adding ip as an option for flags

Signed-off-by: Isabel Jimenez <contact.isabeljimenez@gmail.com>

cluster/options.go

@@ -1,6 +1,7 @@
 package cluster
 
 import (
+	"net"
 	"os"
 	"strconv"
 	"strings"
@@ -49,3 +50,11 @@ func (do DriverOpts) Float(key, env string) (float64, bool) {
 	}
 	return 0.0, false
 }
+
+// IP returns an IP address from the driver options
+func (do DriverOpts) IP(key, env string) (net.IP, bool) {
+	if value, ok := do.String(key, env); ok {
+		return net.ParseIP(value), true
+	}
+	return nil, false
+}

cluster/options_test.go

@@ -1,13 +1,14 @@
 package cluster
 
 import (
+	"net"
 	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
-var opts = DriverOpts{"foo1=bar", "foo2=-5", "foo3=7", "foo4=0.6"}
+var opts = DriverOpts{"foo1=bar", "foo2=-5", "foo3=7", "foo4=0.6", "foo5=127.0.0.1"}
 
 func TestString(t *testing.T) {
 	os.Setenv("FOO_4", "bar")
@@ -125,3 +126,20 @@ func TestFloat(t *testing.T) {
 	assert.False(t, ok)
 	assert.Equal(t, val, 0.0)
 }
+
+func TestIP(t *testing.T) {
+	os.Setenv("FOO_4", "0.0.0.0")
+	defer os.Setenv("FOO_4", "")
+
+	val, ok := opts.IP("foo5", "")
+	assert.True(t, ok)
+	assert.Equal(t, val, net.ParseIP("127.0.0.1"))
+
+	val, ok = opts.IP("", "FOO_4")
+	assert.True(t, ok)
+	assert.Equal(t, val, net.ParseIP("0.0.0.0"))
+
+	val, ok = opts.IP("invalid", "")
+	assert.False(t, ok)
+	assert.Equal(t, val, net.IP(nil))
+}