担忧与可用性的分离

Question

I have always struggled keeping go modules neatly separated and avoiding cyclic dependencies.

Right now I have code like this:

    package chain


type Block struct{
    Content []byte
    Number int
}

var Chain []Block = make([]Block, 10)

func AddBlockToChain(block Block){
    // do some checks
    //...
    // add to chain
    Chain[block.Number] = block
}

func GetBlock(number int) Block {
    // do some checks
    //  ...
    // get from chain
    return Chain[number]
}

To achieve consensus I need some extra info on the block. The info may be different depending on which consensus algorithm I use. I want the consensus algorithm to be interchangeable (e.g. by flag on start up).

It would be convenient to store the info as fields in the block, so that when I call GetBlock(3) or get a block from anywhere else I can not only access the block but also the info on what state of consensus this block is in at the moment.

On the other hand I wanted to keep data that is only relevant for a certain consensus algorithm separate from basic block data - maybe even in a separate package.

How should I design my program? Where should I keep data relevant for a certain consensus algorithm?

Some background info:

I am trying to build a block chain application from scratch. I have a "chain" module responsible for storing blocks of data and a "consensus" module responsible for creating consensus between multiple peers running an instance of my program on what that data is.

Answer 1

consensus.Block and chain.Block are two separate types but since you are embeddding chain.Block in consensus.Block, you can access one from another.

Just pass consensus.Block in AddBlockToChain():

`func AddBlockToChain(block consensus.Block)`

and then access it by: block.Block

Example:

package main

import "fmt"

type ChainBlock struct {
    id int
}

type ConsensusBlock struct {
    ChainBlock
    idCons int
}

func printChainBlockId(consBlock ConsensusBlock) {
    fmt.Println(consBlock.ChainBlock.id)
}

func main() {
    test := ConsensusBlock{
        ChainBlock: ChainBlock{
            id: 42,
        },
        idCons: 44,
    }

    printChainBlockId(admin)
}