Module events

Subscribable events that are published when significant things happen in the replica.

Event enum

Significant occurences in the replica include committing a block, starting a new view, broadcasting a proposal, or receiving a proposal.

Each of these significant occurences correspond to a variant of the event enum. Each variant tuple in turn contains an inner struct type. For example, the insert block variant contains the InsertBlockEvent struct type.

Each inner struct stores information that summarizes the particular kind of event. This information always includes a timestamp corresponding to the exact time when the event occured.

Registering event handlers

Library users can register event handler closures, these are internally called by the library’s event bus thread when the handler’s particular event variant happens.

Custom event handlers can be registered using the replica builder pattern, while default event handlers that log out events (e.g., into the terminal, or into a log file) can be enabled in the configuration.

Timing

Events are always emitted after the corresponding occurence is “completed”. So for example, the insert block event is only emitted after the insertion has been persisted into the backing storage of the block tree.

Structs

• AdvanceViewEvent
  The replica broadcasted an advance view message to all peers.
• CollectPCEvent
  The replica collected a new phase_certificate from the votes it received from the validators in the current view.
• CollectTCEvent
  The replica collected a new timeout_certificate from the votes it received from the validators in the current view.
• CommitBlockEvent
  A block was committed. This involves persistent changes to the Block Tree.
• EndSyncEvent
  The replica exited sync mode, during which it tried to sync with a given peer identifiable by its public key, and inserted a given number of blocks received from the peer into its block tree.
• InsertBlockEvent
  A new block was inserted into the Block Tree in a persistent manner.
• NewViewEvent
  The replica sent a new view message for its current view to the leader of the next view upon moving to a new view.
• NudgeEvent
  The replica nudged for a block by broadcasting a nudge for the block to all validators.
• PhaseVoteEvent
  The replica voted for a phase of a block by sending phase_vote to a leader of the next view.
• ProposeEvent
  The replica proposed a block by broadcasting it as a proposal to all validators.
• PruneBlockEvent
  A block was “pruned” (i.e., the block’s siblings were permanently deleted from the Block Tree).
• ReceiveAdvanceViewEvent
  The replica received an advance_view message from another replica, identified by its verifying_key.
• ReceiveNewViewEvent
  The replica received a new view message for the current view from another replica identifiable by its public key.
• ReceiveNudgeEvent
  The replica received a nudge for the replica’s current view from the leader of the view, identified by its VerifyingKey.
• ReceivePhaseVoteEvent
  The replica received a phase_vote for the replica’s current view from the replica identified by origin.
• ReceiveProposalEvent
  The replica received a proposal for the replica’s current view from the leader of the view, identified by its VerifyingKey.
• ReceiveSyncRequestEvent
  The replica’s sync server received a sync request from a peer identifiable by its public key. Includes information about the requested start height from which the peer wants to sync, and the limit on the number of blocks that can be sent in a sync response.
• ReceiveTimeoutVoteEvent
  The replica received a timeout_certificate for the replica’s current view from another replica, identified by verifying_key.
• SendSyncResponseEvent
  The replica’s sync server sent a sync response to a peer identifiable by its public key. Includes information about the vector of blocks and the Highest Quroum Certificate sent to the peer.
• StartSyncEvent
  The replica entered sync mode and tried to sync with a given peer, identified by its VerifyingKey.
• StartViewEvent
  The replica started a new view with a given ViewNumber.
• TimeoutVoteEvent
  The replica broadcasted a timeout vote message to all peers.
• UpdateHighestPCEvent
  The “Highest PhaseCertificate” stored in the block tree was updated.
• UpdateHighestTCEvent
  The “Highest TimeoutCertificate” stored in the block tree was updated.
• UpdateLockedPCEvent
  The “Locked PhaseCertificate” stored in the block tree was updated.
• UpdateValidatorSetEvent
  The “Committed Validator Set” stored in the block tree, was updated.
• ViewTimeoutEvent
  The replica’s view, with a given ViewNumber, timed out.

Enums

• Event
  Enumerates all events defined for HotStuff-rs.