|
|
"""Kazoo State and Event objects"""from collections import namedtuple
class KazooState(object): """High level connection state values
States inspired by Netflix Curator.
.. attribute:: SUSPENDED
The connection has been lost but may be recovered. We should operate in a "safe mode" until then. When the connection is resumed, it may be discovered that the session expired. A client should not assume that locks are valid during this time.
.. attribute:: CONNECTED
The connection is alive and well.
.. attribute:: LOST
The connection has been confirmed dead. Any ephemeral nodes will need to be recreated upon re-establishing a connection. If locks were acquired or recipes using ephemeral nodes are in use, they can be considered lost as well.
"""
SUSPENDED = "SUSPENDED" CONNECTED = "CONNECTED" LOST = "LOST"
class KeeperState(object): """Zookeeper State
Represents the Zookeeper state. Watch functions will receive a :class:`KeeperState` attribute as their state argument.
.. attribute:: AUTH_FAILED
Authentication has failed, this is an unrecoverable error.
.. attribute:: CONNECTED
Zookeeper is connected.
.. attribute:: CONNECTED_RO
Zookeeper is connected in read-only state.
.. attribute:: CONNECTING
Zookeeper is currently attempting to establish a connection.
.. attribute:: EXPIRED_SESSION
The prior session was invalid, all prior ephemeral nodes are gone.
"""
AUTH_FAILED = "AUTH_FAILED" CONNECTED = "CONNECTED" CONNECTED_RO = "CONNECTED_RO" CONNECTING = "CONNECTING" CLOSED = "CLOSED" EXPIRED_SESSION = "EXPIRED_SESSION"
class EventType(object): """Zookeeper Event
Represents a Zookeeper event. Events trigger watch functions which will receive a :class:`EventType` attribute as their event argument.
.. attribute:: CREATED
A node has been created.
.. attribute:: DELETED
A node has been deleted.
.. attribute:: CHANGED
The data for a node has changed.
.. attribute:: CHILD
The children under a node have changed (a child was added or removed). This event does not indicate the data for a child node has changed, which must have its own watch established.
.. attribute:: NONE
The connection state has been altered.
"""
CREATED = "CREATED" DELETED = "DELETED" CHANGED = "CHANGED" CHILD = "CHILD" NONE = "NONE"
EVENT_TYPE_MAP = { -1: EventType.NONE, 1: EventType.CREATED, 2: EventType.DELETED, 3: EventType.CHANGED, 4: EventType.CHILD,}
class WatchedEvent(namedtuple("WatchedEvent", ("type", "state", "path"))): """A change on ZooKeeper that a Watcher is able to respond to.
The :class:`WatchedEvent` includes exactly what happened, the current state of ZooKeeper, and the path of the node that was involved in the event. An instance of :class:`WatchedEvent` will be passed to registered watch functions.
.. attribute:: type
A :class:`EventType` attribute indicating the event type.
.. attribute:: state
A :class:`KeeperState` attribute indicating the Zookeeper state.
.. attribute:: path
The path of the node for the watch event.
"""
class Callback(namedtuple("Callback", ("type", "func", "args"))): """A callback that is handed to a handler for dispatch
:param type: Type of the callback, currently is only 'watch' :param func: Callback function :param args: Argument list for the callback function
"""
class ZnodeStat( namedtuple( "ZnodeStat", "czxid mzxid ctime mtime version" " cversion aversion ephemeralOwner dataLength" " numChildren pzxid", )): """A ZnodeStat structure with convenience properties
When getting the value of a znode from Zookeeper, the properties for the znode known as a "Stat structure" will be retrieved. The :class:`ZnodeStat` object provides access to the standard Stat properties and additional properties that are more readable and use Python time semantics (seconds since epoch instead of ms).
.. note::
The original Zookeeper Stat name is in parens next to the name when it differs from the convenience attribute. These are **not functions**, just attributes.
.. attribute:: creation_transaction_id (czxid)
The transaction id of the change that caused this znode to be created.
.. attribute:: last_modified_transaction_id (mzxid)
The transaction id of the change that last modified this znode.
.. attribute:: created (ctime)
The time in seconds from epoch when this znode was created. (ctime is in milliseconds)
.. attribute:: last_modified (mtime)
The time in seconds from epoch when this znode was last modified. (mtime is in milliseconds)
.. attribute:: version
The number of changes to the data of this znode.
.. attribute:: acl_version (aversion)
The number of changes to the ACL of this znode.
.. attribute:: owner_session_id (ephemeralOwner)
The session id of the owner of this znode if the znode is an ephemeral node. If it is not an ephemeral node, it will be `None`. (ephemeralOwner will be 0 if it is not ephemeral)
.. attribute:: data_length (dataLength)
The length of the data field of this znode.
.. attribute:: children_count (numChildren)
The number of children of this znode.
"""
@property def acl_version(self): return self.aversion
@property def children_version(self): return self.cversion
@property def created(self): return self.ctime / 1000.0
@property def last_modified(self): return self.mtime / 1000.0
@property def owner_session_id(self): return self.ephemeralOwner or None
@property def creation_transaction_id(self): return self.czxid
@property def last_modified_transaction_id(self): return self.mzxid
@property def data_length(self): return self.dataLength
@property def children_count(self): return self.numChildren
|
