Types

A Proposal is the subject on which all nodes need to reach consensus.

Proposal {
    Payload []byte
    Header []byte
    Metadata []byte	
    VerificationSequence uint64
}

A View has a designated leader and followers. It runs all three phases (prePrepare, prepare, and commit) on the proposals. It can abort on demand.

View {
    Propose(p Proposal) 
    OnReceive(m Message)
    Abort()
}

The Consensus runs the different views, proposes values and delivers the decisions. It also aborts views when they must be changed.

Consensus {
    ViewBuilder
    View
    ViewChanged(id int)
}

The ViewBuilder helps Consensus building new views.

ViewBuilder {
    BuildView(id int, members []int, d Decider, vc ViewChanger) View
}

The Decider delivers the decisions (agreed proposals and signatures) to the Consensus.

Decider {
    Decide(p Proposal, signatures []Signature)
}

The ViewChanger collects the requests to change the current view and runs the view change protocol when needed. It informs the Consensus of the new view.

ViewChanger {
    OnReceive(m Message)
}

The Timeouter is used to track timing. It is started with a given duration and a function to call if the duration passes. When it is started it returns a cancel call to use if an abort of the timeout is required.

Timeouter {
    StartTimer(Duration, func) Cancel
}

A Signature used to prove that a node with a given Id signed something.

Signature {
    Id uint64
    Value []byte
}

A RequestPool dispatches request submissions by the application layer, and tracks their inclusion into blocks, and raises a re-transmission of them to the cluster upon a first timeout, and complains to the view changer upon a second timeout.

RequestPool {
      Submit(request []byte)
}

A Synchronizer reaches the cluster nodes and fetches blocks in order to sync the replica's state. An invocation of Sync() blocks indefinitely until the replica's state is synchronized to the latest verification sequence.

Synchronizer {
     Sync()
}