Add new base class and instance store for new autoplugged api classes

signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>

tools/python/xen/xend/XendAPIStore.py

@@ -0,0 +1,59 @@
+#============================================================================
+# 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) 2007 Tom Wilkie <tom.wilkie@gmail.com>
+#============================================================================
+"""
+This is a place to put instances of XenAPI objects,
+instead of just holding them in arbitrary places.
+
+All objects which subclass XendBase should use this
+mechanism.
+
+You must register both the uuid and type, and get objects
+by type, to ensure safety
+"""
+
+__classes = {}
+
+def register(uuid, type, inst):
+    __classes[(uuid, type)] = inst
+    return inst
+
+def deregister(uuid, type):
+    old = get(uuid, type)
+    del __classes[(uuid, type)]
+    return old
+
+def get(uuid, type):
+    """
+    Get the instances by uuid and type
+    """
+    return __classes.get((uuid, type), None)
+
+def get_all(all_type):
+    """
+    Get all instances by type
+    """
+    return [inst
+            for ((uuid, t), inst) in __classes.items()
+            if t == all_type]        
+
+def get_all_uuid(all_type):
+    """
+    Get all uuids by type
+    """
+    return [uuid
+            for (uuid, t) in __classes.keys()
+            if t == all_type]

tools/python/xen/xend/XendBase.py

@@ -0,0 +1,123 @@
+#!/usr/bin/python
+#============================================================================
+# 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) 2007 Tom Wilkie <tom.wilkie@gmail.com>
+#============================================================================
+"""
+Base class for all XenAPI classes
+"""
+
+from xen.xend.XendError import *
+from xen.xend import XendAPIStore
+
+class XendBase:
+    #
+    # These functions describe the object, and what is exposed via the API
+    #
+    def getClass(self):
+        return "Base"
+    
+    def getAttrRO(self):
+        return ['uuid']
+
+    def getAttrRW(self):
+        return []
+
+    def getAttrInst(self):
+        return []
+
+    def getMethods(self):
+        return ["get_record"]
+
+    def getFuncs(self):
+        return ["get_all", "get_by_uuid", "get_all_records"]
+
+    getClass    = classmethod(getClass)
+    getAttrRO   = classmethod(getAttrRO)
+    getAttrRW   = classmethod(getAttrRW)
+    getAttrInst = classmethod(getAttrInst)
+    getMethods  = classmethod(getMethods)
+    getFuncs    = classmethod(getFuncs)
+    
+    def __init__(self, uuid, record):
+        self.__uuid = uuid
+        
+        # First check this class implements all the correct methods:
+        for attr_ro in self.getAttrRO() + self.getAttrRW():
+            if not hasattr(self, "get_%s" % attr_ro):
+                raise ImplementationError(self.getClass(),
+                                          "get_%s" % attr_ro)
+
+        for attr_rw in self.getAttrRW():
+            if not hasattr(self, "set_%s" % attr_rw):
+                raise ImplementationError(self.getClass(),
+                                          "set_%s" % attr_rw)
+
+        for method in self.getMethods():
+            if not hasattr(self, method):
+                raise ImplementationError(self.getClass(),
+                                          method)
+
+        for func in self.getFuncs():
+            if not hasattr(self.__class__, func):
+                raise ImplementationError(self.getClass(),
+                                          func)
+
+        # Next check that the class is being created with the correct
+        # parameters
+        if not isinstance(record, dict):
+            raise CreateUnspecifiedAttributeError(
+                    "record" , self.getClass())
+        
+        for attr_inst in self.getAttrInst():
+            if attr_inst not in record:
+                raise CreateUnspecifiedAttributeError(
+                    attr_inst, self.getClass())
+            setattr(self, attr_inst, record[attr_inst])
+
+        # Finally register it
+        XendAPIStore.register(uuid, self.getClass(), self)
+
+    def get_uuid(self):
+        return self.__uuid
+
+    def get_record(self):
+        keys = self.getAttrRO() + self.getAttrRW()
+        return dict([(key, getattr(self, "get_%s" % key)())
+                     for key in keys])
+
+    #
+    # Class methods
+    #
+
+    def get_all(cls):
+        return XendAPIStore.get_all_uuid(cls.getClass())
+
+    def get_by_uuid(cls, uuid):
+        # Sanity check the uuid is one of us
+        me = XendAPIStore.get(uuid, cls.getClass())
+        if me is not None and me.getClass() == cls.getClass():
+            # In OSS, ref == uuid
+            return uuid
+        else:
+            raise "Big Error.. TODO!"
+
+    def get_all_records(cls):
+        return [inst.get_record()
+                for inst in XendAPIStore.get_all(cls.getClass())]
+
+    get_all = classmethod(get_all)
+    get_by_uuid = classmethod(get_by_uuid)
+    get_all_records = classmethod(get_all_records)