cmd/k8s-operator: fix Tailscale Service API errors check (#16020)

Updates tailscale/tailscale#15895

Signed-off-by: Irbe Krumina <irbe@tailscale.com>

cmd/k8s-operator/ingress-for-pg.go

@@ -1105,13 +1105,11 @@ func isErrorFeatureFlagNotEnabled(err error) bool {
 	// Tailscale control plane when a Tailscale Service API call is made for a
 	// tailnet that does not have the Tailscale Services feature flag enabled.
 	const messageFFNotEnabled = "feature unavailable for tailnet"
-	var errResp *tailscale.ErrResponse
-	ok := errors.As(err, &errResp)
-	return ok && strings.Contains(errResp.Message, messageFFNotEnabled)
+	return err != nil && strings.Contains(err.Error(), messageFFNotEnabled)
 }
 
 func isErrorTailscaleServiceNotFound(err error) bool {
-	var errResp *tailscale.ErrResponse
+	var errResp tailscale.ErrResponse
 	ok := errors.As(err, &errResp)
 	return ok && errResp.Status == http.StatusNotFound
 }

cmd/k8s-operator/svc-for-pg_test.go

@@ -8,10 +8,8 @@ package main
 import (
 	"context"
 	"encoding/json"
-	"errors"
 	"fmt"
 	"math/rand/v2"
-	"net/http"
 	"net/netip"
 	"testing"
 
@@ -23,7 +21,6 @@ import (
 	"k8s.io/client-go/tools/record"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/client/fake"
-	"tailscale.com/internal/client/tailscale"
 	"tailscale.com/ipn/ipnstate"
 	tsoperator "tailscale.com/k8s-operator"
 	tsapi "tailscale.com/k8s-operator/apis/v1alpha1"
@@ -108,8 +105,7 @@ func TestServicePGReconciler_UpdateHostname(t *testing.T) {
 	if err == nil {
 		t.Fatalf("svc:default-%s not cleaned up", svc.Name)
 	}
-	var errResp *tailscale.ErrResponse
-	if !errors.As(err, &errResp) || errResp.Status != http.StatusNotFound {
+	if !isErrorTailscaleServiceNotFound(err) {
 		t.Fatalf("unexpected error: %v", err)
 	}
 }

cmd/k8s-operator/testutils_test.go

@@ -901,11 +901,11 @@ func (c *fakeTSClient) GetVIPService(ctx context.Context, name tailcfg.ServiceNa
 	c.Lock()
 	defer c.Unlock()
 	if c.vipServices == nil {
-		return nil, &tailscale.ErrResponse{Status: http.StatusNotFound}
+		return nil, tailscale.ErrResponse{Status: http.StatusNotFound}
 	}
 	svc, ok := c.vipServices[name]
 	if !ok {
-		return nil, &tailscale.ErrResponse{Status: http.StatusNotFound}
+		return nil, tailscale.ErrResponse{Status: http.StatusNotFound}
 	}
 	return svc, nil
 }