Fix panic on context switch (rancher#386)

* added bool check for missing focused server, fixed panic

* added main branch to FOSSA workflow

* return error instead of bool

.github/workflows/fossa.yml

@@ -7,6 +7,7 @@ on:
       - v*
     branches:
       - v*
+      - main
 
 jobs:
   fossa:

cmd/common.go

@@ -148,7 +148,11 @@ func getKubeConfigForUser(ctx *cli.Context, user string) (*api.Config, error) {
 		return nil, err
 	}
 
-	focusedServer := cf.FocusedServer()
+	focusedServer, err := cf.FocusedServer()
+	if err != nil {
+		return nil, err
+	}
+
 	kubeConfig := focusedServer.KubeConfigs[fmt.Sprintf(kubeConfigKeyFormat, user, focusedServer.FocusedCluster())]
 	return kubeConfig, nil
 }
@@ -159,10 +163,15 @@ func setKubeConfigForUser(ctx *cli.Context, user string, kubeConfig *api.Config)
 		return err
 	}
 
-	if cf.FocusedServer().KubeConfigs == nil {
-		cf.FocusedServer().KubeConfigs = make(map[string]*api.Config)
+	focusedServer, err := cf.FocusedServer()
+	if err != nil {
+		return err
 	}
-	focusedServer := cf.FocusedServer()
+
+	if focusedServer.KubeConfigs == nil {
+		focusedServer.KubeConfigs = make(map[string]*api.Config)
+	}
+
 	focusedServer.KubeConfigs[fmt.Sprintf(kubeConfigKeyFormat, user, focusedServer.FocusedCluster())] = kubeConfig
 	return cf.Write()
 }
@@ -273,9 +282,9 @@ func lookupConfig(ctx *cli.Context) (*config.ServerConfig, error) {
 		return nil, err
 	}
 
-	cs := cf.FocusedServer()
-	if cs == nil {
-		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

@@ -39,7 +39,11 @@ func contextSwitch(ctx *cli.Context) error {
 		return err
 	}
 
-	server := cf.FocusedServer()
+	server, err := cf.FocusedServer()
+	if err != nil {
+		return err
+	}
+
 	c, err := cliclient.NewManagementClient(server)
 	if err != nil {
 		return err

cmd/kubectl.go

@@ -46,9 +46,9 @@ func runKubectl(ctx *cli.Context) error {
 		return err
 	}
 
-	currentRancherServer := config.FocusedServer()
-	if currentRancherServer == nil {
-		return fmt.Errorf("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
@@ -100,8 +103,12 @@ func (c Config) Write() error {
 	return json.NewEncoder(output).Encode(c)
 }
 
-func (c Config) FocusedServer() *ServerConfig {
-	return c.Servers[c.CurrentServer]
+func (c Config) FocusedServer() (*ServerConfig, error) {
+	currentServer, found := c.Servers[c.CurrentServer]
+	if !found || currentServer == nil {
+		return nil, ErrNoServerSelected
+	}
+	return currentServer, nil
 }
 
 func (c ServerConfig) FocusedCluster() string {