Add api command

cmd/sing-box/cmd_api_tailscale_exit_node.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"os"
+
+	F "github.com/sagernet/sing/common/format"
+
+	"github.com/spf13/cobra"
+)
+
+var commandAPITailscaleExitNode = &cobra.Command{
+	Use:   "exit-node",
+	Short: "Print the current Tailscale exit node",
+	Args:  cobra.NoArgs,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		return runAPITailscaleExitNode()
+	},
+}
+
+func init() {
+	commandAPITailscaleExitNode.PersistentFlags().StringVar(&commandAPITailscaleFlagEndpoint, "endpoint", "", commandAPITailscaleEndpointUsage)
+	commandAPITailscale.AddCommand(commandAPITailscaleExitNode)
+}
+
+func runAPITailscaleExitNode() error {
+	clientConn, client, err := createAPIClient()
+	if err != nil {
+		return err
+	}
+	defer clientConn.Close()
+	endpoint, err := fetchTailscaleEndpoint(client)
+	if err != nil {
+		return err
+	}
+	exitNode := endpoint.GetExitNode()
+	if exitNode == nil {
+		os.Stdout.WriteString("none\n")
+		return nil
+	}
+	name := tailscalePeerName(exitNode)
+	address := tailscalePeerAddress(exitNode)
+	if address == "" {
+		os.Stdout.WriteString(name + "\n")
+		return nil
+	}
+	os.Stdout.WriteString(F.ToString(name, " (", address, ")", "\n"))
+	return nil
+}