socket: handle npipe close. Fixes #3045

Signed-off-by: Nick Santos <nick.santos@docker.com>

Author: nicks

docker/utils/socket.py

@@ -18,6 +18,11 @@ class SocketError(Exception):
  pass
 
 
+# NpipeSockets have their own error types
+# pywintypes.error: (109, 'ReadFile', 'The pipe has been ended.')
+NPIPE_ENDED = 109
+
+
 def read(socket, n=4096):
  """
  Reads at most n bytes from socket
@@ -37,6 +42,15 @@ def read(socket, n=4096):
  except OSError as e:
  if e.errno not in recoverable_errors:
  raise
+ except Exception as e:
+ is_pipe_ended = (isinstance(socket, NpipeSocket) and
+ len(e.args) > 0 and
+ e.args[0] == NPIPE_ENDED)
+ if is_pipe_ended:
+ # npipes don't support duplex sockets, so we interpret
+ # a PIPE_ENDED error as a close operation (0-length read).
+ return 0
+ raise
 
 
 def read_exactly(socket, n):