testNamedSocketClient.py

#!/usr/bin/env python
# encoding: utf-8
'''
usage:
python testNamedSocketClieht.py reload
python testNamedSocketClieht.py stop
'''
import socket
import sys
import time

server_address = '\x00testNamedSocket'

if len(sys.argv) == 2:
    act = str(sys.argv[1]).lower()
    if act in ['stop', 'reload']:
        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
        print 'connecting to %s' % server_address
        try:
            sock.connect(server_address)
        except socket.error, msg:
            print msg
            sys.exit(1)
        try:
            print 'sending "%s"' % act
            sock.sendall(act)

            amount_received = 0
            amount_expected = len(act)            
            while amount_received < amount_expected:
                data = sock.recv(16)
                amount_received += len(data)
                print 'received "%s"' % data
                time.sleep(1)
        finally:
            print 'closing socket'
            sock.close()
    else:
        print "Unknown command"
        sys.exit(2)
    sys.exit(0)
else:
    print "usage: %s stop|reload" % sys.argv[0]
    sys.exit(2)

testNamedSocketServer.py

#!/usr/bin/env python
# encoding: utf-8

import time
import socket
import errno

'''
Put null character at beginning to open a
"Named Unix Socket", without opening file system path.
Only supported by Linux, not by Mac OSX.
'''
server_address = '\x00testNamedSocket'

class TestService():

    sock = None
    connection = None

    def __init__(self):
        print 'init'
        self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
        self.sock.bind(server_address)
        self.sock.setblocking(0)

        # 1 for only keep 1 message queued on buffer.
        self.sock.listen(1)


    def __del__ (self) :
        print 'del'
        if self.connection:
            self.connection.close()

    def delay_reload(self):
        print 'reloading'
        cnt = 5
        while cnt > 0:
            print '.'
            cnt -= 1
            time.sleep(1)

    def delay_stop(self):
        print 'stopping'
        cnt = 10
        while cnt > 0:
            print '.'
            cnt -= 1
            time.sleep(1)

    def check_socket(self):
        try:
            #sock.setblocking(0) will raise error 11 here. 
            self.connection, client_address = self.sock.accept()
            print 'connection from %s' % client_address
            data = self.connection.recv(16)
            if not data:
                print 'no data from %s' % client_address
                return None
            print 'received "%s"' % data
            act = str(data).lower()
            if act in ['stop', 'reload']:
                return act
            else:
                #echo unsupported acts immediately
                self.connection.sendall(data)
        except socket.error, e:
            if errno.EAGAIN == e.errno:
                return None
            else:
                raise e
        return None

    def run(self):
        while True:
            print '-'
            act = self.check_socket()
            if 'reload' == act:
                self.delay_reload()
                self.connection.sendall(act)
            elif 'stop' == act:
                self.delay_stop()
                self.connection.sendall(act)
                break
            else:
                pass
            time.sleep(2)

if __name__ == '__main__':
    mainThread = TestService()
    mainThread.run()