FIX #1858 Add engine port

Added flag `--generic-engine-port` to `generic` drive in order to specify other port than `2376` on
Docker engine.
Updated `generic` driver documentation.

Signed-off-by: Tiago Pires <tandrepires@gmail.com>

docs/drivers/generic.md

@@ -62,6 +62,7 @@ as a sudoer with `NOPASSWD`. See https://help.ubuntu.com/community/Sudoers.
 
 ### Options
 
+-   `--generic-engine-port`: Port to use for Docker Daemon (Note: This flag will not work with boot2docker).
 -   `--generic-ip-address`: **required** IP Address of host.
 -   `--generic-ssh-key`: Path to the SSH user private key.
 -   `--generic-ssh-user`: SSH username used to connect.
@@ -73,6 +74,7 @@ Environment variables and default values:
 
 | CLI option                 | Environment variable | Default                   |
 | -------------------------- | -------------------- | ------------------------- |
+| `--generic-engine-port`    | `GENERIC_ENGINE_PORT`| `2376`                    |
 | **`--generic-ip-address`** | `GENERIC_IP_ADDRESS` | -                         |
 | `--generic-ssh-key`        | `GENERIC_SSH_KEY`    | _(defers to `ssh-agent`)_ |
 | `--generic-ssh-user`       | `GENERIC_SSH_USER`   | `root`                    |

drivers/generic/generic.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/docker/machine/libmachine/drivers"
+	"github.com/docker/machine/libmachine/engine"
 	"github.com/docker/machine/libmachine/log"
 	"github.com/docker/machine/libmachine/mcnflag"
 	"github.com/docker/machine/libmachine/mcnutils"
@@ -17,7 +18,8 @@ import (
 
 type Driver struct {
 	*drivers.BaseDriver
-	SSHKey string
+	EnginePort int
+	SSHKey     string
 }
 
 const (
@@ -28,6 +30,12 @@ const (
 // "docker hosts create"
 func (d *Driver) GetCreateFlags() []mcnflag.Flag {
 	return []mcnflag.Flag{
+		mcnflag.IntFlag{
+			Name:   "generic-engine-port",
+			Usage:  "Docker engine port",
+			Value:  engine.DefaultPort,
+			EnvVar: "GENERIC_ENGINE_PORT",
+		},
 		mcnflag.StringFlag{
 			Name:   "generic-ip-address",
 			Usage:  "IP Address of machine",
@@ -57,6 +65,7 @@ func (d *Driver) GetCreateFlags() []mcnflag.Flag {
 // NewDriver creates and returns a new instance of the driver
 func NewDriver(hostName, storePath string) drivers.Driver {
 	return &Driver{
+		EnginePort: engine.DefaultPort,
 		BaseDriver: &drivers.BaseDriver{
 			MachineName: hostName,
 			StorePath:   storePath,
@@ -89,6 +98,7 @@ func (d *Driver) GetSSHKeyPath() string {
 }
 
 func (d *Driver) SetConfigFromFlags(flags drivers.DriverOptions) error {
+	d.EnginePort = flags.Int("generic-engine-port")
 	d.IPAddress = flags.String("generic-ip-address")
 	d.SSHUser = flags.String("generic-ssh-user")
 	d.SSHKey = flags.String("generic-ssh-key")
@@ -142,7 +152,7 @@ func (d *Driver) GetURL() (string, error) {
 		return "", err
 	}
 
-	return fmt.Sprintf("tcp://%s", net.JoinHostPort(ip, "2376")), nil
+	return fmt.Sprintf("tcp://%s", net.JoinHostPort(ip, strconv.Itoa(d.EnginePort))), nil
 }
 
 func (d *Driver) GetState() (state.State, error) {

drivers/generic/generic_test.go

@@ -12,8 +12,9 @@ func TestSetConfigFromFlags(t *testing.T) {
 
 	checkFlags := &drivers.CheckDriverOptions{
 		FlagsValues: map[string]interface{}{
-			"generic-ip-address": "localhost",
+			"generic-engine-port": "3000",
-			"generic-ssh-key":    "path",
+			"generic-ip-address":  "localhost",
+			"generic-ssh-key":     "path",
 		},
 		CreateFlags: driver.GetCreateFlags(),
 	}

libmachine/provision/configure_swarm.go

@@ -3,6 +3,7 @@ package provision
 import (
 	"fmt"
 	"net/url"
+	"strconv"
 	"strings"
 
 	"github.com/docker/machine/libmachine/auth"
@@ -30,15 +31,30 @@ func configureSwarm(p Provisioner, swarmOptions swarm.Options, authOptions auth.
 		return err
 	}
 
-	parts := strings.Split(u.Host, ":")
+	enginePort := engine.DefaultPort
+	engineURL, err := p.GetDriver().GetURL()
+	if err != nil {
+		return err
+	}
+
+	parts := strings.Split(engineURL, ":")
+	if len(parts) == 3 {
+		dPort, err := strconv.Atoi(parts[2])
+		if err != nil {
+			return err
+		}
+		enginePort = dPort
+	}
+
+	parts = strings.Split(u.Host, ":")
 	port := parts[1]
 
 	dockerDir := p.GetDockerOptionsDir()
 	dockerHost := &mcndockerclient.RemoteDocker{
-		HostURL:    fmt.Sprintf("tcp://%s:%d", ip, engine.DefaultPort),
+		HostURL:    fmt.Sprintf("tcp://%s:%d", ip, enginePort),
 		AuthOption: &authOptions,
 	}
-	advertiseInfo := fmt.Sprintf("%s:%d", ip, engine.DefaultPort)
+	advertiseInfo := fmt.Sprintf("%s:%d", ip, enginePort)
 
 	if swarmOptions.Master {
 		advertiseMasterInfo := fmt.Sprintf("%s:%s", ip, "3376")