Go命令使用kubectl获取更新的输出

Question

I have implemented a CLI using go and I display the status of kubernetese cells. The command is cellery ps

func ps() error {
    cmd := exec.Command("kubectl", "get", "cells")
    stdoutReader, _ := cmd.StdoutPipe()
    stdoutScanner := bufio.NewScanner(stdoutReader)
    go func() {
        for stdoutScanner.Scan() {
            fmt.Println(stdoutScanner.Text())
        }
    }()
    stderrReader, _ := cmd.StderrPipe()
    stderrScanner := bufio.NewScanner(stderrReader)
    go func() {
        for stderrScanner.Scan() {
            fmt.Println(stderrScanner.Text())
            if (stderrScanner.Text() == "No resources found.") {
                os.Exit(0)
            }
        }
    }()
    err := cmd.Start()
    if err != nil {
        fmt.Printf("Error in executing cell ps: %v 
", err)
        os.Exit(1)
    }
    err = cmd.Wait()
    if err != nil {
        fmt.Printf("\x1b[31;1m Cell ps finished with error: \x1b[0m %v 
", err)
        os.Exit(1)
    }
    return nil
}

However cells need time to get into ready state when they are deployed. Therefore I need to give a flag(wait) which would update the CLI output.

The command would be cellery ps -w . However Kubernetese API have not implemented this yet. So I will have to come up with a command.

Answer 1

Basically what you want is to listen to the event of a cell become ready. You can register to the events in a cluster and act upon them. A good example can be found here