consensus

Overview ¶

Package consensus provides a blockchain consensus finding system. It allows client programs to submit blocks to be tracked and to retrieve the 'best' head block for the next round of block computation. A lightweight block interface is provided to allow the package to retrieve basic information about the block.

The default criteria for branch comparison is blockchain height. Client programs may provide a comparator function to inject their own criteria for evaluation.

Example pseudo code of client program:

var c *Consensus = consensus.NewConsensusConsensus(0, nil)
...

// This function is called whenever a block is received from the network
// MyBlock implements the consensus.Block interface
func receiveBlockFromNetwork(b MyBlock) {
	if !c.WasSeen(b) {
		// preform any validation or processing required to
		// ensure block is worthy of submission
		if validate(b) {
			c.AddBlock(b)
		}
	}
}

// This function continuously competes for the next block
func competeForBlocks() {
	for {
		// don't peg the CPU
		// MyBlock implements the consensus.Block interface

		branch := c.GetBestBranch()
		if branch == nil {
			// no best branch is available, wait for more blocks
			time.Sleep(50)
			// to come in from the network
			continue
		}

		// generate the next block based on the head of the best branch
		var head MyBlock = branch[0].(MyBlock)
		var nextBlock MyBlock = generateNextBlock(head)
		c.setCompeted(head)
		sendBlockToNetwork(nextBlock)
		c.AddBlock(nextBlock)
	}
}