Question formatting

internal/tailscale/tailscale.go

@@ -2,7 +2,9 @@ package tailscale
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
+	"os"
 	"os/exec"
 	"strconv"
 	"strings"
@@ -11,17 +13,43 @@ import (
 const cli = "/Applications/Tailscale.app/Contents/MacOS/Tailscale"
 
 func Serve(ctx context.Context, port int) error {
-	return run(ctx, "serve", "--bg", "--https="+strconv.Itoa(port), "http://127.0.0.1:"+strconv.Itoa(port))
+	_, err := run(ctx, "serve", "--bg", "--https="+strconv.Itoa(port), "http://127.0.0.1:"+strconv.Itoa(port))
+	if err != nil {
+		return err
+	}
+	out, err := run(ctx, "serve", "status", "--json")
+	if err != nil {
+		return err
+	}
+	status := struct {
+		Web map[string]json.RawMessage
+	}{}
+	err = json.Unmarshal(out, &status)
+	if err != nil {
+		return fmt.Errorf("parse tailscale serve status: %w", err)
+	}
+	suffix := ":" + strconv.Itoa(port)
+	for host := range status.Web {
+		if strings.HasSuffix(host, suffix) {
+			return nil
+		}
+	}
+	return fmt.Errorf("tailscale serve --https=%d exited 0 but port %d is not in serve status", port, port)
 }
 
 func Off(ctx context.Context, port int) error {
-	return run(ctx, "serve", "--https="+strconv.Itoa(port), "off")
+	_, err := run(ctx, "serve", "--https="+strconv.Itoa(port), "off")
+	return err
 }
 
-func run(ctx context.Context, args ...string) error {
-	out, err := exec.CommandContext(ctx, cli, args...).CombinedOutput()
+func run(ctx context.Context, args ...string) ([]byte, error) {
+	cmd := exec.CommandContext(ctx, cli, args...)
+	cmd.Env = append(os.Environ(), "TAILSCALE_BE_CLI=1")
+	stderr := strings.Builder{}
+	cmd.Stderr = &stderr
+	out, err := cmd.Output()
 	if err != nil {
-		return fmt.Errorf("tailscale %s: %w: %s", strings.Join(args, " "), err, strings.TrimSpace(string(out)))
+		return nil, fmt.Errorf("tailscale %s: %w: %s", strings.Join(args, " "), err, strings.TrimSpace(stderr.String()+string(out)))
 	}
-	return nil
+	return out, nil
 }