🐛 fix: use cluster tag key to list managed egress-only internet gateway

pkg/cloud/services/network/egress_only_gateways.go

@@ -136,21 +136,41 @@ func (s *Service) createEgressOnlyInternetGateway() (*types.EgressOnlyInternetGa
 }
 
 func (s *Service) describeEgressOnlyVpcInternetGateways() ([]types.EgressOnlyInternetGateway, error) {
+	// The API for DescribeEgressOnlyInternetGateways does not support filtering by VPC ID attachment.
+	// More details: https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DescribeEgressOnlyInternetGateways.html
+	// Since the eigw is managed by CAPA, we can filter by the kubernetes cluster tag.
 	out, err := s.EC2Client.DescribeEgressOnlyInternetGateways(context.TODO(), &ec2.DescribeEgressOnlyInternetGatewaysInput{
 		Filters: []types.Filter{
-			filter.EC2.VPCAttachment(s.scope.VPC().ID),
+			filter.EC2.Cluster(s.scope.Name()),
 		},
 	})
 	if err != nil {
 		record.Eventf(s.scope.InfraCluster(), "FailedDescribeEgressOnlyInternetGateway", "Failed to describe egress only internet gateway in vpc %q: %v", s.scope.VPC().ID, err)
 		return nil, errors.Wrapf(err, "failed to describe egress only internet gateways in vpc %q", s.scope.VPC().ID)
 	}
 
-	if len(out.EgressOnlyInternetGateways) == 0 {
+	// For safeguarding, we collect only egress-only internet gateways
+	// that are attached to the VPC.
+	eigws := make([]types.EgressOnlyInternetGateway, 0)
+	for _, eigw := range out.EgressOnlyInternetGateways {
+		for _, attachment := range eigw.Attachments {
+			if aws.ToString(attachment.VpcId) == s.scope.VPC().ID {
+				eigws = append(eigws, eigw)
+			}
+		}
+	}
+
+	if len(eigws) == 0 {
 		return nil, awserrors.NewNotFound(fmt.Sprintf("no egress only internet gateways found in vpc %q", s.scope.VPC().ID))
+	} else if len(eigws) > 1 {
+		eigwIDs := make([]string, len(eigws))
+		for i, eigw := range eigws {
+			eigwIDs[i] = aws.ToString(eigw.EgressOnlyInternetGatewayId)
+		}
+		return nil, awserrors.NewConflict(fmt.Sprintf("expected 1 egress only internet gateway in vpc %q, but found %v: %v", s.scope.VPC().ID, len(eigws), eigwIDs))
 	}
 
-	return out.EgressOnlyInternetGateways, nil
+	return eigws, nil
 }
 
 func (s *Service) getEgressOnlyGatewayTagParams(id string) infrav1.BuildParams {

pkg/cloud/services/network/egress_only_gateways_test.go

@@ -40,9 +40,10 @@ func TestReconcileEgressOnlyInternetGateways(t *testing.T) {
 	defer mockCtrl.Finish()
 
 	testCases := []struct {
-		name   string
-		input  *infrav1.NetworkSpec
-		expect func(m *mocks.MockEC2APIMockRecorder)
+		name              string
+		input             *infrav1.NetworkSpec
+		expect            func(m *mocks.MockEC2APIMockRecorder)
+		wantErrContaining *string
 	}{
 		{
 			name: "has eigw",
@@ -75,6 +76,44 @@ func TestReconcileEgressOnlyInternetGateways(t *testing.T) {
 					Return(nil, nil)
 			},
 		},
+		{
+			name: "has more than 1 eigw, should return error",
+			input: &infrav1.NetworkSpec{
+				VPC: infrav1.VPCSpec{
+					ID:   "vpc-egress-only-gateways",
+					IPv6: &infrav1.IPv6{},
+					Tags: infrav1.Tags{
+						infrav1.ClusterTagKey("test-cluster"): "owned",
+					},
+				},
+			},
+			wantErrContaining: aws.String("expected 1 egress only internet gateway in vpc \"vpc-egress-only-gateways\", but found 2: [eigw-0 eigw-1]"),
+			expect: func(m *mocks.MockEC2APIMockRecorder) {
+				m.DescribeEgressOnlyInternetGateways(context.TODO(), gomock.AssignableToTypeOf(&ec2.DescribeEgressOnlyInternetGatewaysInput{})).
+					Return(&ec2.DescribeEgressOnlyInternetGatewaysOutput{
+						EgressOnlyInternetGateways: []types.EgressOnlyInternetGateway{
+							{
+								EgressOnlyInternetGatewayId: aws.String("eigw-0"),
+								Attachments: []types.InternetGatewayAttachment{
+									{
+										State: types.AttachmentStatusAttached,
+										VpcId: aws.String("vpc-egress-only-gateways"),
+									},
+								},
+							},
+							{
+								EgressOnlyInternetGatewayId: aws.String("eigw-1"),
+								Attachments: []types.InternetGatewayAttachment{
+									{
+										State: types.AttachmentStatusAttached,
+										VpcId: aws.String("vpc-egress-only-gateways"),
+									},
+								},
+							},
+						},
+					}, nil)
+			},
+		},
 		{
 			name: "no eigw attached, creates one",
 			input: &infrav1.NetworkSpec{
@@ -122,10 +161,13 @@ func TestReconcileEgressOnlyInternetGateways(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
+			g := NewWithT(t)
 			ec2Mock := mocks.NewMockEC2API(mockCtrl)
 
 			scheme := runtime.NewScheme()
-			_ = infrav1.AddToScheme(scheme)
+			err := infrav1.AddToScheme(scheme)
+			g.Expect(err).NotTo(HaveOccurred())
+
 			client := fake.NewClientBuilder().WithScheme(scheme).Build()
 			scope, err := scope.NewClusterScope(scope.ClusterScopeParams{
 				Client: client,
@@ -139,18 +181,20 @@ func TestReconcileEgressOnlyInternetGateways(t *testing.T) {
 					},
 				},
 			})
-			if err != nil {
-				t.Fatalf("Failed to create test context: %v", err)
-			}
+			g.Expect(err).NotTo(HaveOccurred())
 
 			tc.expect(ec2Mock.EXPECT())
 
 			s := NewService(scope)
 			s.EC2Client = ec2Mock
 
-			if err := s.reconcileEgressOnlyInternetGateways(); err != nil {
-				t.Fatalf("got an unexpected error: %v", err)
+			err = s.reconcileEgressOnlyInternetGateways()
+			if tc.wantErrContaining != nil {
+				g.Expect(err).To(HaveOccurred())
+				g.Expect(err.Error()).To(ContainSubstring(*tc.wantErrContaining))
+				return
 			}
+			g.Expect(err).NotTo(HaveOccurred())
 		})
 	}
 }
@@ -199,8 +243,8 @@ func TestDeleteEgressOnlyInternetGateways(t *testing.T) {
 				m.DescribeEgressOnlyInternetGateways(context.TODO(), gomock.Eq(&ec2.DescribeEgressOnlyInternetGatewaysInput{
 					Filters: []types.Filter{
 						{
-							Name:   aws.String("attachment.vpc-id"),
-							Values: []string{"vpc-gateways"},
+							Name:   aws.String("tag-key"),
+							Values: []string{infrav1.ClusterTagKey("test-cluster")},
 						},
 					},
 				})).Return(&ec2.DescribeEgressOnlyInternetGatewaysOutput{}, nil)