Move kubeconfig loader utils to cmdutil pkg

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

internal/cmdutil/interactive.go

@@ -1,4 +1,4 @@
-package env
+package cmdutil
 
 import (
 	"os"

internal/cmdutil/kubeconfigloader.go

@@ -0,0 +1,82 @@
+package cmdutil
+
+import (
+	"os"
+	"path/filepath"
+
+	"github.com/pkg/errors"
+
+	"github.com/ahmetb/kubectx/internal/kubeconfig"
+)
+
+var (
+	DefaultLoader kubeconfig.Loader = new(StandardKubeconfigLoader)
+)
+
+type StandardKubeconfigLoader struct{}
+
+type kubeconfigFile struct{ *os.File }
+
+func (*StandardKubeconfigLoader) Load() (kubeconfig.ReadWriteResetCloser, error) {
+	cfgPath, err := kubeconfigPath()
+	if err != nil {
+		return nil, errors.Wrap(err, "cannot determine kubeconfig path")
+	}
+	f, err := os.OpenFile(cfgPath, os.O_RDWR, 0)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, errors.Wrap(err, "kubeconfig file not found")
+		}
+		return nil, errors.Wrap(err, "failed to open file")
+	}
+	return &kubeconfigFile{f}, nil
+}
+
+func (kf *kubeconfigFile) Reset() error {
+	if err := kf.Truncate(0); err != nil {
+		return errors.Wrap(err, "failed to truncate file")
+	}
+	_, err := kf.Seek(0, 0)
+	return errors.Wrap(err, "failed to seek in file")
+}
+
+func kubeconfigPath() (string, error) {
+	// KUBECONFIG env var
+	if v := os.Getenv("KUBECONFIG"); v != "" {
+		list := filepath.SplitList(v)
+		if len(list) > 1 {
+			// TODO KUBECONFIG=file1:file2 currently not supported
+			return "", errors.New("multiple files in KUBECONFIG are currently not supported")
+		}
+		return v, nil
+	}
+
+	// default path
+	home := HomeDir()
+	if home == "" {
+		return "", errors.New("HOME or USERPROFILE environment variable not set")
+	}
+	return filepath.Join(home, ".kube", "config"), nil
+}
+
+func HomeDir() string {
+	if v := os.Getenv("XDG_CACHE_HOME"); v != "" {
+		return v
+	}
+	home := os.Getenv("HOME")
+	if home == "" {
+		home = os.Getenv("USERPROFILE") // windows
+	}
+	return home
+}
+
+// IsNotFoundErr determines if the underlying error is os.IsNotExist. Right now
+// errors from github.com/pkg/errors doesn't work with os.IsNotExist.
+func IsNotFoundErr(err error) bool {
+	for e := err; e != nil; e = errors.Unwrap(e) {
+		if os.IsNotExist(e) {
+			return true
+		}
+	}
+	return false
+}

internal/cmdutil/kubeconfigloader_test.go

@@ -0,0 +1,130 @@
+package cmdutil
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/ahmetb/kubectx/internal/kubeconfig"
+	"github.com/ahmetb/kubectx/internal/testutil"
+)
+
+func Test_homeDir(t *testing.T) {
+	type env struct{ k, v string }
+	cases := []struct {
+		name string
+		envs []env
+		want string
+	}{
+		{
+			name: "XDG_CACHE_HOME precedence",
+			envs: []env{
+				{"XDG_CACHE_HOME", "xdg"},
+				{"HOME", "home"},
+			},
+			want: "xdg",
+		},
+		{
+			name: "HOME over USERPROFILE",
+			envs: []env{
+				{"HOME", "home"},
+				{"USERPROFILE", "up"},
+			},
+			want: "home",
+		},
+		{
+			name: "only USERPROFILE available",
+			envs: []env{
+				{"XDG_CACHE_HOME", ""},
+				{"HOME", ""},
+				{"USERPROFILE", "up"},
+			},
+			want: "up",
+		},
+		{
+			name: "none available",
+			envs: []env{
+				{"XDG_CACHE_HOME", ""},
+				{"HOME", ""},
+				{"USERPROFILE", ""},
+			},
+			want: "",
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(tt *testing.T) {
+			var unsets []func()
+			for _, e := range c.envs {
+				unsets = append(unsets, testutil.WithEnvVar(e.k, e.v))
+			}
+
+			got := HomeDir()
+			if got != c.want {
+				t.Errorf("expected:%q got:%q", c.want, got)
+			}
+			for _, u := range unsets {
+				u()
+			}
+		})
+	}
+}
+
+func Test_kubeconfigPath(t *testing.T) {
+	defer testutil.WithEnvVar("HOME", "/x/y/z")()
+
+	expected := filepath.FromSlash("/x/y/z/.kube/config")
+	got, err := kubeconfigPath()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != expected {
+		t.Fatalf("got=%q expected=%q", got, expected)
+	}
+}
+
+func Test_kubeconfigPath_noEnvVars(t *testing.T) {
+	defer testutil.WithEnvVar("XDG_CACHE_HOME", "")()
+	defer testutil.WithEnvVar("HOME", "")()
+	defer testutil.WithEnvVar("USERPROFILE", "")()
+
+	_, err := kubeconfigPath()
+	if err == nil {
+		t.Fatalf("expected error")
+	}
+}
+
+func Test_kubeconfigPath_envOvveride(t *testing.T) {
+	defer testutil.WithEnvVar("KUBECONFIG", "foo")()
+
+	v, err := kubeconfigPath()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if expected := "foo"; v != expected {
+		t.Fatalf("expected=%q, got=%q", expected, v)
+	}
+}
+
+func Test_kubeconfigPath_envOvverideDoesNotSupportPathSeparator(t *testing.T) {
+	path := strings.Join([]string{"file1", "file2"}, string(os.PathListSeparator))
+	defer testutil.WithEnvVar("KUBECONFIG", path)()
+
+	_, err := kubeconfigPath()
+	if err == nil {
+		t.Fatal("expected error")
+	}
+}
+
+func TestStandardKubeconfigLoader_returnsNotFoundErr(t *testing.T) {
+	defer testutil.WithEnvVar("KUBECONFIG", "foo")()
+	kc := new(kubeconfig.Kubeconfig).WithLoader(DefaultLoader)
+	err := kc.Parse()
+	if err == nil {
+		t.Fatal("expected err")
+	}
+	if !IsNotFoundErr(err) {
+		t.Fatalf("expected ENOENT error; got=%v", err)
+	}
+}