兄弟连区块链教程Fabric1.0源代码分析Peer peer channel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。
Fabric1.0源代码笔记之Peer peer channel命令及子命令实现
1、peer channel create子命令实现（创建通道）
1.1、初始化Orderer客户端
const (
EndorserRequired EndorserRequirement = true
EndorserNotRequired EndorserRequirement = false
OrdererRequired OrdererRequirement = true
OrdererNotRequired OrdererRequirement = false
)
cf, err = InitCmdFactory(EndorserNotRequired, OrdererRequired)
//代码在peer/channel/create.go
cf, err = InitCmdFactory(EndorserNotRequired, OrdererRequired)代码如下：
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，本处暂未使用
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) //构造deliverClient
}
return cmdFact, nil
}
//代码在peer/channel/channel.go
1.2、发送创建区块链的交易
err = sendCreateChainTransaction(cf)
//代码在peer/channel/create.go
sendCreateChainTransaction(cf)代码如下：
func sendCreateChainTransaction(cf *ChannelCmdFactory) error {
var err error
var chCrtEnv *cb.Envelope
if channelTxFile != "" { //peer channel create -f指定通道交易配置文件
chCrtEnv, err = createChannelFromConfigTx(channelTxFile) //获取创世区块
} else {
chCrtEnv, err = createChannelFromDefaults(cf) //没有指定通道交易配置文件
}
chCrtEnv, err = sanityCheckAndSignConfigTx(chCrtEnv) //检查和签名交易配置
var broadcastClient common.BroadcastClient
broadcastClient, err = cf.BroadcastFactory()
defer broadcastClient.Close()
err = broadcastClient.Send(chCrtEnv)
return err
}
//代码在peer/channel/create.go
1.3、获取创世区块并写入文件
var block *cb.Block
block, err = getGenesisBlock(cf) //获取创世区块
b, err := proto.Marshal(block) //块序列化
err = ioutil.WriteFile(file, b, 0644) //写入文件
//代码在peer/channel/create.go
2、peer channel join子命令实现（加入通道）
2.1、初始化Endorser客户端
cf, err = InitCmdFactory(EndorserRequired, OrdererNotRequired)
//代码在peer/channel/join.go
2.2、构造ChaincodeInvocationSpec消息（cscc.JoinChain）
spec, err := getJoinCCSpec()
invocation := &pb.ChaincodeInvocationSpec{ChaincodeSpec: spec}
//代码在peer/channel/join.go
spec, err := getJoinCCSpec()代码如下：
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
}
//代码在peer/channel/join.go
2.3、创建cscc Proposal并签名
creator, err := cf.Signer.Serialize()
//从CIS创建Proposal，CIS即ChaincodeInvocationSpec
//调用CreateChaincodeProposal(typ, chainID, cis, creator)
//而后调用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)
//代码在peer/channel/join.go
CreateChaincodeProposalWithTransient(typ, chainID, cis, creator, nil)代码如下：
func CreateChaincodeProposalWithTransient(typ common.HeaderType, chainID string, cis *peer.ChaincodeInvocationSpec, creator []byte, transientMap map[string][]byte) (*peer.Proposal, str ing, error) {
//创建随机Nonce
nonce, err := crypto.GetRandomNonce()
//计算交易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)
}
//代码在protos/utils/proputils.go
CreateChaincodeProposalWithTxIDNonceAndTransient(txid, typ, chainID, cis, nonce, creator, transientMap)代码如下：
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
}
//代码在protos/utils/proputils.go
2.4、提交并处理Proposal
var proposalResp *pb.ProposalResponse
proposalResp, err = cf.EndorserClient.ProcessProposal(context.Background(), signedProp)
//代码在peer/channel/join.go
3、peer channel update（更新锚节点配置）
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)
//代码在peer/channel
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