Initial support for device flow

Signed-off-by: Jorge Turrado <jorge.turrado@mail.schwarz>

Author: JorTurFer

docs/stackit_auth_login.md

@@ -5,7 +5,7 @@ Logs in to the STACKIT CLI
 ### Synopsis
 
 Logs in to the STACKIT CLI using a user account.
-The authentication is done via a web-based authorization flow, where the command will open a browser window in which you can login to your STACKIT account.
+By default, the authentication uses a web-based authorization flow and opens a browser window where you can login to your STACKIT account. You can alternatively use the OAuth 2.0 device flow for environments where receiving a local callback is not possible.
 
 ```
 stackit auth login [flags]
@@ -16,6 +16,9 @@ stackit auth login [flags]
 ```
   Login to the STACKIT CLI. This command will open a browser window where you can login to your STACKIT account
   $ stackit auth login
+
+  Login to the STACKIT CLI using OAuth 2.0 device flow
+  $ stackit auth login --use-device-flow
 ```
 
 ### Options
@@ -24,6 +27,7 @@ stackit auth login [flags]
   -h, --help       Help for "stackit auth login"
       --port int   The port on which the callback server will listen to. By default, it tries to bind a port between 8000 and 8020.
                    When a value is specified, it will only try to use the specified port. Valid values are within the range of 8000 to 8020.
+      --use-device-flow   Use OAuth 2.0 device authorization grant (device flow) instead of the browser callback flow.
 ```
 
 ### Options inherited from parent commands

internal/cmd/auth/login/login.go

@@ -14,11 +14,13 @@ import (
 )
 
 const (
-	portFlag = "port"
+	portFlag          = "port"
+	useDeviceFlowFlag = "use-device-flow"
 )
 
 type inputModel struct {
-	Port *int
+	Port          *int
+	UseDeviceFlow bool
 }
 
 func NewCmd(params *types.CmdParams) *cobra.Command {
@@ -27,12 +29,15 @@ func NewCmd(params *types.CmdParams) *cobra.Command {
 		Short: "Logs in to the STACKIT CLI",
 		Long: fmt.Sprintf("%s\n%s",
 			"Logs in to the STACKIT CLI using a user account.",
-			"The authentication is done via a web-based authorization flow, where the command will open a browser window in which you can login to your STACKIT account."),
+			"By default, the authentication uses a web-based authorization flow and opens a browser window where you can login to your STACKIT account. You can alternatively use the OAuth 2.0 device flow for environments where receiving a local callback is not possible."),
 		Args: args.NoArgs,
 		Example: examples.Build(
 			examples.NewExample(
 				`Login to the STACKIT CLI. This command will open a browser window where you can login to your STACKIT account`,
 				"$ stackit auth login"),
+			examples.NewExample(
+				`Login to the STACKIT CLI using OAuth 2.0 device flow`,
+				"$ stackit auth login --use-device-flow"),
 		),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			model, err := parseInput(params.Printer, cmd, args)
@@ -43,6 +48,7 @@ func NewCmd(params *types.CmdParams) *cobra.Command {
 			err = auth.AuthorizeUser(params.Printer, auth.UserAuthConfig{
 				IsReauthentication: false,
 				Port:               model.Port,
+				UseDeviceFlow:      model.UseDeviceFlow,
 			})
 			if err != nil {
 				return fmt.Errorf("authorization failed: %w", err)
@@ -62,17 +68,21 @@ func configureFlags(cmd *cobra.Command) {
 		"The port on which the callback server will listen to. By default, it tries to bind a port between 8000 and 8020.\n"+
 			"When a value is specified, it will only try to use the specified port. Valid values are within the range of 8000 to 8020.",
 	)
+	cmd.Flags().Bool(useDeviceFlowFlag, false,
+		"Use OAuth 2.0 device authorization grant (device flow) instead of the browser callback flow.")
 }
 
 func parseInput(p *print.Printer, cmd *cobra.Command, _ []string) (*inputModel, error) {
 	port := flags.FlagToIntPointer(p, cmd, portFlag)
+	useDeviceFlow := flags.FlagToBoolValue(p, cmd, useDeviceFlowFlag)
 	// For the CLI client only callback URLs with localhost:[8000-8020] are valid. Additional callbacks must be enabled in the backend.
 	if port != nil && (*port < 8000 || 8020 < *port) {
 		return nil, fmt.Errorf("port must be between 8000 and 8020")
 	}
 
 	model := inputModel{
-		Port: port,
+		Port:          port,
+		UseDeviceFlow: useDeviceFlow,
 	}
 
 	p.DebugInputModel(model)

internal/cmd/auth/login/login_test.go

@@ -9,7 +9,8 @@ import (
 
 func fixtureFlagValues(mods ...func(flagValues map[string]string)) map[string]string {
 	flagValues := map[string]string{
-		portFlag: "8010",
+		portFlag:          "8010",
+		useDeviceFlowFlag: "false",
 	}
 	for _, mod := range mods {
 		mod(flagValues)
@@ -19,7 +20,8 @@ func fixtureFlagValues(mods ...func(flagValues map[string]string)) map[string]st
 
 func fixtureInputModel(mods ...func(model *inputModel)) *inputModel {
 	model := &inputModel{
-		Port: utils.Ptr(8010),
+		Port:          utils.Ptr(8010),
+		UseDeviceFlow: false,
 	}
 	for _, mod := range mods {
 		mod(model)
@@ -46,7 +48,19 @@ func TestParseInput(t *testing.T) {
 			flagValues:  map[string]string{},
 			isValid:     true,
 			expectedModel: &inputModel{
-				Port: nil,
+				Port:          nil,
+				UseDeviceFlow: false,
+			},
+		},
+		{
+			description: "device flow enabled",
+			flagValues: map[string]string{
+				useDeviceFlowFlag: "true",
+			},
+			isValid: true,
+			expectedModel: &inputModel{
+				Port:          nil,
+				UseDeviceFlow: true,
 			},
 		},
 		{
@@ -56,7 +70,8 @@ func TestParseInput(t *testing.T) {
 			},
 			isValid: true,
 			expectedModel: &inputModel{
-				Port: utils.Ptr(8000),
+				Port:          utils.Ptr(8000),
+				UseDeviceFlow: false,
 			},
 		},
 		{
@@ -73,7 +88,8 @@ func TestParseInput(t *testing.T) {
 			},
 			isValid: true,
 			expectedModel: &inputModel{
-				Port: utils.Ptr(8020),
+				Port:          utils.Ptr(8020),
+				UseDeviceFlow: false,
 			},
 		},
 		{