Removes github.com/hashicorp/go-cleanhttp dependency

client.go

@@ -24,6 +24,7 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
+	"runtime"
 	"strconv"
 	"strings"
 	"sync/atomic"
@@ -33,7 +34,6 @@ import (
 	"github.com/docker/docker/pkg/homedir"
 	"github.com/docker/docker/pkg/jsonmessage"
 	"github.com/docker/docker/pkg/stdcopy"
-	"github.com/hashicorp/go-cleanhttp"
 	"golang.org/x/net/context"
 	"golang.org/x/net/context/ctxhttp"
 )
@@ -212,7 +212,7 @@ func NewVersionedClient(endpoint string, apiVersionString string) (*Client, erro
 		}
 	}
 	c := &Client{
-		HTTPClient:          cleanhttp.DefaultClient(),
+		HTTPClient:          defaultClient(),
 		Dialer:              &net.Dialer{},
 		endpoint:            endpoint,
 		endpointURL:         u,
@@ -326,7 +326,7 @@ func NewVersionedTLSClientFromBytes(endpoint string, certPEMBlock, keyPEMBlock,
 		}
 		tlsConfig.RootCAs = caPool
 	}
-	tr := cleanhttp.DefaultTransport()
+	tr := defaultTransport()
 	tr.TLSClientConfig = tlsConfig
 	if err != nil {
 		return nil, err
@@ -1040,3 +1040,41 @@ func getDockerEnv() (*dockerEnv, error) {
 		dockerCertPath:  dockerCertPath,
 	}, nil
 }
+
+// defaultTransport returns a new http.Transport with similar default values to
+// http.DefaultTransport, but with idle connections and keepalives disabled.
+func defaultTransport() *http.Transport {
+	transport := defaultPooledTransport()
+	transport.DisableKeepAlives = true
+	transport.MaxIdleConnsPerHost = -1
+	return transport
+}
+
+// defaultPooledTransport returns a new http.Transport with similar default
+// values to http.DefaultTransport. Do not use this for transient transports as
+// it can leak file descriptors over time. Only use this for transports that
+// will be re-used for the same host(s).
+func defaultPooledTransport() *http.Transport {
+	transport := &http.Transport{
+		Proxy: http.ProxyFromEnvironment,
+		DialContext: (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 30 * time.Second,
+		}).DialContext,
+		MaxIdleConns:          100,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+		MaxIdleConnsPerHost:   runtime.GOMAXPROCS(0) + 1,
+	}
+	return transport
+}
+
+// defaultClient returns a new http.Client with similar default values to
+// http.Client, but with a non-shared Transport, idle connections disabled, and
+// keepalives disabled.
+func defaultClient() *http.Client {
+	return &http.Client{
+		Transport: defaultTransport(),
+	}
+}

client_unix.go

@@ -10,8 +10,6 @@ import (
 	"context"
 	"net"
 	"net/http"
-
-	"github.com/hashicorp/go-cleanhttp"
 )
 
 // initializeNativeClient initializes the native Unix domain socket client on
@@ -21,7 +19,7 @@ func (c *Client) initializeNativeClient() {
 		return
 	}
 	socketPath := c.endpointURL.Path
-	tr := cleanhttp.DefaultTransport()
+	tr := defaultTransport()
 	tr.Dial = func(network, addr string) (net.Conn, error) {
 		return c.Dialer.Dial(unixProtocol, socketPath)
 	}

client_windows.go

@@ -13,7 +13,6 @@ import (
 	"time"
 
 	"github.com/Microsoft/go-winio"
-	"github.com/hashicorp/go-cleanhttp"
 )
 
 const namedPipeConnectTimeout = 2 * time.Second
@@ -36,7 +35,7 @@ func (c *Client) initializeNativeClient() {
 		timeout := namedPipeConnectTimeout
 		return winio.DialPipe(namedPipePath, &timeout)
 	}
-	tr := cleanhttp.DefaultTransport()
+	tr := defaultTransport()
 	tr.Dial = dialFunc
 	tr.DialContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
 		return dialFunc(network, addr)

container_unix_test.go

@@ -15,8 +15,6 @@ import (
 	"path/filepath"
 	"testing"
 	"time"
-
-	"github.com/hashicorp/go-cleanhttp"
 )
 
 func TestExportContainerViaUnixSocket(t *testing.T) {
@@ -29,7 +27,7 @@ func TestExportContainerViaUnixSocket(t *testing.T) {
 	endpoint := "unix://" + tempSocket
 	u, _ := parseEndpoint(endpoint, false)
 	client := Client{
-		HTTPClient:             cleanhttp.DefaultClient(),
+		HTTPClient:             defaultClient(),
 		Dialer:                 &net.Dialer{},
 		endpoint:               endpoint,
 		endpointURL:            u,