def __init__(self, ordered=False):
# flag indicating whether observers should be maintained in a SortedSet
# or a regular set (unordered)
self._ordered = ordered
# map: URI => ExactUriObservation
self._observations_exact = {}
# map: URI => PrefixUriObservation
self._observations_prefix = StringTrie()
# map: URI => WildcardUriObservation
self._observations_wildcard = WildcardTrieMatcher()
# map: observation ID => UriObservation
self._observation_id_to_observation = {}
def __init__(self, ordered=False):
# flag indicating whether observers should be maintained in a SortedSet
# or a regular set (unordered)
self._ordered = ordered
# map: URI => ExactUriObservation
self._observations_exact = {}
# map: URI => PrefixUriObservation
self._observations_prefix = StringTrie()
# map: URI => WildcardUriObservation
self._observations_wildcard = WildcardTrieMatcher()
# map: observation ID => UriObservation
self._observation_id_to_observation = {}
def __init__(self, ordered=False):
# flag indicating whether observers should be maintained in a SortedSet
# or a regular set (unordered)
self._ordered = ordered
# map: URI => ExactUriObservation
self._observations_exact = {}
# map: URI => PrefixUriObservation
self._observations_prefix = StringTrie()
# map: URI => WildcardUriObservation
if True:
# use a Trie-based implementation (supposed to be faster, but
# otherwise compatible to the naive implementation below)
self._observations_wildcard = WildcardTrieMatcher()
else:
self._observations_wildcard = WildcardMatcher()
# map: observation ID => UriObservation
self._observation_id_to_observation = {}
class UriObservationMap(object):
"""
Represents the current set of observations maintained by a broker/dealer.
To test: trial crossbar.router.test.test_subscription
"""
def __init__(self, ordered=False):
# flag indicating whether observers should be maintained in a SortedSet
# or a regular set (unordered)
self._ordered = ordered
# map: URI => ExactUriObservation
self._observations_exact = {}
# map: URI => PrefixUriObservation
self._observations_prefix = StringTrie()
# map: URI => WildcardUriObservation
self._observations_wildcard = WildcardTrieMatcher()
# map: observation ID => UriObservation
self._observation_id_to_observation = {}
def add_observer(self, observer, uri, match=u"exact", extra=None):
"""
Adds a observer to the observation set and returns the respective observation.
:param observer: The observer to add (this can be any opaque object).
:type observer: obj
:param uri: The URI (or URI pattern) to add the observer to add to.
:type uri: unicode
:param match: The matching policy for observing, one of ``u"exact"``, ``u"prefix"`` or ``u"wildcard"``.
:type match: unicode
:returns: A tuple ``(observation, was_already_observed, was_first_observer)``. Here,
``observation`` is an instance of one of ``ExactUriObservation``, ``PrefixUriObservation`` or ``WildcardUriObservation``.
:rtype: tuple
"""
if not isinstance(uri, six.text_type):
raise Exception("'uri' should be unicode, not {}".format(
type(uri).__name__))
if match == u"exact":
# if the exact-matching URI isn't in our map, create a new observation
#
if uri not in self._observations_exact:
self._observations_exact[uri] = ExactUriObservation(
uri, ordered=self._ordered, extra=extra)
is_first_observer = True
else:
is_first_observer = False
# get the observation
#
observation = self._observations_exact[uri]
elif match == u"prefix":
# if the prefix-matching URI isn't in our map, create a new observation
#
if uri not in self._observations_prefix:
self._observations_prefix[uri] = PrefixUriObservation(
uri, ordered=self._ordered, extra=extra)
is_first_observer = True
else:
is_first_observer = False
# get the observation
#
observation = self._observations_prefix[uri]
elif match == u"wildcard":
# if the wildcard-matching URI isn't in our map, create a new observation
#
if uri not in self._observations_wildcard:
self._observations_wildcard[uri] = WildcardUriObservation(
uri, ordered=self._ordered, extra=extra)
is_first_observer = True
else:
is_first_observer = False
# get the observation
#
observation = self._observations_wildcard[uri]
else:
raise Exception("invalid match strategy '{}'".format(match))
# note observation in observation ID map
#
if is_first_observer:
self._observation_id_to_observation[observation.id] = observation
# add observer if not already in observation
#
if observer not in observation.observers:
observation.observers.add(observer)
was_already_observed = False
else:
was_already_observed = True
return observation, was_already_observed, is_first_observer
def get_observation(self, uri, match=u"exact"):
"""
Get a observation (if any) for given URI and match policy.
:param uri: The URI (or URI pattern) to get the observation for.
:type uri: unicode
:param match: The matching policy for observation to retrieve, one of ``u"exact"``, ``u"prefix"`` or ``u"wildcard"``.
:type match: unicode
:returns: The observation (instance of one of ``ExactUriObservation``, ``PrefixUriObservation`` or ``WildcardUriObservation``)
or ``None``.
:rtype: obj or None
"""
if not isinstance(uri, six.text_type):
raise Exception("'uri' should be unicode, not {}".format(
type(uri).__name__))
if match == u"exact":
return self._observations_exact.get(uri, None)
elif match == u"prefix":
return self._observations_prefix.get(uri, None)
elif match == u"wildcard":
return self._observations_wildcard.get(uri, None)
else:
raise Exception("invalid match strategy '{}'".format(match))
def match_observations(self, uri):
"""
Returns the observations matching the given URI. This is the core method called
by a broker to actually dispatch events.
:param uri: The URI to match.
:type uri: unicode
:returns: A list of observations matching the URI. This is a list of instance of
one of ``ExactUriObservation``, ``PrefixUriObservation`` or ``WildcardUriObservation``.
:rtype: list
"""
observations = []
if not isinstance(uri, six.text_type):
raise Exception("'uri' should be unicode, not {}".format(
type(uri).__name__))
if uri in self._observations_exact:
observations.append(self._observations_exact[uri])
for observation in self._observations_prefix.iter_prefix_values(uri):
observations.append(observation)
for observation in self._observations_wildcard.iter_matches(uri):
observations.append(observation)
return observations
def best_matching_observation(self, uri):
"""
Returns the observation that best matches the given URI. This is the core method called
by a dealer to actually forward calls.
:param uri: The URI to match.
:type uri: unicode
:returns: The observation best matching the URI. This is an instance of
``ExactUriObservation``, ``PrefixUriObservation`` or ``WildcardUriObservation`` or ``None``.
:rtype: obj or None
"""
if not isinstance(uri, six.text_type):
raise Exception("'uri' should be unicode, not {}".format(
type(uri).__name__))
# a exact matching observation is always "best", if any
#
if uri in self._observations_exact:
return self._observations_exact[uri]
# "second best" is the longest prefix-matching observation, if any
# FIXME: do we want this to take precedence over _any_ wildcard (see below)?
#
try:
return self._observations_prefix.longest_prefix_value(uri)
except KeyError:
pass
# FIXME: for wildcard observations, when there are multiple matching, we'd
# like to deterministically select the "most selective one"
# We first need a definition of "most selective", and then we need to implement
# this here.
#
for observation in self._observations_wildcard.iter_matches(uri):
return observation
def get_observation_by_id(self, id):
"""
Get a observation by ID.
:param id: The ID of the observation to retrieve.
:type id: int
:returns: The observation for the given ID or ``None``.
:rtype: obj or None
"""
return self._observation_id_to_observation.get(id, None)
def drop_observer(self, observer, observation):
"""
Drop a observer from a observation.
:param observer: The observer to drop from the given observation.
:type observer: obj
:param observation: The observation from which to drop the observer. An instance
of ``ExactUriObservation``, ``PrefixUriObservation`` or ``WildcardUriObservation`` previously
created and handed out by this observation map.
:type observation: obj
:returns: A tuple ``(was_observed, was_last_observer)``.
:rtype: tuple
"""
if observer in observation.observers:
was_observed = True
# remove observer from observation
#
observation.observers.discard(observer)
# no more observers on this observation!
#
if not observation.observers:
if observation.match == u"exact":
del self._observations_exact[observation.uri]
elif observation.match == u"prefix":
del self._observations_prefix[observation.uri]
elif observation.match == u"wildcard":
del self._observations_wildcard[observation.uri]
else:
# should not arrive here
raise Exception("logic error")
was_last_observer = True
del self._observation_id_to_observation[observation.id]
else:
was_last_observer = False
else:
# observer wasn't on this observation
was_observed = False
return was_observed, was_last_observer
class UriObservationMap(object):
"""
Represents the current set of observations maintained by a broker/dealer.
To test: trial crossbar.router.test.test_subscription
"""
def __init__(self, ordered=False):
# flag indicating whether observers should be maintained in a SortedSet
# or a regular set (unordered)
self._ordered = ordered
# map: URI => ExactUriObservation
self._observations_exact = {}
# map: URI => PrefixUriObservation
self._observations_prefix = StringTrie()
# map: URI => WildcardUriObservation
self._observations_wildcard = WildcardTrieMatcher()
# map: observation ID => UriObservation
self._observation_id_to_observation = {}
def add_observer(self, observer, uri, match=u"exact", extra=None):
"""
Adds a observer to the observation set and returns the respective observation.
:param observer: The observer to add (this can be any opaque object).
:type observer: obj
:param uri: The URI (or URI pattern) to add the observer to add to.
:type uri: unicode
:param match: The matching policy for observing, one of ``u"exact"``, ``u"prefix"`` or ``u"wildcard"``.
:type match: unicode
:returns: A tuple ``(observation, was_already_observed, was_first_observer)``. Here,
``observation`` is an instance of one of ``ExactUriObservation``, ``PrefixUriObservation`` or ``WildcardUriObservation``.
:rtype: tuple
"""
if not isinstance(uri, six.text_type):
raise Exception("'uri' should be unicode, not {}".format(type(uri).__name__))
if match == u"exact":
# if the exact-matching URI isn't in our map, create a new observation
#
if uri not in self._observations_exact:
self._observations_exact[uri] = ExactUriObservation(uri, ordered=self._ordered, extra=extra)
is_first_observer = True
else:
is_first_observer = False
# get the observation
#
observation = self._observations_exact[uri]
elif match == u"prefix":
# if the prefix-matching URI isn't in our map, create a new observation
#
if uri not in self._observations_prefix:
self._observations_prefix[uri] = PrefixUriObservation(uri, ordered=self._ordered, extra=extra)
is_first_observer = True
else:
is_first_observer = False
# get the observation
#
observation = self._observations_prefix[uri]
elif match == u"wildcard":
# if the wildcard-matching URI isn't in our map, create a new observation
#
if uri not in self._observations_wildcard:
self._observations_wildcard[uri] = WildcardUriObservation(uri, ordered=self._ordered, extra=extra)
is_first_observer = True
else:
is_first_observer = False
# get the observation
#
observation = self._observations_wildcard[uri]
else:
raise Exception("invalid match strategy '{}'".format(match))
# note observation in observation ID map
#
if is_first_observer:
self._observation_id_to_observation[observation.id] = observation
# add observer if not already in observation
#
if observer not in observation.observers:
observation.observers.add(observer)
was_already_observed = False
else:
was_already_observed = True
return observation, was_already_observed, is_first_observer
def get_observation(self, uri, match=u"exact"):
"""
Get a observation (if any) for given URI and match policy.
:param uri: The URI (or URI pattern) to get the observation for.
:type uri: unicode
:param match: The matching policy for observation to retrieve, one of ``u"exact"``, ``u"prefix"`` or ``u"wildcard"``.
:type match: unicode
:returns: The observation (instance of one of ``ExactUriObservation``, ``PrefixUriObservation`` or ``WildcardUriObservation``)
or ``None``.
:rtype: obj or None
"""
if not isinstance(uri, six.text_type):
raise Exception("'uri' should be unicode, not {}".format(type(uri).__name__))
if match == u"exact":
return self._observations_exact.get(uri, None)
elif match == u"prefix":
return self._observations_prefix.get(uri, None)
elif match == u"wildcard":
return self._observations_wildcard.get(uri, None)
else:
raise Exception("invalid match strategy '{}'".format(match))
def match_observations(self, uri):
"""
Returns the observations matching the given URI. This is the core method called
by a broker to actually dispatch events.
:param uri: The URI to match.
:type uri: unicode
:returns: A list of observations matching the URI. This is a list of instance of
one of ``ExactUriObservation``, ``PrefixUriObservation`` or ``WildcardUriObservation``.
:rtype: list
"""
observations = []
if not isinstance(uri, six.text_type):
raise Exception("'uri' should be unicode, not {}".format(type(uri).__name__))
if uri in self._observations_exact:
observations.append(self._observations_exact[uri])
for observation in self._observations_prefix.iter_prefix_values(uri):
observations.append(observation)
for observation in self._observations_wildcard.iter_matches(uri):
observations.append(observation)
return observations
def best_matching_observation(self, uri):
"""
Returns the observation that best matches the given URI. This is the core method called
by a dealer to actually forward calls.
:param uri: The URI to match.
:type uri: unicode
:returns: The observation best matching the URI. This is an instance of
``ExactUriObservation``, ``PrefixUriObservation`` or ``WildcardUriObservation`` or ``None``.
:rtype: obj or None
"""
if not isinstance(uri, six.text_type):
raise Exception("'uri' should be unicode, not {}".format(type(uri).__name__))
# a exact matching observation is always "best", if any
#
if uri in self._observations_exact:
return self._observations_exact[uri]
# "second best" is the longest prefix-matching observation, if any
# FIXME: do we want this to take precedence over _any_ wildcard (see below)?
#
try:
return self._observations_prefix.longest_prefix_value(uri)
except KeyError:
pass
# FIXME: for wildcard observations, when there are multiple matching, we'd
# like to deterministically select the "most selective one"
# We first need a definition of "most selective", and then we need to implement
# this here.
#
for observation in self._observations_wildcard.iter_matches(uri):
return observation
def get_observation_by_id(self, id):
"""
Get a observation by ID.
:param id: The ID of the observation to retrieve.
:type id: int
:returns: The observation for the given ID or ``None``.
:rtype: obj or None
"""
return self._observation_id_to_observation.get(id, None)
def drop_observer(self, observer, observation):
"""
Drop a observer from a observation.
:param observer: The observer to drop from the given observation.
:type observer: obj
:param observation: The observation from which to drop the observer. An instance
of ``ExactUriObservation``, ``PrefixUriObservation`` or ``WildcardUriObservation`` previously
created and handed out by this observation map.
:type observation: obj
:returns: A tuple ``(was_observed, was_last_observer)``.
:rtype: tuple
"""
if observer in observation.observers:
was_observed = True
# remove observer from observation
#
observation.observers.discard(observer)
# no more observers on this observation!
#
if not observation.observers:
if observation.match == u"exact":
del self._observations_exact[observation.uri]
elif observation.match == u"prefix":
del self._observations_prefix[observation.uri]
elif observation.match == u"wildcard":
del self._observations_wildcard[observation.uri]
else:
# should not arrive here
raise Exception("logic error")
was_last_observer = True
del self._observation_id_to_observation[observation.id]
else:
was_last_observer = False
else:
# observer wasn't on this observation
was_observed = False
return was_observed, was_last_observer