Handle system interrupts during socket.create_connection

This is in a similar vein to #250, but the root cause of this issue is actually an upstream python issue (http://bugs.python.org/issue20611) which is not fixed in 2.x or <3.5. Python doesn't handle interrupted system calls-- so the applications are responsible for doing so.

This patch simply retries the create_connection call on system call interrupt, while honoring the original timeout request.

Note: although the timeout for `create_tcp_connection` will be honored, if there are interrupts each subsequent call to `create_connection` will have less time to complete.

Author: jacksontj

kazoo/handlers/threading.py

@@ -147,8 +147,8 @@ def select(self, *args, **kwargs):
         timeout = args[3] if len(args) == 4 else None
         # either the time to give up, or None
         end = (time.time() + timeout) if timeout else None
-        while timeout is None or time.time() < end:
-            if timeout:
+        while end is None or time.time() < end:
+            if end is not None:
                 args = list(args)  # make a list, since tuples aren't mutable
                 args[3] = end - time.time()  # set the timeout to the remaining time
             try:
@@ -161,6 +161,8 @@ def select(self, *args, **kwargs):
                 if errnum == errno.EINTR:
                     continue
                 raise
+        # if we hit our timeout, lets return as a timeout
+        return ([], [], [])
 
     def socket(self):
         return utils.create_tcp_socket(socket)

kazoo/handlers/utils.py

@@ -3,6 +3,7 @@
 import errno
 import functools
 import select
+import time
 
 HAS_FNCTL = True
 try:
@@ -182,12 +183,31 @@ def create_tcp_socket(module):
 
 
 def create_tcp_connection(module, address, timeout=None):
+    end = None
     if timeout is None:
         # thanks to create_connection() developers for
         # this ugliness...
-        timeout = module._GLOBAL_DEFAULT_TIMEOUT
+        timeout = module.getdefaulttimeout()
+    if timeout is not None:
+        end = time.time() + timeout
+    sock = None
+
+    while end is None or time.time() < end:
+        try:
+            # if we got a timeout, lets ensure that we decrement the time
+            # otherwise there is no timeout set and we'll call it as such
+            timeout_at = end if end is None else end - time.time()
+            sock = module.create_connection(address, timeout_at)
+            break
+        except Exception as ex:
+            errnum = ex.errno if isinstance(ex, OSError) else ex[0]
+            if errnum == errno.EINTR:
+                continue
+            raise
+
+    if sock is None:
+        raise module.error
 
-    sock = module.create_connection(address, timeout)
     _set_default_tcpsock_options(module, sock)
     return sock