prow/cmd/tackle/main.go
func currentClusters(proj string) (map[string]cluster, error) {
	clusters, err := output("gcloud", "container", "clusters", "list", "--project="+proj, "--format=value(name,zone)")
	if err != nil {
		return nil, fmt.Errorf("list clusters: %v", err)
	}
	options := map[string]cluster{}
	for _, line := range strings.Split(clusters, "\n") {
		if len(line) == 0 {
			continue
		}
		parts := strings.Split(line, "\t")
		if len(parts) != 2 {
			return nil, fmt.Errorf("bad line: %q", line)
		}
		c := cluster{name: parts[0], zone: parts[1], project: proj}
		options[c.name] = c
	}
	return options, nil
}
func currentClusters(proj string) (map[string]cluster, error) {
	clusters, err := output("gcloud", "container", "clusters", "list", "--project="+proj, "--format=value(name,zone)")
	if err != nil {
		return nil, fmt.Errorf("list clusters: %v", err)
	}
	options := map[string]cluster{}
	for _, line := range strings.Split(clusters, "\n") {
		if len(line) == 0 {
			continue
		}
		parts := strings.Split(line, "\t")
		if len(parts) != 2 {
			return nil, fmt.Errorf("bad line: %q", line)
		}
		c := cluster{name: parts[0], zone: parts[1], project: proj}
		options[c.name] = c
	}
	return options, nil
}
// currentClusters returns a {name: cluster} map.