Support multi config files (#222)

* Handle error for multi config files over `--kubeconfig` flag

* Add test cases for multi configs

* Refactor type cases

pkg/kn/commands/namespaced.go

@@ -63,12 +63,17 @@ func (params *KnParams) GetNamespace(cmd *cobra.Command) (string, error) {
 	return namespace, nil
 }
 
+// CurrentNamespace returns the current namespace which is either provided as option or picked up from kubeconfig
 func (params *KnParams) CurrentNamespace() (string, error) {
+	var err error
 	if params.fixedCurrentNamespace != "" {
 		return params.fixedCurrentNamespace, nil
 	}
 	if params.ClientConfig == nil {
-		params.ClientConfig = params.GetClientConfig()
+		params.ClientConfig, err = params.GetClientConfig()
+		if err != nil {
+			return "", err
+		}
 	}
 	name, _, err := params.ClientConfig.Namespace()
 	return name, err

pkg/kn/commands/types.go

@@ -15,7 +15,11 @@
 package commands
 
 import (
+	"errors"
+	"fmt"
 	"io"
+	"os"
+	"path/filepath"
 
 	serving_kn_v1alpha1 "github.com/knative/client/pkg/serving/v1alpha1"
 
@@ -51,11 +55,17 @@ func (params *KnParams) newClient(namespace string) (serving_kn_v1alpha1.KnClien
 	return serving_kn_v1alpha1.NewKnServingClient(client, namespace), nil
 }
 
+// GetConfig returns Serving Client
 func (params *KnParams) GetConfig() (serving_v1alpha1_client.ServingV1alpha1Interface, error) {
-	if params.ClientConfig == nil {
-		params.ClientConfig = params.GetClientConfig()
-	}
 	var err error
+
+	if params.ClientConfig == nil {
+		params.ClientConfig, err = params.GetClientConfig()
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	config, err := params.ClientConfig.ClientConfig()
 	if err != nil {
 		return nil, err
@@ -63,10 +73,28 @@ func (params *KnParams) GetConfig() (serving_v1alpha1_client.ServingV1alpha1Inte
 	return serving_v1alpha1_client.NewForConfig(config)
 }
 
-func (params *KnParams) GetClientConfig() clientcmd.ClientConfig {
+// GetClientConfig gets ClientConfig from KubeCfgPath
+func (params *KnParams) GetClientConfig() (clientcmd.ClientConfig, error) {
 	loadingRules := clientcmd.NewDefaultClientConfigLoadingRules()
-	if len(params.KubeCfgPath) > 0 {
+	if len(params.KubeCfgPath) == 0 {
+		return clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, &clientcmd.ConfigOverrides{}), nil
+	}
+
+	_, err := os.Stat(params.KubeCfgPath)
+	if err == nil {
 		loadingRules.ExplicitPath = params.KubeCfgPath
+		return clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, &clientcmd.ConfigOverrides{}), nil
+	}
+
+	if !os.IsNotExist(err) {
+		return nil, err
+	}
+
+	paths := filepath.SplitList(params.KubeCfgPath)
+	if len(paths) > 1 {
+		return nil, errors.New(fmt.Sprintf("Can not find config file. '%s' looks like a path. "+
+			"Please use the env var KUBECONFIG if you want to check for multiple configuration files", params.KubeCfgPath))
+	} else {
+		return nil, errors.New(fmt.Sprintf("Config file '%s' can not be found", params.KubeCfgPath))
 	}
-	return clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, &clientcmd.ConfigOverrides{})
 }

pkg/kn/commands/types_test.go

@@ -0,0 +1,106 @@
+// Copyright © 2019 The Knative Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package commands
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/knative/client/pkg/util"
+	"gotest.tools/assert"
+	"k8s.io/client-go/tools/clientcmd"
+	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
+)
+
+type getConfigTestCase struct {
+	clientConfig      clientcmd.ClientConfig
+	expectedErrString string
+}
+
+func TestGetConfig(t *testing.T) {
+	for i, tc := range []getConfigTestCase{
+		{
+			clientcmd.NewDefaultClientConfig(clientcmdapi.Config{}, &clientcmd.ConfigOverrides{}),
+			"no configuration has been provided",
+		},
+	} {
+		p := &KnParams{
+			ClientConfig: tc.clientConfig}
+
+		_, err := p.GetConfig()
+
+		switch len(tc.expectedErrString) {
+		case 0:
+			if err != nil {
+				t.Errorf("%d: unexpected error: %s", i, err.Error())
+			}
+		default:
+			if err == nil {
+				t.Errorf("%d: wrong error detected: %s (expected) != %s (actual)", i, tc.expectedErrString, err)
+			}
+			if !strings.Contains(err.Error(), tc.expectedErrString) {
+				t.Errorf("%d: wrong error detected: %s (expected) != %s (actual)", i, tc.expectedErrString, err.Error())
+			}
+		}
+	}
+}
+
+type typeTestCase struct {
+	kubeCfgPath   string
+	explicitPath  string
+	expectedError string
+}
+
+func TestGetClientConfig(t *testing.T) {
+	multiConfigs := fmt.Sprintf("%s%s%s", "/testing/assets/kube-config-01.yml", string(os.PathListSeparator), "/testing/assets/kube-config-02.yml")
+
+	multiConfigs = multiConfigs
+	for _, tc := range []typeTestCase{
+		{
+			"",
+			clientcmd.NewDefaultClientConfigLoadingRules().ExplicitPath,
+			"",
+		},
+		{
+			"/testing/assets/kube-config-01.yml",
+			"",
+			fmt.Sprintf("Config file '%s' can not be found", "/testing/assets/kube-config-01.yml"),
+		},
+		{
+			multiConfigs,
+			"",
+			fmt.Sprintf("Can not find config file. '%s' looks like a path. Please use the env var KUBECONFIG if you want to check for multiple configuration files", multiConfigs),
+		},
+	} {
+		p := &KnParams{
+			KubeCfgPath: tc.kubeCfgPath,
+		}
+
+		clientConfig, err := p.GetClientConfig()
+		if tc.expectedError != "" {
+			assert.Assert(t, util.ContainsAll(err.Error(), tc.expectedError))
+		} else {
+			assert.Assert(t, err == nil, err)
+		}
+
+		if clientConfig != nil {
+			configAccess := clientConfig.ConfigAccess()
+
+			assert.Assert(t, configAccess.GetExplicitFile() == tc.explicitPath)
+		}
+	}
+}