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

Controller {
    ViewBuilder
    View
    ViewChanged(id int)
}

The ViewBuilder helps Controller 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 Controller.

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 Controller 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 LogEntry is an entry that the library wishes to be persisted in the Write Ahead Log (WAL). The TruncateBefore is a hint to the WAL that every LogEntry before can be safely erased.

LogEntry {
    Value []byte
    TruncateBefore bool
}