1 files changed, 107 insertions, 0 deletions
diff --git a/pkg/spec/ports.go b/pkg/spec/ports.go
new file mode 100644
index 000000000..4d9a625bf
--- /dev/null
+++ b/pkg/spec/ports.go
@@ -0,0 +1,107 @@
+package createconfig
+
+import (
+	"fmt"
+	"net"
+	"strconv"
+
+	"github.com/docker/go-connections/nat"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+)
+
+// ExposedPorts parses user and image ports and returns binding information
+func ExposedPorts(expose, publish []string, publishAll bool, imageExposedPorts map[string]struct{}) (map[nat.Port][]nat.PortBinding, error) {
+	containerPorts := make(map[string]string)
+
+	// add expose ports from the image itself
+	for expose := range imageExposedPorts {
+		_, port := nat.SplitProtoPort(expose)
+		containerPorts[port] = ""
+	}
+
+	// add the expose ports from the user (--expose)
+	// can be single or a range
+	for _, expose := range expose {
+		//support two formats for expose, original format <portnum>/[<proto>] or <startport-endport>/[<proto>]
+		_, port := nat.SplitProtoPort(expose)
+		//parse the start and end port and create a sequence of ports to expose
+		//if expose a port, the start and end port are the same
+		start, end, err := nat.ParsePortRange(port)
+		if err != nil {
+			return nil, fmt.Errorf("invalid range format for --expose: %s, error: %s", expose, err)
+		}
+		for i := start; i <= end; i++ {
+			containerPorts[strconv.Itoa(int(i))] = ""
+		}
+	}
+
+	// parse user input'd port bindings
+	pbPorts, portBindings, err := nat.ParsePortSpecs(publish)
+	if err != nil {
+		return nil, err
+	}
+
+	// delete exposed container ports if being used by -p
+	for i := range pbPorts {
+		delete(containerPorts, i.Port())
+	}
+
+	// iterate container ports and make port bindings from them
+	if publishAll {
+		for e := range containerPorts {
+			//support two formats for expose, original format <portnum>/[<proto>] or <startport-endport>/[<proto>]
+			//proto, port := nat.SplitProtoPort(e)
+			p, err := nat.NewPort("tcp", e)
+			if err != nil {
+				return nil, err
+			}
+			rp, err := getRandomPort()
+			if err != nil {
+				return nil, err
+			}
+			logrus.Debug(fmt.Sprintf("Using random host port %d with container port %d", rp, p.Int()))
+			portBindings[p] = CreatePortBinding(rp, "")
+		}
+	}
+
+	// We need to see if any host ports are not populated and if so, we need to assign a
+	// random port to them.
+	for k, pb := range portBindings {
+		if pb[0].HostPort == "" {
+			hostPort, err := getRandomPort()
+			if err != nil {
+				return nil, err
+			}
+			logrus.Debug(fmt.Sprintf("Using random host port %d with container port %s", hostPort, k.Port()))
+			pb[0].HostPort = strconv.Itoa(hostPort)
+		}
+	}
+	return portBindings, nil
+}
+
+func getRandomPort() (int, error) {
+	l, err := net.Listen("tcp", ":0")
+	if err != nil {
+		return 0, errors.Wrapf(err, "unable to get free port")
+	}
+	defer l.Close()
+	_, randomPort, err := net.SplitHostPort(l.Addr().String())
+	if err != nil {
+		return 0, errors.Wrapf(err, "unable to determine free port")
+	}
+	rp, err := strconv.Atoi(randomPort)
+	if err != nil {
+		return 0, errors.Wrapf(err, "unable to convert random port to int")
+	}
+	return rp, nil
+}
+
+//CreatePortBinding takes port (int) and IP (string) and creates an array of portbinding structs
+func CreatePortBinding(hostPort int, hostIP string) []nat.PortBinding {
+	pb := nat.PortBinding{
+		HostPort: strconv.Itoa(hostPort),
+	}
+	pb.HostIP = hostIP
+	return []nat.PortBinding{pb}
+}