Call plugins with custom transports.

Small refactor to be able to use custom transports
to call remote plugins.

Signed-off-by: David Calavera <david.calavera@gmail.com>

plugins/client.go

@@ -6,17 +6,17 @@ import (
 	"io"
 	"io/ioutil"
 	"net/http"
-	"strings"
+	"net/url"
 	"time"
 
 	"github.com/Sirupsen/logrus"
+	"github.com/docker/docker/pkg/plugins/transport"
 	"github.com/docker/go-connections/sockets"
 	"github.com/docker/go-connections/tlsconfig"
 )
 
 const (
-	versionMimetype = "application/vnd.docker.plugins.v1.2+json"
-	defaultTimeOut  = 30
+	defaultTimeOut = 30
 )
 
 // NewClient creates a new plugin client (http).
@@ -29,23 +29,38 @@ func NewClient(addr string, tlsConfig tlsconfig.Options) (*Client, error) {
 	}
 	tr.TLSClientConfig = c
 
-	protoAndAddr := strings.Split(addr, "://")
-	if err := sockets.ConfigureTransport(tr, protoAndAddr[0], protoAndAddr[1]); err != nil {
+	u, err := url.Parse(addr)
+	if err != nil {
 		return nil, err
 	}
-
-	scheme := protoAndAddr[0]
-	if scheme != "https" {
-		scheme = "http"
+	socket := u.Host
+	if socket == "" {
+		// valid local socket addresses have the host empty.
+		socket = u.Path
+	}
+	if err := sockets.ConfigureTransport(tr, u.Scheme, socket); err != nil {
+		return nil, err
+	}
+	scheme := httpScheme(u)
+
+	clientTransport := transport.NewHTTPTransport(tr, scheme, socket)
+	return NewClientWithTransport(clientTransport), nil
+}
+
+// NewClientWithTransport creates a new plugin client with a given transport.
+func NewClientWithTransport(tr transport.Transport) *Client {
+	return &Client{
+		http: &http.Client{
+			Transport: tr,
+		},
+		requestFactory: tr,
 	}
-	return &Client{&http.Client{Transport: tr}, scheme, protoAndAddr[1]}, nil
 }
 
 // Client represents a plugin client.
 type Client struct {
-	http   *http.Client // http client to use
-	scheme string       // scheme protocol of the plugin
-	addr   string       // http address of the plugin
+	http           *http.Client // http client to use
+	requestFactory transport.RequestFactory
 }
 
 // Call calls the specified method with the specified arguments for the plugin.
@@ -94,13 +109,10 @@ func (c *Client) SendFile(serviceMethod string, data io.Reader, ret interface{})
 }
 
 func (c *Client) callWithRetry(serviceMethod string, data io.Reader, retry bool) (io.ReadCloser, error) {
-	req, err := http.NewRequest("POST", "/"+serviceMethod, data)
+	req, err := c.requestFactory.NewRequest(serviceMethod, data)
 	if err != nil {
 		return nil, err
 	}
-	req.Header.Add("Accept", versionMimetype)
-	req.URL.Scheme = c.scheme
-	req.URL.Host = c.addr
 
 	var retries int
 	start := time.Now()
@@ -117,7 +129,7 @@ func (c *Client) callWithRetry(serviceMethod string, data io.Reader, retry bool)
 				return nil, err
 			}
 			retries++
-			logrus.Warnf("Unable to connect to plugin: %s, retrying in %v", c.addr, timeOff)
+			logrus.Warnf("Unable to connect to plugin: %s, retrying in %v", req.URL, timeOff)
 			time.Sleep(timeOff)
 			continue
 		}
@@ -163,3 +175,11 @@ func backoff(retries int) time.Duration {
 func abort(start time.Time, timeOff time.Duration) bool {
 	return timeOff+time.Since(start) >= time.Duration(defaultTimeOut)*time.Second
 }
+
+func httpScheme(u *url.URL) string {
+	scheme := u.Scheme
+	if scheme != "https" {
+		scheme = "http"
+	}
+	return scheme
+}