怎么进行区块链中的fabricchaincode分析

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。

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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
}

上述内容就是怎么进行区块链中的fabric chaincode分析，你们学到知识或技能了吗？如果还想学到更多技能或者丰富自己的知识储备，欢迎关注创新互联行业资讯频道。

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