区块链教程Fabric1.0源代码分析链码 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

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

//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

//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：

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。

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)

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)

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

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

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

//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

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：

//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

区块链教程Fabric1.0源代码分析链码 链码语言平台

原文：http://blog.51cto.com/14041296/2310219