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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen-unstable] Added support for state records in Xend, for keeping storage and network
# HG changeset patch
# User Ewan Mellor <ewan@xxxxxxxxxxxxx>
# Date 1167057505 0
# Node ID ae3f3dd40df45bbaf4619679023ba354ac470bc2
# Parent 4e079a8496b7521f60562d09ca285c0dd436c37d
Added support for state records in Xend, for keeping storage and network
details.
By Alastair Tse <atse@xxxxxxxxxxxxx>.
Signed-off-by: Ewan Mellor <ewan@xxxxxxxxxxxxx>
---
tools/python/xen/xend/XendRoot.py | 8 +
tools/python/xen/xend/XendStateStore.py | 210 ++++++++++++++++++++++++++++++++
2 files changed, 218 insertions(+)
diff -r 4e079a8496b7 -r ae3f3dd40df4 tools/python/xen/xend/XendRoot.py
--- a/tools/python/xen/xend/XendRoot.py Mon Dec 25 14:32:41 2006 +0000
+++ b/tools/python/xen/xend/XendRoot.py Mon Dec 25 14:38:25 2006 +0000
@@ -103,6 +103,9 @@ class XendRoot:
"""Default session storage path."""
xend_domains_path_default = '/var/lib/xend/domains'
+
+ """Default xend management state storage."""
+ xend_state_path_default = '/var/lib/xend/state'
components = {}
@@ -263,6 +266,11 @@ class XendRoot:
"""
return self.get_config_value("xend-domains-path",
self.xend_domains_path_default)
+ def get_xend_state_path(self):
+ """ Get the path for persistent domain configuration storage
+ """
+ return self.get_config_value("xend-state-path",
self.xend_state_path_default)
+
def get_network_script(self):
"""@return the script used to alter the network configuration when
Xend starts and stops, or None if no such script is specified."""
diff -r 4e079a8496b7 -r ae3f3dd40df4 tools/python/xen/xend/XendStateStore.py
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/python/xen/xend/XendStateStore.py Mon Dec 25 14:38:25 2006 +0000
@@ -0,0 +1,210 @@
+#============================================================================
+# 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) 2004, 2005 Mike Wray <mike.wray@xxxxxx>
+# Copyright (c) 2006 Xensource Inc.
+#============================================================================
+
+import os
+
+from xen.xend import uuid
+from xen.xend.XendLogging import log
+from xml.dom import minidom
+from xml.dom import Node
+
+class XendStateStore:
+ """Manages persistent storage of Xend's internal state, mainly
+ relating to API objects.
+
+ It stores objects atomically in the file system as flat XML files
+ categorised by their 'class'.
+
+ For example:
+
+ /var/lib/xend/state/cpu.xml will contain the host cpu state
+ /var/lib/xend/state/sr.xml will contain the storage repository state.
+
+ For the application, it will load the state via this class:
+
+ load_state('cpu') will return a marshalled dictionary object
+ containing the cpu state.
+
+ save_state('cpu', dict) will save the state contained in the dictionary
+ object about the 'cpu'.
+
+ The state is stored where each top level element has a UUID in its
+ attributes. eg:
+
+ host['49c01812-3c28-1ad4-a59d-2a3f81b13ec2'] = {
+ 'name': 'norwich',
+ 'desc': 'Test Xen Host',
+ 'cpu': {'6fc2d1ed-7eb0-4c9d-8006-3657d5483ae0': <obj>,
+ '669df3b8-62be-4e61-800b-bbe8ee63a760': <obj>}
+ }
+
+ will turn into:
+
+ <hosts>
+ <host uuid='49c01812-3c28-1ad4-a59d-2a3f81b13ec2'>
+ <name type='string'>norwich</name>
+ <description type='string'>Test Xen Host</description>
+ <cpu uuid='6fc2d1ed-7eb0-4c9d-8006-3657d5483ae0' />
+ <cpu uuid='669df3b8-62be-4e61-800b-bbe8ee63a760' />
+ </host>
+ </hosts>
+
+ Note that it only dumps one level, so the references to CPU are
+ stored in a separate file.
+
+ """
+
+ def __init__(self, base = "/var/lib/xend/state"):
+ self.base = base
+ if not os.path.exists(self.base):
+ os.makedirs(self.base)
+
+ def _xml_file(self, cls):
+ """Return the absolute filename of the XML state storage file.
+
+ @param cls: name of the class.
+ @type cls: string
+ @rtype: string
+ @return absolute filename of XML file to write/read from.
+ """
+ return os.path.join(self.base, '%s.xml' % cls)
+
+ def load_state(self, cls):
+ """Load the saved state of a class from persistent XML storage.
+
+ References loaded from the XML will just point to an empty
+ dictionary which the caller will need to replace manually.
+
+ @param cls: name of the class to load.
+ @type cls: string
+ @rtype: dict
+ """
+
+ xml_path = self._xml_file(cls)
+ if not os.path.exists(xml_path):
+ return {}
+
+ dom = minidom.parse(xml_path)
+ root = dom.documentElement
+ state = {}
+
+ for child in root.childNodes:
+ if child.nodeType != Node.ELEMENT_NODE:
+ continue # skip non element nodes
+
+ uuid = child.getAttribute('uuid')
+ cls_dict = {}
+ for val_elem in child.childNodes:
+ if val_elem.nodeType != Node.ELEMENT_NODE:
+ continue # skip non element nodes
+
+ val_name = val_elem.tagName
+ val_type = val_elem.getAttribute('type').encode('utf8')
+ val_uuid = val_elem.getAttribute('uuid').encode('utf8')
+ val_elem.normalize()
+ val_text = ''
+ if val_elem.firstChild:
+ val_text = val_elem.firstChild.nodeValue.strip()
+
+ if val_type == '' and val_uuid != '':
+ # this is a reference
+ if val_name not in cls_dict:
+ cls_dict[val_name] = {}
+ cls_dict[val_name][val_uuid] = None
+ elif val_type == 'string':
+ cls_dict[val_name] = val_text.encode('utf8')
+ elif val_type == 'float':
+ cls_dict[val_name] = float(val_text)
+ elif val_type == 'int':
+ cls_dict[val_name] = int(val_text)
+ elif val_type == 'bool':
+ cls_dict[val_name] = bool(int(val_text))
+ state[uuid] = cls_dict
+
+ return state
+
+ def save_state(self, cls, state):
+ """Save a Xen API record struct into an XML persistent storage
+ for future loading when Xend restarts.
+
+ If we encounter a dictionary or a list, we only store the
+ keys because they are going to be UUID references to another
+ object.
+
+ @param cls: Class name (singular) of the record
+ @type cls: string
+ @param state: a Xen API struct of the state of the class.
+ @type state: dict
+ @rtype: None
+ """
+
+ xml_path = self._xml_file(cls)
+
+ doc = minidom.getDOMImplementation().createDocument(None,
+ cls + 's',
+ None)
+ root = doc.documentElement
+
+ # Marshall a dictionary into our custom XML file format.
+ for uuid, info in state.items():
+ node = doc.createElement(cls)
+ root.appendChild(node)
+ node.setAttribute('uuid', uuid)
+
+ for key, val in info.items():
+ store_val = val
+ store_type = None
+
+ # deal with basic types
+ if type(val) in (str, unicode):
+ store_val = val
+ store_type = 'string'
+ elif type(val) == int:
+ store_val = str(val)
+ store_type = 'int'
+ elif type(val) == float:
+ store_val = str(val)
+ store_type = 'float'
+ elif type(val) == bool:
+ store_val = str(int(val))
+ store_type = 'bool'
+
+ if store_type != None:
+ val_node = doc.createElement(key)
+ val_node.setAttribute('type', store_type)
+ node.appendChild(val_node)
+ # attach the value
+ val_text = doc.createTextNode(store_val)
+ val_node.appendChild(val_text)
+ continue
+
+ # deal with dicts and lists
+ if type(val) == dict:
+ for val_uuid in val.keys():
+ val_node = doc.createElement(key)
+ val_node.setAttribute('uuid', val_uuid)
+ node.appendChild(val_node)
+ elif type(val) in (list, tuple):
+ for val_uuid in val:
+ val_node = doc.createElement(key)
+ val_node.setAttribute('uuid', val_uuid)
+ node.appendChild(val_node)
+
+ open(xml_path, 'w').write(doc.toprettyxml())
+
+
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