return error instead of bool

cmd/common.go

@@ -148,9 +148,9 @@ func getKubeConfigForUser(ctx *cli.Context, user string) (*api.Config, error) {
 		return nil, err
 	}
 
-	focusedServer, found := cf.FocusedServer()
-	if !found {
-		return nil, errors.New("no focused server")
+	focusedServer, err := cf.FocusedServer()
+	if err != nil {
+		return nil, err
 	}
 
 	kubeConfig := focusedServer.KubeConfigs[fmt.Sprintf(kubeConfigKeyFormat, user, focusedServer.FocusedCluster())]
@@ -163,9 +163,9 @@ func setKubeConfigForUser(ctx *cli.Context, user string, kubeConfig *api.Config)
 		return err
 	}
 
-	focusedServer, found := cf.FocusedServer()
-	if !found {
-		return errors.New("no focused server")
+	focusedServer, err := cf.FocusedServer()
+	if err != nil {
+		return err
 	}
 
 	if focusedServer.KubeConfigs == nil {
@@ -282,9 +282,9 @@ func lookupConfig(ctx *cli.Context) (*config.ServerConfig, error) {
 		return nil, err
 	}
 
-	cs, found := cf.FocusedServer()
-	if !found {
-		return nil, errors.New("no configuration found, run `login`")
+	cs, err := cf.FocusedServer()
+	if err != nil {
+		return nil, err
 	}
 
 	return cs, nil

cmd/context.go

@@ -1,8 +1,6 @@
 package cmd
 
 import (
-	"errors"
-
 	"github.com/rancher/cli/cliclient"
 	"github.com/sirupsen/logrus"
 	"github.com/urfave/cli"
@@ -41,9 +39,9 @@ func contextSwitch(ctx *cli.Context) error {
 		return err
 	}
 
-	server, found := cf.FocusedServer()
-	if !found {
-		return errors.New("no focused server")
+	server, err := cf.FocusedServer()
+	if err != nil {
+		return err
 	}
 
 	c, err := cliclient.NewManagementClient(server)

cmd/kubectl.go

@@ -1,7 +1,6 @@
 package cmd
 
 import (
-	"errors"
 	"fmt"
 	"os"
 	"os/exec"
@@ -47,9 +46,9 @@ func runKubectl(ctx *cli.Context) error {
 		return err
 	}
 
-	currentRancherServer, found := config.FocusedServer()
-	if !found {
-		return errors.New("no focused server")
+	currentRancherServer, err := config.FocusedServer()
+	if err != nil {
+		return err
 	}
 
 	currentToken := currentRancherServer.AccessKey

config/config.go

@@ -2,6 +2,7 @@ package config
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net/url"
 	"os"
@@ -12,6 +13,8 @@ import (
 	"k8s.io/client-go/tools/clientcmd/api"
 )
 
+var ErrNoServerSelected = errors.New("no server selected")
+
 // Config holds the main config for the user
 type Config struct {
 	Servers map[string]*ServerConfig
@@ -100,9 +103,12 @@ func (c Config) Write() error {
 	return json.NewEncoder(output).Encode(c)
 }
 
-func (c Config) FocusedServer() (*ServerConfig, bool) {
+func (c Config) FocusedServer() (*ServerConfig, error) {
 	currentServer, found := c.Servers[c.CurrentServer]
-	return currentServer, found
+	if !found || currentServer == nil {
+		return nil, ErrNoServerSelected
+	}
+	return currentServer, nil
 }
 
 func (c ServerConfig) FocusedCluster() string {