区块链教程Fabric1.0源代码分析configupdate处理通道配置更新，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 #configupdate（处理通道配置更新）

1、configupdate概述

configupdate，用于接收配置交易，并处理通道配置更新。
相关代码在orderer/configupdate目录。

2、SupportManager接口定义及实现

2.1、SupportManager接口定义

type SupportManager interface {
    GetChain(chainID string) (Support, bool)
    NewChannelConfig(envConfigUpdate *cb.Envelope) (configtxapi.Manager, error)
}
//代码在orderer/configupdate/configupdate.go

2.2、SupportManager接口实现

SupportManager接口实现，即configUpdateSupport结构体及方法。

type configUpdateSupport struct {
    multichain.Manager //type multiLedger struct
}

func (cus configUpdateSupport) GetChain(chainID string) (configupdate.Support, bool) {
    return cus.Manager.GetChain(chainID)
}
//代码在orderer/server.go

multichain.Manager接口及实现multiLedger，见Fabric 1.0源代码笔记 之 Orderer #multichain（多链支持包）

3、Support接口定义及实现

3.1、Support接口定义

type Support interface {
    ProposeConfigUpdate(env *cb.Envelope) (*cb.ConfigEnvelope, error)
}
//代码在orderer/configupdate/configupdate.go

3.2、Support接口实现

Support接口实现，即configManager结构体及方法。

type configManager struct {
    api.Resources
    callOnUpdate []func(api.Manager)
    initializer  api.Initializer
    current      *configSet
}

func (cm *configManager) processConfig(channelGroup *cb.ConfigGroup) (*configResult, error) //./config.go
func (cm *configManager) commitCallbacks() //./manager.go
func (cm *configManager) ProposeConfigUpdate(configtx *cb.Envelope) (*cb.ConfigEnvelope, error) //./manager.go
func (cm *configManager) proposeConfigUpdate(configtx *cb.Envelope) (*cb.ConfigEnvelope, error) //./manager.go
func (cm *configManager) prepareApply(configEnv *cb.ConfigEnvelope) (*configResult, error) //./manager.go
func (cm *configManager) Validate(configEnv *cb.ConfigEnvelope) error //./manager.go
func (cm *configManager) Apply(configEnv *cb.ConfigEnvelope) error //./manager.go
func (cm *configManager) ChainID() string //./manager.go
func (cm *configManager) Sequence() uint64 //./manager.go
func (cm *configManager) ConfigEnvelope() *cb.ConfigEnvelope //./manager.go
func (cm *configManager) verifyDeltaSet(deltaSet map[string]comparable, signedData []*cb.SignedData) error //./update.go
func (cm *configManager) authorizeUpdate(configUpdateEnv *cb.ConfigUpdateEnvelope) (map[string]comparable, error) //./update.go
func (cm *configManager) policyForItem(item comparable) (policies.Policy, bool) //./update.go
func (cm *configManager) computeUpdateResult(updatedConfig map[string]comparable) map[string]comparable //./update.go
//代码在common/configtx/manager.go

4、ConfigUpdateProcessor接口定义及实现

4.1、ConfigUpdateProcessor接口定义

type ConfigUpdateProcessor interface {
    Process(envConfigUpdate *cb.Envelope) (*cb.Envelope, error)
}
//代码在orderer/common/broadcast/broadcast.go

4.2、ConfigUpdateProcessor接口实现

ConfigUpdateProcessor接口实现，即Processor结构体及方法。

type Processor struct {
    signer               crypto.LocalSigner
    manager              SupportManager //即type configUpdateSupport struct，或者即multichain.multiLedger
    systemChannelID      string
    systemChannelSupport Support
}

//构造Processor
func New(systemChannelID string, supportManager SupportManager, signer crypto.LocalSigner) *Processor
//获取channelID
func channelID(env *cb.Envelope) (string, error) 
//处理通道配置更新
func (p *Processor) Process(envConfigUpdate *cb.Envelope) (*cb.Envelope, error)
func (p *Processor) existingChannelConfig(envConfigUpdate *cb.Envelope, channelID string, support Support) (*cb.Envelope, error)
func (p *Processor) proposeNewChannelToSystemChannel(newChannelEnvConfig *cb.Envelope) (*cb.Envelope, error)
func (p *Processor) newChannelConfig(channelID string, envConfigUpdate *cb.Envelope) (*cb.Envelope, error)
//代码在orderer/configupdate/configupdate.go

4.2.1、func New(systemChannelID string, supportManager SupportManager, signer crypto.LocalSigner) *Processor

func New(systemChannelID string, supportManager SupportManager, signer crypto.LocalSigner) *Processor {
    support, ok := supportManager.GetChain(systemChannelID)
    return &Processor{
        systemChannelID:      systemChannelID,
        manager:              supportManager,
        signer:               signer,
        systemChannelSupport: support,
    }
}
//代码在orderer/configupdate/configupdate.go

4.2.2、func (p Processor) Process(envConfigUpdate cb.Envelope) (*cb.Envelope, error)

func (p *Processor) Process(envConfigUpdate *cb.Envelope) (*cb.Envelope, error) {
    channelID, err := channelID(envConfigUpdate)
    support, ok := p.manager.GetChain(channelID) //存在
    if ok {
        return p.existingChannelConfig(envConfigUpdate, channelID, support)
    }
    return p.newChannelConfig(channelID, envConfigUpdate) //不存在
}
//代码在orderer/configupdate/configupdate.go

4.2.3、func (p Processor) existingChannelConfig(envConfigUpdate cb.Envelope, channelID string, support Support) (*cb.Envelope, error)

func (p *Processor) existingChannelConfig(envConfigUpdate *cb.Envelope, channelID string, support Support) (*cb.Envelope, error) {
    configEnvelope, err := support.ProposeConfigUpdate(envConfigUpdate)
    return utils.CreateSignedEnvelope(cb.HeaderType_CONFIG, channelID, p.signer, configEnvelope, msgVersion, epoch)
}
//代码在orderer/configupdate/configupdate.go

4.2.4、func (p Processor) newChannelConfig(channelID string, envConfigUpdate cb.Envelope) (*cb.Envelope, error)

func (p *Processor) newChannelConfig(channelID string, envConfigUpdate *cb.Envelope) (*cb.Envelope, error) {
    ctxm, err := p.manager.NewChannelConfig(envConfigUpdate) //创建新的通道
    newChannelConfigEnv, err := ctxm.ProposeConfigUpdate(envConfigUpdate) //创建新的通道后处理通道配置
    newChannelEnvConfig, err := utils.CreateSignedEnvelope(cb.HeaderType_CONFIG, channelID, p.signer, newChannelConfigEnv, msgVersion, epoch)
    return p.proposeNewChannelToSystemChannel(newChannelEnvConfig)
}
//代码在orderer/configupdate/configupdate.go

5、详解configManager结构体

5.1、configManager结构体定义及方法

type configManager struct {
    api.Resources
    callOnUpdate []func(api.Manager)
    initializer  api.Initializer
    current      *configSet
}

func validateConfigID(configID string) error
func validateChannelID(channelID string) error
func NewManagerImpl(envConfig *cb.Envelope, initializer api.Initializer, callOnUpdate []func(api.Manager)) (api.Manager, error)
func (cm *configManager) commitCallbacks()
func (cm *configManager) ProposeConfigUpdate(configtx *cb.Envelope) (*cb.ConfigEnvelope, error)
func (cm *configManager) proposeConfigUpdate(configtx *cb.Envelope) (*cb.ConfigEnvelope, error)
func (cm *configManager) prepareApply(configEnv *cb.ConfigEnvelope) (*configResult, error)
func (cm *configManager) Validate(configEnv *cb.ConfigEnvelope) error
func (cm *configManager) Apply(configEnv *cb.ConfigEnvelope) error
func (cm *configManager) ChainID() string
func (cm *configManager) Sequence() uint64
func (cm *configManager) ConfigEnvelope() *cb.ConfigEnvelope

func proposeGroup(result *configResult) error
func processConfig(channelGroup *cb.ConfigGroup, proposer api.Proposer) (*configResult, error)
func (cm *configManager) processConfig(channelGroup *cb.ConfigGroup) (*configResult, error)

func (c *configSet) verifyReadSet(readSet map[string]comparable) error
func ComputeDeltaSet(readSet, writeSet map[string]comparable) map[string]comparable
func validateModPolicy(modPolicy string) error
func (cm *configManager) verifyDeltaSet(deltaSet map[string]comparable, signedData []*cb.SignedData) error
func verifyFullProposedConfig(writeSet, fullProposedConfig map[string]comparable) error
//验证所有修改的配置都有相应的修改策略，返回修改过的配置的映射map[string]comparable
func (cm *configManager) authorizeUpdate(configUpdateEnv *cb.ConfigUpdateEnvelope) (map[string]comparable, error)
func (cm *configManager) policyForItem(item comparable) (policies.Policy, bool)
func (cm *configManager) computeUpdateResult(updatedConfig map[string]comparable) map[string]comparable
//Envelope转换为ConfigUpdateEnvelope
func envelopeToConfigUpdate(configtx *cb.Envelope) (*cb.ConfigUpdateEnvelope, error)
//代码在common/configtx/manager.go

5.2、func (cm configManager) ProposeConfigUpdate(configtx cb.Envelope) (*cb.ConfigEnvelope, error)

func (cm *configManager) ProposeConfigUpdate(configtx *cb.Envelope) (*cb.ConfigEnvelope, error) {
    return cm.proposeConfigUpdate(configtx)
}

func (cm *configManager) proposeConfigUpdate(configtx *cb.Envelope) (*cb.ConfigEnvelope, error) {
    //Envelope转换为ConfigUpdateEnvelope
    configUpdateEnv, err := envelopeToConfigUpdate(configtx)
    //验证所有修改的配置都有相应的修改策略，返回修改过的配置的映射map[string]comparable
    configMap, err := cm.authorizeUpdate(configUpdateEnv)
    channelGroup, err := configMapToConfig(configMap) //ConfigGroup
    //实际调用processConfig(channelGroup, cm.initializer)，并最终调用proposeGroup(configResult)
    result, err := cm.processConfig(channelGroup)
    result.rollback()
    return &cb.ConfigEnvelope{
        Config: &cb.Config{
            Sequence:     cm.current.sequence + 1,
            ChannelGroup: channelGroup,
        },
        LastUpdate: configtx,
    }, nil
}
//代码在common/configtx/manager.go

补充ConfigUpdateEnvelope:

type ConfigUpdateEnvelope struct {
    ConfigUpdate []byte //type ConfigUpdate struct
    Signatures   []*ConfigSignature
}

type ConfigUpdate struct {
    ChannelId string
    ReadSet   *ConfigGroup
    WriteSet  *ConfigGroup
}

type ConfigGroup struct {
    Version   uint64
    Groups    map[string]*ConfigGroup
    Values    map[string]*ConfigValue
    Policies  map[string]*ConfigPolicy
    ModPolicy string
}
//代码在protos/common/configtx.pb.go

补充ConfigGroup:

### 5.3、func (cm *configManager) authorizeUpdate(configUpdateEnv *cb.ConfigUpdateEnvelope) (map[string]comparable, error)

func (cm configManager) authorizeUpdate(configUpdateEnv cb.ConfigUpdateEnvelope) (map[string]comparable, error) {
    //反序列化configUpdateEnv.ConfigUpdate
    configUpdate, err := UnmarshalConfigUpdate(configUpdateEnv.ConfigUpdate)

    readSet, err := MapConfig(configUpdate.ReadSet) //map[string]comparable
    err = cm.current.verifyReadSet(readSet)

    writeSet, err := MapConfig(configUpdate.WriteSet) //map[string]comparable

    //从writeSet中逐一对比readSet，去除没有发生变更的
    deltaSet := ComputeDeltaSet(readSet, writeSet)
    signedData, err := configUpdateEnv.AsSignedData() //转换为SignedData

    err = cm.verifyDeltaSet(deltaSet, signedData) //校验deltaSet

    fullProposedConfig := cm.computeUpdateResult(deltaSet) //合并为fullProposedConfig
    err := verifyFullProposedConfig(writeSet, fullProposedConfig)
    return fullProposedConfig, nil
}
//代码在common/configtx/update.go

补充comparable:

type comparable struct {
    *cb.ConfigGroup
    *cb.ConfigValue
    *cb.ConfigPolicy
    key string
    path []string
}
//代码在common/configtx/compare.go

### 5.4、func (cm *configManager) processConfig(channelGroup *cb.ConfigGroup) (*configResult, error)

func (cm configManager) processConfig(channelGroup cb.ConfigGroup) (*configResult, error) {
    configResult, err := processConfig(channelGroup, cm.initializer)
    err = configResult.preCommit()
    return configResult, nil
}
//代码在common/configtx/config.go

补充configResult：

type configResult struct {
    tx interface{}
    groupName string
    groupKey string
    group *cb.ConfigGroup
    valueHandler config.ValueProposer
    policyHandler policies.Proposer
    subResults []*configResult
    deserializedValues map[string]proto.Message
    deserializedPolicies map[string]proto.Message
}

func NewConfigResult(config *cb.ConfigGroup, proposer api.Proposer) (ConfigResult, error)
func (cr *configResult) JSON() string
func (cr configResult) bufferJSON(buffer bytes.Buffer)
//cr.valueHandler.PreCommit(cr.tx)
func (cr *configResult) preCommit() error
//cr.valueHandler.CommitProposals(cr.tx)
//cr.policyHandler.CommitProposals(cr.tx)
func (cr *configResult) commit()
//cr.valueHandler.RollbackProposals(cr.tx)
//cr.policyHandler.RollbackProposals(cr.tx)
func (cr *configResult) rollback()
func proposeGroup(result *configResult) error
func processConfig(channelGroup cb.ConfigGroup, proposer api.Proposer) (configResult, error)
//代码在common/configtx/config.go

#### 5.4.1、func processConfig(channelGroup *cb.ConfigGroup, proposer api.Proposer) (*configResult, error)

func processConfig(channelGroup cb.ConfigGroup, proposer api.Proposer) (configResult, error) {
    helperGroup := cb.NewConfigGroup()
    helperGroup.Groups[RootGroupKey] = channelGroup

    configResult := &configResult{
        group: helperGroup,
        valueHandler: proposer.ValueProposer(),
        policyHandler: proposer.PolicyProposer(),
    }
    err := proposeGroup(configResult)
    return configResult, nil
}
//代码在common/configtx/config.go

#### 5.4.2、func proposeGroup(result *configResult) error

func proposeGroup(result *configResult) error {
    subGroups := make([]string, len(result.group.Groups))
    i := 0
    for subGroup := range result.group.Groups {
        subGroups[i] = subGroup
        i++
    }

    valueDeserializer, subValueHandlers, err := result.valueHandler.BeginValueProposals(result.tx, subGroups)
    subPolicyHandlers, err := result.policyHandler.BeginPolicyProposals(result.tx, subGroups)

    for key, value := range result.group.Values {
        msg, err := valueDeserializer.Deserialize(key, value.Value)
        result.deserializedValues[key] = msg
    }

    for key, policy := range result.group.Policies {
        policy, err := result.policyHandler.ProposePolicy(result.tx, key, policy)
        result.deserializedPolicies[key] = policy
    }

    result.subResults = make([]*configResult, 0, len(subGroups))

    for i, subGroup := range subGroups {
        result.subResults = append(result.subResults, &configResult{
            tx: result.tx,
            groupKey: subGroup,
            groupName: result.groupName + "/" + subGroup,
            group: result.group.Groups[subGroup],
            valueHandler: subValueHandlers[i],
            policyHandler: subPolicyHandlers[i],
            deserializedValues: make(map[string]proto.Message),
            deserializedPolicies: make(map[string]proto.Message),
        })
        err := proposeGroup(result.subResults[i])
    }
    return nil
}
//代码在common/configtx/config.go