adds namespaces overview to fleet command

pkg/fleet/fleet.go

@@ -2,42 +2,47 @@ package fleet
 
 import (
 	"fmt"
+	"os"
+	"text/tabwriter"
+
 	"github.com/pkg/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/cli-runtime/pkg/genericclioptions"
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/client-go/tools/clientcmd/api"
-	"os"
-	"text/tabwriter"
 )
 
-// RunFleetCommand runs the top-level fleet command
+// RunFleetCommand executes the top-level fleet command
 func RunFleetCommand(configFlags *genericclioptions.ConfigFlags) error {
 	clientcfg := configFlags.ToRawKubeConfigLoader()
 	cfg, err := clientcfg.RawConfig()
 	if err != nil {
 		return errors.Wrap(err, "Can't assemble raw config")
 	}
 	w := tabwriter.NewWriter(os.Stdout, 0, 0, 1, ' ', 0)
-	fmt.Fprintln(w, "CLUSTER\tNODES\tAPI")
+	fmt.Fprintln(w, "CLUSTER\tNODES\tNAMESPACES\tAPI")
 	for name, context := range cfg.Contexts {
 		cluster := cfg.Clusters[context.Cluster]
 		apiServerEndpoint := "?"
 		if cluster != nil {
 			apiServerEndpoint = cluster.Server
 		}
-		ninfo, err := nodesOverview(cfg, name)
+		noinfo, err := nodesOverview(cfg, name)
+		if err != nil {
+			noinfo = "?"
+		}
+		nsinfo, err := nsOverview(cfg, name)
 		if err != nil {
-			ninfo = "?"
+			nsinfo = "?"
 		}
-		fmt.Fprintln(w, fmt.Sprintf("%v\t%v\t%v", context.Cluster, ninfo, apiServerEndpoint))
+		fmt.Fprintln(w, fmt.Sprintf("%v\t%v\t%v\t%v", context.Cluster, noinfo, nsinfo, apiServerEndpoint))
 	}
 	w.Flush()
 	return nil
 }
 
-// nodesOverview provides an overview of the cluster's worker nodes in the context
+// nodesOverview returns the cluster's worker nodes overview in given context
 func nodesOverview(cfg api.Config, context string) (string, error) {
 	cs, err := csForContext(cfg, context)
 	if err != nil {
@@ -51,6 +56,20 @@ func nodesOverview(cfg api.Config, context string) (string, error) {
 	return noverview, nil
 }
 
+// nsOverview returns the cluster's namespaces overview in given context
+func nsOverview(cfg api.Config, context string) (string, error) {
+	cs, err := csForContext(cfg, context)
+	if err != nil {
+		return "", errors.Wrap(err, "Can't create a clientset based on config provided")
+	}
+	ns, err := cs.CoreV1().Namespaces().List(metav1.ListOptions{})
+	if err != nil {
+		return "", errors.Wrap(err, "Can't get nodes in cluster")
+	}
+	nsverview := fmt.Sprintf("%v", len(ns.Items))
+	return nsverview, nil
+}
+
 // csForContext returns a client for a given context
 func csForContext(cfg api.Config, context string) (*kubernetes.Clientset, error) {
 	config, err := clientcmd.NewNonInteractiveClientConfig(