@@ -21,6 +21,6 @@ func (cli *Client) ContainerStats(ctx context.Context, containerID string, strea

 		return types.ContainerStats{}, err

 	}

-	osType := GetDockerOS(resp.header.Get("Server"))

+	osType := getDockerOS(resp.header.Get("Server"))

 	return types.ContainerStats{Body: resp.body, OSType: osType}, err

 }

@@ -6,7 +6,6 @@ import (

 	"io"

 	"net/http"

 	"net/url"

-	"regexp"

 	"strconv"

 	"golang.org/x/net/context"

@@ -15,8 +14,6 @@ import (

 	"github.com/docker/docker/api/types/container"

 )

-var headerRegexp = regexp.MustCompile(`\ADocker/.+\s\((.+)\)\z`)

-

 // ImageBuild sends request to the daemon to build images.

 // The Body in the response implement an io.ReadCloser and it's up to the caller to

 // close it.

@@ -39,7 +36,7 @@ func (cli *Client) ImageBuild(ctx context.Context, buildContext io.Reader, optio

 		return types.ImageBuildResponse{}, err

 	}

-	osType := GetDockerOS(serverResp.header.Get("Server"))

+	osType := getDockerOS(serverResp.header.Get("Server"))

 	return types.ImageBuildResponse{

 		Body:   serverResp.body,

@@ -124,13 +121,3 @@ func (cli *Client) imageBuildOptionsToQuery(options types.ImageBuildOptions) (ur

 	return query, nil

 }

-

-// GetDockerOS returns the operating system based on the server header from the daemon.

-func GetDockerOS(serverHeader string) string {

-	var osType string

-	matches := headerRegexp.FindStringSubmatch(serverHeader)

-	if len(matches) > 0 {

-		osType = matches[1]

-	}

-	return osType

-}

@@ -222,7 +222,7 @@ func TestGetDockerOS(t *testing.T) {

 		"Foo/v1.22 (bar)":        "",

 	}

 	for header, os := range cases {

-		g := GetDockerOS(header)

+		g := getDockerOS(header)

 		if g != os {

 			t.Fatalf("Expected %s, got %s", os, g)

 		}

new file mode 100644

@@ -0,0 +1,15 @@

+package client

+

+import "regexp"

+

+var headerRegexp = regexp.MustCompile(`\ADocker/.+\s\((.+)\)\z`)

+

+// getDockerOS returns the operating system based on the server header from the daemon.

+func getDockerOS(serverHeader string) string {

+	var osType string

+	matches := headerRegexp.FindStringSubmatch(serverHeader)

+	if len(matches) > 0 {

+		osType = matches[1]

+	}

+	return osType

+}