use k8s.io/utils/env GetString get env

Signed-off-by: helen <haitao.zhang@daocloud.io>

pkg/karmadactl/util/apiclient/apiclient.go

@@ -10,6 +10,7 @@ import (
 	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/client-go/util/homedir"
 	aggregator "k8s.io/kube-aggregator/pkg/client/clientset_generated/clientset"
+	"k8s.io/utils/env"
 )
 
 var (
@@ -30,12 +31,7 @@ var (
 // 3. In your home directory as ~/.kube/config
 func KubeConfigPath(kubeconfigPath string) string {
 	if kubeconfigPath == "" {
-		env := os.Getenv("KUBECONFIG")
+		kubeconfigPath = env.GetString("KUBECONFIG", defaultKubeConfig)
-		if env != "" {
-			kubeconfigPath = env
-		} else {
-			kubeconfigPath = defaultKubeConfig
-		}
 	}
 
 	return kubeconfigPath
@@ -44,12 +40,7 @@ func KubeConfigPath(kubeconfigPath string) string {
 // RestConfig is to create a rest config from the context and kubeconfig passed as arguments.
 func RestConfig(context, kubeconfigPath string) (*rest.Config, error) {
 	if kubeconfigPath == "" {
-		env := os.Getenv("KUBECONFIG")
+		kubeconfigPath = env.GetString("KUBECONFIG", defaultKubeConfig)
-		if env != "" {
-			kubeconfigPath = env
-		} else {
-			kubeconfigPath = defaultKubeConfig
-		}
 	}
 	if !Exists(kubeconfigPath) {
 		return nil, ErrEmptyConfig

vendor/k8s.io/utils/env/doc.go

@@ -0,0 +1,18 @@
+/*
+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 env provides utility functions for using environment variables.
+package env // import "k8s.io/utils/env"

vendor/k8s.io/utils/env/env.go

@@ -0,0 +1,74 @@
+/*
+Copyright 2015 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 env
+
+import (
+	"os"
+	"strconv"
+)
+
+// GetString returns the env variable for the given key
+// and falls back to the given defaultValue if not set
+func GetString(key, defaultValue string) string {
+	v, ok := os.LookupEnv(key)
+	if ok {
+		return v
+	}
+	return defaultValue
+}
+
+// GetInt returns the env variable (parsed as integer) for
+// the given key and falls back to the given defaultValue if not set
+func GetInt(key string, defaultValue int) (int, error) {
+	v, ok := os.LookupEnv(key)
+	if ok {
+		value, err := strconv.Atoi(v)
+		if err != nil {
+			return defaultValue, err
+		}
+		return value, nil
+	}
+	return defaultValue, nil
+}
+
+// GetFloat64 returns the env variable (parsed as float64) for
+// the given key and falls back to the given defaultValue if not set
+func GetFloat64(key string, defaultValue float64) (float64, error) {
+	v, ok := os.LookupEnv(key)
+	if ok {
+		value, err := strconv.ParseFloat(v, 64)
+		if err != nil {
+			return defaultValue, err
+		}
+		return value, nil
+	}
+	return defaultValue, nil
+}
+
+// GetBool returns the env variable (parsed as bool) for
+// the given key and falls back to the given defaultValue if not set
+func GetBool(key string, defaultValue bool) (bool, error) {
+	v, ok := os.LookupEnv(key)
+	if ok {
+		value, err := strconv.ParseBool(v)
+		if err != nil {
+			return defaultValue, err
+		}
+		return value, nil
+	}
+	return defaultValue, nil
+}

vendor/modules.txt

@@ -1506,6 +1506,7 @@ k8s.io/kubectl/pkg/validation
 k8s.io/utils/buffer
 k8s.io/utils/clock
 k8s.io/utils/clock/testing
+k8s.io/utils/env
 k8s.io/utils/exec
 k8s.io/utils/integer
 k8s.io/utils/internal/third_party/forked/golang/golang-lru