add timeout for b2d release check; warn instead of error if cannot check

Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>

drivers/virtualbox/virtualbox.go

@@ -143,7 +143,7 @@ func (d *Driver) Create() error {
 		// until then always use "latest"
 		isoURL, err = utils.GetLatestBoot2DockerReleaseURL()
 		if err != nil {
-			return err
+			log.Warnf("Unable to check for the latest release: %s", err)
 		}
 
 		// todo: use real constant for .docker

drivers/vmwarefusion/fusion.go

@@ -151,7 +151,7 @@ func (d *Driver) Create() error {
 		// until then always use "latest"
 		isoURL, err = utils.GetLatestBoot2DockerReleaseURL()
 		if err != nil {
-			return err
+			log.Warnf("Unable to check for the latest release: %s", err)
 		}
 
 		// todo: use real constant for .docker

drivers/vmwarevsphere/vsphere.go

@@ -245,7 +245,7 @@ func (d *Driver) Create() error {
 		// until then always use "latest"
 		isoURL, err = utils.GetLatestBoot2DockerReleaseURL()
 		if err != nil {
-			return err
+			log.Warnf("Unable to check for the latest release: %s", err)
 		}
 
 		rootPath := utils.GetDockerDir()

utils/b2d.go

@@ -5,15 +5,33 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"net"
 	"net/http"
 	"os"
 	"path/filepath"
+	"time"
 )
 
+const (
+	timeout = time.Second * 5
+)
+
+func defaultTimeout(network, addr string) (net.Conn, error) {
+	return net.DialTimeout(network, addr, timeout)
+}
+
 // Get the latest boot2docker release tag name (e.g. "v0.6.0").
 // FIXME: find or create some other way to get the "latest release" of boot2docker since the GitHub API has a pretty low rate limit on API requests
 func GetLatestBoot2DockerReleaseURL() (string, error) {
-	rsp, err := http.Get("https://api.github.com/repos/boot2docker/boot2docker/releases")
+	transport := http.Transport{
+		Dial: defaultTimeout,
+	}
+
+	client := http.Client{
+		Transport: &transport,
+	}
+
+	rsp, err := client.Get("https://api.github.com/repos/boot2docker/boot2docker/releases")
 	if err != nil {
 		return "", err
 	}