怎么进行区块链中的fabric chaincode分析

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本篇文章为大家展示了怎么进行区块链中的 fabric chaincode 分析，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。

chaincode 是所有区块链项目的核心，无论是公链还是私链。

fabric 如何形成 chaincode, 下图是 fabric chaincode 的核心模块组成

GenerateDockerfile 是生成 chaincode dockerfile 的函数

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

var buf []string

//let the executable’s name be chaincode ID’s name
buf = append(buf,“FROM“+cutil.GetDockerfileFromConfig(“chaincode.car.runtime”))
buf = append(buf,“ADD binpackage.tar /usr/local/bin”)

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

return dockerFileContents, nil
}

构建镜像函数

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

   // Bundle the .car file into a tar stream so it may be transferred to the builder container
   codepackage, output := io.Pipe()
   go func() {
      tw := tar.NewWriter(output)

      err := cutil.WriteBytesToPackage(codepackage.car , cds.CodePackage, tw)

      tw.Close()
      output.CloseWithError(err)
   }()

   binpackage := bytes.NewBuffer(nil)
   err := util.DockerBuild(util.DockerBuildOptions{
      Cmd:           java -jar /usr/local/bin/chaintool buildcar /chaincode/input/codepackage.car -o /chaincode/output/chaincode ,
      InputStream:  codepackage,
      OutputStream: binpackage,
   })
   if err != nil {
      return fmt.Errorf(Error building CAR: %s , err)
   }

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


 创建容器并上传

func DockerBuild(opts DockerBuildOptions) error {
   client, err := cutil.NewDockerClient()
   if err != nil {
      return fmt.Errorf(Error creating docker client: %s , err)
   }
   if opts.Image == {
      opts.Image = cutil.GetDockerfileFromConfig(chaincode.builder)
      if opts.Image == {
         return fmt.Errorf(No image provided and \ chaincode.builder\ default does not exist)
      }
   }

   logger.Debugf(Attempting build with image %s , opts.Image)

   //-----------------------------------------------------------------------------------
   // Ensure the image exists locally, or pull it from a registry if it doesn t
   //-----------------------------------------------------------------------------------
   _, err = client.InspectImage(opts.Image)
   if err != nil {
      logger.Debugf(Image %s does not exist locally, attempt pull , opts.Image)

      err = client.PullImage(docker.PullImageOptions{Repository: opts.Image}, docker.AuthConfiguration{})
      if err != nil {
         return fmt.Errorf(Failed to pull %s: %s , opts.Image, err)
      }
   }

   //-----------------------------------------------------------------------------------
   // Create an ephemeral container, armed with our Env/Cmd
   //-----------------------------------------------------------------------------------
   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,
      },
   })
   if err != nil {
      return fmt.Errorf(Error creating container: %s , err)
   }
   defer client.RemoveContainer(docker.RemoveContainerOptions{ID: container.ID})

   //-----------------------------------------------------------------------------------
   // Upload our input stream
   //-----------------------------------------------------------------------------------
   err = client.UploadToContainer(container.ID, docker.UploadToContainerOptions{
      Path:         /chaincode/input ,
      InputStream: opts.InputStream,
   })
   if err != nil {
      return fmt.Errorf(Error uploading input to container: %s , err)
   }

   //-----------------------------------------------------------------------------------
   // Attach stdout buffer to capture possible compilation errors
   //-----------------------------------------------------------------------------------
   stdout := bytes.NewBuffer(nil)
   _, err = client.AttachToContainerNonBlocking(docker.AttachToContainerOptions{
      Container:    container.ID,
      OutputStream: stdout,
      ErrorStream:  stdout,
      Logs:         true,
      Stdout:       true,
      Stderr:       true,
      Stream:       true,
   })
   if err != nil {
      return fmt.Errorf(Error attaching to container: %s , err)
   }

   //-----------------------------------------------------------------------------------
   // Launch the actual build, realizing the Env/Cmd specified at container creation
   //-----------------------------------------------------------------------------------
   err = client.StartContainer(container.ID, nil)
   if err != nil {
      return fmt.Errorf(Error executing build: %s \ %s\ , err, stdout.String())
   }

   //-----------------------------------------------------------------------------------
   // Wait for the build to complete and gather the return value
   //-----------------------------------------------------------------------------------
   retval, err := client.WaitContainer(container.ID)
   if err != nil {
      return fmt.Errorf(Error waiting for container to complete: %s , err)
   }
   if retval 0 {
      return fmt.Errorf(Error returned from build: %d \ %s\ , retval, stdout.String())
   }

   //-----------------------------------------------------------------------------------
   // Finally, download the result
   //-----------------------------------------------------------------------------------
   err = client.DownloadFromContainer(container.ID, docker.DownloadFromContainerOptions{
      Path:         /chaincode/output/. ,
      OutputStream: opts.OutputStream,
   })
   if err != nil {
      return fmt.Errorf(Error downloading output: %s , err)
   }

   return nil
}