区块链教程Fabric1.0源代码分析Orderer multichain,2018年下半年,区块链行业正逐渐褪去发展之初的浮躁、回归理性,表面上看相关人才需求与身价似乎正在回落。但事实上,正是初期泡沫的渐退,让人们更多的关注点放在了区块链真正的技术之上。

Fabric 1.0源代码笔记 之 Orderer #multichain(多链支持包)

1、multichain概述

multichain代码集中在orderer/multichain目录下,目录结构如下:

• manager.go,Manager接口定义及实现。
• chainsupport.go,ChainSupport接口定义及实现。
• systemchain.go,system chain。

2、Manager接口定义及实现

2.1、Manager接口定义

用于链的创建和访问。

type Manager interface {
  //获取ChainSupport,以及判断链是否存在
  GetChain(chainID string) (ChainSupport, bool)
  //获取系统通道的通道ID
  SystemChannelID() string
  //支持通道创建请求
  NewChannelConfig(envConfigUpdate *cb.Envelope) (configtxapi.Manager, error)
}
//代码在orderer/multichain/manager.go

2.2、Manager接口实现

Manager接口实现,即multiLedger结构体及方法。

type multiLedger struct {
  chains map[string]*chainSupport
  consenters map[string]Consenter
  ledgerFactory ledger.Factory
  signer crypto.LocalSigner
  systemChannelID string
  systemChannel *chainSupport
}
type configResources struct {
  configtxapi.Manager
}
type ledgerResources struct {
  *configResources
  ledger ledger.ReadWriter
}
//代码在orderer/multichain/manager.go

涉及方法如下:

func (cr *configResources) SharedConfig() config.Orderer
//获取配置交易Envelope
func getConfigTx(reader ledger.Reader) *cb.Envelope
//构造multiLedger
func NewManagerImpl(ledgerFactory ledger.Factory, consenters map[string]Consenter, signer crypto.LocalSigner) Manager
//获取系统链ID
func (ml *multiLedger) SystemChannelID() string
//按chainID获取ChainSupport
func (ml *multiLedger) GetChain(chainID string) (ChainSupport, bool)
//构造ledgerResources
func (ml *multiLedger) newLedgerResources(configTx *cb.Envelope) *ledgerResources
//创建新链
func (ml *multiLedger) newChain(configtx *cb.Envelope)
//通道或链的个数
func (ml *multiLedger) channelsCount() int
//支持创建新的通道
func (ml *multiLedger) NewChannelConfig(envConfigUpdate *cb.Envelope) (configtxapi.Manager, error)
//代码在orderer/multichain/manager.go

func NewManagerImpl(ledgerFactory ledger.Factory, consenters map[string]Consenter, signer crypto.LocalSigner) Manager代码如下:

func NewManagerImpl(ledgerFactory ledger.Factory, consenters map[string]Consenter, signer crypto.LocalSigner) Manager {
  ml := &multiLedger{
    chains: make(map[string]*chainSupport),
    ledgerFactory: ledgerFactory,
    consenters: consenters,
    signer: signer,
  }
  existingChains := ledgerFactory.ChainIDs()
  for _, chainID := range existingChains {
    rl, err := ledgerFactory.GetOrCreate(chainID)
    configTx := getConfigTx(rl)
    ledgerResources := ml.newLedgerResources(configTx)
    chainID := ledgerResources.ChainID()
    if _, ok := ledgerResources.ConsortiumsConfig(); ok { //系统链
      chain := newChainSupport(createSystemChainFilters(ml, ledgerResources), ledgerResources, consenters, signer)
      ml.chains[chainID] = chain
      ml.systemChannelID = chainID
      ml.systemChannel = chain
      defer chain.start()
    } else { //普通链
      chain := newChainSupport(createStandardFilters(ledgerResources), ledgerResources, consenters, signer)
      ml.chains[chainID] = chain
      chain.start()
    }
  }
  return ml
}
//代码在orderer/multichain/manager.go

3、ChainSupport接口定义及实现

3.1、ChainSupport接口定义

type ChainSupport interface {
  PolicyManager() policies.Manager //策略管理
  Reader() ledger.Reader
  Errored() <-chan struct{}
  broadcast.Support
  ConsenterSupport //嵌入ConsenterSupport接口
  Sequence() uint64
  //支持通道更新
  ProposeConfigUpdate(env *cb.Envelope) (*cb.ConfigEnvelope, error)
}
type ConsenterSupport interface {
  crypto.LocalSigner
  BlockCutter() blockcutter.Receiver
  SharedConfig() config.Orderer
  CreateNextBlock(messages []*cb.Envelope) *cb.Block
  WriteBlock(block *cb.Block, committers []filter.Committer, encodedMetadataValue []byte) *cb.Block
  ChainID() string
  Height() uint64
}
type Consenter interface { //定义支持排序机制
  HandleChain(support ConsenterSupport, metadata *cb.Metadata) (Chain, error)
}
type Chain interface {
  //接受消息
  Enqueue(env *cb.Envelope) bool
  Errored() <-chan struct{}
  Start() //开始
  Halt() //挂起
}
//代码在orderer/multichain/chainsupport.go

3.2、ChainSupport和ConsenterSupport接口实现

ChainSupport接口实现,即chainSupport结构体及方法。

type chainSupport struct {
  *ledgerResources
  chain Chain
  cutter blockcutter.Receiver
  filters *filter.RuleSet
  signer crypto.LocalSigner
  lastConfig uint64
  lastConfigSeq uint64
}
//代码在orderer/multichain/chainsupport.go

涉及方法如下:

//构造chainSupport
func newChainSupport(filters *filter.RuleSet,ledgerResources *ledgerResources,consenters map[string]Consenter,signer crypto.LocalSigner,) *chainSupport
func createStandardFilters(ledgerResources *ledgerResources) *filter.RuleSet
func createSystemChainFilters(ml *multiLedger, ledgerResources *ledgerResources) *filter.RuleSet
func (cs *chainSupport) start()
func (cs *chainSupport) NewSignatureHeader() (*cb.SignatureHeader, error)
func (cs *chainSupport) Sign(message []byte) ([]byte, error)
func (cs *chainSupport) Filters() *filter.RuleSet
func (cs *chainSupport) BlockCutter() blockcutter.Receiver
func (cs *chainSupport) Reader() ledger.Reader
func (cs *chainSupport) Enqueue(env *cb.Envelope) bool
func (cs *chainSupport) Errored() <-chan struct{}
//创建块,调取ledger.CreateNextBlock(cs.ledger, messages)
func (cs *chainSupport) CreateNextBlock(messages []*cb.Envelope) *cb.Block
func (cs *chainSupport) addBlockSignature(block *cb.Block)
func (cs *chainSupport) addLastConfigSignature(block *cb.Block)
//写入块
func (cs *chainSupport) WriteBlock(block *cb.Block, committers []filter.Committer, encodedMetadataValue []byte) *cb.Block 
func (cs *chainSupport) Height() uint64
//代码在orderer/multichain/chainsupport.go

func (cs chainSupport) WriteBlock(block cb.Block, committers []filter.Committer, encodedMetadataValue []byte) *cb.Block 代码如下:

func (cs *chainSupport) WriteBlock(block *cb.Block, committers []filter.Committer, encodedMetadataValue []byte) *cb.Block {
  for _, committer := range committers {
    committer.Commit()
  }
  cs.addBlockSignature(block)
  cs.addLastConfigSignature(block)
  err := cs.ledger.Append(block)//账本追加块
  return block
}
//代码在orderer/multichain/chainsupport.go

本文来自:Segmentfault

感谢作者:兄弟连区块链培训

查看原文:区块链教程Fabric1.0源代码分析Orderer multichain

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