Use epoll in Python to develop server programs

Python code: Import socket, logging
Import select, errno

Logger = logging. getlogger ("network-server ")

Def initlog ():
Logger. setlevel (logging. Debug)

FH = logging. filehandler ("network-server.log ")
FH. setlevel (logging. Debug)
Ch = logging. streamhandler ()
Ch. setlevel (logging. Error)

Formatter = logging. formatter ("% (asctime) S-% (name) S-% (levelname) S-% (Message) s ")
Ch. setformatter (formatter)
FH. setformatter (formatter)

Logger. addhandler (FH)
Logger. addhandler (CH)

If _ name _ = "_ main __":
Initlog ()

Try:
Listen_fd = socket. socket (socket. af_inet, socket. sock_stream, 0)
Failed t socket. error, MSG:
Logger. Error ("Create a socket failed ")

Try:
Listen_fd.setsockopt (socket. sol_socket, socket. so_reuseaddr, 1)
Failed t socket. error, MSG:
Logger. Error ("setsocketopt error ")

Try:
Listen_fd.bind ('', 2003 ))
Failed t socket. error, MSG:
Logger. Error ("Listen File ID bind IP error ")

Try:
Listen_fd.listen (10)
Failed t socket. error, MSG:
Logger. Error (MSG)

Try:
Epoll_fd = select. epoll ()
Epoll_fd.register (listen_fd.fileno (), select. epollin)
Before t select. error, MSG:
Logger. Error (MSG)

Connections = {}
Addresses = {}
Datalist = {}
While true:
Epoll_list = epoll_fd.poll ()
For FD, events in epoll_list:
If FD = listen_fd.fileno ():
Conn, ADDR = listen_fd.accept ()
Logger. debug ("Accept connection from % s, % d, FD = % d" % (ADDR [0], ADDR [1], conn. fileno ()))
Conn. setblocking (0)
Epoll_fd.register (conn. fileno (), select. epollin | select. epollet)
Connections [conn. fileno ()] = Conn
Addresses [conn. fileno ()] = ADDR
Elif select. epollin & events:
Datas =''
While true:
Try:
Data = Connections [FD]. Recv (10)
If not data and not datas:
Epoll_fd.unregister (FD)
Connections [FD]. Close ()
Logger. debug ("% s, % d Closed" % (addresses [FD] [0], addresses [FD] [1])
Break
Else:
Datas + = Data
Failed t socket. error, MSG:
If msg. errno = errno. eagain:
Logger. debug ("% s receive % s" % (FD, datas ))
Datalist [FD] = datas
Epoll_fd.modify (FD, select. epollet | select. epollout)
Break
Else:
Epoll_fd.unregister (FD)
Connections [FD]. Close ()
Logger. Error (MSG)
Break
Elif select. epollhup & events:
Epoll_fd.unregister (FD)
Connections [FD]. Close ()
Logger. debug ("% s, % d Closed" % (addresses [FD] [0], addresses [FD] [1])
Elif select. epollout & events:
Sendlen = 0
While true:
Sendlen + = Connections [FD]. Send (datalist [FD] [sendlen:])
If sendlen = Len (datalist [FD]):
Break
Epoll_fd.modify (FD, select. epollin | select. epollet)
Else:
Continue

Client Program, Python code:

Import socket
Import time
Import Logging

Logger = logging. getlogger ("network-client ")
Logger. setlevel (logging. Debug)

FH = logging. filehandler ("network-client.log ")
FH. setlevel (logging. Debug)
Ch = logging. streamhandler ()
Ch. setlevel (logging. Error)

Formatter = logging. formatter ("% (asctime) S-% (name) S-% (levelname) S-% (Message) s ")
Ch. setformatter (formatter)
FH. setformatter (formatter)

Logger. addhandler (FH)
Logger. addhandler (CH)

If _ name _ = "_ main __":
Try:
Connfd = socket. socket (socket. af_inet, socket. sock_stream, 0)
Failed t socket. error, MSG:
Logger. Error (MSG)

Try:
Connfd. Connect ("192.168.31.226", 2003 ))
Logger. debug ("connect to network server success ")
Failed t socket. error, MSG:
Logger. Error (MSG)

For I in range (1, 11 ):
Data = "the number is % d" % I
If connfd. Send (data )! = Len (data ):
Logger. Error ("send data to network server failed ")
Break
Readdata = connfd. Recv (1024)
Print readdata
Time. Sleep (1)

Connfd. Close ()

This is a very simple C/S model program. In fact, the process is not much different from the C language, just to learn the basic syntax in Python and the use of the logging, select, and socket modules. The client sends a string, and the server returns the string to the client, which is triggered by the edge used in epoll.

This is an authoritative article about this.
Http://scotdoyle.com/python-epoll-howto.html
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