Gaojing/devicelogin exit when interactivemode never (#145)

* device login would exit gracefully when interactiveMode: Never, fixed #92 

Co-authored-by: Jing Gao <jing@JingMS>

pkg/token/deviceloginAndNonInteractive_test.go

@@ -0,0 +1,35 @@
+package token
+
+import (
+	"os"
+	"testing"
+)
+
+func TestDeviceloginAndNonInteractive(t *testing.T) {
+	testData := []struct {
+		name            string
+		execInfoEnvTest string
+		options         Options
+		expectedError   string
+	}{
+		{
+			name:            "KUBERNETES_EXEC_INFO.spec.interactive: false and login mode is devicelogin",
+			execInfoEnvTest: `{"kind":"ExecCredential","apiVersion":"client.authentication.k8s.io/v1beta1","spec":{"interactive":false}}`,
+			options: Options{
+				LoginMethod: DeviceCodeLogin,
+			},
+			expectedError: "devicelogin is not supported if interactiveMode is 'never'",
+		},
+	}
+
+	for _, data := range testData {
+		t.Run(data.name, func(t *testing.T) {
+			os.Setenv("KUBERNETES_EXEC_INFO", data.execInfoEnvTest)
+			defer os.Unsetenv("KUBERNETES_EXEC_INFO")
+			ecp, err := New(&data.options)
+			if ecp != nil || err == nil || err.Error() != data.expectedError {
+				t.Fatalf("expected: return defined error, actual: did not return expected error")
+			}
+		})
+	}
+}

pkg/token/execCredentialPlugin.go

@@ -3,11 +3,13 @@ package token
 //go:generate sh -c "mockgen -destination mock_$GOPACKAGE/execCredentialPlugin.go github.com/Azure/kubelogin/pkg/token ExecCredentialPlugin"
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 	"time"
 
 	"github.com/Azure/go-autorest/autorest/adal"
+	"k8s.io/client-go/pkg/apis/clientauthentication"
 	"k8s.io/klog"
 )
 
@@ -29,6 +31,14 @@ type execCredentialPlugin struct {
 }
 
 func New(o *Options) (ExecCredentialPlugin, error) {
+	env := os.Getenv(execInfoEnv)
+	var execCredential clientauthentication.ExecCredential
+	if err := json.Unmarshal([]byte(env), &execCredential); err != nil {
+		return nil, fmt.Errorf("cannot convert to ExecCredential: %w", err)
+	}
+	if !execCredential.Spec.Interactive && o.LoginMethod == DeviceCodeLogin {
+		return nil, fmt.Errorf("devicelogin is not supported if interactiveMode is 'never'")
+	}
 	klog.V(10).Info(o)
 	provider, err := newTokenProvider(o)
 	if err != nil {