兄弟连区块链教程Fabric1.0源代码分析Peer peer node start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 node start命令实现
## 1、peer node加载子命令start和status
peer node加载子命令start和status，代码如下：
```go
func Cmd() *cobra.Command {
nodeCmd.AddCommand(startCmd()) //加载子命令start
nodeCmd.AddCommand(statusCmd()) //加载子命令status
return nodeCmd
}
var nodeCmd = &cobra.Command{
Use: nodeFuncName,
Short: fmt.Sprint(shortDes),
Long: fmt.Sprint(longDes),
}
//代码在peer/node/node.go
```
startCmd()代码如下：
其中serve(args)为peer node start的实现代码，比较复杂，本文将重点讲解。
另statusCmd()代码与startCmd()相近，暂略。
```go
func startCmd() *cobra.Command {
flags := nodeStartCmd.Flags()
flags.BoolVarP(&chaincodeDevMode, "peer-chaincodedev", "", false, "Whether peer in chaincode development mode")
flags.BoolVarP(&peerDefaultChain, "peer-defaultchain", "", false, "Whether to start peer with chain testchainid")
flags.StringVarP(&orderingEndpoint, "orderer", "o", "orderer:7050", "Ordering service endpoint") //orderer
return nodeStartCmd
}
var nodeStartCmd = &cobra.Command{
Use: "start",
Short: "Starts the node.",
Long: `Starts a node that interacts with the network.`,
RunE: func(cmd *cobra.Command, args []string) error {
return serve(args) //serve(args)为peer node start的实现代码
},
}
//代码在peer/node/start.go
```
**注：如下内容均为serve(args)的代码，即peer node start命令执行流程。**
## 2、初始化Ledger（账本）
初始化账本，即如下一条代码：
```go
ledgermgmt.Initialize()
//代码在peer/node/start.go
```
ledgermgmt.Initialize()代码展开如下：
```go
func initialize() {
openedLedgers = make(map[string]ledger.PeerLedger) //openedLedgers为全局变量，存储目前使用的账本列表
provider, err := kvledger.NewProvider() //创建账本Provider实例
ledgerProvider = provider
}
//代码在core/ledger/ledgermgmt/ledger_mgmt.go
```
kvledger.NewProvider()代码如下：
```go
func NewProvider() (ledger.PeerLedgerProvider, error) {
idStore := openIDStore(ledgerconfig.GetLedgerProviderPath()) //打开idStore
//创建并初始化blkstorage
attrsToIndex := []blkstorage.IndexableAttr{
blkstorage.IndexableAttrBlockHash,
blkstorage.IndexableAttrBlockNum,
blkstorage.IndexableAttrTxID,
blkstorage.IndexableAttrBlockNumTranNum,
blkstorage.IndexableAttrBlockTxID,
blkstorage.IndexableAttrTxValidationCode,
}
indexConfig := &blkstorage.IndexConfig{AttrsToIndex: attrsToIndex}
blockStoreProvider := fsblkstorage.NewProvider(
fsblkstorage.NewConf(ledgerconfig.GetBlockStorePath(), ledgerconfig.GetMaxBlockfileSize()),
indexConfig)
//创建并初始化statedb
var vdbProvider statedb.VersionedDBProvider
if !ledgerconfig.IsCouchDBEnabled() {
vdbProvider = stateleveldb.NewVersionedDBProvider()
} else {
vdbProvider, err = statecouchdb.NewVersionedDBProvider()
}
//创建并初始化historydb
var historydbProvider historydb.HistoryDBProvider
historydbProvider = historyleveldb.NewHistoryDBProvider()
//构造Provider
provider := &Provider{idStore, blockStoreProvider, vdbProvider, historydbProvider}
provider.recoverUnderConstructionLedger()
return provider, nil
}
//代码在core/ledger/kvledger/kv_ledger_provider.go
```
Ledger更详细内容，参考：Fabric 1.0源代码笔记 之 Ledger（账本）
## 3、配置及创建PeerServer、创建EventHubServer（事件中心服务器）
```go
//初始化全局变量localAddress和peerEndpoint
err := peer.CacheConfiguration()
peerEndpoint, err := peer.GetPeerEndpoint() //获取peerEndpoint
listenAddr := viper.GetString("peer.listenAddress") //PeerServer监听地址
secureConfig, err := peer.GetSecureConfig() //获取PeerServer安全配置，是否启用TLS、公钥、私钥、根证书
//以监听地址和安全配置，创建Peer GRPC Server
peerServer, err := peer.CreatePeerServer(listenAddr, secureConfig)
//创建EventHubServer（事件中心服务器）
ehubGrpcServer, err := createEventHubServer(secureConfig)
//代码在peer/node/start.go
```
func createEventHubServer(secureConfig comm.SecureServerConfig) (comm.GRPCServer, error)代码如下：
```go
var lis net.Listener
var err error
lis, err = net.Listen("tcp", viper.GetString("peer.events.address")) //创建Listen
grpcServer, err := comm.NewGRPCServerFromListener(lis, secureConfig) //从Listen创建GRPCServer
ehServer := producer.NewEventsServer(
uint(viper.GetInt("peer.events.buffersize")), //最大进行缓冲的消息数
viper.GetDuration("peer.events.timeout")) //缓冲已满的情况下，往缓冲中发送消息的超时
pb.RegisterEventsServer(grpcServer.Server(), ehServer) //EventHubServer注册至grpcServer
return grpcServer, nil
//代码在peer/node/start.go
```
pb.RegisterEventsServer(grpcServer.Server(), ehServer)代码如下：
```go
func RegisterEventsServer(s *grpc.Server, srv EventsServer) {
s.RegisterService(&_Events_serviceDesc, srv)
}
//代码在protos/peer/events.pb.go
```
events（事件服务）更详细内容，参考：Fabric 1.0源代码笔记 之 events（事件服务）
## 4、创建并启动Chaincode Server，并注册系统链码
代码如下：
```go
ccprovider.EnableCCInfoCache() //ccInfoCacheEnabled = true
//创建Chaincode Server
//如果peer.chaincodeListenAddress，没有定义或者定义和peerListenAddress相同，均直接使用peerServer
//否则另行创建NewGRPCServer用于Chaincode Server
ccSrv, ccEpFunc := createChaincodeServer(peerServer, listenAddr)
//Chaincode service注册到grpcServer，并注册系统链码
registerChaincodeSupport(ccSrv.Server(), ccEpFunc)
go ccSrv.Start() //启动grpcServer
//代码在peer/node/start.go
```
ccSrv, ccEpFunc := createChaincodeServer(peerServer, listenAddr)代码如下：创建Chaincode Server。
```go
func createChaincodeServer(peerServer comm.GRPCServer, peerListenAddress string) (comm.GRPCServer, ccEndpointFunc) {
//peer.chaincodeListenAddress，链码容器连接时的监听地址
cclistenAddress := viper.GetString("peer.chaincodeListenAddress")
var srv comm.GRPCServer
var ccEpFunc ccEndpointFunc
//如果peer.chaincodeListenAddress，没有定义或者定义和peerListenAddress相同，均直接使用peerServer
//否则另行创建NewGRPCServer用于Chaincode Server
if cclistenAddress == "" {
ccEpFunc = peer.GetPeerEndpoint
srv = peerServer
} else if cclistenAddress == peerListenAddress {
ccEpFunc = peer.GetPeerEndpoint
srv = peerServer
} else {
config, err := peer.GetSecureConfig()
srv, err = comm.NewGRPCServer(cclistenAddress, config)
ccEpFunc = getChaincodeAddressEndpoint
}
return srv, ccEpFunc
}
//代码在peer/node/start.go
```
registerChaincodeSupport(ccSrv.Server(), ccEpFunc)代码如下：Chaincode service注册到grpcServer。
```go
func registerChaincodeSupport(grpcServer *grpc.Server, ccEpFunc ccEndpointFunc) {
userRunsCC := chaincode.IsDevMode() //是否开发模式
ccStartupTimeout := viper.GetDuration("chaincode.startuptimeout") //启动链码容器的超时
if ccStartupTimeout < time.Duration(5)*time.Second { //至少5秒
ccStartupTimeout = time.Duration(5) * time.Second
} else {
}
//构造ChaincodeSupport
ccSrv := chaincode.NewChaincodeSupport(ccEpFunc, userRunsCC, ccStartupTimeout)
scc.RegisterSysCCs() //注册系统链码
pb.RegisterChaincodeSupportServer(grpcServer, ccSrv) //service注册到grpcServer
}
//代码在peer/node/start.go
```
ccSrv := chaincode.NewChaincodeSupport(ccEpFunc, userRunsCC, ccStartupTimeout)代码如下：构造ChaincodeSupport。
```go
var theChaincodeSupport *ChaincodeSupport
func NewChaincodeSupport(getCCEndpoint func() (*pb.PeerEndpoint, error), userrunsCC bool, ccstartuptimeout time.Duration) *ChaincodeSupport {
//即/var/hyperledger/production/chaincodes
ccprovider.SetChaincodesPath(config.GetPath("peer.fileSystemPath") + string(filepath.Separator) + "chaincodes")
pnid := viper.GetString("peer.networkId") //网络ID
pid := viper.GetString("peer.id") //节点ID
//构造ChaincodeSupport
theChaincodeSupport = &ChaincodeSupport{runningChaincodes: &runningChaincodes{chaincodeMap: make(map[string]*chaincodeRTEnv), launchStarted: make(map[string]bool)}, peerNetworkID:
pnid, peerID: pid}
ccEndpoint, err := getCCEndpoint() //此处传入ccEpFunc
if err != nil {
theChaincodeSupport.peerAddress = viper.GetString("chaincode.peerAddress")
} else {
theChaincodeSupport.peerAddress = ccEndpoint.Address
}
if theChaincodeSupport.peerAddress == "" {
theChaincodeSupport.peerAddress = peerAddressDefault
}
theChaincodeSupport.userRunsCC = userrunsCC //是否开发模式
theChaincodeSupport.ccStartupTimeout = ccstartuptimeout //启动链码容器的超时
theChaincodeSupport.peerTLS = viper.GetBool("peer.tls.enabled") //是否启用TLS
if theChaincodeSupport.peerTLS {
theChaincodeSupport.peerTLSCertFile = config.GetPath("peer.tls.cert.file")
theChaincodeSupport.peerTLSKeyFile = config.GetPath("peer.tls.key.file")
theChaincodeSupport.peerTLSSvrHostOrd = viper.GetString("peer.tls.serverhostoverride")
}
kadef := 0
// Peer和链码之间的心跳超时，小于或等于0意味着关闭
if ka := viper.GetString("chaincode.keepalive"); ka == "" {
theChaincodeSupport.keepalive = time.Duration(kadef) * time.Second //0
} else {
t, terr := strconv.Atoi(ka)
if terr != nil {
t = kadef //0
} else if t <= 0 {
t = kadef //0
}
theChaincodeSupport.keepalive = time.Duration(t) * time.Second //非0
}
execto := time.Duration(30) * time.Second
//invoke和initialize命令执行超时
if eto := viper.GetDuration("chaincode.executetimeout"); eto <= time.Duration(1)*time.Second {
//小于1秒时，默认30秒
} else {
execto = eto
}
theChaincodeSupport.executetimeout = execto
viper.SetEnvPrefix("CORE")
viper.AutomaticEnv()
replacer := strings.NewReplacer(".", "_")
viper.SetEnvKeyReplacer(replacer)
theChaincodeSupport.chaincodeLogLevel = getLogLevelFromViper("level")
theChaincodeSupport.shimLogLevel = getLogLevelFromViper("shim")
theChaincodeSupport.logFormat = viper.GetString("chaincode.logging.format")
return theChaincodeSupport
}
//代码在core/chaincode/chaincode_support.go
```
scc.RegisterSysCCs()代码如下：注册系统链码。
```go
func RegisterSysCCs() {
//cscc、lscc、escc、vscc、qscc
for _, sysCC := range systemChaincodes {
RegisterSysCC(sysCC)
}
}
代码在core/scc/importsysccs.go
```
## 5、注册Admin server和Endorser server
代码如下：
```go
//s.RegisterService(&_Admin_serviceDesc, srv)
//var _Admin_serviceDesc = grpc.ServiceDesc{...}
//core.NewAdminServer()构造ServerAdmin结构体，ServerAdmin结构体实现type AdminServer interface接口
pb.RegisterAdminServer(peerServer.Server(), core.NewAdminServer())
//构造结构体Endorser，Endorser结构体实现type EndorserServer interface接口
serverEndorser := endorser.NewEndorserServer()
//s.RegisterService(&_Endorser_serviceDesc, srv)
//var _Endorser_serviceDesc = grpc.ServiceDesc{...}
pb.RegisterEndorserServer(peerServer.Server(), serverEndorser)
//代码在peer/node/start.go
```
附type AdminServer interface接口定义：
```go
type AdminServer interface {
GetStatus(context.Context, *google_protobuf.Empty) (*ServerStatus, error)
StartServer(context.Context, *google_protobuf.Empty) (*ServerStatus, error)
GetModuleLogLevel(context.Context, *LogLevelRequest) (*LogLevelResponse, error)
SetModuleLogLevel(context.Context, *LogLevelRequest) (*LogLevelResponse, error)
RevertLogLevels(context.Context, *google_protobuf.Empty) (*google_protobuf.Empty, error)
}
//代码在protos/peer/admin.pb.go
```
附type EndorserServer interface接口定义：
```go
type EndorserServer interface {
ProcessProposal(context.Context, *SignedProposal) (*ProposalResponse, error)
}
//代码在protos/peer/peer.pb.go
```
## 6、初始化Gossip服务
```go
bootstrap := viper.GetStringSlice("peer.gossip.bootstrap") //启动节点后gossip连接的初始节点
serializedIdentity, err := mgmt.GetLocalSigningIdentityOrPanic().Serialize() //获取签名身份
messageCryptoService := peergossip.NewMCS( //构造mspMessageCryptoService（消息加密服务）
peer.NewChannelPolicyManagerGetter(), //构造type channelPolicyManagerGetter struct{}
localmsp.NewSigner(), //构造type mspSigner struct {}
mgmt.NewDeserializersManager()) //构造type mspDeserializersManager struct{}
secAdv := peergossip.NewSecurityAdvisor(mgmt.NewDeserializersManager()) //构造mspSecurityAdvisor（安全顾问）
secureDialOpts := func() []grpc.DialOption {
var dialOpts []grpc.DialOption
dialOpts = append(dialOpts, grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(comm.MaxRecvMsgSize()), //MaxRecvMsgSize
grpc.MaxCallSendMsgSize(comm.MaxSendMsgSize()))) //MaxSendMsgSize
dialOpts = append(dialOpts, comm.ClientKeepaliveOptions()...) //ClientKeepaliveOptions
if comm.TLSEnabled() {
tlsCert := peerServer.ServerCertificate()
dialOpts = append(dialOpts, grpc.WithTransportCredentials(comm.GetCASupport().GetPeerCredentials(tlsCert)))
} else {
dialOpts = append(dialOpts, grpc.WithInsecure())
}
return dialOpts
}
err = service.InitGossipService(serializedIdentity, peerEndpoint.Address, peerServer.Server(),
messageCryptoService, secAdv, secureDialOpts, bootstrap...) //构造gossipServiceImpl
defer service.GetGossipService().Stop()
//代码在peer/node/start.go
```
Gossip更详细内容参考：Fabric 1.0源代码笔记 之 gossip（流言算法）
## 7、初始化、部署并执行系统链码（scc）
代码如下：
```go
initSysCCs() //初始化系统链码，调用scc.DeploySysCCs("")
peer.Initialize(func(cid string) { //初始化所有链
scc.DeploySysCCs(cid) //按chain id部署并运行系统链码
})
//代码在peer/node/start.go
```
func Initialize(init func(string))代码如下：
```go
func Initialize(init func(string)) {
chainInitializer = init
var cb *common.Block
var ledger ledger.PeerLedger
ledgermgmt.Initialize()
ledgerIds, err := ledgermgmt.GetLedgerIDs()
for _, cid := range ledgerIds {
ledger, err = ledgermgmt.OpenLedger(cid)
cb, err = getCurrConfigBlockFromLedger(ledger) //获取最新的配置块
err = createChain(cid, ledger, cb)
InitChain(cid) //即调用chainInitializer(cid)，即scc.DeploySysCCs(cid)
}
}
//代码在core/peer/peer.go
```
createChain(cid, ledger, cb)代码如下：
```go
func createChain(cid string, ledger ledger.PeerLedger, cb *common.Block) error {
envelopeConfig, err := utils.ExtractEnvelope(cb, 0) //获取配置交易
configtxInitializer := configtx.NewInitializer() //构造initializer
gossipEventer := service.GetGossipService().NewConfigEventer() //获取gossipServiceInstance，并构造configEventer
gossipCallbackWrapper := func(cm configtxapi.Manager) {
ac, ok := configtxInitializer.ApplicationConfig()
gossipEventer.ProcessConfigUpdate(&chainSupport{
Manager: cm,
Application: ac,
})
//验证可疑节点身份，并关闭无效链接
service.GetGossipService().SuspectPeers(func(identity api.PeerIdentityType) bool {
return true
})
}
trustedRootsCallbackWrapper := func(cm configtxapi.Manager) {
updateTrustedRoots(cm)
}
configtxManager, err := configtx.NewManagerImpl(
envelopeConfig,
configtxInitializer,
[]func(cm configtxapi.Manager){gossipCallbackWrapper, trustedRootsCallbackWrapper},
)
mspmgmt.XXXSetMSPManager(cid, configtxManager.MSPManager())
ac, ok := configtxInitializer.ApplicationConfig()
cs := &chainSupport{
Manager: configtxManager,
Application: ac, // TODO, refactor as this is accessible through Manager
ledger: ledger,
}
c := committer.NewLedgerCommitterReactive(ledger, txvalidator.NewTxValidator(cs), func(block *common.Block) error {
chainID, err := utils.GetChainIDFromBlock(block)
if err != nil {
return err
}
return SetCurrConfigBlock(block, chainID)
})
ordererAddresses := configtxManager.ChannelConfig().OrdererAddresses()
service.GetGossipService().InitializeChannel(cs.ChainID(), c, ordererAddresses)
chains.Lock()
defer chains.Unlock()
chains.list[cid] = &chain{
cs: cs,
cb: cb,
committer: c,
}
return nil
}
//代码在core/peer/peer.go
```
scc更详细内容参考：Fabric 1.0源代码笔记 之 scc（系统链码）
## 8、启动peerServer和ehubGrpcServer，并监控系统信号，以及启动Go自带的profiling支持进行调试
代码如下：
```go
serve := make(chan error)
sigs := make(chan os.Signal, 1)
signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
go func() {
sig := <-sigs //接收系统信号
serve <- nil
}
go func() {
var grpcErr error
grpcErr = peerServer.Start() //启动peerServer
serve <- grpcErr
}
err := writePid(config.GetPath("peer.fileSystemPath")+"/peer.pid", os.Getpid()) //写入pid
go ehubGrpcServer.Start() //启动ehubGrpcServer
if viper.GetBool("peer.profile.enabled") {
go func() { //启动Go自带的profiling支持进行调试
profileListenAddress := viper.GetString("peer.profile.listenAddress")
profileErr := http.ListenAndServe(profileListenAddress, nil)
}
}
return <-serve //等待serve
//代码在peer/node/start.go
```
## 9、按配置文件重新更新模块日志级别
```go
overrideLogModules := []string{"msp", "gossip", "ledger", "cauthdsl", "policies", "grpc"}
for _, module := range overrideLogModules {
err = common.SetLogLevelFromViper(module)
}
flogging.SetPeerStartupModulesMap()
//代码在peer/node/start.go
```
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