區塊鏈教程Fabric1.0原始碼分析Peer peer channel命令及子命令實現，2018年下半年，區塊鏈行業正逐漸褪去發展之初的浮躁、迴歸理性，表面上看相關人才需求與身價似乎正在回落。但事實上，正是初期泡沫的漸退，讓人們更多的關注點放在了區塊鏈真正的技術之上。

Fabric1.0原始碼筆記之Peer peer channel命令及子命令實現

1、peer channel create子命令實現（建立通道）

1.1、初始化Orderer客戶端

const (
    EndorserRequired    EndorserRequirement = true
    EndorserNotRequired EndorserRequirement = false
    OrdererRequired     OrdererRequirement  = true
    OrdererNotRequired  OrdererRequirement  = false
)

cf, err = InitCmdFactory(EndorserNotRequired, OrdererRequired)
//程式碼在peer/channel/create.go
 

cf, err = InitCmdFactory(EndorserNotRequired, OrdererRequired)程式碼如下：

type ChannelCmdFactory struct {
    EndorserClient   pb.EndorserClient //EndorserClient
    Signer           msp.SigningIdentity //Signer
    BroadcastClient  common.BroadcastClient //BroadcastClient
    DeliverClient    deliverClientIntf //DeliverClient
    BroadcastFactory BroadcastClientFactory //BroadcastClientFactory，type BroadcastClientFactory func() (common.BroadcastClient, error)
}

func InitCmdFactory(isEndorserRequired EndorserRequirement, isOrdererRequired OrdererRequirement) (*ChannelCmdFactory, error) {
    var err error
    cmdFact := &ChannelCmdFactory{}
    cmdFact.Signer, err = common.GetDefaultSignerFnc() //GetDefaultSignerFnc = GetDefaultSigner

    cmdFact.BroadcastFactory = func() (common.BroadcastClient, error) {
        return common.GetBroadcastClientFnc(orderingEndpoint, tls, caFile) //GetBroadcastClientFnc = GetBroadcastClient
    }

    //peer channel join或list需要endorser，本處暫未使用
    if isEndorserRequired {
        cmdFact.EndorserClient, err = common.GetEndorserClientFnc()
    }

    //peer channel create或fetch需要orderer
    if isOrdererRequired {
        var opts []grpc.DialOption
        if tls {
            if caFile != "" {
                creds, err := credentials.NewClientTLSFromFile(caFile, "")
                opts = append(opts, grpc.WithTransportCredentials(creds))
            }
        } else {
            opts = append(opts, grpc.WithInsecure())
        }
        conn, err := grpc.Dial(orderingEndpoint, opts...)
        client, err := ab.NewAtomicBroadcastClient(conn).Deliver(context.TODO())
        cmdFact.DeliverClient = newDeliverClient(conn, client, chainID) //構造deliverClient
    }
    return cmdFact, nil
}

//程式碼在peer/channel/channel.go
 

1.2、傳送建立區塊鏈的交易

err = sendCreateChainTransaction(cf)
//程式碼在peer/channel/create.go

sendCreateChainTransaction(cf)程式碼如下：

func sendCreateChainTransaction(cf *ChannelCmdFactory) error {
    var err error
    var chCrtEnv *cb.Envelope

    if channelTxFile != "" { //peer channel create -f指定通道交易配置檔案
        chCrtEnv, err = createChannelFromConfigTx(channelTxFile) //獲取創世區塊
    } else {
        chCrtEnv, err = createChannelFromDefaults(cf) //沒有指定通道交易配置檔案
    }

    chCrtEnv, err = sanityCheckAndSignConfigTx(chCrtEnv) //檢查和簽名交易配置
    var broadcastClient common.BroadcastClient
    broadcastClient, err = cf.BroadcastFactory()
    defer broadcastClient.Close()
    err = broadcastClient.Send(chCrtEnv)
    return err
}
//程式碼在peer/channel/create.go
 

1.3、獲取創世區塊並寫入檔案

var block *cb.Block
block, err = getGenesisBlock(cf) //獲取創世區塊
b, err := proto.Marshal(block) //塊序列化
err = ioutil.WriteFile(file, b, 0644) //寫入檔案
//程式碼在peer/channel/create.go

2、peer channel join子命令實現（加入通道）

2.1、初始化Endorser客戶端

cf, err = InitCmdFactory(EndorserRequired, OrdererNotRequired)
//程式碼在peer/channel/join.go

2.2、構造ChaincodeInvocationSpec訊息（cscc.JoinChain）

spec, err := getJoinCCSpec()
invocation := &pb.ChaincodeInvocationSpec{ChaincodeSpec: spec}
//程式碼在peer/channel/join.go

spec, err := getJoinCCSpec()程式碼如下：

func getJoinCCSpec() (*pb.ChaincodeSpec, error) {
    gb, err := ioutil.ReadFile(genesisBlockPath)
    input := &pb.ChaincodeInput{Args: [][]byte{[]byte(cscc.JoinChain), gb}}
    spec := &pb.ChaincodeSpec{
        Type:        pb.ChaincodeSpec_Type(pb.ChaincodeSpec_Type_value["GOLANG"]),
        ChaincodeId: &pb.ChaincodeID{Name: "cscc"},
        Input:       input,
    }
    return spec, nil
}
//程式碼在peer/channel/join.go

2.3、建立cscc Proposal並簽名

creator, err := cf.Signer.Serialize()
//從CIS建立Proposal，CIS即ChaincodeInvocationSpec
//呼叫CreateChaincodeProposal(typ, chainID, cis, creator)
//而後呼叫CreateChaincodeProposalWithTransient(typ, chainID, cis, creator, nil)
prop, _, err = putils.CreateProposalFromCIS(pcommon.HeaderType_CONFIG, "", invocation, creator)
var signedProp *pb.SignedProposal
signedProp, err = putils.GetSignedProposal(prop, cf.Signer)
//程式碼在peer/channel/join.go

CreateChaincodeProposalWithTransient(typ, chainID, cis, creator, nil)程式碼如下：

func CreateChaincodeProposalWithTransient(typ common.HeaderType, chainID string, cis *peer.ChaincodeInvocationSpec, creator []byte, transientMap map[string][]byte) (*peer.Proposal, str    ing, error) {
    //建立隨機Nonce
    nonce, err := crypto.GetRandomNonce()
    //計算交易ID
    //digest, err := factory.GetDefault().Hash(append(nonce, creator...),&bccsp.SHA256Opts{})
    txid, err := ComputeProposalTxID(nonce, creator)
    return CreateChaincodeProposalWithTxIDNonceAndTransient(txid, typ, chainID, cis, nonce, creator, transientMap)
}
//程式碼在protos/utils/proputils.go

CreateChaincodeProposalWithTxIDNonceAndTransient(txid, typ, chainID, cis, nonce, creator, transientMap)程式碼如下：

func CreateChaincodeProposalWithTxIDNonceAndTransient(txid string, typ common.HeaderType, chainID string, cis *peer.ChaincodeInvocationSpec, nonce, creator []byte, transientMap map[string][]byte) (*peer.Proposal, string, error) {
    ccHdrExt := &peer.ChaincodeHeaderExtension{ChaincodeId: cis.ChaincodeSpec.ChaincodeId}
    ccHdrExtBytes, err := proto.Marshal(ccHdrExt)
    cisBytes, err := proto.Marshal(cis)
    ccPropPayload := &peer.ChaincodeProposalPayload{Input: cisBytes, TransientMap: transientMap}
    ccPropPayloadBytes, err := proto.Marshal(ccPropPayload)
    var epoch uint64 = 0
    timestamp := util.CreateUtcTimestamp()
    hdr := &common.Header{ChannelHeader: MarshalOrPanic(&common.ChannelHeader{
        Type:      int32(typ),
        TxId:      txid,
        Timestamp: timestamp,
        ChannelId: chainID,
        Extension: ccHdrExtBytes,
        Epoch:     epoch}),
        SignatureHeader: MarshalOrPanic(&common.SignatureHeader{Nonce: nonce, Creator: creator})}
    hdrBytes, err := proto.Marshal(hdr)
    return &peer.Proposal{Header: hdrBytes, Payload: ccPropPayloadBytes}, txid, nil
}
//程式碼在protos/utils/proputils.go

2.4、提交併處理Proposal

var proposalResp *pb.ProposalResponse
proposalResp, err = cf.EndorserClient.ProcessProposal(context.Background(), signedProp)
//程式碼在peer/channel/join.go

3、peer channel update（更新錨節點配置）

cf, err = InitCmdFactory(EndorserNotRequired, OrdererRequired)
fileData, err := ioutil.ReadFile(channelTxFile)
ctxEnv, err := utils.UnmarshalEnvelope(fileData)
sCtxEnv, err := sanityCheckAndSignConfigTx(ctxEnv)
var broadcastClient common.BroadcastClient
broadcastClient, err = cf.BroadcastFactory()
defer broadcastClient.Close()
return broadcastClient.Send(sCtxEnv)
//程式碼在peer/channel

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