setup ExposeHostPorts forwards on container start

Fixes testcontainers#2811

Previously ExposedHostPorts would start an SSHD container prior to
starting the testcontainer and inject a PostReadies lifecycle hook into
the testcontainer in order to set up remote port forwarding from the
host to the SSHD container so the testcontainer can talk to the host via
the SSHD container

This would be an issue if the testcontainer depends on accessing the
host port on startup ( e.g., a proxy server ) as the forwarding for the
host access isn't set up until all the WiatFor strategies on the
testcontainer have completed.

The fix is to move the forwarding setup to the PreCreates hook on the
testcontainer. Since remote forwarding doesn't establish a connection to
the host port until a connection is made to the remote port, this should
not be an issue even if the host isn't listening yet and ensures the
remote port is available to the testcontainer immediately.

Author: hathvi

port_forwarding.go

@@ -150,8 +150,8 @@ func exposeHostPorts(ctx context.Context, req *ContainerRequest, ports ...int) (
 	// after the container is ready, create the SSH tunnel
 	// for each exposed port from the host.
 	sshdConnectHook = ContainerLifecycleHooks{
-		PostReadies: []ContainerHook{
-			func(ctx context.Context, c Container) error {
+		PreCreates: []ContainerRequestHook{
+			func(ctx context.Context, req ContainerRequest) error {
 				return sshdContainer.exposeHostPort(ctx, req.HostAccessPorts...)
 			},
 		},

port_forwarding_test.go

@@ -8,13 +8,12 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"testing"
-	"time"
 
 	"github.com/stretchr/testify/require"
 
 	"github.com/testcontainers/testcontainers-go"
-	tcexec "github.com/testcontainers/testcontainers-go/exec"
 	"github.com/testcontainers/testcontainers-go/network"
+	"github.com/testcontainers/testcontainers-go/wait"
 )
 
 const (
@@ -23,42 +22,59 @@ const (
 
 func TestExposeHostPorts(t *testing.T) {
 	tests := []struct {
-		name          string
-		numberOfPorts int
-		hasNetwork    bool
-		hasHostAccess bool
+		name             string
+		numberOfPorts    int
+		hasNetwork       bool
+		bindOnPostStarts bool
 	}{
 		{
 			name:          "single port",
 			numberOfPorts: 1,
-			hasHostAccess: true,
 		},
 		{
 			name:          "single port using a network",
 			numberOfPorts: 1,
 			hasNetwork:    true,
-			hasHostAccess: true,
 		},
 		{
 			name:          "multiple ports",
 			numberOfPorts: 3,
-			hasHostAccess: true,
 		},
 		{
-			name:          "single port with cancellation",
-			numberOfPorts: 1,
-			hasHostAccess: false,
+			name:             "multiple ports bound on PostStarts",
+			numberOfPorts:    3,
+			bindOnPostStarts: true,
 		},
 	}
 
 	for _, tc := range tests {
 		t.Run(tc.name, func(tt *testing.T) {
+			servers := make([]*httptest.Server, tc.numberOfPorts)
 			freePorts := make([]int, tc.numberOfPorts)
+			waitStrategies := make([]wait.Strategy, tc.numberOfPorts)
 			for i := range freePorts {
-				server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				server := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 					fmt.Fprint(w, expectedResponse)
 				}))
-				freePorts[i] = server.Listener.Addr().(*net.TCPAddr).Port
+
+				if !tc.bindOnPostStarts {
+					server.Start()
+				}
+
+				servers[i] = server
+				freePort := server.Listener.Addr().(*net.TCPAddr).Port
+				freePorts[i] = freePort
+				waitStrategies[i] = wait.
+					ForExec([]string{"wget", "-q", "-O", "-", fmt.Sprintf("http://%s:%d", testcontainers.HostInternal, freePort)}).
+					WithExitCodeMatcher(func(code int) bool {
+						return code == 0
+					}).
+					WithResponseMatcher(func(body io.Reader) bool {
+						bs, err := io.ReadAll(body)
+						require.NoError(tt, err)
+						return string(bs) == expectedResponse
+					})
+
 				tt.Cleanup(func() {
 					server.Close()
 				})
@@ -69,7 +85,26 @@ func TestExposeHostPorts(t *testing.T) {
 				ContainerRequest: testcontainers.ContainerRequest{
 					Image:           "alpine:3.17",
 					HostAccessPorts: freePorts,
-					Cmd:             []string{"top"},
+					WaitingFor:      wait.ForAll(waitStrategies...),
+					LifecycleHooks: []testcontainers.ContainerLifecycleHooks{
+						{
+							PostStarts: []testcontainers.ContainerHook{
+								func(ctx context.Context, c testcontainers.Container) error {
+									if tc.bindOnPostStarts {
+										for _, server := range servers {
+											server.Start()
+										}
+									}
+
+									return nil
+								},
+								func(ctx context.Context, c testcontainers.Container) error {
+									return waitStrategies[0].WaitUntilReady(ctx, c)
+								},
+							},
+						},
+					},
+					Cmd: []string{"top"},
 				},
 				// }
 				Started: true,
@@ -87,66 +122,9 @@ func TestExposeHostPorts(t *testing.T) {
 			}
 
 			ctx := context.Background()
-			if !tc.hasHostAccess {
-				var cancel context.CancelFunc
-				ctx, cancel = context.WithTimeout(ctx, 10*time.Second)
-				defer cancel()
-			}
-
 			c, err := testcontainers.GenericContainer(ctx, req)
-			testcontainers.CleanupContainer(t, c)
 			require.NoError(tt, err)
-
-			if tc.hasHostAccess {
-				// create a container that has host access, which will
-				// automatically forward the port to the container
-				assertContainerHasHostAccess(tt, c, freePorts...)
-			} else {
-				// force cancellation because of timeout
-				time.Sleep(11 * time.Second)
-
-				assertContainerHasNoHostAccess(tt, c, freePorts...)
-			}
+			_ = c.Terminate(ctx)
 		})
 	}
 }
-
-func httpRequest(t *testing.T, c testcontainers.Container, port int) (int, string) {
-	// wgetHostInternal {
-	code, reader, err := c.Exec(
-		context.Background(),
-		[]string{"wget", "-q", "-O", "-", fmt.Sprintf("http://%s:%d", testcontainers.HostInternal, port)},
-		tcexec.Multiplexed(),
-	)
-	// }
-	require.NoError(t, err)
-
-	// read the response
-	bs, err := io.ReadAll(reader)
-	require.NoError(t, err)
-
-	return code, string(bs)
-}
-
-func assertContainerHasHostAccess(t *testing.T, c testcontainers.Container, ports ...int) {
-	for _, port := range ports {
-		code, response := httpRequest(t, c, port)
-		if code != 0 {
-			t.Fatalf("expected status code [%d] but got [%d]", 0, code)
-		}
-
-		if response != expectedResponse {
-			t.Fatalf("expected [%s] but got [%s]", expectedResponse, response)
-		}
-	}
-}
-
-func assertContainerHasNoHostAccess(t *testing.T, c testcontainers.Container, ports ...int) {
-	for _, port := range ports {
-		_, response := httpRequest(t, c, port)
-
-		if response == expectedResponse {
-			t.Fatalf("expected not to get [%s] but got [%s]", expectedResponse, response)
-		}
-	}
-}