Provide more verbose empty config error for all config load actions

Author: soltysh

staging/src/k8s.io/cli-runtime/pkg/genericclioptions/BUILD

@@ -5,6 +5,7 @@ go_library(
     srcs = [
         "builder_flags.go",
         "builder_flags_fake.go",
+        "client_config.go",
         "config_flags.go",
         "config_flags_fake.go",
         "doc.go",

staging/src/k8s.io/cli-runtime/pkg/genericclioptions/client_config.go

@@ -0,0 +1,71 @@
+/*
+Copyright 2020 The Kubernetes 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 genericclioptions
+
+import (
+	restclient "k8s.io/client-go/rest"
+	"k8s.io/client-go/tools/clientcmd"
+	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
+)
+
+var (
+	ErrEmptyConfig = clientcmd.NewEmptyConfigError(`Missing or incomplete configuration info.  Please point to an existing, complete config file:
+
+
+  1. Via the command-line flag --kubeconfig
+  2. Via the KUBECONFIG environment variable
+  3. In your home directory as ~/.kube/config
+
+To view or setup config directly use the 'config' command.`)
+)
+
+var _ = clientcmd.ClientConfig(&clientConfig{})
+
+type clientConfig struct {
+	defaultClientConfig clientcmd.ClientConfig
+}
+
+func (c *clientConfig) RawConfig() (clientcmdapi.Config, error) {
+	config, err := c.defaultClientConfig.RawConfig()
+	// replace client-go's ErrEmptyConfig error with our custom, more verbose version
+	if clientcmd.IsEmptyConfig(err) {
+		return config, ErrEmptyConfig
+	}
+	return config, err
+}
+
+func (c *clientConfig) ClientConfig() (*restclient.Config, error) {
+	config, err := c.defaultClientConfig.ClientConfig()
+	// replace client-go's ErrEmptyConfig error with our custom, more verbose version
+	if clientcmd.IsEmptyConfig(err) {
+		return config, ErrEmptyConfig
+	}
+	return config, err
+}
+
+func (c *clientConfig) Namespace() (string, bool, error) {
+	namespace, ok, err := c.defaultClientConfig.Namespace()
+	// replace client-go's ErrEmptyConfig error with our custom, more verbose version
+	if clientcmd.IsEmptyConfig(err) {
+		return namespace, ok, ErrEmptyConfig
+	}
+	return namespace, ok, err
+}
+
+func (c *clientConfig) ConfigAccess() clientcmd.ConfigAccess {
+	return c.defaultClientConfig.ConfigAccess()
+}

staging/src/k8s.io/cli-runtime/pkg/genericclioptions/config_flags.go

@@ -55,16 +55,7 @@ const (
 	flagHTTPCacheDir     = "cache-dir"
 )
 
-var (
-	defaultCacheDir = filepath.Join(homedir.HomeDir(), ".kube", "http-cache")
-	ErrEmptyConfig  = clientcmd.NewEmptyConfigError(`Missing or incomplete configuration info.  Please point to an existing, complete config file:
-
-  1. Via the command-line flag --kubeconfig
-  2. Via the KUBECONFIG environment variable
-  3. In your home directory as ~/.kube/config
-
-To view or setup config directly use the 'config' command.`)
-)
+var defaultCacheDir = filepath.Join(homedir.HomeDir(), ".kube", "http-cache")
 
 // RESTClientGetter is an interface that the ConfigFlags describe to provide an easier way to mock for commands
 // and eliminate the direct coupling to a struct type.  Users may wish to duplicate this type in their own packages
@@ -119,12 +110,7 @@ type ConfigFlags struct {
 // to a .kubeconfig file, loading rules, and config flag overrides.
 // Expects the AddFlags method to have been called.
 func (f *ConfigFlags) ToRESTConfig() (*rest.Config, error) {
-	config, err := f.ToRawKubeConfigLoader().ClientConfig()
-	// replace client-go's ErrEmptyConfig error with our custom, more verbose version
-	if clientcmd.IsEmptyConfig(err) {
-		return nil, ErrEmptyConfig
-	}
-	return config, err
+	return f.ToRawKubeConfigLoader().ClientConfig()
 }
 
 // ToRawKubeConfigLoader binds config flag values to config overrides
@@ -204,16 +190,11 @@ func (f *ConfigFlags) toRawKubeConfigLoader() clientcmd.ClientConfig {
 		overrides.Timeout = *f.Timeout
 	}
 
-	var clientConfig clientcmd.ClientConfig
-
 	// we only have an interactive prompt when a password is allowed
 	if f.Password == nil {
-		clientConfig = clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, overrides)
-	} else {
-		clientConfig = clientcmd.NewInteractiveDeferredLoadingClientConfig(loadingRules, overrides, os.Stdin)
+		return &clientConfig{clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, overrides)}
 	}
-
-	return clientConfig
+	return &clientConfig{clientcmd.NewInteractiveDeferredLoadingClientConfig(loadingRules, overrides, os.Stdin)}
 }
 
 // toRawKubePersistentConfigLoader binds config flag values to config overrides