Added server proxy and session manager for Xen-API clients.

Signed-off-by: Ewan Mellor <ewan@xensource.com>

tools/python/xen/xm/XenAPI.py

@@ -0,0 +1,132 @@
+#============================================================================
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of version 2.1 of the GNU Lesser General Public
+# License as published by the Free Software Foundation.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#============================================================================
+# Copyright (C) 2006 XenSource Inc.
+#============================================================================
+#
+# Parts of this file are based upon xmlrpclib.py, the XML-RPC client
+# interface included in the Python distribution.
+#
+# Copyright (c) 1999-2002 by Secret Labs AB
+# Copyright (c) 1999-2002 by Fredrik Lundh
+#
+# By obtaining, using, and/or copying this software and/or its
+# associated documentation, you agree that you have read, understood,
+# and will comply with the following terms and conditions:
+#
+# Permission to use, copy, modify, and distribute this software and
+# its associated documentation for any purpose and without fee is
+# hereby granted, provided that the above copyright notice appears in
+# all copies, and that both that copyright notice and this permission
+# notice appear in supporting documentation, and that the name of
+# Secret Labs AB or the author not be used in advertising or publicity
+# pertaining to distribution of the software without specific, written
+# prior permission.
+#
+# SECRET LABS AB AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD
+# TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANT-
+# ABILITY AND FITNESS.  IN NO EVENT SHALL SECRET LABS AB OR THE AUTHOR
+# BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY
+# DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+# WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+# ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+# OF THIS SOFTWARE.
+# --------------------------------------------------------------------
+
+import xmlrpclib
+
+import xen.util.xmlrpclib2
+
+
+class Failure(Exception):
+    def __init__(self, details):
+        self.details = details
+
+    def __str__(self):
+        return "Xen-API failure: %s" % str(self.details)
+
+
+class Session(xen.util.xmlrpclib2.ServerProxy):
+    """A server proxy and session manager for communicating with Xend using
+    the Xen-API.
+
+    Example:
+
+    session = Session('http://localhost:9363/')
+    session.login_with_password('me', 'mypassword')
+    session.xenapi.VM.start(vm_uuid)
+    session.xenapi.session.logout()
+
+    For now, this class also supports the legacy XML-RPC API, using
+    session.xend.domain('Domain-0') and similar.  This support will disappear
+    once there is a working Xen-API replacement for every call in the legacy
+    API.
+    """
+
+    def __init__(self, uri, transport=None, encoding=None, verbose=0,
+                 allow_none=1):
+        xen.util.xmlrpclib2.ServerProxy.__init__(self, uri, transport,
+                                                 encoding, verbose,
+                                                 allow_none)
+        self._session = None
+
+
+    def _xen_request(self, methodname, params):
+        full_params = (self._session,) + params
+        return _parse_result(getattr(self, methodname)(*full_params))
+
+
+    def _login(self, method, username, password):
+        self._session = _parse_result(
+            getattr(self, 'session.%s' % method)(username, password))
+
+
+    def __getattr__(self, name):
+        if name == 'xenapi':
+            return _Dispatcher(self._xen_request, None)
+        elif name.startswith('login'):
+            return lambda u, p: self._login(name, u, p)
+        else:
+            return xen.util.xmlrpclib2.ServerProxy.__getattr__(self, name)
+
+
+def _parse_result(result):
+    if 'Status' not in result:
+        raise xmlrpclib.Fault(500, 'Missing Status in response from server')
+    if result['Status'] == 'Success':
+        if 'Value' in result:
+            return result['Value']
+        else:
+            raise xmlrpclib.Fault(500,
+                                  'Missing Value in response from server')
+    else:
+        if 'ErrorDescription' in result:
+            raise Failure(result['ErrorDescription'])
+        else:
+            raise xmlrpclib.Fault(
+                500, 'Missing ErrorDescription in response from server')
+
+
+# Based upon _Method from xmlrpclib.
+class _Dispatcher:
+    def __init__(self, send, name):
+        self.__send = send
+        self.__name = name
+    def __getattr__(self, name):
+        if self.__name is None:
+            return _Dispatcher(self.__send, name)
+        else:
+            return _Dispatcher(self.__send, "%s.%s" % (self.__name, name))
+    def __call__(self, *args):
+        return self.__send(self.__name, args)