Pyro: memoize socket.gethost* calls

README

@@ -39,7 +39,8 @@ Acknowledgement for non-cylc Work:
     Unmodified external software library released under the LGPL license.
     See [metomi/isodatetime](https://github.com/metomi/isodatetime).
   * lib/Pyro/:
-    Unmodified external software library released under the MIT license.
+    External software library released under the MIT license.
+    Minor modification based on version 3.16.
     See [Pyro 3.16](https://pypi.python.org/pypi/Pyro).
 
 Licences for non-cylc work included in this distribution can be found in the

lib/Pyro/ext/remote.py

@@ -21,6 +21,7 @@
 import Pyro.naming
 import Pyro.core
 import Pyro.util
+from Pyro.util import HostUtil
 
 from Pyro.protocol import ProtocolError
 
@@ -103,7 +104,7 @@ def unregister_objects():
 
 def host_ipaddr(interface = None):
 	if sys.platform == "win32":
-		return socket.gethostbyname(socket.gethostname())
+		return HostUtil.inst().gethostbyname()
 
 	cmd = "/sbin/ifconfig"
 	if interface:
@@ -135,7 +136,7 @@ def host_ipaddr(interface = None):
 
 	fd.close()
 
-	return this_host or socket.gethostbyname(socket.gethostname())
+	return this_host or HostUtil.inst().gethostbyname()
 
 def find_nameserver(hostname = None, portnum = None):
 	if hostname and hostname.find('://') > 0:
@@ -151,7 +152,7 @@ def find_nameserver(hostname = None, portnum = None):
 			ns = locator.getNS(host = hostname, port = portnum)
 
 		except (Pyro.core.PyroError, socket.error), x:
-			localhost = socket.gethostbyname('localhost')
+			localhost = HostUtil.inst().gethostbyname('localhost')
 			if verbose:
 				print "Error:", x
 				print """

lib/Pyro/naming.py

@@ -11,6 +11,7 @@
 import sys, os, socket, time, traceback, errno
 import dircache, shutil, SocketServer
 import Pyro.constants, Pyro.core, Pyro.errors, Pyro.protocol, Pyro.util
+from Pyro.util import HostUtil
 if Pyro.util.supports_multithreading():
 	import threading
 
@@ -119,7 +120,7 @@ def __sendSysCommand(self,request,host=None,port=None,trace=0,logerrors=1,role=P
 				raise Pyro.errors.PyroError(msg)
 			if bcaddr:
 				try:
-					socket.gethostbyname(bcaddr)
+					HostUtil.inst().gethostbyname(bcaddr)
 				except socket.error:
 					msg="invalid broadcast address '%s'" % bcaddr
 					if trace:

lib/Pyro/protocol.py

@@ -17,6 +17,7 @@
 	import md5
 	md5=md5.md5
 import Pyro.constants, Pyro.util
+from Pyro.util import HostUtil
 
 from Pyro.errors import *
 from Pyro.errors import _InternalNoModuleError
@@ -57,17 +58,17 @@ class SSLError(Exception): pass
 def getHostname(ip=None):
 	try:
 		if ip:
-			(hn,alias,ips) = socket.gethostbyaddr(ip)
+			hn,alias, ips = HostUtil.inst().gethostbyaddr(ip)
 			return hn
 		else:
-			return socket.gethostname()
+			return HostUtil.inst().gethostname()
 	except socket.error:
 		return None
 
 #------ Get IP address (return None on error)
 def getIPAddress(host=None):
 	try:
-		return socket.gethostbyname(host or getHostname())
+		return HostUtil.inst().gethostbyname(host or getHostname())
 	except socket.error:
 		return None
 
@@ -1041,7 +1042,7 @@ def __init__(self, port, host='', threaded=_has_threading,prtcol='PYRO'):
 		self.connections = []  # connection threads
 		self.initTLS=lambda tls: None  # default do-nothing func
 		if host:
-			socket.gethostbyname(host)  # validate hostname
+			HostUtil.inst().gethostbyname(host)  # validate hostname
 		try:
 			if prtcol=='PYROSSL':
 				try:

lib/Pyro/util.py

@@ -48,6 +48,45 @@ def clear(self): self.flag=0
 	def wait(self,timeout=None):
 		raise RuntimeError("cannot wait in non-threaded environment")
 
+
+class HostUtil(object):
+    """Wrap and memoize socket.gethost* results."""
+
+    _INST = None
+
+    @classmethod
+    def inst(cls, reset=False):
+        """Return the singleton of this class."""
+        if cls._INST is None or reset:
+            cls._INST = cls()
+        return cls._INST
+
+    def __init__(self):
+        self.hostname = None
+        self.hostbyname = {}
+        self.hostbyaddr = {}
+
+    def gethostbyaddr(self, addr):
+        """Wrap and memoize socket.gethostbyaddr."""
+        if addr not in self.hostbyaddr:
+            self.hostbyaddr[addr] = socket.gethostbyaddr(addr)
+        return self.hostbyaddr[addr]
+
+    def gethostbyname(self, name=None):
+        """Wrap and memoize socket.gethostbyname."""
+        if name is None:
+            name = self.gethostname()
+        if name not in self.hostbyname:
+            self.hostbyname[name] = socket.gethostbyname(name)
+        return self.hostbyname[name]
+
+    def gethostname(self):
+        """Wrap and memoize socket.gethostname."""
+        if self.hostname is None:
+            self.hostname = socket.gethostname()
+        return self.hostname
+
+
 def getEventObject():
 	if supports_multithreading():
 		from threading import Event
@@ -333,7 +372,7 @@ def getGUID():
 		# For A: should use the machine's MAC ethernet address, but there is no
 		# portable way to get it... use the IP address + 2 bytes process id.
 		try:
-			ip=socket.gethostbyname(socket.gethostname())
+			ip = HostUtil.inst().gethostbyname()
 			networkAddrStr=binascii.hexlify(socket.inet_aton(ip))+"%04x" % os.getpid()
 		except socket.error:
 			# can't get IP address... use another value, like our Python id() and PID

lib/Pyro/wxnsc.py

@@ -27,7 +27,7 @@
 #
 # Standard modules
 #
-import os, sys, socket
+import os, sys
 import traceback, cStringIO
 
 #
@@ -42,6 +42,7 @@
 from Pyro.errors import NamingError, ConnectionClosedError,\
                         ConnectionDeniedError
 import Pyro.core
+from Pyro.util import HostUtil
 
 #----------------------------------------------------------------------#
 # Module constants
@@ -652,7 +653,7 @@ def _setNSData(self):
       Updates the display of current Name Server information.
       """
       try:
-         ns_name, t, ns_ip = socket.gethostbyaddr(self.nsHost)
+         ns_name, t, ns_ip = HostUtil.inst().gethostbyaddr(self.nsHost)
          ns_ip = ns_ip[0]
       except:
          ns_name, ns_ip = self.nsHost, ''