@@ -11,7 +11,6 @@ import (

 	"github.com/Sirupsen/logrus"

 	Cli "github.com/docker/docker/cli"

-	derr "github.com/docker/docker/errors"

 	"github.com/docker/docker/opts"

 	"github.com/docker/docker/pkg/promise"

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

@@ -21,6 +20,11 @@ import (

 	"github.com/docker/libnetwork/resolvconf/dns"

 )

+const (

+	errCmdNotFound          = "Container command not found or does not exist."

+	errCmdCouldNotBeInvoked = "Container command could not be invoked."

+)

+

 func (cid *cidFile) Close() error {

 	cid.file.Close()

@@ -46,20 +50,13 @@ func (cid *cidFile) Write(id string) error {

 // return 125 for generic docker daemon failures

 func runStartContainerErr(err error) error {

 	trimmedErr := strings.Trim(err.Error(), "Error response from daemon: ")

-	statusError := Cli.StatusError{}

-	derrCmdNotFound := derr.ErrorCodeCmdNotFound.Message()

-	derrCouldNotInvoke := derr.ErrorCodeCmdCouldNotBeInvoked.Message()

-	derrNoSuchImage := derr.ErrorCodeNoSuchImageHash.Message()

-	derrNoSuchImageTag := derr.ErrorCodeNoSuchImageTag.Message()

+	statusError := Cli.StatusError{StatusCode: 125}

+

 	switch trimmedErr {

-	case derrCmdNotFound:

+	case errCmdNotFound:

 		statusError = Cli.StatusError{StatusCode: 127}

-	case derrCouldNotInvoke:

+	case errCmdCouldNotBeInvoked:

 		statusError = Cli.StatusError{StatusCode: 126}

-	case derrNoSuchImage, derrNoSuchImageTag:

-		statusError = Cli.StatusError{StatusCode: 125}

-	default:

-		statusError = Cli.StatusError{StatusCode: 125}

 	}

 	return statusError

 }

new file mode 100644

@@ -0,0 +1,69 @@

+package httputils

+

+import (

+	"net/http"

+	"strings"

+

+	"github.com/Sirupsen/logrus"

+)

+

+// httpStatusError is an interface

+// that errors with custom status codes

+// implement to tell the api layer

+// which response status to set.

+type httpStatusError interface {

+	HTTPErrorStatusCode() int

+}

+

+// inputValidationError is an interface

+// that errors generated by invalid

+// inputs can implement to tell the

+// api layer to set a 400 status code

+// in the response.

+type inputValidationError interface {

+	IsValidationError() bool

+}

+

+// WriteError decodes a specific docker error and sends it in the response.

+func WriteError(w http.ResponseWriter, err error) {

+	if err == nil || w == nil {

+		logrus.WithFields(logrus.Fields{"error": err, "writer": w}).Error("unexpected HTTP error handling")

+		return

+	}

+

+	var statusCode int

+	errMsg := err.Error()

+

+	switch e := err.(type) {

+	case httpStatusError:

+		statusCode = e.HTTPErrorStatusCode()

+	case inputValidationError:

+		statusCode = http.StatusBadRequest

+	default:

+		// FIXME: this is brittle and should not be necessary, but we still need to identify if

+		// there are errors falling back into this logic.

+		// If we need to differentiate between different possible error types,

+		// we should create appropriate error types that implement the httpStatusError interface.

+		errStr := strings.ToLower(errMsg)

+		for keyword, status := range map[string]int{

+			"not found":             http.StatusNotFound,

+			"no such":               http.StatusNotFound,

+			"bad parameter":         http.StatusBadRequest,

+			"conflict":              http.StatusConflict,

+			"impossible":            http.StatusNotAcceptable,

+			"wrong login/password":  http.StatusUnauthorized,

+			"hasn't been activated": http.StatusForbidden,

+		} {

+			if strings.Contains(errStr, keyword) {

+				statusCode = status

+				break

+			}

+		}

+	}

+

+	if statusCode == 0 {

+		statusCode = http.StatusInternalServerError

+	}

+

+	http.Error(w, errMsg, statusCode)

+}

@@ -9,8 +9,6 @@ import (

 	"golang.org/x/net/context"

-	"github.com/Sirupsen/logrus"

-	"github.com/docker/distribution/registry/api/errcode"

 	"github.com/docker/docker/api"

 	"github.com/docker/docker/pkg/version"

 )

@@ -85,78 +83,6 @@ func ParseMultipartForm(r *http.Request) error {

 	return nil

 }

-// WriteError decodes a specific docker error and sends it in the response.

-func WriteError(w http.ResponseWriter, err error) {

-	if err == nil || w == nil {

-		logrus.WithFields(logrus.Fields{"error": err, "writer": w}).Error("unexpected HTTP error handling")

-		return

-	}

-

-	statusCode := http.StatusInternalServerError

-	errMsg := err.Error()

-

-	// Based on the type of error we get we need to process things

-	// slightly differently to extract the error message.

-	// In the 'errcode.*' cases there are two different type of

-	// error that could be returned. errocode.ErrorCode is the base

-	// type of error object - it is just an 'int' that can then be

-	// used as the look-up key to find the message. errorcode.Error

-	// extends errorcode.Error by adding error-instance specific

-	// data, like 'details' or variable strings to be inserted into

-	// the message.

-	//

-	// Ideally, we should just be able to call err.Error() for all

-	// cases but the errcode package doesn't support that yet.

-	//

-	// Additionally, in both errcode cases, there might be an http

-	// status code associated with it, and if so use it.

-	switch err.(type) {

-	case errcode.ErrorCode:

-		daError, _ := err.(errcode.ErrorCode)

-		statusCode = daError.Descriptor().HTTPStatusCode

-		errMsg = daError.Message()

-

-	case errcode.Error:

-		// For reference, if you're looking for a particular error

-		// then you can do something like :

-		//   import ( derr "github.com/docker/docker/errors" )

-		//   if daError.ErrorCode() == derr.ErrorCodeNoSuchContainer { ... }

-

-		daError, _ := err.(errcode.Error)

-		statusCode = daError.ErrorCode().Descriptor().HTTPStatusCode

-		errMsg = daError.Message

-

-	default:

-		// This part of will be removed once we've

-		// converted everything over to use the errcode package

-

-		// FIXME: this is brittle and should not be necessary.

-		// If we need to differentiate between different possible error types,

-		// we should create appropriate error types with clearly defined meaning

-		errStr := strings.ToLower(err.Error())

-		for keyword, status := range map[string]int{

-			"not found":             http.StatusNotFound,

-			"no such":               http.StatusNotFound,

-			"bad parameter":         http.StatusBadRequest,

-			"conflict":              http.StatusConflict,

-			"impossible":            http.StatusNotAcceptable,

-			"wrong login/password":  http.StatusUnauthorized,

-			"hasn't been activated": http.StatusForbidden,

-		} {

-			if strings.Contains(errStr, keyword) {

-				statusCode = status

-				break

-			}

-		}

-	}

-

-	if statusCode == 0 {

-		statusCode = http.StatusInternalServerError

-	}

-

-	http.Error(w, errMsg, statusCode)

-}

-

 // WriteJSON writes the value v to the http response stream as json with standard json encoding.

 func WriteJSON(w http.ResponseWriter, code int, v interface{}) error {

 	w.Header().Set("Content-Type", "application/json")

@@ -6,11 +6,18 @@ import (

 	"runtime"

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

-	"github.com/docker/docker/errors"

 	"github.com/docker/docker/pkg/version"

 	"golang.org/x/net/context"

 )

+type badRequestError struct {

+	error

+}

+

+func (badRequestError) HTTPErrorStatusCode() int {

+	return http.StatusBadRequest

+}

+

 // NewVersionMiddleware creates a new Version middleware.

 func NewVersionMiddleware(versionCheck string, defaultVersion, minVersion version.Version) Middleware {

 	serverVersion := version.Version(versionCheck)

@@ -23,10 +30,10 @@ func NewVersionMiddleware(versionCheck string, defaultVersion, minVersion versio

 			}

 			if apiVersion.GreaterThan(defaultVersion) {

-				return errors.ErrorCodeNewerClientVersion.WithArgs(apiVersion, defaultVersion)

+				return badRequestError{fmt.Errorf("client is newer than server (client API version: %s, server API version: %s)", apiVersion, defaultVersion)}

 			}

 			if apiVersion.LessThan(minVersion) {

-				return errors.ErrorCodeOldClientVersion.WithArgs(apiVersion, minVersion)

+				return badRequestError{fmt.Errorf("client version %s is too old. Minimum supported API version is %s, please upgrade your client to a newer version", apiVersion, minVersion)}

 			}

 			header := fmt.Sprintf("Docker/%s (%s)", serverVersion, runtime.GOOS)

@@ -53,12 +53,12 @@ func TestVersionMiddlewareWithErrors(t *testing.T) {

 	err := h(ctx, resp, req, vars)

 	if !strings.Contains(err.Error(), "client version 0.1 is too old. Minimum supported API version is 1.2.0") {

-		t.Fatalf("Expected ErrorCodeOldClientVersion, got %v", err)

+		t.Fatalf("Expected too old client error, got %v", err)

 	}

 	vars["version"] = "100000"

 	err = h(ctx, resp, req, vars)

 	if !strings.Contains(err.Error(), "client is newer than server") {

-		t.Fatalf("Expected ErrorCodeNewerClientVersion, got %v", err)

+		t.Fatalf("Expected client newer than server error, got %v", err)

 	}

 }

@@ -4,7 +4,6 @@ import (

 	"bytes"

 	"encoding/base64"

 	"encoding/json"

-	"errors"

 	"fmt"

 	"io"

 	"net/http"

@@ -17,7 +16,6 @@ import (

 	"github.com/docker/docker/pkg/ioutils"

 	"github.com/docker/docker/pkg/progress"

 	"github.com/docker/docker/pkg/streamformatter"

-	"github.com/docker/docker/utils"

 	"github.com/docker/engine-api/types"

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

 	"github.com/docker/go-units"

@@ -117,7 +115,7 @@ func (br *buildRouter) postBuild(ctx context.Context, w http.ResponseWriter, r *

 		if !output.Flushed() {

 			return err

 		}

-		_, err = w.Write(sf.FormatError(errors.New(utils.GetErrorMessage(err))))

+		_, err = w.Write(sf.FormatError(err))

 		if err != nil {

 			logrus.Warnf("could not write error response: %v", err)

 		}

@@ -11,15 +11,12 @@ import (

 	"time"

 	"github.com/Sirupsen/logrus"

-	"github.com/docker/distribution/registry/api/errcode"

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

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

-	derr "github.com/docker/docker/errors"

 	"github.com/docker/docker/pkg/ioutils"

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

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

 	"github.com/docker/docker/runconfig"

-	"github.com/docker/docker/utils"

 	"github.com/docker/engine-api/types"

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

 	"github.com/docker/engine-api/types/filters"

@@ -126,7 +123,7 @@ func (s *containerRouter) getContainersLogs(ctx context.Context, w http.Response

 			// The client may be expecting all of the data we're sending to

 			// be multiplexed, so send it through OutStream, which will

 			// have been set up to handle that if needed.

-			fmt.Fprintf(logsConfig.OutStream, "Error running logs job: %s\n", utils.GetErrorMessage(err))

+			fmt.Fprintf(logsConfig.OutStream, "Error running logs job: %v\n", err)

 		default:

 			return err

 		}

@@ -182,6 +179,10 @@ func (s *containerRouter) postContainersStop(ctx context.Context, w http.Respons

 	return nil

 }

+type errContainerIsRunning interface {

+	ContainerIsRunning() bool

+}

+

 func (s *containerRouter) postContainersKill(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {

 	if err := httputils.ParseForm(r); err != nil {

 		return err

@@ -199,15 +200,17 @@ func (s *containerRouter) postContainersKill(ctx context.Context, w http.Respons

 	}

 	if err := s.backend.ContainerKill(name, uint64(sig)); err != nil {

-		theErr, isDerr := err.(errcode.ErrorCoder)

-		isStopped := isDerr && theErr.ErrorCode() == derr.ErrorCodeNotRunning

+		var isStopped bool

+		if e, ok := err.(errContainerIsRunning); ok {

+			isStopped = !e.ContainerIsRunning()

+		}

 		// Return error that's not caused because the container is stopped.

 		// Return error if the container is not running and the api is >= 1.20

 		// to keep backwards compatibility.

 		version := httputils.VersionFromContext(ctx)

 		if version.GreaterThanOrEqualTo("1.20") || !isStopped {

-			return fmt.Errorf("Cannot kill container %s: %v", name, utils.GetErrorMessage(err))

+			return fmt.Errorf("Cannot kill container %s: %v", name, err)

 		}

 	}

@@ -430,7 +433,7 @@ func (s *containerRouter) postContainersAttach(ctx context.Context, w http.Respo

 	hijacker, ok := w.(http.Hijacker)

 	if !ok {

-		return derr.ErrorCodeNoHijackConnection.WithArgs(containerName)

+		return fmt.Errorf("error attaching to container %s, hijack connection missing", containerName)

 	}

 	setupStreams := func() (io.ReadCloser, io.Writer, io.Writer, error) {

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

 	"github.com/Sirupsen/logrus"

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

 	"github.com/docker/docker/pkg/stdcopy"

-	"github.com/docker/docker/utils"

 	"github.com/docker/engine-api/types"

 	"golang.org/x/net/context"

 )

@@ -46,7 +45,7 @@ func (s *containerRouter) postContainerExecCreate(ctx context.Context, w http.Re

 	// Register an instance of Exec in container.

 	id, err := s.backend.ContainerExecCreate(execConfig)

 	if err != nil {

-		logrus.Errorf("Error setting up exec command in container %s: %s", name, utils.GetErrorMessage(err))

+		logrus.Errorf("Error setting up exec command in container %s: %v", name, err)

 		return err

 	}

@@ -113,7 +112,7 @@ func (s *containerRouter) postContainerExecStart(ctx context.Context, w http.Res

 		if execStartCheck.Detach {

 			return err

 		}

-		logrus.Errorf("Error running exec in container: %v\n", utils.GetErrorMessage(err))

+		logrus.Errorf("Error running exec in container: %v\n", err)

 	}

 	return nil

 }

@@ -20,7 +20,6 @@ type Backend interface {

 type containerBackend interface {

 	Commit(name string, config *types.ContainerCommitConfig) (imageID string, err error)

-	Exists(containerName string) bool

 }

 type imageBackend interface {

@@ -14,7 +14,6 @@ import (

 	"github.com/docker/distribution/registry/api/errcode"

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

 	"github.com/docker/docker/builder/dockerfile"

-	derr "github.com/docker/docker/errors"

 	"github.com/docker/docker/pkg/ioutils"

 	"github.com/docker/docker/pkg/streamformatter"

 	"github.com/docker/docker/reference"

@@ -49,10 +48,6 @@ func (s *imageRouter) postCommit(ctx context.Context, w http.ResponseWriter, r *

 		c = &container.Config{}

 	}

-	if !s.backend.Exists(cname) {

-		return derr.ErrorCodeNoSuchContainer.WithArgs(cname)

-	}

-

 	newConfig, err := dockerfile.BuildFromConfig(c, r.Form["changes"])

 	if err != nil {

 		return err

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

 // Backend is all the methods that need to be implemented

 // to provide network specific functionality.

 type Backend interface {

-	NetworkControllerEnabled() bool

-

 	FindNetwork(idName string) (libnetwork.Network, error)

 	GetNetworkByName(idName string) (libnetwork.Network, error)

 	GetNetworksByID(partialID string) []libnetwork.Network

@@ -1,13 +1,6 @@

 package network

-import (

-	"net/http"

-

-	"github.com/docker/docker/api/server/httputils"

-	"github.com/docker/docker/api/server/router"

-	"github.com/docker/docker/errors"

-	"golang.org/x/net/context"

-)

+import "github.com/docker/docker/api/server/router"

 // networkRouter is a router to talk with the network controller

 type networkRouter struct {

@@ -32,24 +25,13 @@ func (r *networkRouter) Routes() []router.Route {

 func (r *networkRouter) initRoutes() {

 	r.routes = []router.Route{

 		// GET

-		router.NewGetRoute("/networks", r.controllerEnabledMiddleware(r.getNetworksList)),

-		router.NewGetRoute("/networks/{id:.*}", r.controllerEnabledMiddleware(r.getNetwork)),

+		router.NewGetRoute("/networks", r.getNetworksList),

+		router.NewGetRoute("/networks/{id:.*}", r.getNetwork),

 		// POST

-		router.NewPostRoute("/networks/create", r.controllerEnabledMiddleware(r.postNetworkCreate)),

-		router.NewPostRoute("/networks/{id:.*}/connect", r.controllerEnabledMiddleware(r.postNetworkConnect)),

-		router.NewPostRoute("/networks/{id:.*}/disconnect", r.controllerEnabledMiddleware(r.postNetworkDisconnect)),

+		router.NewPostRoute("/networks/create", r.postNetworkCreate),

+		router.NewPostRoute("/networks/{id:.*}/connect", r.postNetworkConnect),

+		router.NewPostRoute("/networks/{id:.*}/disconnect", r.postNetworkDisconnect),

 		// DELETE

-		router.NewDeleteRoute("/networks/{id:.*}", r.controllerEnabledMiddleware(r.deleteNetwork)),

-	}

-}

-

-func (r *networkRouter) controllerEnabledMiddleware(handler httputils.APIFunc) httputils.APIFunc {

-	if r.backend.NetworkControllerEnabled() {

-		return handler

+		router.NewDeleteRoute("/networks/{id:.*}", r.deleteNetwork),

 	}

-	return networkControllerDisabled

-}

-

-func networkControllerDisabled(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {

-	return errors.ErrorNetworkControllerNotEnabled.WithArgs()

 }

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

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

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

 	"github.com/docker/docker/pkg/authorization"

-	"github.com/docker/docker/utils"

 	"github.com/gorilla/mux"

 	"golang.org/x/net/context"

 )

@@ -134,7 +133,7 @@ func (s *Server) makeHTTPHandler(handler httputils.APIFunc) http.HandlerFunc {

 		}

 		if err := handlerFunc(ctx, w, r, vars); err != nil {

-			logrus.Errorf("Handler for %s %s returned error: %s", r.Method, r.URL.Path, utils.GetErrorMessage(err))

+			logrus.Errorf("Handler for %s %s returned error: %v", r.Method, r.URL.Path, err)

 			httputils.WriteError(w, err)

 		}

 	}

@@ -19,7 +19,6 @@ import (

 	"github.com/Sirupsen/logrus"

 	"github.com/docker/docker/api"

 	"github.com/docker/docker/builder"

-	derr "github.com/docker/docker/errors"

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

 	"github.com/docker/docker/pkg/system"

 	runconfigopts "github.com/docker/docker/runconfig/opts"

@@ -40,12 +39,12 @@ func nullDispatch(b *Builder, args []string, attributes map[string]bool, origina

 //

 func env(b *Builder, args []string, attributes map[string]bool, original string) error {

 	if len(args) == 0 {

-		return derr.ErrorCodeAtLeastOneArg.WithArgs("ENV")

+		return errAtLeastOneArgument("ENV")

 	}

 	if len(args)%2 != 0 {

 		// should never get here, but just in case

-		return derr.ErrorCodeTooManyArgs.WithArgs("ENV")

+		return errTooManyArguments("ENV")

 	}

 	if err := b.flags.Parse(); err != nil {

@@ -99,7 +98,7 @@ func env(b *Builder, args []string, attributes map[string]bool, original string)

 // Sets the maintainer metadata.

 func maintainer(b *Builder, args []string, attributes map[string]bool, original string) error {

 	if len(args) != 1 {

-		return derr.ErrorCodeExactlyOneArg.WithArgs("MAINTAINER")

+		return errExactlyOneArgument("MAINTAINER")

 	}

 	if err := b.flags.Parse(); err != nil {

@@ -116,11 +115,11 @@ func maintainer(b *Builder, args []string, attributes map[string]bool, original

 //

 func label(b *Builder, args []string, attributes map[string]bool, original string) error {

 	if len(args) == 0 {

-		return derr.ErrorCodeAtLeastOneArg.WithArgs("LABEL")

+		return errAtLeastOneArgument("LABEL")

 	}

 	if len(args)%2 != 0 {

 		// should never get here, but just in case

-		return derr.ErrorCodeTooManyArgs.WithArgs("LABEL")

+		return errTooManyArguments("LABEL")

 	}

 	if err := b.flags.Parse(); err != nil {

@@ -152,7 +151,7 @@ func label(b *Builder, args []string, attributes map[string]bool, original strin

 //

 func add(b *Builder, args []string, attributes map[string]bool, original string) error {

 	if len(args) < 2 {

-		return derr.ErrorCodeAtLeastTwoArgs.WithArgs("ADD")

+		return errAtLeastOneArgument("ADD")

 	}

 	if err := b.flags.Parse(); err != nil {

@@ -168,7 +167,7 @@ func add(b *Builder, args []string, attributes map[string]bool, original string)

 //

 func dispatchCopy(b *Builder, args []string, attributes map[string]bool, original string) error {

 	if len(args) < 2 {

-		return derr.ErrorCodeAtLeastTwoArgs.WithArgs("COPY")

+		return errAtLeastOneArgument("COPY")

 	}

 	if err := b.flags.Parse(); err != nil {

@@ -184,7 +183,7 @@ func dispatchCopy(b *Builder, args []string, attributes map[string]bool, origina

 //

 func from(b *Builder, args []string, attributes map[string]bool, original string) error {

 	if len(args) != 1 {

-		return derr.ErrorCodeExactlyOneArg.WithArgs("FROM")

+		return errExactlyOneArgument("FROM")

 	}

 	if err := b.flags.Parse(); err != nil {

@@ -233,7 +232,7 @@ func from(b *Builder, args []string, attributes map[string]bool, original string

 //

 func onbuild(b *Builder, args []string, attributes map[string]bool, original string) error {

 	if len(args) == 0 {

-		return derr.ErrorCodeAtLeastOneArg.WithArgs("ONBUILD")

+		return errAtLeastOneArgument("ONBUILD")

 	}

 	if err := b.flags.Parse(); err != nil {

@@ -243,9 +242,9 @@ func onbuild(b *Builder, args []string, attributes map[string]bool, original str

 	triggerInstruction := strings.ToUpper(strings.TrimSpace(args[0]))

 	switch triggerInstruction {

 	case "ONBUILD":

-		return derr.ErrorCodeChainOnBuild

+		return fmt.Errorf("Chaining ONBUILD via `ONBUILD ONBUILD` isn't allowed")

 	case "MAINTAINER", "FROM":

-		return derr.ErrorCodeBadOnBuildCmd.WithArgs(triggerInstruction)

+		return fmt.Errorf("%s isn't allowed as an ONBUILD trigger", triggerInstruction)

 	}

 	original = regexp.MustCompile(`(?i)^\s*ONBUILD\s*`).ReplaceAllString(original, "")

@@ -260,7 +259,7 @@ func onbuild(b *Builder, args []string, attributes map[string]bool, original str

 //

 func workdir(b *Builder, args []string, attributes map[string]bool, original string) error {

 	if len(args) != 1 {

-		return derr.ErrorCodeExactlyOneArg.WithArgs("WORKDIR")

+		return errExactlyOneArgument("WORKDIR")

 	}

 	if err := b.flags.Parse(); err != nil {

@@ -293,7 +292,7 @@ func workdir(b *Builder, args []string, attributes map[string]bool, original str

 //

 func run(b *Builder, args []string, attributes map[string]bool, original string) error {

 	if b.image == "" && !b.noBaseImage {

-		return derr.ErrorCodeMissingFrom

+		return fmt.Errorf("Please provide a source image with `from` prior to run")

 	}

 	if err := b.flags.Parse(); err != nil {

@@ -491,7 +490,7 @@ func expose(b *Builder, args []string, attributes map[string]bool, original stri

 	portsTab := args

 	if len(args) == 0 {

-		return derr.ErrorCodeAtLeastOneArg.WithArgs("EXPOSE")

+		return errAtLeastOneArgument("EXPOSE")

 	}

 	if err := b.flags.Parse(); err != nil {

@@ -530,7 +529,7 @@ func expose(b *Builder, args []string, attributes map[string]bool, original stri

 //

 func user(b *Builder, args []string, attributes map[string]bool, original string) error {

 	if len(args) != 1 {

-		return derr.ErrorCodeExactlyOneArg.WithArgs("USER")

+		return errExactlyOneArgument("USER")

 	}

 	if err := b.flags.Parse(); err != nil {

@@ -547,7 +546,7 @@ func user(b *Builder, args []string, attributes map[string]bool, original string

 //

 func volume(b *Builder, args []string, attributes map[string]bool, original string) error {

 	if len(args) == 0 {

-		return derr.ErrorCodeAtLeastOneArg.WithArgs("VOLUME")

+		return errAtLeastOneArgument("VOLUME")

 	}

 	if err := b.flags.Parse(); err != nil {

@@ -560,7 +559,7 @@ func volume(b *Builder, args []string, attributes map[string]bool, original stri

 	for _, v := range args {

 		v = strings.TrimSpace(v)

 		if v == "" {

-			return derr.ErrorCodeVolumeEmpty

+			return fmt.Errorf("Volume specified can not be an empty string")

 		}

 		b.runConfig.Volumes[v] = struct{}{}

 	}

@@ -631,3 +630,15 @@ func arg(b *Builder, args []string, attributes map[string]bool, original string)

 	return b.commit("", b.runConfig.Cmd, fmt.Sprintf("ARG %s", arg))

 }

+

+func errAtLeastOneArgument(command string) error {

+	return fmt.Errorf("%s requires at least one argument", command)

+}

+

+func errExactlyOneArgument(command string) error {

+	return fmt.Errorf("%s requires exactly one argument", command)

+}

+

+func errTooManyArguments(command string) error {

+	return fmt.Errorf("Bad input to %s, too many arguments", command)

+}

@@ -16,7 +16,6 @@ import (

 	"github.com/docker/docker/daemon/logger"

 	"github.com/docker/docker/daemon/logger/jsonfilelog"

 	"github.com/docker/docker/daemon/network"

-	derr "github.com/docker/docker/errors"

 	"github.com/docker/docker/image"

 	"github.com/docker/docker/layer"

 	"github.com/docker/docker/pkg/promise"

@@ -199,7 +198,7 @@ func (container *Container) SetupWorkingDirectory() error {

 	if err := system.MkdirAll(pth, 0755); err != nil {

 		pthInfo, err2 := os.Stat(pth)

 		if err2 == nil && pthInfo != nil && !pthInfo.IsDir() {

-			return derr.ErrorCodeNotADir.WithArgs(container.Config.WorkingDir)

+			return fmt.Errorf("Cannot mkdir: %s is not a directory", container.Config.WorkingDir)

 		}

 		return err

@@ -277,13 +276,6 @@ func (container *Container) ConfigPath() (string, error) {

 	return container.GetRootResourcePath(configFileName)

 }

-func validateID(id string) error {

-	if id == "" {

-		return derr.ErrorCodeEmptyID

-	}

-	return nil

-}

-

 // Returns true if the container exposes a certain port

 func (container *Container) exposes(p nat.Port) bool {

 	_, exists := container.Config.ExposedPorts[p]

@@ -307,7 +299,7 @@ func (container *Container) GetLogConfig(defaultConfig containertypes.LogConfig)

 func (container *Container) StartLogger(cfg containertypes.LogConfig) (logger.Logger, error) {

 	c, err := logger.GetLogDriver(cfg.Type)

 	if err != nil {

-		return nil, derr.ErrorCodeLoggingFactory.WithArgs(err)

+		return nil, fmt.Errorf("Failed to get logging factory: %v", err)

 	}

 	ctx := logger.Context{

 		Config:              cfg.Config,

@@ -14,7 +14,6 @@ import (

 	"github.com/Sirupsen/logrus"

 	"github.com/docker/docker/daemon/execdriver"

-	derr "github.com/docker/docker/errors"

 	"github.com/docker/docker/pkg/chrootarchive"

 	"github.com/docker/docker/pkg/symlink"

 	"github.com/docker/docker/pkg/system"

@@ -34,6 +33,11 @@ import (

 // DefaultSHMSize is the default size (64MB) of the SHM which will be mounted in the container

 const DefaultSHMSize int64 = 67108864

+var (

+	errInvalidEndpoint = fmt.Errorf("invalid endpoint while building port map info")

+	errInvalidNetwork  = fmt.Errorf("invalid network settings while building port map info")

+)

+

 // Container holds the fields specific to unixen implementations.

 // See CommonContainer for standard fields common to all containers.

 type Container struct {

@@ -116,12 +120,12 @@ func (container *Container) GetEndpointInNetwork(n libnetwork.Network) (libnetwo

 func (container *Container) buildPortMapInfo(ep libnetwork.Endpoint) error {

 	if ep == nil {

-		return derr.ErrorCodeEmptyEndpoint

+		return errInvalidEndpoint

 	}

 	networkSettings := container.NetworkSettings

 	if networkSettings == nil {

-		return derr.ErrorCodeEmptyNetwork

+		return errInvalidNetwork

 	}

 	if len(networkSettings.Ports) == 0 {

@@ -151,7 +155,7 @@ func getEndpointPortMapInfo(ep libnetwork.Endpoint) (nat.PortMap, error) {

 			for _, tp := range exposedPorts {

 				natPort, err := nat.NewPort(tp.Proto.String(), strconv.Itoa(int(tp.Port)))

 				if err != nil {

-					return pm, derr.ErrorCodeParsingPort.WithArgs(tp.Port, err)

+					return pm, fmt.Errorf("Error parsing Port value(%v):%v", tp.Port, err)

 				}

 				pm[natPort] = nil

 			}

@@ -195,12 +199,12 @@ func getSandboxPortMapInfo(sb libnetwork.Sandbox) nat.PortMap {

 // BuildEndpointInfo sets endpoint-related fields on container.NetworkSettings based on the provided network and endpoint.

 func (container *Container) BuildEndpointInfo(n libnetwork.Network, ep libnetwork.Endpoint) error {

 	if ep == nil {

-		return derr.ErrorCodeEmptyEndpoint

+		return errInvalidEndpoint

 	}

 	networkSettings := container.NetworkSettings

 	if networkSettings == nil {

-		return derr.ErrorCodeEmptyNetwork

+		return errInvalidNetwork

 	}

 	epInfo := ep.Info()

@@ -377,7 +381,7 @@ func (container *Container) BuildCreateEndpointOptions(n libnetwork.Network, epC

 				portStart, portEnd, err = newP.Range()

 			}

 			if err != nil {

-				return nil, derr.ErrorCodeHostPort.WithArgs(binding[i].HostPort, err)

+				return nil, fmt.Errorf("Error parsing HostPort value(%s):%v", binding[i].HostPort, err)

 			}

 			pbCopy.HostPort = uint16(portStart)

 			pbCopy.HostPortEnd = uint16(portEnd)

@@ -1,6 +1,7 @@

 package container

 import (

+	"fmt"

 	"io"

 	"os/exec"

 	"strings"

@@ -10,10 +11,8 @@ import (

 	"github.com/Sirupsen/logrus"

 	"github.com/docker/docker/daemon/execdriver"

-	derr "github.com/docker/docker/errors"

 	"github.com/docker/docker/pkg/promise"

 	"github.com/docker/docker/pkg/stringid"

-	"github.com/docker/docker/utils"

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

 )

@@ -190,7 +189,7 @@ func (m *containerMonitor) start() error {

 				if m.container.RestartCount == 0 {

 					m.container.ExitCode = 127

 					m.resetContainer(false)

-					return derr.ErrorCodeCmdNotFound

+					return fmt.Errorf("Container command not found or does not exist.")

 				}

 			}

 			// set to 126 for container cmd can't be invoked errors

@@ -198,7 +197,7 @@ func (m *containerMonitor) start() error {

 				if m.container.RestartCount == 0 {

 					m.container.ExitCode = 126

 					m.resetContainer(false)

-					return derr.ErrorCodeCmdCouldNotBeInvoked

+					return fmt.Errorf("Container command could not be invoked.")

 				}

 			}

@@ -206,7 +205,7 @@ func (m *containerMonitor) start() error {

 				m.container.ExitCode = -1

 				m.resetContainer(false)

-				return derr.ErrorCodeCantStart.WithArgs(m.container.ID, utils.GetErrorMessage(err))

+				return fmt.Errorf("Cannot start container %s: %v", m.container.ID, err)

 			}

 			logrus.Errorf("Error running container: %s", err)

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

 	"time"

 	"github.com/docker/docker/daemon/execdriver"

-	derr "github.com/docker/docker/errors"

 	"github.com/docker/go-units"

 )

@@ -113,7 +112,7 @@ func wait(waitChan <-chan struct{}, timeout time.Duration) error {

 	}

 	select {

 	case <-time.After(timeout):

-		return derr.ErrorCodeTimedOut.WithArgs(timeout)

+		return fmt.Errorf("Timed out: %v", timeout)

 	case <-waitChan:

 		return nil

 	}

@@ -256,14 +255,15 @@ func (s *State) IsRestarting() bool {

 }

 // SetRemovalInProgress sets the container state as being removed.

-func (s *State) SetRemovalInProgress() error {

+// It returns true if the container was already in that state.

+func (s *State) SetRemovalInProgress() bool {

 	s.Lock()

 	defer s.Unlock()

 	if s.RemovalInProgress {

-		return derr.ErrorCodeAlreadyRemoving

+		return true

 	}

 	s.RemovalInProgress = true

-	return nil

+	return false

 }

 // ResetRemovalInProgress make the RemovalInProgress state to false.

@@ -9,7 +9,7 @@ import (

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

 	"github.com/docker/docker/container"

 	"github.com/docker/docker/daemon/logger"

-	derr "github.com/docker/docker/errors"

+	"github.com/docker/docker/errors"

 	"github.com/docker/docker/pkg/stdcopy"

 )

@@ -17,10 +17,11 @@ import (

 func (daemon *Daemon) ContainerAttach(prefixOrName string, c *backend.ContainerAttachConfig) error {

 	container, err := daemon.GetContainer(prefixOrName)

 	if err != nil {

-		return derr.ErrorCodeNoSuchContainer.WithArgs(prefixOrName)

+		return err

 	}

 	if container.IsPaused() {

-		return derr.ErrorCodePausedContainer.WithArgs(prefixOrName)

+		err := fmt.Errorf("Container %s is paused. Unpause the container before attach", prefixOrName)

+		return errors.NewRequestConflictError(err)

 	}

 	inStream, outStream, errStream, err := c.GetStreams()

@@ -17,7 +17,7 @@ import (

 	"github.com/docker/docker/daemon/execdriver"

 	"github.com/docker/docker/daemon/links"

 	"github.com/docker/docker/daemon/network"

-	derr "github.com/docker/docker/errors"

+	"github.com/docker/docker/errors"

 	"github.com/docker/docker/pkg/fileutils"

 	"github.com/docker/docker/pkg/idtools"