adding support for --context flag, updating readme, bumping version t…

…o 0.2.0

README.md

@@ -76,11 +76,28 @@ example-node-2    tiller        tiller-deploy         140m (14%)      180m (18%)
 
 It's worth noting that utilization numbers from pods will likely not add up to the total node utilization numbers. Unlike request and limit numbers where node and cluster level numbers represent a sum of pod values, node metrics come directly from metrics-server and will likely include other forms of resource utilization.
 
+### Filtering By Labels
+For more advanced usage, kube-capacity also supports filtering by pod, namespace, and/or node labels. The following examples show how to use these filters:
+
+```
+kube-capacity --pod-labels app=nginx
+kube-capacity --namespace-labels team=api
+kube-capacity --node-labels kubernetes.io/role=node
+```
+
 ## Prerequisites
 Any commands requesting cluster utilization are dependent on [metrics-server](https://github.com/kubernetes-incubator/metrics-server) running on your cluster. If it's not already installed, you can install it with the official [helm chart](https://github.com/helm/charts/tree/master/stable/metrics-server).
 
-## Kubernetes Configuration
-If a `KUBECONFIG` environment variable is specified, kube-capacity will attempt to use the config at that path, otherwise it will default to `~/.kube/config`.
+## Flags Supported
+```
+      --context string            context to use for Kubernetes config
+  -h, --help                      help for kube-capacity
+  -n, --namespace-labels string   labels to filter namespaces with
+      --node-labels string        labels to filter nodes with
+  -l, --pod-labels string         labels to filter pods with
+  -p, --pods                      includes pods in output
+  -u, --util                      includes resource utilization in output
+```
 
 ## Similar Projects
 There are already some great projects out there that have similar goals.

pkg/capacity/list.go

@@ -28,8 +28,8 @@ import (
 )
 
 // List gathers cluster resource data and outputs it
-func List(showPods, showUtil bool, podLabels, nodeLabels, namespaceLabels string) {
-	clientset, err := kube.NewClientSet()
+func List(showPods, showUtil bool, podLabels, nodeLabels, namespaceLabels, kubeContext string) {
+	clientset, err := kube.NewClientSet(kubeContext)
 	if err != nil {
 		fmt.Printf("Error connecting to Kubernetes: %v\n", err)
 		os.Exit(1)
@@ -38,7 +38,7 @@ func List(showPods, showUtil bool, podLabels, nodeLabels, namespaceLabels string
 	podList, nodeList := getPodsAndNodes(clientset, podLabels, nodeLabels, namespaceLabels)
 	pmList := &v1beta1.PodMetricsList{}
 	if showUtil {
-		mClientset, err := kube.NewMetricsClientSet()
+		mClientset, err := kube.NewMetricsClientSet(kubeContext)
 		if err != nil {
 			fmt.Printf("Error connecting to Metrics API: %v\n", err)
 			os.Exit(4)
@@ -75,7 +75,7 @@ func getPodsAndNodes(clientset kubernetes.Interface, podLabels, nodeLabels, name
 	}
 
 	for _, pod := range podList.Items {
-		if ! nodes[pod.Spec.NodeName] {
+		if !nodes[pod.Spec.NodeName] {
 			continue
 		}
 
@@ -101,7 +101,7 @@ func getPodsAndNodes(clientset kubernetes.Interface, podLabels, nodeLabels, name
 		newPodItems := []corev1.Pod{}
 
 		for _, pod := range podList.Items {
-			if ! namespaces[pod.GetNamespace()] {
+			if !namespaces[pod.GetNamespace()] {
 				continue
 			}
 

pkg/cmd/root.go

@@ -27,26 +27,28 @@ var showUtil bool
 var podLabels string
 var nodeLabels string
 var namespaceLabels string
+var kubeContext string
 
 var rootCmd = &cobra.Command{
 	Use:   "kube-capacity",
-	Short: "kube-capacity provides an overview of the resource requests, limits, and utilization in a Kubernetes cluster",
-	Long:  "kube-capacity provides an overview of the resource requests, limits, and utilization in a Kubernetes cluster",
+	Short: "kube-capacity provides an overview of the resource requests, limits, and utilization in a Kubernetes cluster.",
+	Long:  "kube-capacity provides an overview of the resource requests, limits, and utilization in a Kubernetes cluster.",
 	Run: func(cmd *cobra.Command, args []string) {
 		if err := cmd.ParseFlags(args); err != nil {
 			fmt.Printf("Error parsing flags: %v", err)
 		}
 
-		capacity.List(showPods, showUtil, podLabels, nodeLabels, namespaceLabels)
+		capacity.List(showPods, showUtil, podLabels, nodeLabels, namespaceLabels, kubeContext)
 	},
 }
 
 func init() {
-	rootCmd.PersistentFlags().BoolVarP(&showPods, "pods", "p", false, "Set this flag to include pods in output")
-	rootCmd.PersistentFlags().BoolVarP(&showUtil, "util", "u", false, "Set this flag to include resource utilization in output")
-	rootCmd.PersistentFlags().StringVarP(&podLabels, "pod-labels", "l", "", "Labels to filter pods with.")
-	rootCmd.PersistentFlags().StringVarP(&nodeLabels, "node-labels", "", "", "Labels to filter nodes with.")
-	rootCmd.PersistentFlags().StringVarP(&namespaceLabels, "namespace-labels", "n", "", "Labels to filter namespaces with.")
+	rootCmd.PersistentFlags().BoolVarP(&showPods, "pods", "p", false, "includes pods in output")
+	rootCmd.PersistentFlags().BoolVarP(&showUtil, "util", "u", false, "includes resource utilization in output")
+	rootCmd.PersistentFlags().StringVarP(&podLabels, "pod-labels", "l", "", "labels to filter pods with")
+	rootCmd.PersistentFlags().StringVarP(&nodeLabels, "node-labels", "", "", "labels to filter nodes with")
+	rootCmd.PersistentFlags().StringVarP(&namespaceLabels, "namespace-labels", "n", "", "labels to filter namespaces with")
+	rootCmd.PersistentFlags().StringVarP(&kubeContext, "context", "", "", "context to use for Kubernetes config")
 }
 
 // Execute is the primary entrypoint for this CLI

pkg/cmd/version.go

@@ -28,6 +28,6 @@ var versionCmd = &cobra.Command{
 	Use:   "version",
 	Short: "Print the version number of kube-capacity",
 	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Println("kube-capacity version 0.1.3")
+		fmt.Println("kube-capacity version 0.2.0")
 	},
 }

pkg/kube/clientset.go

@@ -25,8 +25,8 @@ import (
 )
 
 // NewClientSet returns a new Kubernetes clientset
-func NewClientSet() (*kubernetes.Clientset, error) {
-	config, err := getKubeConfig()
+func NewClientSet(kubeContext string) (*kubernetes.Clientset, error) {
+	config, err := getKubeConfig(kubeContext)
 	if err != nil {
 		return nil, err
 	}
@@ -35,18 +35,18 @@ func NewClientSet() (*kubernetes.Clientset, error) {
 }
 
 // NewMetricsClientSet returns a new clientset for Kubernetes metrics
-func NewMetricsClientSet() (*metrics.Clientset, error) {
-	config, err := getKubeConfig()
+func NewMetricsClientSet(kubeContext string) (*metrics.Clientset, error) {
+	config, err := getKubeConfig(kubeContext)
 	if err != nil {
 		return nil, err
 	}
 
 	return metrics.NewForConfig(config)
 }
 
-func getKubeConfig() (*rest.Config, error) {
+func getKubeConfig(kubeContext string) (*rest.Config, error) {
 	return clientcmd.NewNonInteractiveDeferredLoadingClientConfig(
 		clientcmd.NewDefaultClientConfigLoadingRules(),
-		&clientcmd.ConfigOverrides{},
+		&clientcmd.ConfigOverrides{CurrentContext: kubeContext},
 	).ClientConfig()
 }