channels.go

package main

import (
	"fmt"
	"os"
	"golang.org/x/sync/errgroup"
)

func main() {
	nodeNames := []string{"host-1", "host-2", "host-3"}
	nodeStatuses := make(map[string]string)
	
	type drainStatus struct {
		nodeName string
		status   string
	}
	
	var g errgroup.Group
	statuses := make(chan drainStatus)
	for _, nodeName := range nodeNames {
		nodeName := nodeName
		g.Go(func() error {
			switch nodeName {
			case "host-1":
				statuses <- drainStatus{
					nodeName: nodeName,
					status:   "draining",
				}
			case "host-2":
				statuses <- drainStatus{
					nodeName: nodeName,
					status:   "cordoned",
				}
			case "host-3":
				statuses <- drainStatus{
					nodeName: nodeName,
					status:   "drained",
				}
			}
			
			// in actuality, we get all pods on the node, then iterate over pods and start a go routine for each to either delete or evict the pod
			// and after waiting for the errgroup on the pods, we set the status of the node to "draining"
			// if len(pods) == 0, we set node status to "drained" before we begin the for loop mentioned right above
			// there is another case we determine and set node status to "drained" too before beginning the loop for pods. 
			
			
			return nil
		})
		
	}
	
	s := <-statuses
	nodeStatuses[s.nodeName] = s.status

	if err := g.Wait(); err != nil {
		fmt.Println("error")
		os.Exit(1)
	}
	fmt.Println(nodeStatuses)
	
}