兄弟连区块链教程Fabric1.0源代码分析Chaincode（链码）体系总结

兄弟连 区块链教程 Fabric1.0源代码分析Chaincode（链码）体系总结，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 Chaincode（链码）

## 1、Chaincode概述

Chaincode，即链码或智能合约，代码分布在protos/peer目录、core/chaincode和core/common/ccprovider目录，目录结构如下：

* protos/peer目录：

* chaincode.pb.go，ChaincodeDeploymentSpec、ChaincodeInvocationSpec结构体定义。

* core/chaincode目录：

* platforms目录，链码的编写语言平台实现，如golang或java。

* platforms.go，Platform接口定义，及部分 工具 函数。

* java目录，java语言平台实现。

* golang目录，golang语言平台实现。

* core/common/ccprovider目录：ccprovider相关实现。

## 2、protos相关结构体定义

### 2.1、ChaincodeDeploymentSpec结构体定义（用于Chaincode部署）

#### 2.1.1 ChaincodeDeploymentSpec结构体定义

```go

type ChaincodeDeploymentSpec struct {

ChaincodeSpec *ChaincodeSpec //ChaincodeSpec消息

EffectiveDate *google_protobuf1.Timestamp

CodePackage   []byte //链码文件打包

ExecEnv       ChaincodeDeploymentSpec_ExecutionEnvironment //链码执行环境，DOCKER或SYSTEM

}

type ChaincodeDeploymentSpec_ExecutionEnvironment int32

const (

ChaincodeDeploymentSpec_DOCKER ChaincodeDeploymentSpec_ExecutionEnvironment = 0

ChaincodeDeploymentSpec_SYSTEM ChaincodeDeploymentSpec_ExecutionEnvironment = 1

)

//代码在protos/peer/chaincode.pb.go

```

#### 2.1.2、ChaincodeSpec结构体定义

```go

type ChaincodeSpec struct {

Type        ChaincodeSpec_Type //链码的编写语言，GOLANG、JAVA

ChaincodeId *ChaincodeID //ChaincodeId，链码路径、链码名称、链码版本

Input       *ChaincodeInput //链码的具体执行参数信息

Timeout     int32

}

type ChaincodeSpec_Type int32

const (

ChaincodeSpec_UNDEFINED ChaincodeSpec_Type = 0

ChaincodeSpec_GOLANG    ChaincodeSpec_Type = 1

ChaincodeSpec_NODE      ChaincodeSpec_Type = 2

ChaincodeSpec_CAR       ChaincodeSpec_Type = 3

ChaincodeSpec_JAVA      ChaincodeSpec_Type = 4

)

type ChaincodeID struct {

Path string

Name string

Version string

}

type ChaincodeInput struct { //链码的具体执行参数信息

Args [][]byte

}

//代码在protos/peer/chaincode.pb.go

```

### 2.2、ChaincodeInvocationSpec结构体定义

```go

type ChaincodeInvocationSpec struct {

ChaincodeSpec *ChaincodeSpec //参考本文2.2

IdGenerationAlg string

}

//代码在protos/peer/chaincode.pb.go

```

## 3、ccprovider目录相关实现

### 3.1、ChaincodeData结构体

```go

type ChaincodeData struct {

Name string

Version string

Escc string

Vscc string

Policy []byte //chaincode 实例的背书策略

Data []byte

Id []byte

InstantiationPolicy []byte //实例化策略

}

//获取ChaincodeData，优先从缓存中读取

func GetChaincodeData(ccname string, ccversion string) (*ChaincodeData, error)

//代码在core/common/ccprovider/ccprovider.go

```

func GetChaincodeData(ccname string, ccversion string) (*ChaincodeData, error)代码如下：

```go

var ccInfoFSProvider = &CCInfoFSImpl{}

var ccInfoCache = NewCCInfoCache(ccInfoFSProvider)

func GetChaincodeData(ccname string, ccversion string) (*ChaincodeData, error) {

//./peer/node/start.go: ccprovider.EnableCCInfoCache()

//如果启用ccInfoCache，优先从缓存中读取ChaincodeData

if ccInfoCacheEnabled {

return ccInfoCache.GetChaincodeData(ccname, ccversion)

}

ccpack, err := ccInfoFSProvider.GetChaincode(ccname, ccversion)

return ccpack.GetChaincodeData(), nil

}

//代码在core/common/ccprovider/ccprovider.go

```

### 3.2、ccInfoCacheImpl结构体

```go

type ccInfoCacheImpl struct {

sync.RWMutex

cache        map[string]*ChaincodeData //ChaincodeData

cacheSupport CCCacheSupport

}

//构造ccInfoCacheImpl

func NewCCInfoCache(cs CCCacheSupport) *ccInfoCacheImpl

//获取ChaincodeData，优先从c.cache中获取，如果c.cache中没有，则从c.cacheSupport（即CCInfoFSImpl）中获取并写入c.cache

func (c *ccInfoCacheImpl) GetChaincodeData(ccname string, ccversion string) (*ChaincodeData, error)

//代码在core/common/ccprovider/ccinfocache.go

```

func (c *ccInfoCacheImpl) GetChaincodeData(ccname string, ccversion string) (*ChaincodeData, error) 代码如下：

```go

func (c *ccInfoCacheImpl) GetChaincodeData(ccname string, ccversion string) (*ChaincodeData, error) {

key := ccname + "/" + ccversion

c.RLock()

ccdata, in := c.cache[key] //优先从c.cache中获取

c.RUnlock()

if !in { //如果c.cache中没有

var err error

//从c.cacheSupport中获取

ccpack, err := c.cacheSupport.GetChaincode(ccname, ccversion)

c.Lock()

//并写入c.cache

ccdata = ccpack.GetChaincodeData()

c.cache[key] = ccdata

c.Unlock()

}

return ccdata, nil

}

//代码在core/common/ccprovider/ccinfocache.go

```

### 3.3、CCCacheSupport接口定义及实现

#### 3.3.1、CCCacheSupport接口定义

```go

type CCCacheSupport interface {

//获取Chaincode包

GetChaincode(ccname string, ccversion string) (CCPackage, error)

}

//代码在core/common/ccprovider/ccprovider.go

```

#### 3.3.2、CCCacheSupport接口实现（即CCInfoFSImpl结构体）

```go

type CCInfoFSImpl struct{}

//从文件系统中读取并构造CDSPackage或SignedCDSPackage

func (*CCInfoFSImpl) GetChaincode(ccname string, ccversion string) (CCPackage, error) {

cccdspack := &CDSPackage{}

_, _, err := cccdspack.InitFromFS(ccname, ccversion)

if err != nil {

//try signed CDS

ccscdspack := &SignedCDSPackage{}

_, _, err = ccscdspack.InitFromFS(ccname, ccversion)

if err != nil {

return nil, err

}

return ccscdspack, nil

}

return cccdspack, nil

}

//将ChaincodeDeploymentSpec序列化后写入文件系统

func (*CCInfoFSImpl) PutChaincode(depSpec *pb.ChaincodeDeploymentSpec) (CCPackage, error) {

buf, err := proto.Marshal(depSpec)

cccdspack := &CDSPackage{}

_, err := cccdspack.InitFromBuffer(buf)

err = cccdspack.PutChaincodeToFS()

}

//代码在core/common/ccprovider/ccprovider.go

```

### 3.4、CCPackage接口定义及实现

#### 3.4.1、CCPackage接口定义

```go

type CCPackage interface {

//从字节初始化包

InitFromBuffer(buf []byte) (*ChaincodeData, error)

//从文件系统初始化包

InitFromFS(ccname string, ccversion string) ([]byte, *pb.ChaincodeDeploymentSpec, error)

//将chaincode包写入文件系统

PutChaincodeToFS() error

//从包中获取ChaincodeDeploymentSpec

GetDepSpec() *pb.ChaincodeDeploymentSpec

//从包中获取序列化的ChaincodeDeploymentSpec

GetDepSpecBytes() []byte

//校验ChaincodeData

ValidateCC(ccdata *ChaincodeData) error

//包转换为proto.Message

GetPackageObject() proto.Message

//获取ChaincodeData

GetChaincodeData() *ChaincodeData

//基于包计算获取chaincode Id

GetId() []byte

}

//代码在core/common/ccprovider/ccprovider.go

```

#### 3.4.2、CCPackage接口实现（CDSPackage）

```go

type CDSData struct {

CodeHash []byte //ChaincodeDeploymentSpec.CodePackage哈希

MetaDataHash []byte //ChaincodeSpec.ChaincodeId.Name和ChaincodeSpec.ChaincodeId.Version哈希

}

type CDSPackage struct {

buf     []byte //ChaincodeDeploymentSpec哈希

depSpec *pb.ChaincodeDeploymentSpec //ChaincodeDeploymentSpec

data    *CDSData

datab   []byte

id      []byte //id为CDSData.CodeHash和CDSData.MetaDataHash求哈希

}

//获取ccpack.id

func (ccpack *CDSPackage) GetId() []byte

//获取ccpack.depSpec

func (ccpack *CDSPackage) GetDepSpec() *pb.ChaincodeDeploymentSpec

//获取ccpack.buf，即ChaincodeDeploymentSpec哈希

func (ccpack *CDSPackage) GetDepSpecBytes() []byte

//获取ccpack.depSpec

func (ccpack *CDSPackage) GetPackageObject() proto.Message

//构造ChaincodeData

func (ccpack *CDSPackage) GetChaincodeData() *ChaincodeData

//获取ChaincodeDeploymentSpec哈希、CDSData、id

func (ccpack *CDSPackage) getCDSData(cds *pb.ChaincodeDeploymentSpec) ([]byte, []byte, *CDSData, error)

//校验CDSPackage和ChaincodeData

func (ccpack *CDSPackage) ValidateCC(ccdata *ChaincodeData) error

//[]byte反序列化为ChaincodeDeploymentSpec，构造CDSPackage，进而构造ChaincodeData

func (ccpack *CDSPackage) InitFromBuffer(buf []byte) (*ChaincodeData, error)

//从文件系统中获取ChaincodeData，即buf, err := GetChaincodePackage(ccname, ccversion)和_, err = ccpack.InitFromBuffer(buf)

func (ccpack *CDSPackage) InitFromFS(ccname string, ccversion string) ([]byte, *pb.ChaincodeDeploymentSpec, error)

//ccpack.buf写入文件，文件名为/var/hyperledger/production/chaincodes/Name.Version

func (ccpack *CDSPackage) PutChaincodeToFS() error

//代码在core/common/ccprovider/cdspackage.go

```

### 3.5、CCContext结构体

```go

type CCContext struct { //ChaincodeD上下文

ChainID string

Name string

Version string

TxID string

Syscc bool

SignedProposal *pb.SignedProposal

Proposal *pb.Proposal

canonicalName string

}

//构造CCContext

func NewCCContext(cid, name, version, txid string, syscc bool, signedProp *pb.SignedProposal, prop *pb.Proposal) *CCContext

//name + ":" + version

func (cccid *CCContext) GetCanonicalName() string

//代码在core/common/ccprovider/ccprovider.go

```

## 4、chaincode目录相关实现

### 4.1、ChaincodeProviderFactory接口定义及实现

#### 4.1.1、ChaincodeProviderFactory接口定义

```go

type ChaincodeProviderFactory interface {

//构造ChaincodeProvider实例

NewChaincodeProvider() ChaincodeProvider

}

func RegisterChaincodeProviderFactory(ccfact ChaincodeProviderFactory) {

ccFactory = ccfact

}

func GetChaincodeProvider() ChaincodeProvider {

return ccFactory.NewChaincodeProvider()

}

//代码在core/common/ccprovider/ccprovider.go

```

#### 4.1.2、ChaincodeProviderFactory接口实现

```go

type ccProviderFactory struct {

}

func (c *ccProviderFactory) NewChaincodeProvider() ccprovider.ChaincodeProvider {

return &ccProviderImpl{}

}

func init() {

ccprovider.RegisterChaincodeProviderFactory(&ccProviderFactory{})

}

//代码在core/chaincode/ccproviderimpl.go

```

### 4.2、ChaincodeProvider接口定义及实现

#### 4.2.1、ChaincodeProvider接口定义

```go

type ChaincodeProvider interface {

GetContext(ledger ledger.PeerLedger) (context.Context, error)

GetCCContext(cid, name, version, txid string, syscc bool, signedProp *pb.SignedProposal, prop *pb.Proposal) interface{}

GetCCValidationInfoFromLSCC(ctxt context.Context, txid string, signedProp *pb.SignedProposal, prop *pb.Proposal, chainID string, chaincodeID string) (string, []byte, error)

ExecuteChaincode(ctxt context.Context, cccid interface{}, args [][]byte) (*pb.Response, *pb.ChaincodeEvent, error)

Execute(ctxt context.Context, cccid interface{}, spec interface{}) (*pb.Response, *pb.ChaincodeEvent, error)

ExecuteWithErrorFilter(ctxt context.Context, cccid interface{}, spec interface{}) ([]byte, *pb.ChaincodeEvent, error)

Stop(ctxt context.Context, cccid interface{}, spec *pb.ChaincodeDeploymentSpec) error

ReleaseContext()

}

//代码在core/common/ccprovider/ccprovider.go

```

#### 4.2.2、ChaincodeProvider接口实现

```go

type ccProviderImpl struct {

txsim ledger.TxSimulator //交易模拟器

}

type ccProviderContextImpl struct {

ctx *ccprovider.CCContext

}

//获取context.Context，添加TXSimulatorKey绑定c.txsim

func (c *ccProviderImpl) GetContext(ledger ledger.PeerLedger) (context.Context, error)

//构造CCContext，并构造ccProviderContextImpl

func (c *ccProviderImpl) GetCCContext(cid, name, version, txid string, syscc bool, signedProp *pb.SignedProposal, prop *pb.Proposal) interface{}

//调用GetChaincodeDataFromLSCC(ctxt, txid, signedProp, prop, chainID, chaincodeID)获取ChaincodeData中Vscc和Policy

func (c *ccProviderImpl) GetCCValidationInfoFromLSCC(ctxt context.Context, txid string, signedProp *pb.SignedProposal, prop *pb.Proposal, chainID string, chaincodeID string) (string, []byte, error)

//调用ExecuteChaincode(ctxt, cccid.(*ccProviderContextImpl).ctx, args)执行上下文中指定的链码

func (c *ccProviderImpl) ExecuteChaincode(ctxt context.Context, cccid interface{}, args [][]byte) (*pb.Response, *pb.ChaincodeEvent, error)

//调用Execute(ctxt, cccid.(*ccProviderContextImpl).ctx, spec)

func (c *ccProviderImpl) Execute(ctxt context.Context, cccid interface{}, spec interface{}) (*pb.Response, *pb.ChaincodeEvent, error)

//调用ExecuteWithErrorFilter(ctxt, cccid.(*ccProviderContextImpl).ctx, spec)

func (c *ccProviderImpl) ExecuteWithErrorFilter(ctxt context.Context, cccid interface{}, spec interface{}) ([]byte, *pb.ChaincodeEvent, error)

//调用theChaincodeSupport.Stop(ctxt, cccid.(*ccProviderContextImpl).ctx, spec)

func (c *ccProviderImpl) Stop(ctxt context.Context, cccid interface{}, spec *pb.ChaincodeDeploymentSpec) error

//调用c.txsim.Done()

func (c *ccProviderImpl) ReleaseContext() {

//代码在core/chaincode/ccproviderimpl.go

```

### 4.3、ChaincodeSupport结构体

ChaincodeSupport更详细内容，参考：Fabric 1.0源代码笔记 之 Chaincode（链码） #ChaincodeSupport（链码支持服务端）

### 4.4、ExecuteChaincode函数（执行链码）

执行链码上下文中指定的链码。

```go

func ExecuteChaincode(ctxt context.Context, cccid *ccprovider.CCContext, args [][]byte) (*pb.Response, *pb.ChaincodeEvent, error) {

var spec *pb.ChaincodeInvocationSpec

var err error

var res *pb.Response

var ccevent *pb.ChaincodeEvent

spec, err = createCIS(cccid.Name, args) //构造ChaincodeInvocationSpec

res, ccevent, err = Execute(ctxt, cccid, spec)

return res, ccevent, err

}

//代码在core/chaincode/chaincodeexec.go

```

res, ccevent, err = Execute(ctxt, cccid, spec)代码如下：

```go

func Execute(ctxt context.Context, cccid *ccprovider.CCContext, spec interface{}) (*pb.Response, *pb.ChaincodeEvent, error) {

var err error

var cds *pb.ChaincodeDeploymentSpec

var ci *pb.ChaincodeInvocationSpec

cctyp := pb.ChaincodeMessage_INIT //初始化

if cds, _ = spec.(*pb.ChaincodeDeploymentSpec); cds == nil { //优先判断ChaincodeDeploymentSpec

if ci, _ = spec.(*pb.ChaincodeInvocationSpec); ci == nil { //其次判断ChaincodeInvocationSpec

panic("Execute should be called with deployment or invocation spec")

}

cctyp = pb.ChaincodeMessage_TRANSACTION //交易

}

_, cMsg, err := theChaincodeSupport.Launch(ctxt, cccid, spec)

var ccMsg *pb.ChaincodeMessage

ccMsg, err = createCCMessage(cctyp, cccid.TxID, cMsg)

resp, err := theChaincodeSupport.Execute(ctxt, cccid, ccMsg, theChaincodeSupport.executetimeout)

if resp.ChaincodeEvent != nil {

resp.ChaincodeEvent.ChaincodeId = cccid.Name

resp.ChaincodeEvent.TxId = cccid.TxID

}

if resp.Type == pb.ChaincodeMessage_COMPLETED {

res := &pb.Response{}

unmarshalErr := proto.Unmarshal(resp.Payload, res)

return res, resp.ChaincodeEvent, nil

}

}

//代码在core/chaincode

```

## 5、platforms（链码的编写语言平台）

platforms更详细内容，参考：Fabric 1.0源代码笔记 之 Chaincode（链码） #platforms（链码语言平台）欢迎继续关注兄弟连 区块链教程 分享!