handle EMFILE error (too many open files) gracefully while accepting new clients.

--HG--
extra : transplant_source : %F3%93%87q%87a%18Z7%09%F3%87%3C1%25%60%D3%EB%11o

gevent/pywsgi.py

@@ -27,7 +27,7 @@ import time
 import traceback
 
 from urllib import unquote
-from gevent import socket
+from gevent import socket, sleep
 import BaseHTTPServer
 from gevent.pool import Pool
 from gevent.greenlet import Greenlet
@@ -414,6 +414,12 @@ def server(sock, site, log=None, environ=None, max_size=None, max_http_version=D
                 try:
                     client_socket = sock.accept()
                 except socket.error, e:
+                    if e[0] == errno.EMFILE:
+                        # we ran out of file descriptors and will call accept in a busy loop...
+                        # ...which we avoid by sleeping a bit
+                        print "WARNING: pywsgi: out of file descriptors. cannot accept outstanding connections."
+                        sleep(1.0)
+                        continue
                     if e[0] != errno.EPIPE and e[0] != errno.EBADF:
                         raise
                 pool.spawn(serv.process_request, client_socket)