Kubectl like output format for my cobra project

Question

I am new to golang and trying to develop a commandline tool using cobra. I would like to provide flags like kubectl offers to it's users. As a first step i would like to implement kubectl standard format like this

kubectl get pods -n mpo
NAME                                                    READY   STATUS      RESTARTS   AGE
my-deployment-5588bf7844-n2nw7                        1/1     Running     0          3d
my-deployment-5588bf7844-qcpsl                        1/1     Running     0          3d

Could please direct me to a simple example project (kubectl github project is too difficult for me to understand) or code where i could understand how to implement this output format.

Answer 1

You can format strings in Go with padding on either side. See this post for example.

Below, I format all strings with right padding. The first column gets 40 char padding as the pod name might be long. The other columns get only 10 chars padding.

fmt.Printf("%-40s %-10s %-10s\n", "NAME", "READY", "STATUS")
fmt.Printf("%-40s %-10s %-10s\n", "my-deployment-5588bf7844-n2nw7", " 1/1", "Running")
fmt.Printf("%-40s %-10s %-10s\n", "my-deployment-5588bf7844-n2nw7", " 1/1", "Running")
}

https://play.golang.com/p/8ZZH5XmqTpR

That said, using tabwriter, may be another, potentially even better option.

// io.Writer, minwidth, tabwidth, padding int, padchar byte, flags uint
w := tabwriter.NewWriter(os.Stdout, 10, 1, 5, ' ', 0)
fmt.Fprintln(w, "NAME\tREADY\tSTATUS")
fmt.Fprintln(w, "my-deployment-5588bf7844-n2nw7\t1/1\tRunning")
fmt.Fprintln(w, "my-deployment-5588bf7844-n2nw7\t1/1\tRunning")
w.Flush()

https://play.golang.com/p/QS01cuR34Jx