EVENTSTREAM_EVENTS.md

EventStream events in Proto.Remote and Proto.Cluster

This document lists key events published on Proto.Actor's EventStream and how they coordinate behaviour between the Remote and Cluster modules. For each event we show who publishes it, when it is raised, and which components subscribe to it.

MemberBlocked

• Published by: BlockList when new member IDs are added to the block list (e.g. unresponsive or leaving members) (src/Proto.Remote/BlockList.cs)
• Subscribed by: MemberList to log the block and recompute topology. If the local node is blocked it invokes SelfBlocked (src/Proto.Cluster/Membership/MemberList.cs)

EndpointTerminatedEvent

• Published by:
  • ServerConnector when a remote connection is refused or fails (src/Proto.Remote/Endpoints/ServerConnector.cs and src/Proto.Remote/Endpoints/ServerConnector.cs)
  • RemotingGrpcService when a channel closes (src/Proto.Remote/Endpoints/RemotingGrpcService.cs)
  • MemberList when a cluster member leaves (src/Proto.Cluster/Membership/MemberList.cs)
• Subscribed by: EndpointManager which disposes the endpoint and optionally blocks the address or system ID (src/Proto.Remote/Endpoints/EndpointManager.cs and src/Proto.Remote/Endpoints/EndpointManager.cs)

ClusterTopology

• Published by: MemberList.UpdateClusterTopology whenever membership changes (join/leave/block) and broadcast to all members (src/Proto.Cluster/Membership/MemberList.cs and src/Proto.Cluster/Membership/MemberList.cs)
• Subscribed by: many cluster components, for example:
  • Cluster removes cached PIDs for members that left (src/Proto.Cluster/Cluster.cs)
  • PartitionManager updates placement selectors and forwards the update to partition actors (src/Proto.Cluster/Partition/PartitionManager.cs)
  • IdentityStorageLookup cleans storage for departing members (src/Proto.Cluster/Identity/IdentityStorageLookup.cs)

ActivationTerminating

• Published by: ClusterExtension when a cluster-identity actor is stopping (src/Proto.Cluster/ClusterExtension.cs)
• Subscribed by: placement/activation actors to remove local state and broadcast termination:
  • PartitionActivatorActor subscribes on start (src/Proto.Cluster/PartitionActivator/PartitionActivatorActor.cs)
  • PartitionPlacementActor subscribes and forwards the event to itself (src/Proto.Cluster/Partition/PartitionPlacementActor.cs)
  • IdentityStoragePlacementActor subscribes for clean-up (src/Proto.Cluster/Identity/IdentityStoragePlacementActor.cs)

ActivationTerminated

• Published by: actors handling ActivationTerminating; e.g. PartitionActivatorActor broadcasts the termination to all nodes so caches can be cleared (src/Proto.Cluster/PartitionActivator/PartitionActivatorActor.cs)
• Subscribed by: components maintaining activation indexes/caches, such as PartitionIdentityActor, which removes the PID and clears the cache on receipt (src/Proto.Cluster/Partition/PartitionIdentityActor.cs and src/Proto.Cluster/Partition/PartitionIdentityActor.cs)

GossipUpdate

• Published by: GossipActor for each gossip state update received from a peer (src/Proto.Cluster/Gossip/GossipActor.cs)
• Subscribed by:
  • MemberList to merge block lists learned via gossip (src/Proto.Cluster/Membership/MemberList.cs)
  • GossipMemberStrategy to track member heartbeats and actor counts (src/Proto.Cluster/Membership/GossipMemberStrategy.cs)

DeadLetterEvent

• Published by: remote endpoints when a message cannot be delivered, either by the endpoint itself or when targeting a blocked address (src/Proto.Remote/Endpoints/Endpoint.cs, src/Proto.Remote/Endpoints/Endpoint.cs and src/Proto.Remote/Endpoints/BlockedEndpoint.cs)
• Subscribed by: optional diagnostics subscribers; no core cluster/remote component subscribes by default.

These events provide loose coupling between modules, allowing remote and cluster infrastructure to react to membership changes, connection failures, and activation lifecycle events.