Add callbacks-based system to Neutron
This system helps Neutron entities to cooperate in a loose manner. This is especially important in face of the advanced service split, where each service gets to live independently from the core. This is also useful to clean up some of the tight coupling between ML2 and L3, or L3 and VPN/FW. This work was touted to be part of the effort on the v3 plugin API design. (aka perestroika), however that is not going to bear the expected fruits in time for the Kilo release. This framework is instead pretty crucial to cleaning up the split between the various Neutron components and some of the coupling between ML2 and DVR. Subsequent patches will show how this framework is put into practice in relation to cleaning up/decoupling the various Neutron components, however, a devref how-to is added in the context of this patch to further clarify how the proposed mechanism works and can be used. Related-blueprint: services-split Related-blueprint: plugin-interface-perestroika Change-Id: I498aeb0773822707e82763f1f0022c580308bde0
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=======================
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Neutron Callback System
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=======================
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In Neutron, core and service components may need to cooperate during the
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execution of certain operations, or they may need to react upon the occurrence
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of certain events. For instance, when a Neutron resource is associated to
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multiple services, the components in charge of these services may need to play
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an active role in determining what the right state of the resource needs to be.
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The cooperation may be achieved by making each object aware of each other, but
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this leads to tight coupling, or alternatively it can be achieved by using a
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callback-based system, where the same objects are allowed to cooperate in a
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loose manner.
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This is particularly important since the spin off of the advanced services like
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VPN, Firewall and Load Balancer, where each service's codebase lives independently
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from the core and from one another. This means that the tight coupling is no longer
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a practical solution for object cooperation. In addition to this, if more services
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are developed independently, there is no viable integration between them and the
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Neutron core. A callback system, and its registry, tries to address these issues.
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In object-oriented software systems, method invocation is also known as message
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passing: an object passes a message to another object, and it may or may not expect
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a message back. This point-to-point interaction can take place between the parties
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directly involved in the communication, or it can happen via an intermediary. The
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intermediary is then in charge of keeping track of who is interested in the messages
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and in delivering the messages forth and back, when required. As mentioned earlier,
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the use of an intermediary has the benefit of decoupling the parties involved
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in the communications, as now they only need to know about the intermediary; the
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other benefit is that the use of an intermediary opens up the possibility of
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multiple party communication: more than one object can express interest in
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receiving the same message, and the same message can be delivered to more than
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one object. To this aim, the intermediary is the entity that exists throughout
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the system lifecycle, as it needs to be able to track whose interest is associated
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to what message.
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In a design for a system that enables callback-based communication, the following
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aspects need to be taken into account:
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* how to become consumer of messages (i.e. how to be on the receiving end of the message);
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* how to become producer of messages (i.e. how to be on the sending end of the message);
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* how to consume/produce messages selectively;
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Translate and narrow this down to Neutron needs, and this means the design of a callback
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system where messages are about lifecycle events (e.g. before creation, before
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deletion, etc.) of Neutron resources (e.g. networks, routers, ports, etc.), where the
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various parties can express interest in knowing when these events for a specific
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resources take place.
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Rather than keeping the conversation abstract, let us delve into some examples, that would
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help understand better some of the principles behind the provided mechanism.
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Subscribing to events
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=====================
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Imagine that you have entity A, B, and C that have some common business over router creation.
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A wants to tell B and C that the router has been created and that they need to get on and
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do whatever they are supposed to do. In a callback-less world this would work like so:
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::
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# A is done creating the resource
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# A gets hold of the references of B and C
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# A calls B
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# A calls C
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B->my_random_method_for_knowning_about_router_created()
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C->my_random_very_difficult_to_remember_method_about_router_created()
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If B and/or C change, things become sour. In a callback-based world, things become a lot
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more uniform and straightward:
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::
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# B and C ask I to be notified when A is done creating the resource
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# ...
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# A is done creating the resource
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# A gets hold of the reference to the intermediary I
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# A calls I
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I->notify()
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Since B and C will have expressed interest in knowing about A's business, 'I' will
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deliver the messages to B and C. If B and C changes, A and 'I' do not need to change.
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In practical terms this scenario would be translated in the code below:
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::
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from neutron.callbacks import events
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from neutron.callbacks import resources
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from neutron.callbacks import registry
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def callback1(resource, event, trigger, **kwargs):
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print 'Callback1 called by trigger: ', trigger
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print 'kwargs: ', kwargs
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def callback2(resource, event, trigger, **kwargs):
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print 'Callback2 called by trigger: ', trigger
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print 'kwargs: ', kwargs
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# B and C express interest with I
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registry.subscribe(callback1, resources.ROUTER, events.BEFORE_CREATE)
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registry.subscribe(callback2, resources.ROUTER, events.BEFORE_CREATE)
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print 'Subscribed'
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# A notifies
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def do_notify():
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kwargs = {'foo': 'bar'}
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registry.notify(resources.ROUTER, events.BEFORE_CREATE, do_notify, **kwargs)
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print 'Notifying...'
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do_notify()
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The output is:
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::
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> Subscribed
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> Notifying...
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> Callback2 called by trigger: <function do_notify at 0x7f2a5d663410>
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> kwargs: {'foo': 'bar'}
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> Callback1 called by trigger: <function do_notify at 0x7f2a5d663410>
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> kwargs: {'foo': 'bar'}
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Thanks to the intermediary existence throughout the life of the system, A, B, and C
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are flexible to evolve their internals, dynamics, and lifecycles.
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Subscribing and aborting events
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===============================
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Interestingly in Neutron, certain events may need to be forbidden from happening due to the
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nature of the resources involved. To this aim, the callback-based mechanism has been designed
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to support a use case where, when callbacks subscribe to specific events, the action that
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results from it, may lead to the propagation of a message back to the sender, so that it itself
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can be alerted and stop the execution of the activity that led to the message dispatch in the
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first place.
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The typical example is where a resource, like a router, is used by one or more high-level
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service(s), like a VPN or a Firewall, and actions like interface removal or router destruction
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cannot not take place, because the resource is shared.
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To address this scenario, special events are introduced, 'BEFORE_*' events, to which callbacks
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can subscribe and have the opportunity to 'abort', by raising an exception when notified.
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Since multiple callbacks may express an interest in the same event for a particular resource,
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and since callbacks are executed independently from one another, this may lead to situations
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where notifications that occurred before the exception must be aborted. To this aim, when an
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exception occurs during the notification process, an abort_* event is propagated immediately
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after. It is up to the callback developer to determine whether subscribing to an abort
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notification is required in order to revert the actions performed during the initial execution
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of the callback (when the BEFORE_* event was fired). Exceptions caused by callbacks registered
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to abort events are ignored. The snippet below shows this in action:
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::
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from neutron.callbacks import events
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from neutron.callbacks import exceptions
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from neutron.callbacks import resources
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from neutron.callbacks import registry
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def callback1(resource, event, trigger, **kwargs):
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raise Exception('I am failing!')
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def callback2(resource, event, trigger, **kwargs):
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print 'Callback2 called by %s on event %s' % (trigger, event)
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registry.subscribe(callback1, resources.ROUTER, events.BEFORE_CREATE)
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registry.subscribe(callback2, resources.ROUTER, events.BEFORE_CREATE)
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registry.subscribe(callback2, resources.ROUTER, events.ABORT_CREATE)
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print 'Subscribed'
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def do_notify():
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kwargs = {'foo': 'bar'}
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registry.notify(resources.ROUTER, events.BEFORE_CREATE, do_notify, **kwargs)
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print 'Notifying...'
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try:
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do_notify()
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except exceptions.CallbackFailure as e:
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print 'Error: ', e
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The output is:
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::
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> Subscribed
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> Notifying...
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> Callback2 called by <function do_notify at 0x7f3194c7f410> on event before_create
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> Callback2 called by <function do_notify at 0x7f3194c7f410> on event abort_create
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> Error: Callback __main__.callback1 failed with "I am failing!"
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In this case, upon the notification of the BEFORE_CREATE event, Callback1 triggers an exception
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that can be used to stop the action from taking place in do_notify(). On the other end, Callback2
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will be executing twice, once for dealing with the BEFORE_CREATE event, and once to undo the
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actions during the ABORT_CREATE event. It is worth noting that it is not mandatory to have
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the same callback register to both BEFORE_* and the respective ABORT_* event; as a matter of
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fact, it is best to make use of different callbacks to keep the two logic separate.
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Unsubscribing to events
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=======================
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There are a few options to unsubscribe registered callbacks:
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* clear(): it unsubscribes all subscribed callbacks: this can be useful especially when
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winding down the system, and notifications shall no longer be triggered.
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* unsubscribe(): it selectively unsubscribes a callback for a specific resource's event.
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Say callback C has subscribed to event A for resource R, any notification of event A
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for resource R will no longer be handed over to C, after the unsubscribe() invocation.
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* unsubscribe_by_resource(): say that callback C has subscribed to event A, B, and C for
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resource R, any notification of events related to resource R will no longer be handed
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over to C, after the unsubscribe_by_resource() invocation.
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* unsubscribe_all(): say that callback C has subscribed to events A, B for resource R1,
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and events C, D for resource R2, any notification of events pertaining resouces R1 and
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R2 will no longer be handed over to C, after the unsubscribe_all() invocation.
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The snippet below shows these concepts in action:
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::
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from neutron.callbacks import events
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from neutron.callbacks import exceptions
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from neutron.callbacks import resources
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from neutron.callbacks import registry
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def callback1(resource, event, trigger, **kwargs):
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print 'Callback1 called by %s on event %s for resource %s' % (trigger, event, resource)
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def callback2(resource, event, trigger, **kwargs):
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print 'Callback2 called by %s on event %s for resource %s' % (trigger, event, resource)
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registry.subscribe(callback1, resources.ROUTER, events.BEFORE_READ)
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registry.subscribe(callback1, resources.ROUTER, events.BEFORE_CREATE)
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registry.subscribe(callback1, resources.ROUTER, events.AFTER_DELETE)
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registry.subscribe(callback1, resources.PORT, events.BEFORE_UPDATE)
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registry.subscribe(callback2, resources.ROUTER_GATEWAY, events.BEFORE_UPDATE)
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print 'Subscribed'
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def do_notify():
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print 'Notifying...'
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kwargs = {'foo': 'bar'}
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registry.notify(resources.ROUTER, events.BEFORE_READ, do_notify, **kwargs)
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registry.notify(resources.ROUTER, events.BEFORE_CREATE, do_notify, **kwargs)
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registry.notify(resources.ROUTER, events.AFTER_DELETE, do_notify, **kwargs)
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registry.notify(resources.PORT, events.BEFORE_UPDATE, do_notify, **kwargs)
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registry.notify(resources.ROUTER_GATEWAY, events.BEFORE_UPDATE, do_notify, **kwargs)
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do_notify()
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registry.unsubscribe(callback1, resources.ROUTER, events.BEFORE_READ)
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do_notify()
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registry.unsubscribe_by_resource(callback1, resources.PORT)
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do_notify()
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registry.unsubscribe_all(callback1)
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do_notify()
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registry.clear()
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do_notify()
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The output is:
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::
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Subscribed
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Notifying...
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Callback1 called by <function do_notify at 0x7f062c8f67d0> on event before_read for resource router
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Callback1 called by <function do_notify at 0x7f062c8f67d0> on event before_create for resource router
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Callback1 called by <function do_notify at 0x7f062c8f67d0> on event after_delete for resource router
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Callback1 called by <function do_notify at 0x7f062c8f67d0> on event before_update for resource port
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Callback2 called by <function do_notify at 0x7f062c8f67d0> on event before_update for resource router_gateway
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Notifying...
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Callback1 called by <function do_notify at 0x7f062c8f67d0> on event before_create for resource router
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Callback1 called by <function do_notify at 0x7f062c8f67d0> on event after_delete for resource router
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Callback1 called by <function do_notify at 0x7f062c8f67d0> on event before_update for resource port
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Callback2 called by <function do_notify at 0x7f062c8f67d0> on event before_update for resource router_gateway
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Notifying...
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Callback1 called by <function do_notify at 0x7f062c8f67d0> on event before_create for resource router
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Callback1 called by <function do_notify at 0x7f062c8f67d0> on event after_delete for resource router
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Callback2 called by <function do_notify at 0x7f062c8f67d0> on event before_update for resource router_gateway
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Notifying...
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Callback2 called by <function do_notify at 0x7f062c8f67d0> on event before_update for resource router_gateway
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Notifying...
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FAQ
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===
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Q. What is the relationship between Callbacks and Taskflow?
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A. There is no overlap between Callbacks and Taskflow or mutual exclusion; as matter of fact they
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can be combined; You could have a callback that goes on and trigger a taskflow. It is a nice
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way of separating implementation from abstraction, because you can keep the callback in place
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and change Taskflow with something else.
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Q. Is there any ordering guarantee during notifications? In other words, can I have one callback
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be notified before another(s)?
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A. No, the ordering in which callbacks are notified is completely arbitrary by design: callbacks
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should know nothing about each other, and ordering should not matter; a callback will always be
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notified and its outcome should always be the same regardless as to in which order is it
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notified. Priorities can be a future extension, if a use case arises that require enforced
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ordering.
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Q. Is the registry thread-safe?
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A. Short answer is no: it is not safe to make mutations while callbacks are being called (more
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details as to why can be found `here <https://hg.python.org/releasing/2.7.9/file/753a8f457ddc/Objects/dictobject.c#l937>`_).
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A mutation could happen if a 'subscribe'/'unsuscribe' operation interleaves with the execution
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of the notify loop. Albeit there is a possibility that things may end up in a bad state, the
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registry works correctly under the assumption that subscriptions happen at the very beginning
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of the life of the process and that the unsubscriptions (if any) take place at the very end.
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In this case, chances that things do go badly may be pretty slim. Making the registry
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thread-safe will be considered as a future improvement.
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Q. Can I use lambdas or 'closures' as callbacks?
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A. Currently a weakref.proxy(callback) is registered instead of the callback itself. This means
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that certain constructs like lambdas, cannot be used as callbacks. Even though this limitation
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could be easily lifted, use of methods or module functions should be preferred over lambdas
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or nested functions for maintanability and testability reasons.
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@ -47,6 +47,7 @@ Neutron Internals
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l2_agents
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advanced_services
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oslo-incubator
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callbacks
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Module Reference
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@ -0,0 +1,44 @@
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
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# License for the specific language governing permissions and limitations
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# under the License.
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BEFORE_CREATE = 'before_create'
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BEFORE_READ = 'before_read'
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BEFORE_UPDATE = 'before_update'
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BEFORE_DELETE = 'before_delete'
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AFTER_CREATE = 'after_create'
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AFTER_READ = 'after_read'
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AFTER_UPDATE = 'after_update'
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AFTER_DELETE = 'after_delete'
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ABORT_CREATE = 'abort_create'
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ABORT_READ = 'abort_read'
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ABORT_UPDATE = 'abort_update'
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ABORT_DELETE = 'abort_delete'
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ABORT = 'abort_'
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BEFORE = 'before_'
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VALID = (
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BEFORE_CREATE,
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BEFORE_READ,
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BEFORE_UPDATE,
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BEFORE_DELETE,
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AFTER_CREATE,
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AFTER_READ,
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AFTER_UPDATE,
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AFTER_DELETE,
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ABORT_CREATE,
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ABORT_READ,
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ABORT_UPDATE,
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ABORT_DELETE,
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)
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@ -0,0 +1,36 @@
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from neutron.common import exceptions
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class Invalid(exceptions.NeutronException):
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message = _("The value '%(value)s' for %(element)s is not valid.")
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class CallbackFailure(Exception):
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def __init__(self, errors):
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self.errors = errors
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def __str__(self):
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return ','.join(str(error) for error in self.errors)
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class NotificationError(object):
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def __init__(self, callback_id, error):
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self.callback_id = callback_id
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self.error = error
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def __str__(self):
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return 'Callback %s failed with "%s"' % (self.callback_id, self.error)
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@ -0,0 +1,164 @@
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
|
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# not use this file except in compliance with the License. You may obtain
|
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# a copy of the License at
|
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#
|
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
|
||||
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
||||
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
||||
# License for the specific language governing permissions and limitations
|
||||
# under the License.
|
||||
|
||||
import collections
|
||||
import weakref
|
||||
|
||||
from oslo_utils import reflection
|
||||
|
||||
from neutron.callbacks import events
|
||||
from neutron.callbacks import exceptions
|
||||
from neutron.callbacks import resources
|
||||
from neutron.i18n import _LE, _LI
|
||||
from neutron.openstack.common import log as logging
|
||||
|
||||
LOG = logging.getLogger(__name__)
|
||||
|
||||
|
||||
class CallbacksManager(object):
|
||||
"""A callback system that allows objects to cooperate in a loose manner."""
|
||||
|
||||
def __init__(self):
|
||||
self.clear()
|
||||
|
||||
def subscribe(self, callback, resource, event):
|
||||
"""Subscribe callback for a resource event.
|
||||
|
||||
The same callback may register for more than one event.
|
||||
|
||||
:param callback: the callback. It must raise or return a boolean.
|
||||
:param resource: the resource. It must be a valid resource.
|
||||
:param event: the event. It must be a valid event.
|
||||
"""
|
||||
LOG.debug("Subscribe: %(callback)s %(resource)s %(event)s",
|
||||
{'callback': callback, 'resource': resource, 'event': event})
|
||||
if resource not in resources.VALID:
|
||||
raise exceptions.Invalid(element='resource', value=resource)
|
||||
if event not in events.VALID:
|
||||
raise exceptions.Invalid(element='event', value=event)
|
||||
|
||||
callback_id = _get_id(callback)
|
||||
self._callbacks[resource][event][callback_id] = weakref.proxy(callback)
|
||||
# We keep a copy of callbacks to speed the unsubscribe operation.
|
||||
if callback_id not in self._index:
|
||||
self._index[callback_id] = collections.defaultdict(set)
|
||||
self._index[callback_id][resource].add(event)
|
||||
|
||||
def unsubscribe(self, callback, resource, event):
|
||||
"""Unsubscribe callback from the registry.
|
||||
|
||||
:param callback: the callback.
|
||||
:param resource: the resource.
|
||||
:param event: the event.
|
||||
"""
|
||||
LOG.debug("Unsubscribe: %(callback)s %(resource)s %(event)s",
|
||||
{'callback': callback, 'resource': resource, 'event': event})
|
||||
|
||||
callback_id = self._find(callback)
|
||||
if not callback_id:
|
||||
LOG.debug("Callback %s not found", callback_id)
|
||||
return
|
||||
if resource and event:
|
||||
del self._callbacks[resource][event][callback_id]
|
||||
self._index[callback_id][resource].discard(event)
|
||||
if not self._index[callback_id][resource]:
|
||||
del self._index[callback_id][resource]
|
||||
if not self._index[callback_id]:
|
||||
del self._index[callback_id]
|
||||
else:
|
||||
value = '%s,%s' % (resource, event)
|
||||
raise exceptions.Invalid(element='resource,event', value=value)
|
||||
|
||||
def unsubscribe_by_resource(self, callback, resource):
|
||||
"""Unsubscribe callback for any event associated to the resource.
|
||||
|
||||
:param callback: the callback.
|
||||
:param resource: the resource.
|
||||
"""
|
||||
callback_id = self._find(callback)
|
||||
if callback_id:
|
||||
if resource in self._index[callback_id]:
|
||||
for event in self._index[callback_id][resource]:
|
||||
del self._callbacks[resource][event][callback_id]
|
||||
del self._index[callback_id][resource]
|
||||
if not self._index[callback_id]:
|
||||
del self._index[callback_id]
|
||||
|
||||
def unsubscribe_all(self, callback):
|
||||
"""Unsubscribe callback for all events and all resources.
|
||||
|
||||
|
||||
:param callback: the callback.
|
||||
"""
|
||||
callback_id = self._find(callback)
|
||||
if callback_id:
|
||||
for resource, resource_events in self._index[callback_id].items():
|
||||
for event in resource_events:
|
||||
del self._callbacks[resource][event][callback_id]
|
||||
del self._index[callback_id]
|
||||
|
||||
def notify(self, resource, event, trigger, **kwargs):
|
||||
"""Notify all subscribed callback(s).
|
||||
|
||||
Dispatch the resource's event to the subscribed callbacks.
|
||||
|
||||
:param resource: the resource.
|
||||
:param event: the event.
|
||||
:param trigger: the trigger. A reference to the sender of the event.
|
||||
"""
|
||||
errors = self._notify_loop(resource, event, trigger, **kwargs)
|
||||
if errors and event.startswith(events.BEFORE):
|
||||
abort_event = event.replace(
|
||||
events.BEFORE, events.ABORT)
|
||||
self._notify_loop(resource, abort_event, trigger)
|
||||
raise exceptions.CallbackFailure(errors=errors)
|
||||
|
||||
def clear(self):
|
||||
"""Brings the manager to a clean slate."""
|
||||
self._callbacks = collections.defaultdict(dict)
|
||||
self._index = collections.defaultdict(dict)
|
||||
for resource in resources.VALID:
|
||||
for event in events.VALID:
|
||||
self._callbacks[resource][event] = collections.defaultdict()
|
||||
|
||||
def _notify_loop(self, resource, event, trigger, **kwargs):
|
||||
"""The notification loop."""
|
||||
LOG.info(_LI("Notify callbacks for %(resource)s, %(event)s"),
|
||||
{'resource': resource, 'event': event})
|
||||
|
||||
errors = []
|
||||
# TODO(armax): consider using a GreenPile
|
||||
for callback_id, callback in self._callbacks[resource][event].items():
|
||||
try:
|
||||
LOG.info(_LI("Calling callback %s"), callback_id)
|
||||
callback(resource, event, trigger, **kwargs)
|
||||
except Exception as e:
|
||||
LOG.exception(_LE("Error during notification for "
|
||||
"%(callback)s %(resource)s, %(event)s"),
|
||||
{'callback': callback_id,
|
||||
'resource': resource,
|
||||
'event': event})
|
||||
errors.append(exceptions.NotificationError(callback_id, e))
|
||||
return errors
|
||||
|
||||
def _find(self, callback):
|
||||
"""Return the callback_id if found, None otherwise."""
|
||||
callback_id = _get_id(callback)
|
||||
return callback_id if callback_id in self._index else None
|
||||
|
||||
|
||||
def _get_id(callback):
|
||||
"""Return a unique identifier for the callback."""
|
||||
# TODO(armax): consider using something other than names
|
||||
# https://www.python.org/dev/peps/pep-3155/, but this
|
||||
# might be okay for now.
|
||||
return reflection.get_callable_name(callback)
|
||||
|
|
@ -0,0 +1,48 @@
|
|||
# Licensed under the Apache License, Version 2.0 (the "License"); you may
|
||||
# not use this file except in compliance with the License. You may obtain
|
||||
# a copy of the License at
|
||||
#
|
||||
# http://www.apache.org/licenses/LICENSE-2.0
|
||||
#
|
||||
# Unless required by applicable law or agreed to in writing, software
|
||||
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
||||
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
||||
# License for the specific language governing permissions and limitations
|
||||
# under the License.
|
||||
|
||||
from neutron.callbacks import manager
|
||||
|
||||
|
||||
# TODO(armax): consider adding locking
|
||||
CALLBACK_MANAGER = None
|
||||
|
||||
|
||||
def _get_callback_manager():
|
||||
global CALLBACK_MANAGER
|
||||
if CALLBACK_MANAGER is None:
|
||||
CALLBACK_MANAGER = manager.CallbacksManager()
|
||||
return CALLBACK_MANAGER
|
||||
|
||||
|
||||
def subscribe(callback, resource, event):
|
||||
_get_callback_manager().subscribe(callback, resource, event)
|
||||
|
||||
|
||||
def unsubscribe(callback, resource, event):
|
||||
_get_callback_manager().unsubscribe(callback, resource, event)
|
||||
|
||||
|
||||
def unsubscribe_by_resource(callback, resource):
|
||||
_get_callback_manager().unsubscribe_by_resource(callback, resource)
|
||||
|
||||
|
||||
def unsubscribe_all(callback):
|
||||
_get_callback_manager().unsubscribe_all(callback)
|
||||
|
||||
|
||||
def notify(resource, event, trigger, **kwargs):
|
||||
_get_callback_manager().notify(resource, event, trigger, **kwargs)
|
||||
|
||||
|
||||
def clear():
|
||||
_get_callback_manager().clear()
|
||||
|
|
@ -0,0 +1,23 @@
|
|||
# Licensed under the Apache License, Version 2.0 (the "License"); you may
|
||||
# not use this file except in compliance with the License. You may obtain
|
||||
# a copy of the License at
|
||||
#
|
||||
# http://www.apache.org/licenses/LICENSE-2.0
|
||||
#
|
||||
# Unless required by applicable law or agreed to in writing, software
|
||||
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
||||
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
||||
# License for the specific language governing permissions and limitations
|
||||
# under the License.
|
||||
|
||||
PORT = 'port'
|
||||
ROUTER = 'router'
|
||||
ROUTER_GATEWAY = 'router_gateway'
|
||||
ROUTER_INTERFACE = 'router_interface'
|
||||
|
||||
VALID = (
|
||||
PORT,
|
||||
ROUTER,
|
||||
ROUTER_GATEWAY,
|
||||
ROUTER_INTERFACE,
|
||||
)
|
||||
|
|
@ -0,0 +1,193 @@
|
|||
# Copyright 2015 OpenStack Foundation
|
||||
#
|
||||
# Licensed under the Apache License, Version 2.0 (the "License"); you may
|
||||
# not use this file except in compliance with the License. You may obtain
|
||||
# a copy of the License at
|
||||
#
|
||||
# http://www.apache.org/licenses/LICENSE-2.0
|
||||
#
|
||||
# Unless required by applicable law or agreed to in writing, software
|
||||
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
||||
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
||||
# License for the specific language governing permissions and limitations
|
||||
# under the License.
|
||||
|
||||
import mock
|
||||
import testtools
|
||||
|
||||
from neutron.callbacks import events
|
||||
from neutron.callbacks import exceptions
|
||||
from neutron.callbacks import manager
|
||||
from neutron.callbacks import resources
|
||||
from neutron.tests import base
|
||||
|
||||
|
||||
def callback_1(*args, **kwargs):
|
||||
callback_1.counter += 1
|
||||
callback_id_1 = manager._get_id(callback_1)
|
||||
|
||||
|
||||
def callback_2(*args, **kwargs):
|
||||
callback_2.counter += 1
|
||||
callback_id_2 = manager._get_id(callback_2)
|
||||
|
||||
|
||||
def callback_raise(*args, **kwargs):
|
||||
raise Exception()
|
||||
|
||||
|
||||
class CallBacksManagerTestCase(base.BaseTestCase):
|
||||
|
||||
def setUp(self):
|
||||
super(CallBacksManagerTestCase, self).setUp()
|
||||
self.manager = manager.CallbacksManager()
|
||||
callback_1.counter = 0
|
||||
callback_2.counter = 0
|
||||
|
||||
def test_subscribe_invalid_resource_raise(self):
|
||||
with testtools.ExpectedException(exceptions.Invalid):
|
||||
self.manager.subscribe(mock.ANY, 'foo_resource', mock.ANY)
|
||||
|
||||
def test_subscribe_invalid_event_raise(self):
|
||||
self.assertRaises(exceptions.Invalid,
|
||||
self.manager.subscribe,
|
||||
mock.ANY, mock.ANY, 'foo_event')
|
||||
|
||||
def test_subscribe(self):
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_CREATE)
|
||||
self.assertIsNotNone(
|
||||
self.manager._callbacks[resources.PORT][events.BEFORE_CREATE])
|
||||
self.assertIn(callback_id_1, self.manager._index)
|
||||
|
||||
def test_subscribe_is_idempotent(self):
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_CREATE)
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_CREATE)
|
||||
self.assertEqual(
|
||||
1,
|
||||
len(self.manager._callbacks[resources.PORT][events.BEFORE_CREATE]))
|
||||
callbacks = self.manager._index[callback_id_1][resources.PORT]
|
||||
self.assertEqual(1, len(callbacks))
|
||||
|
||||
def test_subscribe_multiple_callbacks(self):
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_CREATE)
|
||||
self.manager.subscribe(
|
||||
callback_2, resources.PORT, events.BEFORE_CREATE)
|
||||
self.assertEqual(2, len(self.manager._index))
|
||||
self.assertEqual(
|
||||
2,
|
||||
len(self.manager._callbacks[resources.PORT][events.BEFORE_CREATE]))
|
||||
|
||||
def test_unsubscribe(self):
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_CREATE)
|
||||
self.manager.unsubscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_CREATE)
|
||||
self.assertNotIn(
|
||||
callback_id_1,
|
||||
self.manager._callbacks[resources.PORT][events.BEFORE_CREATE])
|
||||
self.assertNotIn(callback_id_1, self.manager._index)
|
||||
|
||||
def test_unsubscribe_unknown_callback(self):
|
||||
self.manager.subscribe(
|
||||
callback_2, resources.PORT, events.BEFORE_CREATE)
|
||||
self.manager.unsubscribe(callback_1, mock.ANY, mock.ANY)
|
||||
self.assertEqual(1, len(self.manager._index))
|
||||
|
||||
def test_unsubscribe_is_idempotent(self):
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_CREATE)
|
||||
self.manager.unsubscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_CREATE)
|
||||
self.manager.unsubscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_CREATE)
|
||||
self.assertNotIn(callback_id_1, self.manager._index)
|
||||
self.assertNotIn(callback_id_1,
|
||||
self.manager._callbacks[resources.PORT][events.BEFORE_CREATE])
|
||||
|
||||
def test_unsubscribe_by_resource(self):
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_CREATE)
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_DELETE)
|
||||
self.manager.subscribe(
|
||||
callback_2, resources.PORT, events.BEFORE_DELETE)
|
||||
self.manager.unsubscribe_by_resource(callback_1, resources.PORT)
|
||||
self.assertNotIn(
|
||||
callback_id_1,
|
||||
self.manager._callbacks[resources.PORT][events.BEFORE_CREATE])
|
||||
self.assertIn(
|
||||
callback_id_2,
|
||||
self.manager._callbacks[resources.PORT][events.BEFORE_DELETE])
|
||||
self.assertNotIn(callback_id_1, self.manager._index)
|
||||
|
||||
def test_unsubscribe_all(self):
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_CREATE)
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_DELETE)
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.ROUTER, events.BEFORE_CREATE)
|
||||
self.manager.unsubscribe_all(callback_1)
|
||||
self.assertNotIn(
|
||||
callback_id_1,
|
||||
self.manager._callbacks[resources.PORT][events.BEFORE_CREATE])
|
||||
self.assertNotIn(callback_id_1, self.manager._index)
|
||||
|
||||
def test_notify_none(self):
|
||||
self.manager.notify(resources.PORT, events.BEFORE_CREATE, mock.ANY)
|
||||
self.assertEqual(0, callback_1.counter)
|
||||
self.assertEqual(0, callback_2.counter)
|
||||
|
||||
def test_notify_with_exception(self):
|
||||
with mock.patch.object(self.manager, '_notify_loop') as n:
|
||||
n.return_value = ['error']
|
||||
self.assertRaises(exceptions.CallbackFailure,
|
||||
self.manager.notify,
|
||||
mock.ANY, events.BEFORE_CREATE, mock.ANY)
|
||||
expected_calls = [
|
||||
mock.call(mock.ANY, 'before_create', mock.ANY),
|
||||
mock.call(mock.ANY, 'abort_create', mock.ANY)
|
||||
]
|
||||
n.assert_has_calls(expected_calls)
|
||||
|
||||
def test_notify_handle_exception(self):
|
||||
self.manager.subscribe(
|
||||
callback_raise, resources.PORT, events.BEFORE_CREATE)
|
||||
e = self.assertRaises(exceptions.CallbackFailure, self.manager.notify,
|
||||
resources.PORT, events.BEFORE_CREATE, self)
|
||||
self.assertIsInstance(e.errors[0], exceptions.NotificationError)
|
||||
|
||||
def test_notify_called_once_with_no_failures(self):
|
||||
with mock.patch.object(self.manager, '_notify_loop') as n:
|
||||
n.return_value = False
|
||||
self.manager.notify(resources.PORT, events.BEFORE_CREATE, mock.ANY)
|
||||
n.assert_called_once_with(
|
||||
resources.PORT, events.BEFORE_CREATE, mock.ANY)
|
||||
|
||||
def test__notify_loop_single_event(self):
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_CREATE)
|
||||
self.manager.subscribe(
|
||||
callback_2, resources.PORT, events.BEFORE_CREATE)
|
||||
self.manager._notify_loop(
|
||||
resources.PORT, events.BEFORE_CREATE, mock.ANY)
|
||||
self.assertEqual(1, callback_1.counter)
|
||||
self.assertEqual(1, callback_2.counter)
|
||||
|
||||
def test__notify_loop_multiple_events(self):
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.PORT, events.BEFORE_CREATE)
|
||||
self.manager.subscribe(
|
||||
callback_1, resources.ROUTER, events.BEFORE_DELETE)
|
||||
self.manager.subscribe(
|
||||
callback_2, resources.PORT, events.BEFORE_CREATE)
|
||||
self.manager._notify_loop(
|
||||
resources.PORT, events.BEFORE_CREATE, mock.ANY)
|
||||
self.manager._notify_loop(
|
||||
resources.ROUTER, events.BEFORE_DELETE, mock.ANY)
|
||||
self.assertEqual(2, callback_1.counter)
|
||||
self.assertEqual(1, callback_2.counter)
|
||||
Loading…
Reference in New Issue