feat(kubens): add unset option

cmd/kubens/flags.go

@@ -52,6 +52,8 @@ func parseArgs(argv []string) Op {
 			return VersionOp{}
 		case "--current", "-c":
 			return CurrentOp{}
+		case "--unset", "-u":
+			return UnsetOp{}
 		default:
 			return getSwitchOp(v, false)
 		}

cmd/kubens/flags_test.go

@@ -45,6 +45,12 @@ func Test_parseArgs_new(t *testing.T) {
 		{name: "current long form",
 			args: []string{"--current"},
 			want: CurrentOp{}},
+		{name: "unset shorthand",
+			args: []string{"-u"},
+			want: UnsetOp{}},
+		{name: "unset long form",
+			args: []string{"--unset"},
+			want: UnsetOp{}},
 		{name: "switch by name",
 			args: []string{"foo"},
 			want: SwitchOp{Target: "foo"}},

cmd/kubens/help.go

@@ -39,7 +39,8 @@ func printUsage(out io.Writer) error {
   %PROG% -                  : switch to the previous namespace in this context
   %PROG% -c, --current      : show the current namespace
   %PROG% -h,--help          : show this message
-  %PROG% -V,--version       : show version`
+  %PROG% -V,--version       : show version
+  %PROG% -u,--unset       	: unset the current context`
 
 	// TODO this replace logic is duplicated between this and kubectx
 	help = strings.ReplaceAll(help, "%PROG%", selfName())

cmd/kubens/unset.go

@@ -0,0 +1,58 @@
+// Copyright 2021 Google LLC
+//
+// 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 main
+
+import (
+	"io"
+
+	"github.com/pkg/errors"
+
+	"github.com/ahmetb/kubectx/internal/kubeconfig"
+	"github.com/ahmetb/kubectx/internal/printer"
+)
+
+// UnsetOp indicates intention to remove current-context preference.
+type UnsetOp struct{}
+
+func (_ UnsetOp) Run(_, stderr io.Writer) error {
+	kc := new(kubeconfig.Kubeconfig).WithLoader(kubeconfig.DefaultLoader)
+	defer kc.Close()
+	if err := kc.Parse(); err != nil {
+		return errors.Wrap(err, "kubeconfig error")
+	}
+
+	_, err := clearNamespace(kc)
+	if err != nil {
+		return err
+	}
+	err = printer.Success(stderr, "Active namespace unset for kubens.")
+	return err
+}
+
+func clearNamespace(kc *kubeconfig.Kubeconfig) (string, error) {
+	ctx := kc.GetCurrentContext()
+	ns := ""
+	if ctx == "" {
+		return "", errors.New("current-context is not set")
+	}
+
+	if err := kc.SetNamespace(ctx, ns); err != nil {
+		return "", errors.Wrapf(err, "failed to clear namespace")
+	}
+	if err := kc.Save(); err != nil {
+		return "", errors.Wrap(err, "failed to save kubeconfig file")
+	}
+	return ns, nil
+}