fix: trying to bind to an outbound ip returns an empty list of port b…

…indings (#533)

Keep calling docker inspect with a short delay until all port bindings are properly populated.

dockertest.go

@@ -487,7 +487,7 @@ func (d *Pool) RunWithOptions(opts *RunOptions, hcOpts ...func(*dc.HostConfig))
 		return nil, err
 	}
 
-	c, err = d.Client.InspectContainer(c.ID)
+	c, err = d.inspectContainerWithRetries(c.ID)
 	if err != nil {
 		return nil, err
 	}
@@ -505,6 +505,37 @@ func (d *Pool) RunWithOptions(opts *RunOptions, hcOpts ...func(*dc.HostConfig))
 	}, nil
 }
 
+// inspectContainerWithRetries will repeat the inspect call until the container has port bindings assigned.
+func (d *Pool) inspectContainerWithRetries(id string) (*dc.Container, error) {
+	const maxRetries = 10
+	var (
+		retryNum int
+		c        *dc.Container
+		err      error
+	)
+	for retryNum <= maxRetries {
+		if retryNum > 0 {
+			time.Sleep(100 * time.Millisecond)
+		}
+		c, err = d.Client.InspectContainer(id)
+		if err != nil {
+			return nil, err
+		}
+		if hasEmptyPortBindings := func() bool {
+			for _, bindings := range c.NetworkSettings.Ports {
+				if len(bindings) == 0 {
+					return true
+				}
+			}
+			return false
+		}(); !hasEmptyPortBindings {
+			return c, nil
+		}
+		retryNum++
+	}
+	return c, err
+}
+
 // Run starts a docker container.
 //
 //	pool.Run("mysql", "5.3", []string{"FOO=BAR", "BAR=BAZ"})

dockertest_test.go

@@ -8,6 +8,7 @@ import (
 	"database/sql"
 	"fmt"
 	"log"
+	"net"
 	"net/http"
 	"os"
 	"strconv"
@@ -490,3 +491,28 @@ func TestExecStatus(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, 42, exitCode)
 }
+
+func TestOutboundIPPortBinding(t *testing.T) {
+	outboundIP := func() string {
+		conn, err := net.Dial("udp", "8.8.8.8:80")
+		require.NoError(t, err)
+		defer conn.Close()
+		localAddr := conn.LocalAddr().(*net.UDPAddr)
+		return localAddr.IP.String()
+	}()
+	resource, err := pool.RunWithOptions(
+		&dockertest.RunOptions{
+			Repository: "postgres",
+			Tag:        "9.5",
+			Env:        []string{"POSTGRES_PASSWORD=secret"},
+			PortBindings: map[dc.Port][]dc.PortBinding{
+				"5432/tcp": {{HostIP: outboundIP, HostPort: "0"}},
+			},
+		})
+	require.NoError(t, err)
+	mappedPort := resource.GetPort("5432/tcp")
+	require.NotEmpty(t, mappedPort)
+	boundIP := resource.GetBoundIP("5432/tcp")
+	require.Equal(t, outboundIP, boundIP)
+	require.NoError(t, pool.Purge(resource))
+}