Fix Issue 44 - Get the docker client from the tgz file

go/src/gosetup/main.go

@@ -1,19 +1,27 @@
 package main
 
 import (
+	"archive/tar"
+	"compress/gzip"
+	"github.com/Sirupsen/logrus"
+	"github.com/samalba/dockerclient"
+	"io"
+	"net/http"
 	"os"
 	"path"
-	"net/http"
-	"io"
+	"strconv"
+	"strings"
+)
 
-	"github.com/Sirupsen/logrus"
-	"github.com/samalba/dockerclient"
+const (
+	baseURL = "https://get.docker.com/builds/Linux/x86_64"
 )
 
 // instance of DockerClient allowing for making calls to the docker daemon
 // remote API
 var dockerClient *dockerclient.DockerClient
 
+type copier func(out *os.File, resp *http.Response)
 
 func main() {
 
@@ -32,14 +40,14 @@ func main() {
 	}
 	dockerDaemonVersion := version.Version
 
-	// name of docker binary that is needed 
+	// name of docker binary that is needed
 	dockerBinaryName := "docker-" + dockerDaemonVersion
 	logrus.Println("looking for docker binary named:", dockerBinaryName)
 
 	filename := path.Join("/bin", dockerBinaryName)
-	
+
 	if _, err := os.Stat(filename); os.IsNotExist(err) {
-		
+
 		logrus.Println("docker binary (version " + dockerDaemonVersion + ") not found.")
 		logrus.Println("downloading", dockerBinaryName, "...")
 
@@ -48,20 +56,95 @@ func main() {
 			logrus.Fatal(err.Error())
 		}
 		defer out.Close()
-		resp, err := http.Get("https://get.docker.com/builds/Linux/x86_64/docker-" + dockerDaemonVersion)
+
+		versionComp, err := CompareVersions(dockerDaemonVersion, "1.11.0")
 		if err != nil {
 			logrus.Fatal(err.Error())
 		}
-		defer resp.Body.Close()
-
-		_, err = io.Copy(out, resp.Body)
+
+		if versionComp >= 0 {
+			getClient(out, "https://get.docker.com/builds/Linux/x86_64/docker-"+dockerDaemonVersion+".tgz", extractClient)
+		} else {
+			getClient(out, "https://get.docker.com/builds/Linux/x86_64/docker-"+dockerDaemonVersion, copyClient)
+		}
+
+		err = os.Chmod(filename, 0700)
 		if err != nil {
 			logrus.Fatal(err.Error())
 		}
+	}
+}
 
-		err = os.Chmod(filename, 0700)
+func CompareVersions(v1 string, v2 string) (comp int, err error) {
+	v1Parts := strings.Split(v1, ".")
+	v2Parts := strings.Split(v2, ".")
+
+	for i := 0; i < len(v1Parts) && i < len(v2Parts); i++ {
+		v1int, err := strconv.Atoi(v1Parts[i])
+		if err != nil {
+			return -2, err
+		}
+
+		v2int, err := strconv.Atoi(v2Parts[i])
+		if err != nil {
+			return -2, err
+		}
+
+		if v1int < v2int {
+			return -1, nil
+		} else if v1int > v2int {
+			return 1, nil
+		}
+	}
+
+	if len(v1Parts) < len(v2Parts) {
+		return -1, nil
+	} else if len(v1Parts) > len(v2Parts) {
+		return 1, nil
+	}
+	return 0, nil
+}
+
+func copyClient(out *os.File, resp *http.Response) {
+	_, err := io.Copy(out, resp.Body)
+	if err != nil {
+		logrus.Fatal(err.Error())
+	}
+}
+
+func extractClient(out *os.File, resp *http.Response) {
+	gr, err := gzip.NewReader(resp.Body)
+	defer gr.Close()
+	if err != nil {
+		logrus.Fatal(err.Error())
+	}
+
+	tr := tar.NewReader(gr)
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
 		if err != nil {
 			logrus.Fatal(err.Error())
 		}
-    }
+
+		if hdr.Typeflag == tar.TypeReg && hdr.Name == "docker/docker" {
+			_, err = io.Copy(out, tr)
+			if err != nil {
+				logrus.Fatal(err.Error())
+			}
+			break
+		}
+		logrus.Println("not yet")
+	}
+}
+
+func getClient(out *os.File, URL string, cp copier) {
+	resp, err := http.Get(URL)
+	if err != nil {
+		logrus.Fatal(err.Error())
+	}
+	defer resp.Body.Close()
+	cp(out, resp)
 }