cli/cmd: use NewClientset to construct Kubernetes clientset

NewClientsetFromFile is now deprecated, as we want to gradually switch
to loading kubeconfig file from the file content rather than from the
file path.

This commit preserves existing functionality, but uses new function,
which should simplify the change later for loading from the file
content.

Signed-off-by: Mateusz Gozdek <mateusz@kinvolk.io>

cli/cmd/cluster-apply.go

@@ -16,6 +16,7 @@ package cmd
 
 import (
 	"fmt"
+	"io/ioutil"
 
 	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
@@ -125,7 +126,12 @@ func runClusterApply(cmd *cobra.Command, args []string) {
 }
 
 func verifyCluster(kubeconfigPath string, expectedNodes int) error {
-	cs, err := k8sutil.NewClientsetFromFile(kubeconfigPath)
+	kubeconfig, err := ioutil.ReadFile(kubeconfigPath) // #nosec G304
+	if err != nil {
+		return errors.Wrapf(err, "failed to read kubeconfig file")
+	}
+
+	cs, err := k8sutil.NewClientset(kubeconfig)
 	if err != nil {
 		return errors.Wrapf(err, "failed to set up clientset")
 	}

cli/cmd/component-delete.go

@@ -17,6 +17,7 @@ package cmd
 import (
 	"context"
 	"fmt"
+	"io/ioutil"
 	"strings"
 
 	log "github.com/sirupsen/logrus"
@@ -167,7 +168,12 @@ func deleteHelmRelease(c components.Component, kubeconfig string, deleteNSBool b
 }
 
 func deleteNS(ns string, kubeconfig string) error {
-	cs, err := k8sutil.NewClientsetFromFile(kubeconfig)
+	kubeconfigContent, err := ioutil.ReadFile(kubeconfig) // #nosec G304
+	if err != nil {
+		return fmt.Errorf("failed to read kubeconfig file: %v", err)
+	}
+
+	cs, err := k8sutil.NewClientset(kubeconfigContent)
 	if err != nil {
 		return err
 	}

cli/cmd/health.go

@@ -16,6 +16,7 @@ package cmd
 
 import (
 	"fmt"
+	"io/ioutil"
 	"os"
 	"text/tabwriter"
 
@@ -47,7 +48,13 @@ func runHealth(cmd *cobra.Command, args []string) {
 	if err != nil {
 		contextLogger.Fatalf("Error in finding kubeconfig file: %s", err)
 	}
-	cs, err := k8sutil.NewClientsetFromFile(kubeconfig)
+
+	kubeconfigContent, err := ioutil.ReadFile(kubeconfig) // #nosec G304
+	if err != nil {
+		contextLogger.Fatalf("Failed to read kubeconfig file: %v", err)
+	}
+
+	cs, err := k8sutil.NewClientset(kubeconfigContent)
 	if err != nil {
 		contextLogger.Fatalf("Error in creating setting up Kubernetes client: %q", err)
 	}