Enhancing `docker-machine ip` to support multiple host arguments

Fixes #999

Signed-off-by: Dave Henderson <Dave.Henderson@ca.ibm.com>

commands/commands.go

@@ -234,7 +234,7 @@ var Commands = []cli.Command{
 	{
 		Name:        "ip",
 		Usage:       "Get the IP address of a machine",
-		Description: "Argument is a machine name. Will use the active machine if none is provided.",
+		Description: "Argument(s) are one or more machine names. Will use the active machine if none is provided.",
 		Action:      cmdIp,
 	},
 	{
@@ -342,6 +342,7 @@ func machineCommand(actionName string, host *libmachine.Host, errorChan chan<- e
 		"restart":       host.Restart,
 		"kill":          host.Kill,
 		"upgrade":       host.Upgrade,
+		"ip":            host.PrintIP,
 	}
 
 	log.Debugf("command=%s machine=%s", actionName, host.Name)

commands/ip.go

@@ -1,18 +1,13 @@
 package commands
 
 import (
-	"fmt"
-
 	log "github.com/Sirupsen/logrus"
 
 	"github.com/codegangsta/cli"
 )
 
 func cmdIp(c *cli.Context) {
-	ip, err := getHost(c).Driver.GetIP()
+	if err := runActionWithContext("ip", c); err != nil {
-	if err != nil {
 		log.Fatal(err)
 	}
-
-	fmt.Println(ip)
 }

docs/index.md

@@ -535,11 +535,16 @@ Show help text.
 
 #### ip
 
-Get the IP address of a machine.
+Get the IP address of one or more machines.
 
 ```
 $ docker-machine ip
 192.168.99.104
+$ docker-machine ip dev
+192.168.99.104
+$ docker-machine ip dev dev2
+192.168.99.104
+192.168.99.105
 ```
 
 #### kill
@@ -1051,5 +1056,3 @@ details, see [PR #553](https://github.com/docker/machine/issues/553).
 * Improvements and isolation of provisioning functionality, so Machine can
 provision and configure the Docker Engine based on OS detection. For details,
 see [PR #553](https://github.com/docker/machine/issues/553).
-
-

libmachine/host.go

@@ -334,6 +334,15 @@ func (h *Host) SaveConfig() error {
 	return nil
 }
 
+func (h *Host) PrintIP() error {
+	if ip, err := h.Driver.GetIP(); err != nil {
+		return err
+	} else {
+		fmt.Println(ip)
+	}
+	return nil
+}
+
 func sshAvailableFunc(h *Host) func() bool {
 	return func() bool {
 		log.Debug("Getting to WaitForSSH function...")

libmachine/host_test.go

@@ -1,16 +1,21 @@
 package libmachine
 
 import (
+	"bytes"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"os"
-
+	"strings"
 	"testing"
 
+	"github.com/docker/machine/drivers/fakedriver"
 	_ "github.com/docker/machine/drivers/none"
 	"github.com/docker/machine/libmachine/auth"
 	"github.com/docker/machine/libmachine/engine"
 	"github.com/docker/machine/libmachine/swarm"
+
+	"github.com/stretchr/testify/assert"
 )
 
 const (
@@ -22,8 +27,13 @@ const (
 
 var (
 	hostTestStorePath string
+	stdout            *os.File
 )
 
+func init() {
+	stdout = os.Stdout
+}
+
 func getTestStore() (Store, error) {
 	tmpDir, err := ioutil.TempDir("", "machine-test-")
 	if err != nil {
@@ -39,6 +49,7 @@ func getTestStore() (Store, error) {
 }
 
 func cleanup() {
+	os.Stdout = stdout
 	os.RemoveAll(hostTestStorePath)
 }
 
@@ -124,7 +135,7 @@ func TestValidateHostnameValid(t *testing.T) {
 	for _, v := range hosts {
 		isValid := ValidateHostName(v)
 		if !isValid {
-			t.Fatal("Thought a valid hostname was invalid: %s", v)
+			t.Fatalf("Thought a valid hostname was invalid: %s", v)
 		}
 	}
 }
@@ -139,7 +150,7 @@ func TestValidateHostnameInvalid(t *testing.T) {
 	for _, v := range hosts {
 		isValid := ValidateHostName(v)
 		if isValid {
-			t.Fatal("Thought an invalid hostname was valid: %s", v)
+			t.Fatalf("Thought an invalid hostname was valid: %s", v)
 		}
 	}
 }
@@ -172,3 +183,46 @@ func TestHostOptions(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+func TestPrintIPEmptyGivenLocalEngine(t *testing.T) {
+	defer cleanup()
+	host, _ := getDefaultTestHost()
+
+	out, w := captureStdout()
+
+	assert.Nil(t, host.PrintIP())
+	w.Close()
+
+	assert.Equal(t, "", strings.TrimSpace(<-out))
+}
+
+func TestPrintIPPrintsGivenRemoteEngine(t *testing.T) {
+	defer cleanup()
+	host, _ := getDefaultTestHost()
+	host.Driver = &fakedriver.FakeDriver{}
+
+	out, w := captureStdout()
+
+	assert.Nil(t, host.PrintIP())
+
+	w.Close()
+
+	assert.Equal(t, "1.2.3.4", strings.TrimSpace(<-out))
+}
+
+func captureStdout() (chan string, *os.File) {
+	r, w, _ := os.Pipe()
+
+	// This is reversed in cleanup()
+	os.Stdout = w
+
+	out := make(chan string)
+
+	go func() {
+		var testOutput bytes.Buffer
+		io.Copy(&testOutput, r)
+		out <- testOutput.String()
+	}()
+
+	return out, w
+}