兄弟连区块链教程Fabric1.0源代码分析链码 链码语言平台

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# Fabric 1.0源代码笔记 之 Chaincode(链码) #platforms(链码语言平台)


## 1、platforms概述


platforms代码集中在core/chaincode/platforms目录下。


* core/chaincode/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platforms相关工具函数。

    * util目录,Docker相关工具函数。

    * java目录,java语言平台实现。

    * golang目录,golang语言平台实现。


## 2、Platform接口定义


```go

type Platform interface {

    //验证ChaincodeSpec

    ValidateSpec(spec *pb.ChaincodeSpec) error

    //验证ChaincodeDeploymentSpec

    ValidateDeploymentSpec(spec *pb.ChaincodeDeploymentSpec) error

    //获取部署Payload

    GetDeploymentPayload(spec *pb.ChaincodeSpec) ([]byte, error)

    //生成Dockerfile

    GenerateDockerfile(spec *pb.ChaincodeDeploymentSpec) (string, error)

    //生成DockerBuild

    GenerateDockerBuild(spec *pb.ChaincodeDeploymentSpec, tw *tar.Writer) error

}

//代码在core/chaincode/platforms/platforms.go

```


## 3、platforms相关工具函数


### 3.1、platforms相关工具函数


```go

//按链码类型构造Platform接口实例,如golang.Platform{}

func Find(chaincodeType pb.ChaincodeSpec_Type) (Platform, error)

//调取platform.GetDeploymentPayload(spec),获取部署Payload

func GetDeploymentPayload(spec *pb.ChaincodeSpec) ([]byte, error)

//优先获取tls根证书,如无则获取tls证书

func getPeerTLSCert() ([]byte, error)

//调取platform.GenerateDockerfile(cds),创建Dockerfile

func generateDockerfile(platform Platform, cds *pb.ChaincodeDeploymentSpec, tls bool) ([]byte, error)

//调取platform.GenerateDockerBuild(cds, tw),创建DockerBuild

func generateDockerBuild(platform Platform, cds *pb.ChaincodeDeploymentSpec, inputFiles InputFiles, tw *tar.Writer) error

//调取generateDockerfile(platform, cds, cert != nil)

func GenerateDockerBuild(cds *pb.ChaincodeDeploymentSpec) (io.Reader, error)

//代码在core/chaincode/platforms/platforms.go

```


### 3.2、Docker相关工具函数


```go

//contents+hash合并后再哈希

func ComputeHash(contents []byte, hash []byte) []byte

//哈希目录下文件并打包

func HashFilesInDir(rootDir string, dir string, hash []byte, tw *tar.Writer) ([]byte, error)

//目录是否存在

func IsCodeExist(tmppath string) error

//编译链码

func DockerBuild(opts DockerBuildOptions) error

//代码在core/chaincode/platforms/util/utils.go

```


func DockerBuild(opts DockerBuildOptions) error代码如下:


```go

type DockerBuildOptions struct {

    Image        string

    Env          []string

    Cmd          string

    InputStream  io.Reader

    OutputStream io.Writer

}


func DockerBuild(opts DockerBuildOptions) error {

    client, err := cutil.NewDockerClient()

    if err != nil {

        return fmt.Errorf("Error creating docker client: %s", err)

    }

    if opts.Image == "" {

        //通用的本地编译环境

        opts.Image = cutil.GetDockerfileFromConfig("chaincode.builder")

    }


    //确认镜像是否存在或从远程拉取

    _, err = client.InspectImage(opts.Image)

    if err != nil {

        err = client.PullImage(docker.PullImageOptions{Repository: opts.Image}, docker.AuthConfiguration{})

    }


    //创建一个暂时的容器

    container, err := client.CreateContainer(docker.CreateContainerOptions{

        Config: &docker.Config{

            Image:        opts.Image,

            Env:          opts.Env,

            Cmd:          []string{"/bin/sh", "-c", opts.Cmd},

            AttachStdout: true,

            AttachStderr: true,

        },

    })

    //删除容器

    defer client.RemoveContainer(docker.RemoveContainerOptions{ID: container.ID})


    //上传输入

    err = client.UploadToContainer(container.ID, docker.UploadToContainerOptions{

        Path:        "/chaincode/input",

        InputStream: opts.InputStream,

    })


    stdout := bytes.NewBuffer(nil)

    _, err = client.AttachToContainerNonBlocking(docker.AttachToContainerOptions{

        Container:    container.ID,

        OutputStream: stdout,

        ErrorStream:  stdout,

        Logs:         true,

        Stdout:       true,

        Stderr:       true,

        Stream:       true,

    })


    //启动容器

    err = client.StartContainer(container.ID, nil)

    //等待容器返回

    retval, err := client.WaitContainer(container.ID)

    //获取容器输出

    err = client.DownloadFromContainer(container.ID, docker.DownloadFromContainerOptions{

        Path:         "/chaincode/output/.",

        OutputStream: opts.OutputStream,

    })

    return nil

}

//代码在core/chaincode/platforms/util/utils.go

```


## 4、golang语言平台实现


### 4.1、golang.Platform结构体定义及方法


Platform接口golang语言平台实现,即golang.Platform结构体定义及方法。


```go

type Platform struct {

}


//验证ChaincodeSpec,即检查spec.ChaincodeId.Path是否存在

func (goPlatform *Platform) ValidateSpec(spec *pb.ChaincodeSpec) error

//验证ChaincodeDeploymentSpec,即检查cds.CodePackage(tar.gz文件)解压后文件合法性

func (goPlatform *Platform) ValidateDeploymentSpec(cds *pb.ChaincodeDeploymentSpec) error

//获取部署Payload,即将链码目录下文件及导入包所依赖的外部包目录下文件达成tar.gz包

func (goPlatform *Platform) GetDeploymentPayload(spec *pb.ChaincodeSpec) ([]byte, error)

func (goPlatform *Platform) GenerateDockerfile(cds *pb.ChaincodeDeploymentSpec) (string, error)

func (goPlatform *Platform) GenerateDockerBuild(cds *pb.ChaincodeDeploymentSpec, tw *tar.Writer) error


func pathExists(path string) (bool, error) //路径是否存在

func decodeUrl(spec *pb.ChaincodeSpec) (string, error) //spec.ChaincodeId.Path去掉http://或https://

func getGopath() (string, error) //获取GOPATH

func filter(vs []string, f func(string) bool) []string //按func(string) bool过滤[]string

func vendorDependencies(pkg string, files Sources) //重新映射依赖关系

//代码在core/chaincode/platforms/golang/platform.go

```


#### 4.1.1 func (goPlatform *Platform) GetDeploymentPayload(spec *pb.ChaincodeSpec) ([]byte, error)


```go

func (goPlatform *Platform) GetDeploymentPayload(spec *pb.ChaincodeSpec) ([]byte, error) {

    var err error

    code, err := getCode(spec) //获取代码,即构造CodeDescriptor,Gopath为代码真实路径,Pkg为代码相对路径

    env, err := getGoEnv()

    gopaths := splitEnvPaths(env["GOPATH"]) //GOPATH

    goroots := splitEnvPaths(env["GOROOT"]) //GOROOT,go安装路径

    gopaths[code.Gopath] = true //链码真实路径

    env["GOPATH"] = flattenEnvPaths(gopaths) //GOPATH、GOROOT、链码真实路径重新拼合为新GOPATH


    imports, err := listImports(env, code.Pkg) //获取导入包列表

    var provided = map[string]bool{ //如下两个包为ccenv已自带,可删除

        "github.com/hyperledger/fabric/core/chaincode/shim": true,

        "github.com/hyperledger/fabric/protos/peer":         true,

    }


    imports = filter(imports, func(pkg string) bool {

        if _, ok := provided[pkg]; ok == true { //从导入包中删除ccenv已自带的包

            return false

        }

        for goroot := range goroots { //删除goroot中自带的包

            fqp := filepath.Join(goroot, "src", pkg)

            exists, err := pathExists(fqp)

            if err == nil && exists {

                return false

            }

        }   

        return true

    })


    deps := make(map[string]bool)

    for _, pkg := range imports {

        transitives, err := listDeps(env, pkg) //列出所有导入包的依赖包

        deps[pkg] = true

        for _, dep := range transitives {

            deps[dep] = true

        }

    }

    delete(deps, "") //删除空


    fileMap, err := findSource(code.Gopath, code.Pkg) //遍历链码路径下文件

    for dep := range deps {

        for gopath := range gopaths {

            fqp := filepath.Join(gopath, "src", dep)

            exists, err := pathExists(fqp)

            if err == nil && exists {

                files, err := findSource(gopath, dep) //遍历依赖包下文件

                for _, file := range files {

                    fileMap[file.Name] = file

                }


            }

        }

    }


    files := make(Sources, 0) //数组

    for _, file := range fileMap {

        files = append(files, file)

    }

    vendorDependencies(code.Pkg, files) //重新映射依赖关系

    sort.Sort(files)


    payload := bytes.NewBuffer(nil)

    gw := gzip.NewWriter(payload)

    tw := tar.NewWriter(gw)

    for _, file := range files {

        err = cutil.WriteFileToPackage(file.Path, file.Name, tw) //将文件写入压缩包中

    }

    tw.Close()

    gw.Close()

    return payload.Bytes(), nil

}

//代码在core/chaincode/platforms/golang/platform.go

```


#### 4.1.2、func (goPlatform *Platform) GenerateDockerfile(cds *pb.ChaincodeDeploymentSpec) (string, error)


```go

func (goPlatform *Platform) GenerateDockerfile(cds *pb.ChaincodeDeploymentSpec) (string, error) {

    var buf []string

    //go语言链码部署依赖的基础镜像

    buf = append(buf, "FROM "+cutil.GetDockerfileFromConfig("chaincode.golang.runtime"))

    //binpackage.tar添加到/usr/local/bin目录下

    buf = append(buf, "ADD binpackage.tar /usr/local/bin")

    dockerFileContents := strings.Join(buf, "\n")

    return dockerFileContents, nil

}

//代码在core/chaincode/platforms/golang/platform.go

```


#### 4.1.3、func (goPlatform *Platform) GenerateDockerBuild(cds *pb.ChaincodeDeploymentSpec, tw *tar.Writer) error


```go

func (goPlatform *Platform) GenerateDockerBuild(cds *pb.ChaincodeDeploymentSpec, tw *tar.Writer) error {

    spec := cds.ChaincodeSpec

    pkgname, err := decodeUrl(spec)

    const ldflags = "-linkmode external -extldflags '-static'"


    codepackage := bytes.NewReader(cds.CodePackage)

    binpackage := bytes.NewBuffer(nil)

    //编译链码

    err = util.DockerBuild(util.DockerBuildOptions{

        Cmd:          fmt.Sprintf("GOPATH=/chaincode/input:$GOPATH go build -ldflags \"%s\" -o /chaincode/output/chaincode %s", ldflags, pkgname),

        InputStream:  codepackage,

        OutputStream: binpackage,

    })

    return cutil.WriteBytesToPackage("binpackage.tar", binpackage.Bytes(), tw)

}

//代码在core/chaincode/platforms/golang/platform.go

```


### 4.2、env相关函数


```go

type Env map[string]string

type Paths map[string]bool


func getEnv() Env //获取环境变量,写入map[string]string

func getGoEnv() (Env, error) //执行go env获取go环境变量,写入map[string]string

func flattenEnv(env Env) []string //拼合env,形式k=v,写入[]string

func splitEnvPaths(value string) Paths //分割多个路径字符串,linux下按:分割

func flattenEnvPaths(paths Paths) string //拼合多个路径字符串,以:分隔

//代码在core/chaincode/platforms/golang/env.go

```


### 4.3、list相关函数


```go

//执行命令pgm,支持设置timeout,timeout后将kill进程

func runProgram(env Env, timeout time.Duration, pgm string, args ...string) ([]byte, error)

//执行go list -f 规则 链码路径,获取导入包列表或依赖包列表

func list(env Env, template, pkg string) ([]string, error)

//执行go list -f "{{ join .Deps \"\\n\"}}" 链码路径,获取依赖包列表

func listDeps(env Env, pkg string) ([]string, error)

//执行go list -f "{{ join .Imports \"\\n\"}}" 链码路径,获取导入包列表

func listImports(env Env, pkg string) ([]string, error)

//代码在core/chaincode/platforms/golang/list.go

```


### 4.4、Sources类型及方法


```go

type Sources []SourceDescriptor

type SourceMap map[string]SourceDescriptor


type SourceDescriptor struct {

    Name, Path string

    Info       os.FileInfo

}


type CodeDescriptor struct {

    Gopath, Pkg string

    Cleanup     func()

}

//代码在core/chaincode/platforms/golang/package.go

```


涉及方法如下:


```go

//获取代码真实路径

func getCodeFromFS(path string) (codegopath string, err error)

//获取代码,即构造CodeDescriptor,Gopath为代码真实路径,Pkg为代码相对路径

func getCode(spec *pb.ChaincodeSpec) (*CodeDescriptor, error)

//数组长度

func (s Sources) Len() int

//交换数组i,j内容

func (s Sources) Swap(i, j int)

//比较i,j的名称

func (s Sources) Less(i, j int) bool

//遍历目录下文件,填充type SourceMap map[string]SourceDescriptor

func findSource(gopath, pkg string) (SourceMap, error)

//代码在core/chaincode/platforms/golang/package.go

```

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