diff --git a/Doc/library/socketserver.rst b/Doc/library/socketserver.rst index c900ea71581..2c85c863a25 100644 --- a/Doc/library/socketserver.rst +++ b/Doc/library/socketserver.rst @@ -44,7 +44,7 @@ to behave autonomously; the default is :const:`False`, meaning that Python will not exit until all threads created by :class:`ThreadingMixIn` have exited. Server classes have the same external methods and attributes, no matter what -network protocol they use: +network protocol they use. Server Creation Notes @@ -193,6 +193,13 @@ The server classes support the following class variables: The type of socket used by the server; :const:`socket.SOCK_STREAM` and :const:`socket.SOCK_DGRAM` are two possible values. +.. data:: timeout + + Timeout duration, measured in seconds, or :const:`None` if no timeout is desired. + If no incoming requests are received within the timeout period, + the :meth:`handle_timeout` method is called and then the server resumes waiting for + requests. + There are various server methods that can be overridden by subclasses of base server classes like :class:`TCPServer`; these methods aren't useful to external users of the server object. @@ -220,6 +227,13 @@ users of the server object. method raises an exception. The default action is to print the traceback to standard output and continue handling further requests. +.. function:: handle_timeout() + + This function is called when the :attr:`timeout` attribute has been set to a + value other than :const:`None` and the timeout period has passed with no + requests being received. The default action for forking servers is + to collect the status of any child processes that have exited, while + in threading servers this method does nothing. .. function:: process_request(request, client_address) diff --git a/Lib/SocketServer.py b/Lib/SocketServer.py index 5506aa5b8ea..2eed9144921 100644 --- a/Lib/SocketServer.py +++ b/Lib/SocketServer.py @@ -158,6 +158,7 @@ class BaseServer: - server_bind() - server_activate() - get_request() -> request, client_address + - handle_timeout() - verify_request(request, client_address) - server_close() - process_request(request, client_address) @@ -171,6 +172,7 @@ class BaseServer: Class variables that may be overridden by derived classes or instances: + - timeout - address_family - socket_type - allow_reuse_address @@ -182,6 +184,8 @@ class BaseServer: """ + timeout = None + def __init__(self, server_address, RequestHandlerClass): """Constructor. May be extended, do not override.""" self.server_address = server_address @@ -204,8 +208,9 @@ class BaseServer: # finishing a request is fairly arbitrary. Remember: # # - handle_request() is the top-level call. It calls - # get_request(), verify_request() and process_request() - # - get_request() is different for stream or datagram sockets + # await_request(), verify_request() and process_request() + # - get_request(), called by await_request(), is different for + # stream or datagram sockets # - process_request() is the place that may fork a new process # or create a new thread to finish the request # - finish_request() instantiates the request handler class; @@ -214,7 +219,7 @@ class BaseServer: def handle_request(self): """Handle one request, possibly blocking.""" try: - request, client_address = self.get_request() + request, client_address = self.await_request() except socket.error: return if self.verify_request(request, client_address): @@ -224,6 +229,28 @@ class BaseServer: self.handle_error(request, client_address) self.close_request(request) + def await_request(self): + """Call get_request or handle_timeout, observing self.timeout. + + Returns value from get_request() or raises socket.timeout exception if + timeout was exceeded. + """ + if self.timeout is not None: + # If timeout == 0, you're responsible for your own fd magic. + import select + fd_sets = select.select([self], [], [], self.timeout) + if not fd_sets[0]: + self.handle_timeout() + raise socket.timeout("Listening timed out") + return self.get_request() + + def handle_timeout(self): + """Called if no new request arrives within self.timeout. + + Overridden by ForkingMixIn. + """ + pass + def verify_request(self, request, client_address): """Verify the request. May be overridden. @@ -289,6 +316,7 @@ class TCPServer(BaseServer): - server_bind() - server_activate() - get_request() -> request, client_address + - handle_timeout() - verify_request(request, client_address) - process_request(request, client_address) - close_request(request) @@ -301,6 +329,7 @@ class TCPServer(BaseServer): Class variables that may be overridden by derived classes or instances: + - timeout - address_family - socket_type - request_queue_size (only for stream sockets) @@ -405,11 +434,12 @@ class ForkingMixIn: """Mix-in class to handle each request in a new process.""" + timeout = 300 active_children = None max_children = 40 def collect_children(self): - """Internal routine to wait for died children.""" + """Internal routine to wait for children that have exited.""" while self.active_children: if len(self.active_children) < self.max_children: options = os.WNOHANG @@ -424,6 +454,13 @@ class ForkingMixIn: if not pid: break self.active_children.remove(pid) + def handle_timeout(self): + """Wait for zombies after self.timeout seconds of inactivity. + + May be extended, do not override. + """ + self.collect_children() + def process_request(self, request, client_address): """Fork a new subprocess to process the request.""" self.collect_children() diff --git a/Misc/ACKS b/Misc/ACKS index 2ae4528b0ac..cf65424e4ac 100644 --- a/Misc/ACKS +++ b/Misc/ACKS @@ -521,6 +521,7 @@ Martijn Pieters François Pinard Zach Pincus Michael Piotrowski +Michael Pomraning Iustin Pop John Popplewell Amrit Prem diff --git a/Misc/NEWS b/Misc/NEWS index 35d96344be8..9e25b966962 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -704,6 +704,9 @@ Library be equal to calling getsockname() on the server's socket. Fixed by patch #1545011. +- Patch #742598: Add .timeout attribute to SocketServer that calls + .handle_timeout() when no requests are received. + - Bug #1651235: When a tuple was passed to a ctypes function call, Python would crash instead of raising an error.