These are visible on the grafana dashboard,
in order to be able to see on which commit
stats have been recorded.
It's enabled via: `-Dakka.sbt.graphite=true`
Resolves#15103
Instead of isTerminated we now use death watch on subscribers.
! Breaking change - ActorClassification based event buses now require
and actor system. Previously no actors were involved, but now someone
has to `watch` the subscribers. The unsubscriber is an system actor,
and won't be stopped automagically if a bus stops to be used (hard to
determine what "stops being used" is)
* Replaced isTerminated checks with watching actors
* backing structure for ActorClassification swaped from
ConcurrentHashMap to immutable.Map with CAS operations on it. This is
required to avoid races and guarantee register/unregister ordering
(messages sent with proper sequence numbers) to the unsubscriber.
Performance tested it and still above 1.3million subscribe+unsubscribe
ops per second (mac i7, retina), where as the CHM version was
4 million - but that one could only work in the presence of
itTerminated - so we pay the price here for removing it.
* `ActorClassification` starts the unsubscriber instance by itself,
the unsubscriber is an system actor, and can be stopped via
`ActorClassification#shutdown`
* Will unregister from unsubscriber, when no more subscriptions for
given subscriber are left in this bus.
* Added missing "Java API: " for some types
* Updated docs to point out the automatic subscriber purging (on terminated)
* Replace stash with internal bufferi, j.u.LinkedList
* Replace FSM with become
* Adaptive backoff, important to backoff, but not for too long,
depends on environment and use case
* Prioritize heartbeat messages from remote watcher and cluster
failure detector
* Use payload messages as heartbeats for transport failure detector,
change transport failure detector to be based on absolute timeout,
see ticket #13989 and #13742
* Log remote disassociate from transport failure detector,
see ticket #13985
* Add benchmark sample in akka-sample-remote-scala
* Moved to removing actors proactively when they are terminated instead of
checking `isTerminated` during publish.
* Subscribers which have registered before initializing the unsubscriber
will be aggregated in a Seq until one is registered and then it will
take responsibility of unregistering them on termination.
* Initialization of the unsubscriber can only be run once - attempting
to initialize the event stream with another unsubscriber will fail,
and init will return false.
* Assumed having an init (mutable) method on the `EventBus` is fine, as
it has such methods already and @patriknw's comment in the task for
this.
* since we must check if the subscriber has any subscribed channels left
we had to expose this detail from SubchannelClassification via
`hasSubscriptions`. Increases cost of ubsubscribe(actor, channel) a bit.
* Evacuated the expensive `hasSubscription` call out of eventstream's `unsubscribe` call, and instead making the Unsubscriber check this before it stops watching an actor. If in the mean time the same actor got subscribed, there will be a new Subscribe message emited - so we're good on that side. Also, if it would terminate before the unsubscriber gets the Register message it will call `watch(actor)` on a dead actor, which results in getting Terminated for it, thus we'll stop watching it from the Unsubscriber as expected.
Final squash and small cleanup. Please review again;
Two changes have been made:
- In AkkaBuild, forced using UTF-8 to verify HTML files containing
diagrams
- In the documentation chapter Building Akka, added a section clarifying
the Graphviz dependency of generating Scaladoc Content Hierarchies
These fixes eliminates the issues I faced while building Akka on Windows
with NetBeans. The first issue is a Windows specific issue where the
default charset cannot be UTF-8. The second is Windows related in the
sense that Graphviz, the optional dependency of Scaladoc, had to be
manually resolved.
