@@ -7,13 +7,11 @@ import (

 	"fmt"

 	"io"

 	"net/http"

-	"path/filepath"

 	"reflect"

 	"strings"

 	"text/template"

 	"github.com/docker/docker/cliconfig"

-	"github.com/docker/docker/pkg/homedir"

 	flag "github.com/docker/docker/pkg/mflag"

 	"github.com/docker/docker/pkg/sockets"

 	"github.com/docker/docker/pkg/term"

@@ -212,7 +210,7 @@ func NewDockerCli(in io.ReadCloser, out, err io.Writer, keyFile string, proto, a

 	}

 	sockets.ConfigureTCPTransport(tr, proto, addr)

-	configFile, e := cliconfig.Load(filepath.Join(homedir.Get(), ".docker"))

+	configFile, e := cliconfig.Load(cliconfig.ConfigDir())

 	if e != nil {

 		fmt.Fprintf(err, "WARNING: Error loading config file:%v\n", e)

 	}

@@ -25,9 +25,24 @@ const (

 )

 var (

+	configDir            = os.Getenv("DOCKER_CONFIG")

 	ErrConfigFileMissing = errors.New("The Auth config file is missing")

 )

+func init() {

+	if configDir == "" {

+		configDir = filepath.Join(homedir.Get(), ".docker")

+	}

+}

+

+func ConfigDir() string {

+	return configDir

+}

+

+func SetConfigDir(dir string) {

+	configDir = dir

+}

+

 // Registry Auth Info

 type AuthConfig struct {

 	Username      string `json:"username,omitempty"`

@@ -56,7 +71,7 @@ func NewConfigFile(fn string) *ConfigFile {

 // FIXME: use the internal golang config parser

 func Load(configDir string) (*ConfigFile, error) {

 	if configDir == "" {

-		configDir = filepath.Join(homedir.Get(), ".docker")

+		configDir = ConfigDir()

 	}

 	configFile := ConfigFile{

@@ -13,8 +13,8 @@ import (

 	"github.com/Sirupsen/logrus"

 	apiserver "github.com/docker/docker/api/server"

 	"github.com/docker/docker/autogen/dockerversion"

+	"github.com/docker/docker/cliconfig"

 	"github.com/docker/docker/daemon"

-	"github.com/docker/docker/pkg/homedir"

 	flag "github.com/docker/docker/pkg/mflag"

 	"github.com/docker/docker/pkg/pidfile"

 	"github.com/docker/docker/pkg/signal"

@@ -39,7 +39,7 @@ func init() {

 func migrateKey() (err error) {

 	// Migrate trust key if exists at ~/.docker/key.json and owned by current user

-	oldPath := filepath.Join(homedir.Get(), ".docker", defaultTrustKeyFile)

+	oldPath := filepath.Join(cliconfig.ConfigDir(), defaultTrustKeyFile)

 	newPath := filepath.Join(getDaemonConfDir(), defaultTrustKeyFile)

 	if _, statErr := os.Stat(newPath); os.IsNotExist(statErr) && currentUserIsOwner(oldPath) {

 		defer func() {

@@ -10,6 +10,7 @@ import (

 	"github.com/Sirupsen/logrus"

 	"github.com/docker/docker/api/client"

 	"github.com/docker/docker/autogen/dockerversion"

+	"github.com/docker/docker/cliconfig"

 	"github.com/docker/docker/opts"

 	flag "github.com/docker/docker/pkg/mflag"

 	"github.com/docker/docker/pkg/reexec"

@@ -43,6 +44,10 @@ func main() {

 		return

 	}

+	if *flConfigDir != "" {

+		cliconfig.SetConfigDir(*flConfigDir)

+	}

+

 	if *flLogLevel != "" {

 		lvl, err := logrus.ParseLevel(*flLogLevel)

 		if err != nil {

@@ -7,8 +7,8 @@ import (

 	"runtime"

 	"sort"

+	"github.com/docker/docker/cliconfig"

 	"github.com/docker/docker/opts"

-	"github.com/docker/docker/pkg/homedir"

 	flag "github.com/docker/docker/pkg/mflag"

 	"github.com/docker/docker/pkg/tlsconfig"

 )

@@ -73,19 +73,20 @@ var (

 func init() {

 	if dockerCertPath == "" {

-		dockerCertPath = filepath.Join(homedir.Get(), ".docker")

+		dockerCertPath = cliconfig.ConfigDir()

 	}

 }

 func getDaemonConfDir() string {

 	// TODO: update for Windows daemon

 	if runtime.GOOS == "windows" {

-		return filepath.Join(homedir.Get(), ".docker")

+		return cliconfig.ConfigDir()

 	}

 	return "/etc/docker"

 }

 var (

+	flConfigDir = flag.String([]string{"-config"}, cliconfig.ConfigDir(), "Location of client config files")

 	flVersion   = flag.Bool([]string{"v", "-version"}, false, "Print version information and quit")

 	flDaemon    = flag.Bool([]string{"d", "-daemon"}, false, "Enable daemon mode")

 	flDebug     = flag.Bool([]string{"D", "-debug"}, false, "Enable debug mode")

@@ -105,7 +106,7 @@ func setDefaultConfFlag(flag *string, def string) {

 		if *flDaemon {

 			*flag = filepath.Join(getDaemonConfDir(), def)

 		} else {

-			*flag = filepath.Join(homedir.Get(), ".docker", def)

+			*flag = filepath.Join(cliconfig.ConfigDir(), def)

 		}

 	}

 }

@@ -10,7 +10,7 @@ parent = "smn_cli"

 # Using the command line

-> **Note:** if you are using a remote Docker daemon, such as Boot2Docker, 

+> **Note:** If you are using a remote Docker daemon, such as Boot2Docker,

 > then _do not_ type the `sudo` before the `docker` commands shown in the

 > documentation's examples.

@@ -38,6 +38,7 @@ the [installation](/installation) instructions for your operating system.

 For easy reference, the following list of environment variables are supported

 by the `docker` command line:

+* `DOCKER_CONFIG` The location of your client configuration files.

 * `DOCKER_CERT_PATH` The location of your authentication keys.

 * `DOCKER_DRIVER` The graph driver to use.

 * `DOCKER_HOST` Daemon socket to connect to.

@@ -60,10 +61,21 @@ variables.

 ## Configuration files

-The Docker command line stores its configuration files in a directory called

-`.docker` within your `HOME` directory. Docker manages most of the files in

-`.docker` and you should not modify them. However, you *can modify* the

-`.docker/config.json` file to control certain aspects of how the `docker`

+By default, the Docker command line stores its configuration files in a

+directory called `.docker` within your `HOME` directory. However, you can

+specify a different location via the `DOCKER_CONFIG` environment variable

+or the `--config` command line option. If both are specified, then the

+`--config` option overrides the `DOCKER_CONFIG` environment variable.

+For example:

+

+    docker --config ~/testconfigs/ ps

+

+Instructs Docker to use the configuration files in your `~/testconfigs/`

+directory when running the `ps` command.

+

+Docker manages most of the files in the configuration directory

+and you should not modify them. However, you *can modify* the

+`config.json` file to control certain aspects of how the `docker`

 command behaves.

 Currently, you can modify the `docker` command behavior using environment

@@ -18,6 +18,7 @@ parent = "smn_cli"

       --api-cors-header=""                   Set CORS headers in the remote API

       -b, --bridge=""                        Attach containers to a network bridge

       --bip=""                               Specify network bridge IP

+      --config=~/.docker                     Location of client config files

       -D, --debug=false                      Enable debug mode

       -d, --daemon=false                     Enable daemon mode

       --default-gateway=""                   Container default gateway IPv4 address

@@ -64,3 +64,85 @@ func (s *DockerSuite) TestConfigHttpHeader(c *check.C) {

 		c.Fatalf("Missing/bad header: %q\nout:%v", headers, out)

 	}

 }

+

+func (s *DockerSuite) TestConfigDir(c *check.C) {

+	cDir, _ := ioutil.TempDir("", "fake-home")

+

+	// First make sure pointing to empty dir doesn't generate an error

+	cmd := exec.Command(dockerBinary, "--config", cDir, "ps")

+	out, rc, err := runCommandWithOutput(cmd)

+

+	if rc != 0 || err != nil {

+		c.Fatalf("ps1 didn't work:\nrc:%d\nout%s\nerr:%v", rc, out, err)

+	}

+

+	// Test with env var too

+	cmd = exec.Command(dockerBinary, "ps")

+	cmd.Env = append(os.Environ(), "DOCKER_CONFIG="+cDir)

+	out, rc, err = runCommandWithOutput(cmd)

+

+	if rc != 0 || err != nil {

+		c.Fatalf("ps2 didn't work:\nrc:%d\nout%s\nerr:%v", rc, out, err)

+	}

+

+	// Start a server so we can check to see if the config file was

+	// loaded properly

+	var headers map[string][]string

+

+	server := httptest.NewServer(http.HandlerFunc(

+		func(w http.ResponseWriter, r *http.Request) {

+			headers = r.Header

+		}))

+	defer server.Close()

+

+	// Create a dummy config file in our new config dir

+	data := `{

+		"HttpHeaders": { "MyHeader": "MyValue" }

+	}`

+

+	tmpCfg := filepath.Join(cDir, "config.json")

+	err = ioutil.WriteFile(tmpCfg, []byte(data), 0600)

+	if err != nil {

+		c.Fatalf("Err creating file(%s): %v", tmpCfg, err)

+	}

+

+	cmd = exec.Command(dockerBinary, "--config", cDir, "-H="+server.URL[7:], "ps")

+	out, _, _ = runCommandWithOutput(cmd)

+

+	if headers["Myheader"] == nil || headers["Myheader"][0] != "MyValue" {

+		c.Fatalf("ps3 - Missing header: %q\nout:%v", headers, out)

+	}

+

+	// Reset headers and try again using env var this time

+	headers = map[string][]string{}

+	cmd = exec.Command(dockerBinary, "-H="+server.URL[7:], "ps")

+	cmd.Env = append(os.Environ(), "DOCKER_CONFIG="+cDir)

+	out, _, _ = runCommandWithOutput(cmd)

+

+	if headers["Myheader"] == nil || headers["Myheader"][0] != "MyValue" {

+		c.Fatalf("ps4 - Missing header: %q\nout:%v", headers, out)

+	}

+

+	// Reset headers and make sure flag overrides the env var

+	headers = map[string][]string{}

+	cmd = exec.Command(dockerBinary, "--config", cDir, "-H="+server.URL[7:], "ps")

+	cmd.Env = append(os.Environ(), "DOCKER_CONFIG=MissingDir")

+	out, _, _ = runCommandWithOutput(cmd)

+

+	if headers["Myheader"] == nil || headers["Myheader"][0] != "MyValue" {

+		c.Fatalf("ps5 - Missing header: %q\nout:%v", headers, out)

+	}

+

+	// Reset headers and make sure flag overrides the env var.

+	// Almost same as previous but make sure the "MissingDir" isn't

+	// ignore - we don't want to default back to the env var.

+	headers = map[string][]string{}

+	cmd = exec.Command(dockerBinary, "--config", "MissingDir", "-H="+server.URL[7:], "ps")

+	cmd.Env = append(os.Environ(), "DOCKER_CONFIG="+cDir)

+	out, _, _ = runCommandWithOutput(cmd)

+

+	if headers["Myheader"] != nil {

+		c.Fatalf("ps6 - Headers are there but shouldn't be: %q\nout:%v", headers, out)

+	}

+

+}

@@ -35,6 +35,9 @@ To see the man page for a command run **man docker <command>**.

 **--bip**=""

   Use the provided CIDR notation address for the dynamically created bridge (docker0); Mutually exclusive of \-b

+**--config**=""

+  Specifies the location of the Docker client configuration files. The default is '~/.docker'.

+

 **-D**, **--debug**=*true*|*false*

   Enable debug mode. Default is false.