query namespace exists with GET Namespace

More efficient ns switches with kubens by querying only the namespace (instead
of listing all namespaces).

Signed-off-by: Ahmet Alp Balkan <ahmetb@google.com>

.goreleaser.yml

@@ -15,6 +15,9 @@ builds:
     - windows
   goarch:
     - amd64
+    - arm
+    - arm64
+  goarm: [6, 7]
 - id: kubens
   main: ./cmd/kubens
   binary: kubens
@@ -26,9 +29,18 @@ builds:
     - windows
   goarch:
     - amd64
+    - arm
+    - arm64
+  goarm: [6, 7]
 archives:
 - id: kubectx-archive
-  name_template: "kubectx_{{ .Tag }}_{{ .Os }}_{{ .Arch }}{{ if .Arm }}v{{ .Arm }}{{ end }}"
+  name_template: |-
+    kubectx_{{ .Tag }}_{{ .Os }}_{{ .Arch -}}
+    {{- with .Arm -}}
+      {{- if (eq . "6") -}}hf
+      {{- else -}}v{{- . -}}
+      {{- end -}}
+    {{- end -}}
   builds:
     - kubectx
   replacements:
@@ -39,7 +51,13 @@ archives:
       format: zip
   files: ["LICENSE"]
 - id: kubens-archive
-  name_template: "kubens_{{ .Tag }}_{{ .Os }}_{{ .Arch }}{{ if .Arm }}v{{ .Arm }}{{ end }}"
+  name_template: |-
+    kubens_{{ .Tag }}_{{ .Os }}_{{ .Arch -}}
+    {{- with .Arm -}}
+      {{- if (eq . "6") -}}hf
+      {{- else -}}v{{- . -}}
+      {{- end -}}
+    {{- end -}}
   builds:
     - kubens
   replacements:
@@ -49,12 +67,6 @@ archives:
     - goos: windows
       format: zip
   files: ["LICENSE"]
-changelog:
-  sort: asc
-  filters:
-    exclude:
-    - '^docs:'
-    - '^test:'
 checksum:
   name_template: "checksums.txt"
   algorithm: sha256

cmd/kubectx/main.go

@@ -8,6 +8,7 @@ import (
 	"github.com/ahmetb/kubectx/internal/cmdutil"
 	"github.com/ahmetb/kubectx/internal/env"
 	"github.com/ahmetb/kubectx/internal/printer"
+	"github.com/fatih/color"
 )
 
 type Op interface {
@@ -15,15 +16,15 @@ type Op interface {
 }
 
 func main() {
-	cmdutil.PrintDeprecatedEnvWarnings(os.Stderr, os.Environ())
+	cmdutil.PrintDeprecatedEnvWarnings(color.Error, os.Environ())
 
 	op := parseArgs(os.Args[1:])
-	if err := op.Run(os.Stdout, os.Stderr); err != nil {
-		printer.Error(os.Stderr, err.Error())
+	if err := op.Run(color.Output, color.Error); err != nil {
+		printer.Error(color.Error, err.Error())
 
 		if _, ok := os.LookupEnv(env.EnvDebug); ok {
 			// print stack trace in verbose mode
-			fmt.Fprintf(os.Stderr, "[DEBUG] error: %+v\n", err)
+			fmt.Fprintf(color.Error, "[DEBUG] error: %+v\n", err)
 		}
 		defer os.Exit(1)
 	}

cmd/kubens/fzf.go

@@ -53,8 +53,8 @@ func (op InteractiveSwitchOp) Run(_, stderr io.Writer) error {
 	}
 	name, err := switchNamespace(kc, choice)
 	if err != nil {
-		return errors.Wrap(err, "failed to switch context")
+		return errors.Wrap(err, "failed to switch namespace")
 	}
-	printer.Success(stderr, "Switched to context %s.", printer.SuccessColor.Sprint(name))
+	printer.Success(stderr, "Active namespace is %q.", printer.SuccessColor.Sprint(name))
 	return nil
 }

cmd/kubens/help.go

@@ -40,5 +40,5 @@ func selfName() string {
 	if strings.HasPrefix(me, pluginPrefix) {
 		return "kubectl " + strings.TrimPrefix(me, pluginPrefix)
 	}
-	return "kubectx"
+	return "kubens"
 }

cmd/kubens/list.go

@@ -54,15 +54,7 @@ func queryNamespaces(kc *kubeconfig.Kubeconfig) ([]string, error) {
 		return []string{"ns1", "ns2"}, nil
 	}
 
-	b, err := kc.Bytes()
-	if err != nil {
-		return nil, errors.Wrap(err, "failed to convert in-memory kubeconfig to yaml")
-	}
-	cfg, err := clientcmd.RESTConfigFromKubeConfig(b)
-	if err != nil {
-		return nil, errors.Wrap(err, "failed to initialize config")
-	}
-	clientset, err := kubernetes.NewForConfig(cfg)
+	clientset, err := newKubernetesClientSet(kc)
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to initialize k8s REST client")
 	}
@@ -87,3 +79,15 @@ func queryNamespaces(kc *kubeconfig.Kubeconfig) ([]string, error) {
 	}
 	return out, nil
 }
+
+func newKubernetesClientSet(kc *kubeconfig.Kubeconfig) (*kubernetes.Clientset, error) {
+	b, err := kc.Bytes()
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to convert in-memory kubeconfig to yaml")
+	}
+	cfg, err := clientcmd.RESTConfigFromKubeConfig(b)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to initialize config")
+	}
+	return kubernetes.NewForConfig(cfg)
+}

cmd/kubens/main.go

@@ -8,6 +8,7 @@ import (
 	"github.com/ahmetb/kubectx/internal/cmdutil"
 	"github.com/ahmetb/kubectx/internal/env"
 	"github.com/ahmetb/kubectx/internal/printer"
+	"github.com/fatih/color"
 )
 
 type Op interface {
@@ -15,14 +16,14 @@ type Op interface {
 }
 
 func main() {
-	cmdutil.PrintDeprecatedEnvWarnings(os.Stderr, os.Environ())
+	cmdutil.PrintDeprecatedEnvWarnings(color.Error, os.Environ())
 	op := parseArgs(os.Args[1:])
-	if err := op.Run(os.Stdout, os.Stderr); err != nil {
-		printer.Error(os.Stderr, err.Error())
+	if err := op.Run(color.Output, color.Error); err != nil {
+		printer.Error(color.Error, err.Error())
 
 		if _, ok := os.LookupEnv(env.EnvDebug); ok {
 			// print stack trace in verbose mode
-			fmt.Fprintf(os.Stderr, "[DEBUG] error: %+v\n", err)
+			fmt.Fprintf(color.Error, "[DEBUG] error: %+v\n", err)
 		}
 		defer os.Exit(1)
 	}

cmd/kubens/statefile.go

@@ -5,6 +5,8 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"runtime"
+	"strings"
 
 	"github.com/ahmetb/kubectx/internal/cmdutil"
 )
@@ -18,7 +20,14 @@ type NSFile struct {
 
 func NewNSFile(ctx string) NSFile { return NSFile{dir: defaultDir, ctx: ctx} }
 
-func (f NSFile) path() string { return filepath.Join(f.dir, f.ctx) }
+func (f NSFile) path() string {
+	fn := f.ctx
+	if isWindows() {
+		// bug 230: eks clusters contain ':' in ctx name, not a valid file name for win32
+		fn = strings.ReplaceAll(fn, ":", "__")
+	}
+	return filepath.Join(f.dir, fn)
+}
 
 // Load reads the previous namespace setting, or returns empty if not exists.
 func (f NSFile) Load() (string, error) {
@@ -40,3 +49,11 @@ func (f NSFile) Save(value string) error {
 	}
 	return ioutil.WriteFile(f.path(), []byte(value), 0644)
 }
+
+// isWindows determines if the process is running on windows OS.
+func isWindows() bool {
+	if os.Getenv("_FORCE_GOOS") == "windows" { // for testing
+		return true
+	}
+	return runtime.GOOS == "windows"
+}

cmd/kubens/statefile_test.go

@@ -3,7 +3,11 @@ package main
 import (
 	"io/ioutil"
 	"os"
+	"runtime"
+	"strings"
 	"testing"
+
+	"github.com/ahmetb/kubectx/internal/testutil"
 )
 
 func TestNSFile(t *testing.T) {
@@ -36,3 +40,28 @@ func TestNSFile(t *testing.T) {
 		t.Fatalf("Load()=%q; expected=%q", v, expected)
 	}
 }
+
+func TestNSFile_path_windows(t *testing.T) {
+	defer testutil.WithEnvVar("_FORCE_GOOS", "windows")()
+	fp := NewNSFile("a:b:c").path()
+
+	if expected := "a__b__c"; !strings.HasSuffix(fp, expected) {
+		t.Fatalf("file did not have expected ending %q: %s", expected, fp)
+	}
+}
+
+func Test_isWindows(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("won't test this case on windows")
+	}
+
+	got := isWindows()
+	if got {
+		t.Fatalf("isWindows() returned true for %s", runtime.GOOS)
+	}
+
+	defer testutil.WithEnvVar("_FORCE_GOOS", "windows")()
+	if !isWindows() {
+		t.Fatalf("isWindows() failed to detect windows with env override.")
+	}
+}

cmd/kubens/switch.go

@@ -2,8 +2,11 @@ package main
 
 import (
 	"io"
+	"os"
 
 	"github.com/pkg/errors"
+	errors2 "k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 
 	"github.com/ahmetb/kubectx/internal/cmdutil"
 	"github.com/ahmetb/kubectx/internal/kubeconfig"
@@ -75,14 +78,20 @@ func switchNamespace(kc *kubeconfig.Kubeconfig, ns string) (string, error) {
 }
 
 func namespaceExists(kc *kubeconfig.Kubeconfig, ns string) (bool, error) {
-	nses, err := queryNamespaces(kc)
+	// for tests
+	if os.Getenv("_MOCK_NAMESPACES") != "" {
+		return ns == "ns1" || ns == "ns2", nil
+	}
+
+	clientset, err := newKubernetesClientSet(kc)
 	if err != nil {
-		return false, err
+		return false, errors.Wrap(err, "failed to initialize k8s REST client")
 	}
-	for _, v := range nses {
-		if v == ns {
-			return true, nil
-		}
+
+	namespace, err := clientset.CoreV1().Namespaces().Get(ns, metav1.GetOptions{})
+	if errors2.IsNotFound(err) {
+		return false, nil
 	}
-	return false, nil
+	return namespace != nil, errors.Wrapf(err, "failed to query "+
+		"namespace %q from k8s API", ns)
 }