Off-chain protocols

This package defines the off-chain protocols for managing channels. These protocols are abstract rules which nodes should follow in order to reach a desired goal.

To implement the protocols, we make use of an abstraction we call the Objective. Objectives are named for the goal which the off-chain protocol aspires to achieve.

The following table shows some example objectives and their implemetation status:

Objective type	Implemented
direct-fund	x
direct-defund	x
virtual-fund	x
virtual-defund	x
challenge

The set of objectives comprises the functional core of a go-nitro node. They expose only pure functions -- but otherwise take on as much responsibility as possible, leaving only a small amount of responsibility to an imperative shell.

Each Objective type is implemented by a Go struct implementing the Objective interface. Each instance of an Objective type will hold its own data.

The imperative shell will typically be responsible for:

• spawning new objective instances of one type or another
• reading and persisting objectives to and from a store.
• listening to peers and the blockchain for events relevant to the objective
• "updating" objectives by passing events to their Update(event) function (an updated copy is returned)
• "cranking" objectives by calling Crank() (side effects are returned)
• executing side effects