from threading import Event, Lock
from uuid import uuid1
-from weakref import WeakKeyDictionary
-from listener import SessionListener
-from ncclient.content.builders import RPCBuilder
-from ncclient.content.parsers import RPCReplyParser
+from ncclient.xml_ import *
+from ncclient.transport import SessionListener
-class RPC:
+from errors import OperationError, TimeoutExpiredError, MissingCapabilityError
+
+import logging
+logger = logging.getLogger("ncclient.operations.rpc")
+
+
+class RPCError(OperationError):
+
+ "Represents an `rpc-error`. It is a type of :exc:`OperationError` and can be raised as such."
- _listeners = WeakKeyDictionary()
- _lock = Lock()
+ tag_to_attr = {
+ qualify("error-type"): "_type",
+ qualify("error-tag"): "_tag",
+ qualify("error-severity"): "_severity",
+ qualify("error-info"): "_info",
+ qualify("error-path"): "_path",
+ qualify("error-message"): "_message"
+ }
- def __init__(self, session):
- self._session = session
- self._id = None
- self._reply = None # RPCReply
- self._reply_event = None
+ def __init__(self, raw):
+ self._raw = raw
+ for attr in RPCError.tag_to_attr.values():
+ setattr(self, attr, None)
+ for subele in raw:
+ attr = RPCError.tag_to_attr.get(subele.tag, None)
+ if attr is not None:
+ setattr(self, attr, subele.text if attr != "_info" else to_xml(subele) )
+ if self.message is not None:
+ OperationError.__init__(self, self.message)
+ else:
+ OperationError.__init__(self, self.to_dict())
- @property
- def _listener(self):
- with self._lock:
- return self._listeners.setdefault(self._session, SessionListener())
+ def to_dict(self):
+ return dict([ (attr[1:], getattr(self, attr)) for attr in RPCError.tag_to_attr.values() ])
- def deliver(self, raw):
- self._reply = RPCReply(raw)
- self._reply_event.set()
+ @property
+ def xml(self):
+ "The `rpc-error` element as returned in XML."
+ return self._raw
- def _do_request(self, op, reply_event=None):
- self._id = uuid1().urn
- # get the listener instance for this session
- # <rpc-reply> with message id will reach response_cb
- self._listener.register(self._id, self)
- # only effective the first time, transport.session.Subject internally
- # uses a set type for listeners
- self._session.add_listener(self._listener)
- req = RPCBuilder.build(self._id, op)
- self._session.send(req)
- if reply_event is not None: # if we were provided an Event to use
- self._reply_event = reply_event
- else: # otherwise, block till response received and return it
- self._reply_event = Event()
- self._reply_event.wait()
- self._reply.parse()
- return self._reply
+ @property
+ def type(self):
+ "The contents of the `error-type` element."
+ return self._type
- def request(self, *args, **kwds):
- raise NotImplementedError
+ @property
+ def tag(self):
+ "The contents of the `error-tag` element."
+ return self._tag
@property
- def has_reply(self):
- try:
- return self._reply_event.isSet()
- except TypeError: # reply_event is None
- return False
+ def severity(self):
+ "The contents of the `error-severity` element."
+ return self._severity
@property
- def reply(self):
- return self._reply
+ def path(self):
+ "The contents of the `error-path` element if present or `None`."
+ return self._path
@property
- def id(self):
- return self._id
+ def message(self):
+ "The contents of the `error-message` element if present or `None`."
+ return self._message
@property
- def session(self):
- return self._session
+ def info(self):
+ "XML string or `None`; representing the `error-info` element."
+ return self._info
+
class RPCReply:
+
+ """Represents an *rpc-reply*. Only concerns itself with whether the operation was successful.
+
+ .. note::
+ If the reply has not yet been parsed there is an implicit, one-time parsing overhead to
+ accessing some of the attributes defined by this class.
+ """
+
+ ERROR_CLS = RPCError
+ "Subclasses can specify a different error class, but it should be a subclass of `RPCError`."
def __init__(self, raw):
self._raw = raw
self._parsed = False
- self._errs = []
-
- def __str__(self):
+ self._root = None
+ self._errors = []
+
+ def __repr__(self):
return self._raw
def parse(self):
- if not self._parsed:
- errs = RPCReplyParser.parse(self._raw)
- for raw, err_dict in errs:
- self._errs.append(RPCError(raw, err_dict))
- self._parsed = True
+ "Parses the *rpc-reply*."
+ if self._parsed: return
+ root = self._root = to_ele(self._raw) # The <rpc-reply> element
+ # Per RFC 4741 an <ok/> tag is sent when there are no errors or warnings
+ ok = root.find(qualify("ok"))
+ if ok is None:
+ # Create RPCError objects from <rpc-error> elements
+ error = root.find(qualify("rpc-error"))
+ if error is not None:
+ for err in root.getiterator(error.tag):
+ # Process a particular <rpc-error>
+ self._errors.append(self.ERROR_CLS(err))
+ self._parsing_hook(root)
+ self._parsed = True
+
+ def _parsing_hook(self, root):
+ "No-op by default. Gets passed the *root* element for the reply."
+ pass
@property
- def raw(self):
+ def xml(self):
+ "*rpc-reply* element as returned."
return self._raw
@property
- def parsed(self):
- return self._parsed
+ def ok(self):
+ "Boolean value indicating if there were no errors."
+ return not self.errors # empty list => false
@property
- def ok(self):
- return True if self._parsed and not self._errs else False
+ def error(self):
+ "Returns the first :class:`RPCError` and `None` if there were no errors."
+ self.parse()
+ if self._errors:
+ return self._errors[0]
+ else:
+ return None
@property
def errors(self):
- return self._errs
+ "List of `RPCError` objects. Will be empty if there were no *rpc-error* elements in reply."
+ self.parse()
+ return self._errors
-class RPCError(Exception): # raise it if you like
+
+class RPCReplyListener(SessionListener): # internal use
- def __init__(self, raw, err_dict):
- self._raw = raw
- self._dict = err_dict
+ creation_lock = Lock()
+
+ # one instance per session -- maybe there is a better way??
+ def __new__(cls, session):
+ with RPCReplyListener.creation_lock:
+ instance = session.get_listener_instance(cls)
+ if instance is None:
+ instance = object.__new__(cls)
+ instance._lock = Lock()
+ instance._id2rpc = {}
+ #instance._pipelined = session.can_pipeline
+ session.add_listener(instance)
+ return instance
- def __str__(self):
- # TODO
- return self._raw
+ def register(self, id, rpc):
+ with self._lock:
+ self._id2rpc[id] = rpc
+
+ def callback(self, root, raw):
+ tag, attrs = root
+ if tag != qualify("rpc-reply"):
+ return
+ for key in attrs: # in the <rpc-reply> attributes
+ if key == "message-id": # if we found msgid attr
+ id = attrs[key] # get the msgid
+ with self._lock:
+ try:
+ rpc = self._id2rpc[id] # the corresponding rpc
+ logger.debug("Delivering to %r" % rpc)
+ rpc.deliver_reply(raw)
+ except KeyError:
+ raise OperationError("Unknown 'message-id': %s", id)
+ # no catching other exceptions, fail loudly if must
+ else:
+ # if no error delivering, can del the reference to the RPC
+ del self._id2rpc[id]
+ break
+ else:
+ raise OperationError("Could not find 'message-id' attribute in <rpc-reply>")
+
+ def errback(self, err):
+ try:
+ for rpc in self._id2rpc.values():
+ rpc.deliver_error(err)
+ finally:
+ self._id2rpc.clear()
+
+
+class RaiseMode(object):
+
+ NONE = 0
+ "Don't attempt to raise any type of `rpc-error` as :exc:`RPCError`."
+
+ ERRORS = 1
+ "Raise only when the `error-type` indicates it is an honest-to-god error."
+
+ ALL = 2
+ "Don't look at the `error-type`, always raise."
+
+
+class RPC(object):
- def __dict__(self):
- return self._dict
+ """Base class for all operations, directly corresponding to *rpc* requests. Handles making the request, and taking delivery of the reply."""
+
+ DEPENDS = []
+ """Subclasses can specify their dependencies on capabilities as a list of URI's or abbreviated names, e.g. ':writable-running'. These are verified at the time of instantiation. If the capability is not available, :exc:`MissingCapabilityError` is raised."""
- @property
- def raw(self):
- return self._raw
+ REPLY_CLS = RPCReply
+ "By default :class:`RPCReply`. Subclasses can specify a :class:`RPCReply` subclass."
- @property
- def type(self):
- return self._dict.get('type', None)
+ def __init__(self, session, async=False, timeout=30, raise_mode=RaiseMode.NONE):
+ """
+ *session* is the :class:`~ncclient.transport.Session` instance
+
+ *async* specifies whether the request is to be made asynchronously, see :attr:`is_async`
+
+ *timeout* is the timeout for a synchronous request, see :attr:`timeout`
+
+ *raise_mode* specifies the exception raising mode, see :attr:`raise_mode`
+ """
+ self._session = session
+ try:
+ for cap in self.DEPENDS:
+ self._assert(cap)
+ except AttributeError:
+ pass
+ self._async = async
+ self._timeout = timeout
+ self._raise_mode = raise_mode
+ self._id = uuid1().urn # Keeps things simple instead of having a class attr with running ID that has to be locked
+ self._listener = RPCReplyListener(session)
+ self._listener.register(self._id, self)
+ self._reply = None
+ self._error = None
+ self._event = Event()
- @property
- def severity(self):
- return self._dict.get('severity', None)
+ def _wrap(self, subele):
+ # internal use
+ ele = new_ele("rpc", {"message-id": self._id}, xmlns=BASE_NS_1_0)
+ ele.append(subele)
+ return to_xml(ele)
+
+ def _request(self, op):
+ """Implementations of :meth:`request` call this method to send the request and process the reply.
+
+ In synchronous mode, blocks until the reply is received and returns :class:`RPCReply`. Depending on the :attr:`raise_mode` a `rpc-error` element in the reply may lead to an :exc:`RPCError` exception.
+
+ In asynchronous mode, returns immediately, returning `self`. The :attr:`event` attribute will be set when the reply has been received (see :attr:`reply`) or an error occured (see :attr:`error`).
+
+ *op* is the operation to be requested as an :class:`~xml.etree.ElementTree.Element`
+ """
+ logger.info('Requesting %r' % self.__class__.__name__)
+ req = self._wrap(op)
+ self._session.send(req)
+ if self._async:
+ logger.debug('Async request, returning %r', self)
+ return self
+ else:
+ logger.debug('Sync request, will wait for timeout=%r' % self._timeout)
+ self._event.wait(self._timeout)
+ if self._event.isSet():
+ if self._error:
+ # Error that prevented reply delivery
+ raise self._error
+ self._reply.parse()
+ if self._reply.error is not None:
+ # <rpc-error>'s [ RPCError ]
+ if self._raise_mode == RaiseMode.ALL:
+ raise self._reply.error
+ elif (self._raise_mode == RaiseMode.ERRORS and self._reply.error.type == "error"):
+ raise self._reply.error
+ return self._reply
+ else:
+ raise TimeoutExpiredError
+
+ def request(self):
+ """Subclasses must implement this method. Typically only the request needs to be built as an
+ :class:`~xml.etree.ElementTree.Element` and everything else can be handed off to
+ :meth:`_request`."""
+ pass
+
+ def _assert(self, capability):
+ """Subclasses can use this method to verify that a capability is available with the NETCONF
+ server, before making a request that requires it. A :exc:`MissingCapabilityError` will be
+ raised if the capability is not available."""
+ if capability not in self._session.server_capabilities:
+ raise MissingCapabilityError('Server does not support [%s]' % capability)
+
+ def deliver_reply(self, raw):
+ # internal use
+ self._reply = self.REPLY_CLS(raw)
+ self._event.set()
+
+ def deliver_error(self, err):
+ # internal use
+ self._error = err
+ self._event.set()
@property
- def tag(self):
- return self._dict.get('tag', None)
+ def reply(self):
+ ":class:`RPCReply` element if reply has been received or `None`"
+ return self._reply
@property
- def path(self):
- return self._dict.get('path', None)
+ def error(self):
+ """:exc:`Exception` type if an error occured or `None`.
+
+ .. note::
+ This represents an error which prevented a reply from being received. An *rpc-error*
+ does not fall in that category -- see `RPCReply` for that.
+ """
+ return self._error
@property
- def message(self):
- return self._dict.get('message', None)
+ def id(self):
+ "The *message-id* for this RPC."
+ return self._id
@property
- def info(self):
- return self._dict.get('info', None)
+ def session(self):
+ "The `~ncclient.transport.Session` object associated with this RPC."
+ return self._session
+
+ @property
+ def event(self):
+ """:class:`~threading.Event` that is set when reply has been received or when an error preventing
+ delivery of the reply occurs.
+ """
+ return self._event
+
+ def __set_async(self, async=True):
+ self._async = async
+ if async and not session.can_pipeline:
+ raise UserWarning('Asynchronous mode not supported for this device/session')
+
+ def __set_raise_mode(self, mode):
+ assert(choice in ("all", "errors", "none"))
+ self._raise_mode = mode
+
+ def __set_timeout(self, timeout):
+ self._timeout = timeout
+
+ raise_mode = property(fget=lambda self: self._raise_mode, fset=__set_raise_mode)
+ """Depending on this exception raising mode, an `rpc-error` in the reply may be raised as an :exc:`RPCError` exception. Valid values are the constants defined in :class:`RaiseMode`. """
+
+ is_async = property(fget=lambda self: self._async, fset=__set_async)
+ """Specifies whether this RPC will be / was requested asynchronously. By default RPC's are synchronous."""
+
+ timeout = property(fget=lambda self: self._timeout, fset=__set_timeout)
+ """Timeout in seconds for synchronous waiting defining how long the RPC request will block on a reply before raising :exc:`TimeoutExpiredError`.
+
+ Irrelevant for asynchronous usage.
+ """
projects / ncclient / blobdiff