log_handler.setFormatter(formatter)
root_logger.addHandler(log_handler)
class SocketHandler(object):
""" Class for handling incoming socket connections. Used by workers.
"""
def __init__(self, conn_queue):
self.conn_queue = conn_queue
self.request_handler = None
def start_conn_handling(self):
log.debug('Waiting for connection....')
serialized_socket = self.conn_queue.get()
fd = rebuild_handle(serialized_socket)
connection = socket.fromfd(fd, socket.AF_INET, socket.SOCK_STREAM)
log.info('Handling connection: %r' % connection)
if self.request_handler:
self.request_handler(connection)
else:
self.echo_handler(connection)
log.info('Handler: Finished successfully.')
def register_handler(self, handler):
""" Register a callback for handing incoming packets.
"""
if callable(handler):
self.request_handler = handler
else:
raise Exception('%r should be calable' % handler)
def echo_handler(self, connection):
""" Fallback handler incase of no handlers. Echos the requests.
"""
while True:
request = connection.recv(1024)
if 'end' in request:
break
elif request:
connection.send(request)
connection.send(ctrl(']'))
connection.close()
class Server:
""" Socket server which spawns multiple processes that handles new connections accepted
by the server. Uses Apache style preforking.
"""
def __init__(self, addr, procs=5, logdir=os.path.dirname(__file__), loglevel=logging.DEBUG):
""" Initialize the server.
Args:
addr: address inwhich the server to listen on
procs: number of processes it should fork
"""
self.addr = addr
self.procs = procs
self.logdir = logdir
self.loglevel = loglevel
self.proc_pool = {}
self.conn_queue = Queue(self.procs)
def spawn_worker_processes(self):
""" Spawn all the worker processes
"""
for i in range(self.procs):
proc = Worker(self.conn_queue, self.logdir, self.loglevel, name='Worker-%d' %i)
self.proc_pool[proc.name] = proc
proc.start()
log.debug('Process %s started' %proc.name)
def serve_forever(self):
""" Accepts connection from multiple clients.
"""
# register SIGTERM for graceful exit.
def stop_gracefully(signum, frame):
self.stop_server()
signal.signal(signal.SIGINT, stop_gracefully)
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind(self.addr)
log.debug('%s listening on %s' % (type(self).__name__, self.addr))
# start listening on this port
sock.listen(5)
# sock.setblocking(0)
# spawn worker processes
self.spawn_worker_processes()
try:
while True:
# start accepting connections
log.debug('Main: Waiting for incoming connections')
connection, address = sock.accept()
# connection.setblocking(0)
serialized_socket = reduce_handle(connection.fileno())
self.conn_queue.put(serialized_socket)
except socket.error:
log.warning('Interrupt: Stopping main process')
self.stop_server()
finally:
sock.close()
def stop_server(self):
""" Stop the server. Stop all the spawned processes.
"""
log.info('Stopping all worker processes')
for procname, proc in self.proc_pool.iteritems():
if proc.is_alive():
log.info('Stopping process %r' %proc.name)
proc.terminate()
class Worker(Process, SocketHandler):
""" A worker process which handles the client request.
"""
def __init__(self, conn_queue, logdir, loglevel, group=None, target=None, name=None, args=(), kwargs={}):
"""
Args:
sock: shared server socket
"""
self.conn_queue = conn_queue
self.logdir = logdir
self.loglevel = loglevel
self.log = logging.getLogger(name or self.__class__.__name__)
Process.__init__(self, group, target, name, args, kwargs)
SocketHandler.__init__(self, conn_queue)
def run(self):
""" Listen on the new socket given by the server process.
NOTE: This will be a seperate process.
"""
# setup logging for workers
logpath = os.path.join(self.logdir, '%s.log' %self.name)
setup_logging(logpath, self.loglevel)
# start connection handling
while True:
self.start_conn_handling()
if __name__ == '__main__':
logging.basicConfig(level=logging.DEBUG)
server = Server(('localhost', 4545))
server.serve_forever()