code: func (Pipe) Default(ctx *context.Context) error {
  	for i := range ctx.Config.Dockers {
  		var docker = &ctx.Config.Dockers[i]
  
  		if docker.Image != "" {
  			deprecate.Notice("docker.image")
  			deprecate.Notice("docker.tag_templates")
  
  			if len(docker.TagTemplates) == 0 {
  				docker.TagTemplates = []string{"{{ .Version }}"}
  			}
  
  			for _, tag := range docker.TagTemplates {
  				docker.ImageTemplates = append(
  					docker.ImageTemplates,
  					fmt.Sprintf("%s:%s", docker.Image, tag),
  				)
  			}
  		}
  
  		if docker.Binary != "" {
  			deprecate.Notice("docker.binary")
  			docker.Binaries = append(docker.Binaries, docker.Binary)
  		}
  
  		if docker.Goos == "" {
  			docker.Goos = "linux"
  		}
  		if docker.Goarch == "" {
  			docker.Goarch = "amd64"
  		}
  	}
  	// only set defaults if there is exactly 1 docker setup in the config file.
  	if len(ctx.Config.Dockers) != 1 {
  		return nil
  	}
  	if len(ctx.Config.Dockers[0].Binaries) == 0 {
  		ctx.Config.Dockers[0].Binaries = []string{
  			ctx.Config.Builds[0].Binary,
  		}
  	}
  	if ctx.Config.Dockers[0].Dockerfile == "" {
  		ctx.Config.Dockers[0].Dockerfile = "Dockerfile"
  	}
  	return nil
  }
docs: // Default sets the pipe defaults