兄弟连区块链教程Fabric1.0源代码分析Peer peer

　　兄弟连区块链教程Fabric1.0源代码分析Peer peer chaincode命令及子命令实现，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 Peer #peer chaincode命令及子命令实现

## 1、peer chaincode install子命令实现（安装链码）

### 1.0、peer chaincode install子命令概述

peer chaincode install，将链码的源码和环境封装为一个链码安装打包文件，并传输到背书节点。

peer chaincode install支持如下两种方式：

* 指定代码方式，peer chaincode install -n <链码名称> -v <链码版本> -p <链码路径>

* 基于链码打包文件方式，peer chaincode install <链码打包文件>

### 1.1、初始化Endorser客户端

```go

cf, err = InitCmdFactory(true, false)

//代码在peer/chaincode/install.go

```

cf, err = InitCmdFactory(true, false)代码如下：

```go

func InitCmdFactory(isEndorserRequired, isOrdererRequired bool) (*ChaincodeCmdFactory, error) {

    var err error

    var endorserClient pb.EndorserClient

    if isEndorserRequired {

        //获取Endorser客户端

        endorserClient, err = common.GetEndorserClientFnc() //func GetEndorserClient() (pb.EndorserClient, error)

    }

    //获取签名

    signer, err := common.GetDefaultSignerFnc()

    var broadcastClient common.BroadcastClient

    if isOrdererRequired {

        //此处未用到，暂略

    }

    //构造ChaincodeCmdFactory

    return &ChaincodeCmdFactory{

        EndorserClient:  endorserClient,

        Signer:          signer,

        BroadcastClient: broadcastClient,

    }, nil

}

//代码在peer/chaincode/common.go

```

### 1.2、构造ChaincodeDeploymentSpec消息（链码信息及链码文件打包）

```go

if ccpackfile == "" { //指定代码方式，重新构造构造ChaincodeDeploymentSpec消息

    ccpackmsg, err = genChaincodeDeploymentSpec(cmd, chaincodeName, chaincodeVersion)

} else { //基于链码打包文件方式，直接读取ChaincodeDeploymentSpec消息

    var cds *pb.ChaincodeDeploymentSpec

    ccpackmsg, cds, err = getPackageFromFile(ccpackfile)

}

//代码在peer/chaincode/install.go

```

ccpackmsg, err = genChaincodeDeploymentSpec(cmd, chaincodeName, chaincodeVersion)代码如下：

```go

func genChaincodeDeploymentSpec(cmd *cobra.Command, chaincodeName, chaincodeVersion string) (*pb.ChaincodeDeploymentSpec, error) {

    //已经存在，直接报错

    if existed, _ := ccprovider.ChaincodePackageExists(chaincodeName, chaincodeVersion); existed {

        return nil, fmt.Errorf("chaincode %s:%s already exists", chaincodeName, chaincodeVersion)

    }

    spec, err := getChaincodeSpec(cmd)

    cds, err := getChaincodeDeploymentSpec(spec, true)

    return cds, nil

}

//代码在peer/chaincode/install.go

```

spec, err := getChaincodeSpec(cmd)代码如下：

```go

func getChaincodeSpec(cmd *cobra.Command) (*pb.ChaincodeSpec, error) {

    spec := &pb.ChaincodeSpec{}

    err := checkChaincodeCmdParams(cmd) //检查参数合法性

    input := &pb.ChaincodeInput{}

    //flags.StringVarP(&chaincodeCtorJSON, "ctor", "c", "{}"，ctor为链码具体执行参数信息，默认为{}

    err := json.Unmarshal([]byte(chaincodeCtorJSON), &input)

    //flags.StringVarP(&chaincodeLang, "lang", "l", "golang"，lang为链码的编写语言，默认为golang

    chaincodeLang = strings.ToUpper(chaincodeLang)

    spec = &pb.ChaincodeSpec{

        Type:        pb.ChaincodeSpec_Type(pb.ChaincodeSpec_Type_value[chaincodeLang]),

        ChaincodeId: &pb.ChaincodeID{Path: chaincodePath, Name: chaincodeName, Version: chaincodeVersion},

        Input:       input,

    }

    return spec, nil

}

//代码在peer/chaincode/common.go

```

cds, err := getChaincodeDeploymentSpec(spec, true)代码如下：

```go

func getChaincodeDeploymentSpec(spec *pb.ChaincodeSpec, crtPkg bool) (*pb.ChaincodeDeploymentSpec, error) {

    var codePackageBytes []byte

    if chaincode.IsDevMode() == false && crtPkg {

        var err error

        err = checkSpec(spec) //检查spec合法性

        codePackageBytes, err = container.GetChaincodePackageBytes(spec) //打包链码文件及依赖文件

    }

    //构造ChaincodeDeploymentSpec

    chaincodeDeploymentSpec := &pb.ChaincodeDeploymentSpec{ChaincodeSpec: spec, CodePackage: codePackageBytes}

    return chaincodeDeploymentSpec, nil

//代码在peer/chaincode/common.go

```

### 1.3、创建lscc Proposal并签名

```go

creator, err := cf.Signer.Serialize() //获取签名者

//按ChaincodeDeploymentSpec构造Proposal，即链码ChaincodeDeploymentSpec消息作为参数传递给lscc系统链码并调用

//调用createProposalFromCDS(chainID, cds, creator, policy, escc, vscc, "deploy")

prop, _, err := utils.CreateInstallProposalFromCDS(msg, creator)

var signedProp *pb.SignedProposal

signedProp, err = utils.GetSignedProposal(prop, cf.Signer) //签名提案

//代码在peer/chaincode/install.go

```

createProposalFromCDS(chainID, cds, creator, policy, escc, vscc, "deploy")代码如下：

```go

func createProposalFromCDS(chainID string, msg proto.Message, creator []byte, policy []byte, escc []byte, vscc []byte, propType string) (*peer.Proposal, string, error) {

    var ccinp *peer.ChaincodeInput

    var b []byte

    var err error

    b, err = proto.Marshal(msg)

    switch propType {

    case "deploy":

        fallthrough

    case "upgrade":

        cds, ok := msg.(*peer.ChaincodeDeploymentSpec)

        ccinp = &peer.ChaincodeInput{Args: [][]byte{[]byte(propType), []byte(chainID), b, policy, escc, vscc}}

    case "install":

        ccinp = &peer.ChaincodeInput{Args: [][]byte{[]byte(propType), b}}

    }

    lsccSpec := &peer.ChaincodeInvocationSpec{ //构造lscc ChaincodeInvocationSpec

        ChaincodeSpec: &peer.ChaincodeSpec{

            Type:        peer.ChaincodeSpec_GOLANG,

            ChaincodeId: &peer.ChaincodeID{Name: "lscc"},

            Input:       ccinp}}

    return CreateProposalFromCIS(common.HeaderType_ENDORSER_TRANSACTION, chainID, lsccSpec, creator)

}

//代码在protos/utils/proputils.go

```

### 1.4、提交并处理Proposal

```go

proposalResponse, err := cf.EndorserClient.ProcessProposal(context.Background(), signedProp)

//代码在peer/chaincode/install.go

```

## 2、peer chaincode instantiate子命令实现（实例化链码）

### 2.0、peer chaincode instantiate概述

peer chaincode instantiate命令通过构造生命周期管理系统链码（LSCC）的交易，将安装过的链码在指定通道上进行实例化调用。

在peer上创建容器启动，并执行初始化操作。


### 2.1、初始化EndorserClient、Signer、及BroadcastClient

与2.1接近，附BroadcastClient初始化代码如下：

```go

cf, err = InitCmdFactory(true, true)

//代码在peer/chaincode/instantiate.go

```

```go

func InitCmdFactory(isEndorserRequired, isOrdererRequired bool) (*ChaincodeCmdFactory, error) {

    //初始化EndorserClient、Signer

    var broadcastClient common.BroadcastClient

    if isOrdererRequired {

        //flags.StringVarP(&orderingEndpoint, "orderer", "o", "", "Ordering service endpoint")

        //orderingEndpoint为orderer服务地址

        broadcastClient, err = common.GetBroadcastClientFnc(orderingEndpoint, tls, caFile)

    }

}

//代码在peer/chaincode/common.go

```

BroadcastClient更详细内容，参考Fabric 1.0源代码笔记 之 Peer #BroadcastClient（Broadcast客户端）

### 2.2、构造ChaincodeDeploymentSpec消息

```go

spec, err := getChaincodeSpec(cmd) //构造ChaincodeSpec，参考本文1.2

//构造ChaincodeDeploymentSpec，参考本文1.2，但无法打包链码文件

cds, err := getChaincodeDeploymentSpec(spec, false)

//代码在peer/chaincode/instantiate.go

```

### 2.3、创建lscc Proposal并签名

```go

creator, err := cf.Signer.Serialize() //获取签名者

//policyMarhsalled为flags.StringVarP(&policy, "policy", "P", common.UndefinedParamValue,即链码关联的背书策略

//即调用 createProposalFromCDS(chainID, cds, creator, policy, escc, vscc, "deploy")，参考本文1.3

prop, _, err := utils.CreateDeployProposalFromCDS(chainID, cds, creator, policyMarhsalled, []byte(escc), []byte(vscc))

var signedProp *pb.SignedProposal

signedProp, err = utils.GetSignedProposal(prop, cf.Signer) //签名提案

//代码在peer/chaincode/instantiate.go

```

### 2.4、提交并处理Proposal、获取Proposal响应并创建签名交易Envelope

```go

proposalResponse, err := cf.EndorserClient.ProcessProposal(context.Background(), signedProp)

if proposalResponse != nil {

    env, err := utils.CreateSignedTx(prop, cf.Signer, proposalResponse) //由Proposal创建签名交易Envelope

    return env, nil

}

//代码在peer/chaincode/instantiate.go

```

env, err := utils.CreateSignedTx(prop, cf.Signer, proposalResponse)代码如下：

```go

func CreateSignedTx(proposal *peer.Proposal, signer msp.SigningIdentity, resps ...*peer.ProposalResponse) (*common.Envelope, error) {

    hdr, err := GetHeader(proposal.Header) //反序列化为common.Header

    pPayl, err := GetChaincodeProposalPayload(proposal.Payload) //反序列化为peer.ChaincodeProposalPayload

    signerBytes, err := signer.Serialize() //signer序列化

    shdr, err := GetSignatureHeader(hdr.SignatureHeader) //反序列化为common.SignatureHeader

    if bytes.Compare(signerBytes, shdr.Creator) != 0 { //Proposal创建者需与当前签名者相同

        return nil, fmt.Errorf("The signer needs to be the same as the one referenced in the header")

    }

    hdrExt, err := GetChaincodeHeaderExtension(hdr) //Header.ChannelHeader反序列化为peer.ChaincodeHeaderExtension

    var a1 []byte

    for n, r := range resps {

        if n == 0 {

            a1 = r.Payload

            if r.Response.Status != 200 { //检查Response.Status是否为200

                return nil, fmt.Errorf("Proposal response was not successful, error code %d, msg %s", r.Response.Status, r.Response.Message)

            }

            continue

        }

        if bytes.Compare(a1, r.Payload) != 0 { //检查所有ProposalResponse.Payload是否相同

            return nil, fmt.Errorf("ProposalResponsePayloads do not match")

        }

    }

    endorsements := make([]*peer.Endorsement, len(resps))

    for n, r := range resps {

        endorsements[n] = r.Endorsement

    }

    //如下为逐层构建common.Envelope

    cea := &peer.ChaincodeEndorsedAction{ProposalResponsePayload: resps[0].Payload, Endorsements: endorsements}

    propPayloadBytes, err := GetBytesProposalPayloadForTx(pPayl, hdrExt.PayloadVisibility)

    cap := &peer.ChaincodeActionPayload{ChaincodeProposalPayload: propPayloadBytes, Action: cea}

    capBytes, err := GetBytesChaincodeActionPayload(cap)

    taa := &peer.TransactionAction{Header: hdr.SignatureHeader, Payload: capBytes}

    taas := make([]*peer.TransactionAction, 1)

    taas[0] = taa

    tx := &peer.Transaction{Actions: taas}

    txBytes, err := GetBytesTransaction(tx)

    payl := &common.Payload{Header: hdr, Data: txBytes}

    paylBytes, err := GetBytesPayload(payl)

    sig, err := signer.Sign(paylBytes)

    return &common.Envelope{Payload: paylBytes, Signature: sig}, nil

}

//代码在protos/utils/txutils.go

```

common.Envelope更详细内容，参考：Fabric 1.0源代码笔记 之 附录-关键数据结构

### 2.5、向orderer广播交易Envelope

```go

err = cf.BroadcastClient.Send(env)

//代码在peer/chaincode/instantiate.go

```

## 3、peer chaincode invoke子命令实现（调用链码）

### 3.0、peer chaincode invoke概述

通过invoke命令可以调用运行中的链码的方法。

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### 3.1、初始化EndorserClient、Signer、及BroadcastClient

参考本文1.1和2.1。

```go

cf, err = InitCmdFactory(true, true)

//代码在peer/chaincode/invoke.go

```

### 3.2、构造ChaincodeInvocationSpec

```go

spec, err := getChaincodeSpec(cmd) //构造ChaincodeSpec

invocation := &pb.ChaincodeInvocationSpec{ChaincodeSpec: spec} //构造ChaincodeInvocationSpec

//代码在peer/chaincode/common.go

```

### 3.3、创建Chaincode Proposal并签名

```go

creator, err := signer.Serialize()

var prop *pb.Proposal

prop, _, err = putils.CreateProposalFromCIS(pcommon.HeaderType_ENDORSER_TRANSACTION, cID, invocation, creator)

var signedProp *pb.SignedProposal

signedProp, err = putils.GetSignedProposal(prop, signer) //Proposal签名

//代码在peer/chaincode/common.go

```

### 3.4、提交并处理Proposal、获取Proposal响应

```go

var proposalResp *pb.ProposalResponse

proposalResp, err = endorserClient.ProcessProposal(context.Background(), signedProp)

//代码在peer/chaincode/common.go

```

### 3.5、创建签名交易Envelope并向orderer广播交易Envelope

```go

if invoke {

    env, err := putils.CreateSignedTx(prop, signer, proposalResp) //创建签名交易

    err = bc.Send(env) //广播交易

}

//代码在peer/chaincode/common.go

```

## 4、peer chaincode query子命令实现（查询链码）

与3、peer chaincode invoke子命令实现（调用链码）基本相同，区别在于提交并处理Proposal后，不再创建交易以及广播交易。

感谢关注兄弟连区块链教程分享！