-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Debugging a strange problem today, I got the following result:
Sockets open by stdlib libraries are open without the "keepalive" option, so the system default is used. The system default under linux is "no keepalive". So, if you are using a URLlib connection, POP3 connection, IMAP connection, etc., any stdlib that internally creates a socket, and your server goes away suddendly (you lose network connectivity, by instance), the library will wait FOREVER for the server. The client can't detect that the server is not longer available. The "keepalive" option will send a probe packed every X minutes of inactivity, to check if the other side is still alive, even if the connection is idle. The issue is bad, but the solution is simple enough. Options: 1. All "client" libraries should create sockets with the "KEEPALIVE" option. 2. Modify the socket C module to create all sockets as "Keepalive" by default. 3. To have a global variable in the socket module to change the default for future sockets. Something like current "socket.setdefaulttimeout()". The default should be "keepalive". 4. Modify client libraries to accept a new optional socket-like object as an optional parameter. This would allow things like transparent compression or encryption, or to replace the socket connection by anything else (read/write to shared memory or database, for example). This is an issue in Linux because by default the sockets are not "keepalive". In other Unix systems, the default is "keepalive". I don't know about MS Windows. What do you think?. The solution seems trivial, after deciding the right way to go. PS: "socket.setdefaulttimeout()" is not enough, because it could shutdown a perfectly functional connection, just because it was idle for too long. - -- Jesus Cea Avion _/_/ _/_/_/ _/_/_/ j...@jcea.es - http://www.jcea.es/ _/_/ _/_/ _/_/ _/_/ _/_/ jabber / xmpp:j...@jabber.org _/_/ _/_/ _/_/_/_/_/ . _/_/ _/_/ _/_/ _/_/ _/_/ "Things are not so easy" _/_/ _/_/ _/_/ _/_/ _/_/ _/_/ "My name is Dump, Core Dump" _/_/_/ _/_/_/ _/_/ _/_/ "El amor es poner tu felicidad en la felicidad de otro" - Leibniz -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQCVAwUBS8OV2Zlgi5GaxT1NAQIJhwP8CH+gij4KfrJ1oHW5ys4PboH5Ru0pgdly Wbsza0+uj3p68P1vDnC9jIr7j+fI3ql3DOc8zUoIKGpJoaWVspbv3c4vI4ATLHo+ J6I18dpkviRT8/sT/69vMvghaGndiO0Sks/S4tDjhNstYH7oGjWxi63cKqtGPY/p WSTLpwrd4SY= =vkT4 -----END PGP SIGNATURE----- _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
