hscontrol, cli: add auth register and approve commands

Implement AuthRegister and AuthApprove gRPC handlers and add
corresponding CLI commands (headscale auth register, approve, reject)
for managing pending auth requests including SSH check approvals.

Updates #1850

cmd/headscale/cli/auth.go

@@ -0,0 +1,93 @@
+package cli
+
+import (
+	"context"
+	"fmt"
+
+	v1 "github.com/juanfont/headscale/gen/go/headscale/v1"
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	rootCmd.AddCommand(authCmd)
+
+	authRegisterCmd.Flags().StringP("user", "u", "", "User")
+	authRegisterCmd.Flags().String("auth-id", "", "Auth ID")
+	mustMarkRequired(authRegisterCmd, "user", "auth-id")
+	authCmd.AddCommand(authRegisterCmd)
+
+	authApproveCmd.Flags().String("auth-id", "", "Auth ID")
+	mustMarkRequired(authApproveCmd, "auth-id")
+	authCmd.AddCommand(authApproveCmd)
+
+	authRejectCmd.Flags().String("auth-id", "", "Auth ID")
+	mustMarkRequired(authRejectCmd, "auth-id")
+	authCmd.AddCommand(authRejectCmd)
+}
+
+var authCmd = &cobra.Command{
+	Use:   "auth",
+	Short: "Manage node authentication and approval",
+}
+
+var authRegisterCmd = &cobra.Command{
+	Use:   "register",
+	Short: "Register a node to your network",
+	RunE: grpcRunE(func(ctx context.Context, client v1.HeadscaleServiceClient, cmd *cobra.Command, args []string) error {
+		user, _ := cmd.Flags().GetString("user")
+		authID, _ := cmd.Flags().GetString("auth-id")
+
+		request := &v1.AuthRegisterRequest{
+			AuthId: authID,
+			User:   user,
+		}
+
+		response, err := client.AuthRegister(ctx, request)
+		if err != nil {
+			return fmt.Errorf("registering node: %w", err)
+		}
+
+		return printOutput(
+			cmd,
+			response.GetNode(),
+			fmt.Sprintf("Node %s registered", response.GetNode().GetGivenName()))
+	}),
+}
+
+var authApproveCmd = &cobra.Command{
+	Use:   "approve",
+	Short: "Approve a pending authentication request",
+	RunE: grpcRunE(func(ctx context.Context, client v1.HeadscaleServiceClient, cmd *cobra.Command, args []string) error {
+		authID, _ := cmd.Flags().GetString("auth-id")
+
+		request := &v1.AuthApproveRequest{
+			AuthId: authID,
+		}
+
+		response, err := client.AuthApprove(ctx, request)
+		if err != nil {
+			return fmt.Errorf("approving auth request: %w", err)
+		}
+
+		return printOutput(cmd, response, "Auth request approved")
+	}),
+}
+
+var authRejectCmd = &cobra.Command{
+	Use:   "reject",
+	Short: "Reject a pending authentication request",
+	RunE: grpcRunE(func(ctx context.Context, client v1.HeadscaleServiceClient, cmd *cobra.Command, args []string) error {
+		authID, _ := cmd.Flags().GetString("auth-id")
+
+		request := &v1.AuthRejectRequest{
+			AuthId: authID,
+		}
+
+		response, err := client.AuthReject(ctx, request)
+		if err != nil {
+			return fmt.Errorf("rejecting auth request: %w", err)
+		}
+
+		return printOutput(cmd, response, "Auth request rejected")
+	}),
+}

cmd/headscale/cli/nodes.go

@@ -64,8 +64,9 @@ var nodeCmd = &cobra.Command{
 }
 
 var registerNodeCmd = &cobra.Command{
-	Use:   "register",
-	Short: "Registers a node to your network",
+	Use:        "register",
+	Short:      "Registers a node to your network",
+	Deprecated: "use 'headscale auth register --auth-id <id> --user <user>' instead",
 	RunE: grpcRunE(func(ctx context.Context, client v1.HeadscaleServiceClient, cmd *cobra.Command, args []string) error {
 		user, _ := cmd.Flags().GetString("user")
 		registrationID, _ := cmd.Flags().GetString("key")