chore: resolve IPv4-IPv6 issues

docker.go

@@ -156,11 +156,7 @@ func (c *DockerContainer) PortEndpoint(ctx context.Context, port nat.Port, proto
 // Warning: this is based on your Docker host setting. Will fail if using an SSH tunnel
 // You can use the "TC_HOST" env variable to set this yourself
 func (c *DockerContainer) Host(ctx context.Context) (string, error) {
-	host, err := c.provider.DaemonHost(ctx)
-	if err != nil {
-		return "", err
-	}
-	return host, nil
+	return GetDockerHostIP(), nil
 }
 
 // Inspect gets the raw container info, caching the result for subsequent calls
@@ -189,7 +185,12 @@ func (c *DockerContainer) MappedPort(ctx context.Context, port nat.Port) (nat.Po
 
 	ports := inspect.NetworkSettings.Ports
 
-	for k, p := range ports {
+	boundPorts, err := core.BoundPortsFromBindings(ports)
+	if err != nil {
+		return "", err
+	}
+
+	for k, p := range boundPorts {
 		if k.Port() != port.Port() {
 			continue
 		}
@@ -199,7 +200,7 @@ func (c *DockerContainer) MappedPort(ctx context.Context, port nat.Port) (nat.Po
 		if len(p) == 0 {
 			continue
 		}
-		return nat.NewPort(k.Proto(), p[0].HostPort)
+		return nat.NewPort(k.Proto(), p.Port())
 	}
 
 	return "", errors.New("port not found")

docker_client.go

@@ -57,16 +57,19 @@ func (c *DockerClient) Info(ctx context.Context) (system.Info, error) {
   API Version: %v
   Operating System: %v
   Total Memory: %v MB
-  Resolved Docker Host: %s
+  Resolved Docker Host: %s - %s
   Resolved Docker Socket Path: %s
   Test SessionID: %s
   Test ProcessID: %s
 `
 
+	dockerHost := core.ExtractDockerHost(ctx)
+
 	Logger.Printf(infoMessage, packagePath,
 		dockerInfo.ServerVersion, c.Client.ClientVersion(),
 		dockerInfo.OperatingSystem, dockerInfo.MemTotal/1024/1024,
-		core.ExtractDockerHost(ctx),
+		dockerHost,
+		core.GetDockerHostIPs(),
 		core.ExtractDockerSocket(ctx),
 		core.SessionID(),
 		core.ProcessID(),

internal/core/bound_ports.go

@@ -0,0 +1,52 @@
+package core
+
+import (
+	"fmt"
+
+	"github.com/docker/go-connections/nat"
+)
+
+type BoundPorts map[nat.Port]nat.Port
+
+// BoundPortsFromBindings returns a map of container ports to host ports.
+// They are resolved from the port bindings in the inspect response,
+// using the host IP addresses of the Docker host.
+// This will resolve the issue of the host port being bound to multiple IP addresses
+// in the IPv4 and IPv6 case.
+func BoundPortsFromBindings(portMap nat.PortMap) (BoundPorts, error) {
+	hostIPs := GetDockerHostIPs()
+
+	boundPorts := make(BoundPorts)
+
+	for containerPort, bindings := range portMap {
+		if len(bindings) == 0 {
+			continue
+		}
+
+		hostPort, err := resolveHostPortBinding(hostIPs, bindings)
+		if err != nil {
+			return nil, fmt.Errorf("failed to resolve host port binding for port %s: %w", containerPort, err)
+		}
+
+		boundPorts[containerPort] = hostPort
+	}
+
+	return boundPorts, nil
+}
+
+// resolveHostPortBinding resolves the host port binding for the host IPs.
+// It will return the host port for the first matching IP family (IPv4 or IPv6).
+func resolveHostPortBinding(hostIPs []HostIP, portBindings []nat.PortBinding) (nat.Port, error) {
+	for _, hp := range hostIPs {
+		family := hp.Family
+
+		for _, portBinding := range portBindings {
+			hostIP := newHostIP(portBinding.HostIP)
+			if hostIP.Family == family {
+				return nat.Port(portBinding.HostPort), nil
+			}
+		}
+	}
+
+	return "", fmt.Errorf("no host port found for host IPs %v", hostIPs)
+}

internal/core/bound_ports_test.go

@@ -0,0 +1,91 @@
+package core
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/docker/go-connections/nat"
+)
+
+func TestResolveHostPortBinding(t *testing.T) {
+	type testCase struct {
+		name         string
+		expectedPort nat.Port
+		hostIPs      []HostIP
+		bindings     []nat.PortBinding
+		expectedErr  error
+	}
+
+	testCases := []testCase{
+		{
+			name: "should return IPv6-mapped host port when preferred",
+			hostIPs: []HostIP{
+				{Family: IPv6, Address: "::1"},
+				{Family: IPv4, Address: "127.0.0.1"},
+			},
+			bindings: []nat.PortBinding{
+				{HostIP: "0.0.0.0", HostPort: "50000"},
+				{HostIP: "::", HostPort: "50001"},
+			},
+			expectedPort: nat.Port("50001"),
+		},
+		{
+			name: "should return IPv4-mapped host port when preferred",
+			hostIPs: []HostIP{
+				{Family: IPv4, Address: "127.0.0.1"},
+				{Family: IPv6, Address: "::1"},
+			},
+			bindings: []nat.PortBinding{
+				{HostIP: "0.0.0.0", HostPort: "50000"},
+				{HostIP: "::", HostPort: "50001"},
+			},
+			expectedPort: nat.Port("50000"),
+		},
+		{
+			name: "should return mapped host port when dual stack IP",
+			hostIPs: []HostIP{
+				{Family: IPv4, Address: "127.0.0.1"},
+				{Family: IPv6, Address: "::1"},
+			},
+			bindings: []nat.PortBinding{
+				{HostIP: "", HostPort: "50000"},
+			},
+			expectedPort: nat.Port("50000"),
+		},
+		{
+			name: "should throw when no host port available for host IP family",
+			hostIPs: []HostIP{
+				{Family: IPv6, Address: "::1"},
+			},
+			bindings: []nat.PortBinding{
+				{HostIP: "0.0.0.0", HostPort: "50000"},
+			},
+			expectedPort: nat.Port(""), // that's the zero value returned by ResolveHostPortBinding
+			expectedErr:  fmt.Errorf("no host port found for host IPs [%s (IPv6)]", "::1"),
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			resolvedPort, err := resolveHostPortBinding(tc.hostIPs, tc.bindings)
+
+			switch {
+			case err == nil && tc.expectedErr == nil:
+				break
+			case err == nil && tc.expectedErr != nil:
+				t.Errorf("did not receive expected error: %s", tc.expectedErr.Error())
+				return
+			case err != nil && tc.expectedErr == nil:
+				t.Errorf("unexpected error: %v", err)
+				return
+			case err.Error() != tc.expectedErr.Error():
+				t.Errorf("errors mismatch: %s != %s", err.Error(), tc.expectedErr.Error())
+				return
+			}
+
+			if resolvedPort != tc.expectedPort {
+				t.Errorf("resolved port mismatch: got %s, expected %s", resolvedPort, tc.expectedPort)
+			}
+		})
+	}
+}

internal/core/docker_host_ips.go

@@ -0,0 +1,79 @@
+package core
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"sync"
+)
+
+type IPFamily string
+
+const (
+	IPv4 IPFamily = "IPv4"
+	IPv6 IPFamily = "IPv6"
+)
+
+var (
+	hostIPs     []HostIP
+	hostIPsOnce sync.Once
+)
+
+type HostIP struct {
+	Address string
+	Family  IPFamily
+}
+
+func (h HostIP) String() string {
+	return fmt.Sprintf("%s (%s)", h.Address, h.Family)
+}
+
+func newHostIP(host string) HostIP {
+	var hip HostIP
+
+	ip := net.ParseIP(host)
+	if ip == nil {
+		host = "127.0.0.1"
+		ip = net.ParseIP(host)
+	}
+
+	hip.Address = host
+
+	if ip.To4() != nil {
+		hip.Family = IPv4
+	} else if ip.To16() != nil {
+		hip.Family = IPv6
+	}
+
+	return hip
+}
+
+// GetDockerHostIPs returns the IP addresses of the Docker host.
+// The function is protected by a sync.Once to avoid unnecessary calculations.
+func GetDockerHostIPs() []HostIP {
+	hostIPsOnce.Do(func() {
+		dockerHost := ExtractDockerHost(context.Background())
+		hostIPs = getDockerHostIPs(dockerHost)
+	})
+
+	return hostIPs
+}
+
+// getDockerHostIPs returns the IP addresses of the Docker host.
+// The function is helpful for testing purposes,
+// as it's not protected by the sync.Once.
+func getDockerHostIPs(host string) []HostIP {
+	hip := newHostIP(host)
+
+	ips, err := net.LookupIP(hip.Address)
+	if err != nil {
+		return []HostIP{hip}
+	}
+
+	var hips = []HostIP{}
+	for _, ip := range ips {
+		hips = append(hostIPs, newHostIP(ip.String()))
+	}
+
+	return hips
+}

internal/core/docker_host_ips_test.go

@@ -0,0 +1,54 @@
+package core
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetDockerHostIPs(t *testing.T) {
+	type args struct {
+		host string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		hostIps []HostIP
+	}{
+		{
+			name: "should return a list of resolved host IPs when host is not an IP",
+			args: args{
+				host: "localhost",
+			},
+			hostIps: []HostIP{{Address: "127.0.0.1", Family: IPv4}},
+		},
+		{
+			name: "should return host IP and v4 family when host is an IPv4 IP",
+			args: args{
+				host: "127.0.0.1",
+			},
+			hostIps: []HostIP{{Address: "127.0.0.1", Family: IPv4}},
+		},
+		{
+			name: "should return host IP and v4 family when host is an IPv4 IP with tcp schema",
+			args: args{
+				host: "tcp://127.0.0.1:64692",
+			},
+			hostIps: []HostIP{{Address: "127.0.0.1", Family: IPv4}},
+		},
+		{
+			name: "should return host IP and v6 family when host is an IPv6 IP",
+			args: args{
+				host: "::1",
+			},
+			hostIps: []HostIP{{Address: "::1", Family: IPv6}},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			hips := getDockerHostIPs(tt.args.host)
+			assert.Equal(t, tt.hostIps, hips)
+		})
+	}
+}

modules/cockroachdb/cockroachdb_test.go

@@ -17,13 +17,13 @@ import (
 
 func TestCockroach_Insecure(t *testing.T) {
 	suite.Run(t, &AuthNSuite{
-		url: "postgres://root@localhost:xxxxx/defaultdb?sslmode=disable",
+		url: "postgres://root@" + testcontainers.GetDockerHostIP() + ":xxxxx/defaultdb?sslmode=disable",
 	})
 }
 
 func TestCockroach_NotRoot(t *testing.T) {
 	suite.Run(t, &AuthNSuite{
-		url: "postgres://test@localhost:xxxxx/defaultdb?sslmode=disable",
+		url: "postgres://test@" + testcontainers.GetDockerHostIP() + ":xxxxx/defaultdb?sslmode=disable",
 		opts: []testcontainers.ContainerCustomizer{
 			cockroachdb.WithUser("test"),
 		},
@@ -32,7 +32,7 @@ func TestCockroach_NotRoot(t *testing.T) {
 
 func TestCockroach_Password(t *testing.T) {
 	suite.Run(t, &AuthNSuite{
-		url: "postgres://foo:bar@localhost:xxxxx/defaultdb?sslmode=disable",
+		url: "postgres://foo:bar@" + testcontainers.GetDockerHostIP() + ":xxxxx/defaultdb?sslmode=disable",
 		opts: []testcontainers.ContainerCustomizer{
 			cockroachdb.WithUser("foo"),
 			cockroachdb.WithPassword("bar"),
@@ -45,7 +45,7 @@ func TestCockroach_TLS(t *testing.T) {
 	require.NoError(t, err)
 
 	suite.Run(t, &AuthNSuite{
-		url: "postgres://root@localhost:xxxxx/defaultdb?sslmode=verify-full",
+		url: "postgres://root@" + testcontainers.GetDockerHostIP() + ":xxxxx/defaultdb?sslmode=verify-full",
 		opts: []testcontainers.ContainerCustomizer{
 			cockroachdb.WithTLS(tlsCfg),
 		},

modules/cockroachdb/examples_test.go

@@ -45,5 +45,5 @@ func ExampleRunContainer() {
 
 	// Output:
 	// true
-	// postgres://root@localhost:xxx/defaultdb?sslmode=disable
+	// postgres://root@127.0.0.1:xxx/defaultdb?sslmode=disable
 }

modules/postgres/postgres_test.go

@@ -96,7 +96,7 @@ func TestPostgres(t *testing.T) {
 			// Ensure connection string is using generic format
 			id, err := container.MappedPort(ctx, "5432/tcp")
 			require.NoError(t, err)
-			assert.Equal(t, fmt.Sprintf("postgres://%s:%s@%s:%s/%s?sslmode=disable&application_name=test", user, password, "localhost", id.Port(), dbname), connStr)
+			assert.Equal(t, fmt.Sprintf("postgres://%s:%s@%s:%s/%s?sslmode=disable&application_name=test", user, password, testcontainers.GetDockerHostIP(), id.Port(), dbname), connStr)
 
 			// perform assertions
 			db, err := sql.Open("postgres", connStr)