Round 4

Signed-off-by: Doug Davis <dug@us.ibm.com>

docs/api/errcode/errors.go

@@ -1,106 +1,29 @@
 package errcode
 
 import (
+	"encoding/json"
 	"fmt"
-	"net/http"
 	"strings"
-	"sync"
 )
 
+// ErrorCoder is the base interface for ErrorCode and Error allowing
+// users of each to just call ErrorCode to get the real ID of each
+type ErrorCoder interface {
+	ErrorCode() ErrorCode
+}
+
 // ErrorCode represents the error type. The errors are serialized via strings
 // and the integer format may change and should *never* be exported.
 type ErrorCode int
 
-// ErrorDescriptor provides relevant information about a given error code.
+// ErrorCode just returns itself
-type ErrorDescriptor struct {
+func (ec ErrorCode) ErrorCode() ErrorCode {
-	// Code is the error code that this descriptor describes.
+	return ec
-	Code ErrorCode
-
-	// Value provides a unique, string key, often captilized with
-	// underscores, to identify the error code. This value is used as the
-	// keyed value when serializing api errors.
-	Value string
-
-	// Message is a short, human readable decription of the error condition
-	// included in API responses.
-	Message string
-
-	// Description provides a complete account of the errors purpose, suitable
-	// for use in documentation.
-	Description string
-
-	// HTTPStatusCode provides the http status code that is associated with
-	// this error condition.
-	HTTPStatusCode int
 }
 
-var (
+// Error returns the ID/Value
-	errorCodeToDescriptors = map[ErrorCode]ErrorDescriptor{}
+func (ec ErrorCode) Error() string {
-	idToDescriptors        = map[string]ErrorDescriptor{}
+	return ec.Descriptor().Value
-	groupToDescriptors     = map[string][]ErrorDescriptor{}
-)
-
-// ErrorCodeUnknown is a generic error that can be used as a last
-// resort if there is no situation-specific error message that can be used
-var ErrorCodeUnknown = Register("registry.api.errcode", ErrorDescriptor{
-	Value:   "UNKNOWN",
-	Message: "unknown error",
-	Description: `Generic error returned when the error does not have an
-									        API classification.`,
-	HTTPStatusCode: http.StatusInternalServerError,
-})
-
-var nextCode = 1000
-var registerLock sync.Mutex
-
-// Register will make the passed-in error known to the environment and
-// return a new ErrorCode
-func Register(group string, descriptor ErrorDescriptor) ErrorCode {
-	registerLock.Lock()
-	defer registerLock.Unlock()
-	code := ErrorCode(nextCode)
-
-	descriptor.Code = code
-
-	if _, ok := idToDescriptors[descriptor.Value]; ok {
-		panic(fmt.Sprintf("ErrorValue %s is already registered", descriptor.Value))
-	}
-	if _, ok := errorCodeToDescriptors[descriptor.Code]; ok {
-		panic(fmt.Sprintf("ErrorCode %d is already registered", descriptor.Code))
-	}
-
-	groupToDescriptors[group] = append(groupToDescriptors[group], descriptor)
-	errorCodeToDescriptors[code] = descriptor
-	idToDescriptors[descriptor.Value] = descriptor
-
-	nextCode++
-	return code
-}
-
-// ParseErrorCode returns the value by the string error code.
-// `ErrorCodeUnknown` will be returned if the error is not known.
-func ParseErrorCode(value string) ErrorCode {
-	ed, ok := idToDescriptors[value]
-	if ok {
-		return ed.Code
-	}
-
-	return ErrorCodeUnknown
-}
-
-// GetGroupNames returns the list of Error group names that are registered
-func GetGroupNames() []string {
-	keys := []string{}
-
-	for k := range groupToDescriptors {
-		keys = append(keys, k)
-	}
-	return keys
-}
-
-// GetErrorCodeGroup returns the named group of error descriptors
-func GetErrorCodeGroup(name string) []ErrorDescriptor {
-	return groupToDescriptors[name]
 }
 
 // Descriptor returns the descriptor for the error code.
@@ -143,12 +66,30 @@ func (ec *ErrorCode) UnmarshalText(text []byte) error {
 	return nil
 }
 
+// WithDetail creates a new Error struct based on the passed-in info and
+// set the Detail property appropriately
+func (ec ErrorCode) WithDetail(detail interface{}) Error {
+	if err, ok := detail.(error); ok {
+		detail = err.Error()
+	}
+
+	return Error{
+		Code:   ec,
+		Detail: detail,
+	}
+}
+
 // Error provides a wrapper around ErrorCode with extra Details provided.
 type Error struct {
 	Code   ErrorCode   `json:"code"`
 	Detail interface{} `json:"detail,omitempty"`
 }
 
+// ErrorCode returns the ID/Value of this Error
+func (e Error) ErrorCode() ErrorCode {
+	return e.Code
+}
+
 // Error returns a human readable representation of the error.
 func (e Error) Error() string {
 	return fmt.Sprintf("%s: %s",
@@ -161,30 +102,43 @@ func (e Error) Message() string {
 	return e.Code.Message()
 }
 
+// ErrorDescriptor provides relevant information about a given error code.
+type ErrorDescriptor struct {
+	// Code is the error code that this descriptor describes.
+	Code ErrorCode
+
+	// Value provides a unique, string key, often captilized with
+	// underscores, to identify the error code. This value is used as the
+	// keyed value when serializing api errors.
+	Value string
+
+	// Message is a short, human readable decription of the error condition
+	// included in API responses.
+	Message string
+
+	// Description provides a complete account of the errors purpose, suitable
+	// for use in documentation.
+	Description string
+
+	// HTTPStatusCode provides the http status code that is associated with
+	// this error condition.
+	HTTPStatusCode int
+}
+
+// ParseErrorCode returns the value by the string error code.
+// `ErrorCodeUnknown` will be returned if the error is not known.
+func ParseErrorCode(value string) ErrorCode {
+	ed, ok := idToDescriptors[value]
+	if ok {
+		return ed.Code
+	}
+
+	return ErrorCodeUnknown
+}
+
 // Errors provides the envelope for multiple errors and a few sugar methods
 // for use within the application.
-type Errors []Error
+type Errors []error
-
-// NewError creates a new Error struct based on the passed-in info
-func NewError(code ErrorCode, details ...interface{}) Error {
-	if len(details) > 1 {
-		panic("please specify zero or one detail items for this error")
-	}
-
-	var detail interface{}
-	if len(details) > 0 {
-		detail = details[0]
-	}
-
-	if err, ok := detail.(error); ok {
-		detail = err.Error()
-	}
-
-	return Error{
-		Code:   code,
-		Detail: detail,
-	}
-}
 
 func (errs Errors) Error() string {
 	switch len(errs) {
@@ -205,3 +159,67 @@ func (errs Errors) Error() string {
 func (errs Errors) Len() int {
 	return len(errs)
 }
+
+// jsonError extends Error with 'Message' so that we can include the
+// error text, just in case the receiver of the JSON doesn't have this
+// particular ErrorCode registered
+type jsonError struct {
+	Code    ErrorCode   `json:"code"`
+	Message string      `json:"message"`
+	Detail  interface{} `json:"detail,omitempty"`
+}
+
+// MarshalJSON converts slice of error, ErrorCode or Error into a
+// slice of Error - then serializes
+func (errs Errors) MarshalJSON() ([]byte, error) {
+	var tmpErrs []jsonError
+
+	for _, daErr := range errs {
+		var err Error
+
+		switch daErr.(type) {
+		case ErrorCode:
+			err = daErr.(ErrorCode).WithDetail(nil)
+		case Error:
+			err = daErr.(Error)
+		default:
+			err = ErrorCodeUnknown.WithDetail(daErr)
+
+		}
+
+		tmpErrs = append(tmpErrs, jsonError{
+			Code:    err.Code,
+			Message: err.Message(),
+			Detail:  err.Detail,
+		})
+	}
+
+	return json.Marshal(tmpErrs)
+}
+
+// UnmarshalJSON deserializes []Error and then converts it into slice of
+// Error or ErrorCode
+func (errs *Errors) UnmarshalJSON(data []byte) error {
+	var tmpErrs []jsonError
+
+	if err := json.Unmarshal(data, &tmpErrs); err != nil {
+		return err
+	}
+
+	var newErrs Errors
+	for _, daErr := range tmpErrs {
+		if daErr.Detail == nil {
+			// Error's w/o details get converted to ErrorCode
+			newErrs = append(newErrs, daErr.Code)
+		} else {
+			// Error's w/ details are untouched
+			newErrs = append(newErrs, Error{
+				Code:   daErr.Code,
+				Detail: daErr.Detail,
+			})
+		}
+	}
+
+	*errs = newErrs
+	return nil
+}

docs/api/errcode/errors_test.go

@@ -79,8 +79,8 @@ var ErrorCodeTest2 = Register("v2.errors", ErrorDescriptor{
 func TestErrorsManagement(t *testing.T) {
 	var errs Errors
 
-	errs = append(errs, NewError(ErrorCodeTest1))
+	errs = append(errs, ErrorCodeTest1)
-	errs = append(errs, NewError(ErrorCodeTest2,
+	errs = append(errs, ErrorCodeTest2.WithDetail(
 		map[string]interface{}{"digest": "sometestblobsumdoesntmatter"}))
 
 	p, err := json.Marshal(errs)
@@ -89,10 +89,10 @@ func TestErrorsManagement(t *testing.T) {
 		t.Fatalf("error marashaling errors: %v", err)
 	}
 
-	expectedJSON := "[{\"code\":\"TEST1\"},{\"code\":\"TEST2\",\"detail\":{\"digest\":\"sometestblobsumdoesntmatter\"}}]"
+	expectedJSON := "[{\"code\":\"TEST1\",\"message\":\"test error 1\"},{\"code\":\"TEST2\",\"message\":\"test error 2\",\"detail\":{\"digest\":\"sometestblobsumdoesntmatter\"}}]"
 
 	if string(p) != expectedJSON {
-		t.Fatalf("unexpected json: %q != %q", string(p), expectedJSON)
+		t.Fatalf("unexpected json:\ngot:\n%q\n\nexpected:\n%q", string(p), expectedJSON)
 	}
 
 	// Now test the reverse
@@ -106,8 +106,8 @@ func TestErrorsManagement(t *testing.T) {
 	}
 
 	// Test again with a single value this time
-	errs = Errors{NewError(ErrorCodeUnknown)}
+	errs = Errors{ErrorCodeUnknown}
-	expectedJSON = "[{\"code\":\"UNKNOWN\"}]"
+	expectedJSON = "[{\"code\":\"UNKNOWN\",\"message\":\"unknown error\"}]"
 	p, err = json.Marshal(errs)
 
 	if err != nil {

docs/api/errcode/register.go

@@ -0,0 +1,86 @@
+package errcode
+
+import (
+	"fmt"
+	"net/http"
+	"sort"
+	"sync"
+)
+
+var (
+	errorCodeToDescriptors = map[ErrorCode]ErrorDescriptor{}
+	idToDescriptors        = map[string]ErrorDescriptor{}
+	groupToDescriptors     = map[string][]ErrorDescriptor{}
+)
+
+// ErrorCodeUnknown is a generic error that can be used as a last
+// resort if there is no situation-specific error message that can be used
+var ErrorCodeUnknown = Register("errcode", ErrorDescriptor{
+	Value:   "UNKNOWN",
+	Message: "unknown error",
+	Description: `Generic error returned when the error does not have an
+			                                            API classification.`,
+	HTTPStatusCode: http.StatusInternalServerError,
+})
+
+var nextCode = 1000
+var registerLock sync.Mutex
+
+// Register will make the passed-in error known to the environment and
+// return a new ErrorCode
+func Register(group string, descriptor ErrorDescriptor) ErrorCode {
+	registerLock.Lock()
+	defer registerLock.Unlock()
+
+	descriptor.Code = ErrorCode(nextCode)
+
+	if _, ok := idToDescriptors[descriptor.Value]; ok {
+		panic(fmt.Sprintf("ErrorValue %q is already registered", descriptor.Value))
+	}
+	if _, ok := errorCodeToDescriptors[descriptor.Code]; ok {
+		panic(fmt.Sprintf("ErrorCode %v is already registered", descriptor.Code))
+	}
+
+	groupToDescriptors[group] = append(groupToDescriptors[group], descriptor)
+	errorCodeToDescriptors[descriptor.Code] = descriptor
+	idToDescriptors[descriptor.Value] = descriptor
+
+	nextCode++
+	return descriptor.Code
+}
+
+type byValue []ErrorDescriptor
+
+func (a byValue) Len() int           { return len(a) }
+func (a byValue) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+func (a byValue) Less(i, j int) bool { return a[i].Value < a[j].Value }
+
+// GetGroupNames returns the list of Error group names that are registered
+func GetGroupNames() []string {
+	keys := []string{}
+
+	for k := range groupToDescriptors {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	return keys
+}
+
+// GetErrorCodeGroup returns the named group of error descriptors
+func GetErrorCodeGroup(name string) []ErrorDescriptor {
+	desc := groupToDescriptors[name]
+	sort.Sort(byValue(desc))
+	return desc
+}
+
+// GetErrorAllDescriptors returns a slice of all ErrorDescriptors that are
+// registered, irrespective of what group they're in
+func GetErrorAllDescriptors() []ErrorDescriptor {
+	result := []ErrorDescriptor{}
+
+	for _, group := range GetGroupNames() {
+		result = append(result, GetErrorCodeGroup(group)...)
+	}
+	sort.Sort(byValue(result))
+	return result
+}

docs/api/v2/errors.go

@@ -6,9 +6,11 @@ import (
 	"github.com/docker/distribution/registry/api/errcode"
 )
 
+const errGroup = "registry.api.v2"
+
 var (
 	// ErrorCodeUnsupported is returned when an operation is not supported.
-	ErrorCodeUnsupported = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeUnsupported = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "UNSUPPORTED",
 		Message: "The operation is unsupported.",
 		Description: `The operation was unsupported due to a missing
@@ -16,7 +18,7 @@ var (
 	})
 
 	// ErrorCodeUnauthorized is returned if a request is not authorized.
-	ErrorCodeUnauthorized = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeUnauthorized = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "UNAUTHORIZED",
 		Message: "access to the requested resource is not authorized",
 		Description: `The access controller denied access for the operation on
@@ -27,7 +29,7 @@ var (
 
 	// ErrorCodeDigestInvalid is returned when uploading a blob if the
 	// provided digest does not match the blob contents.
-	ErrorCodeDigestInvalid = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeDigestInvalid = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "DIGEST_INVALID",
 		Message: "provided digest did not match uploaded content",
 		Description: `When a blob is uploaded, the registry will check that
@@ -39,7 +41,7 @@ var (
 	})
 
 	// ErrorCodeSizeInvalid is returned when uploading a blob if the provided
-	ErrorCodeSizeInvalid = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeSizeInvalid = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "SIZE_INVALID",
 		Message: "provided length did not match content length",
 		Description: `When a layer is uploaded, the provided size will be
@@ -50,7 +52,7 @@ var (
 
 	// ErrorCodeNameInvalid is returned when the name in the manifest does not
 	// match the provided name.
-	ErrorCodeNameInvalid = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeNameInvalid = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "NAME_INVALID",
 		Message: "invalid repository name",
 		Description: `Invalid repository name encountered either during
@@ -60,7 +62,7 @@ var (
 
 	// ErrorCodeTagInvalid is returned when the tag in the manifest does not
 	// match the provided tag.
-	ErrorCodeTagInvalid = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeTagInvalid = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "TAG_INVALID",
 		Message: "manifest tag did not match URI",
 		Description: `During a manifest upload, if the tag in the manifest
@@ -69,7 +71,7 @@ var (
 	})
 
 	// ErrorCodeNameUnknown when the repository name is not known.
-	ErrorCodeNameUnknown = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeNameUnknown = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "NAME_UNKNOWN",
 		Message: "repository name not known to registry",
 		Description: `This is returned if the name used during an operation is
@@ -78,7 +80,7 @@ var (
 	})
 
 	// ErrorCodeManifestUnknown returned when image manifest is unknown.
-	ErrorCodeManifestUnknown = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeManifestUnknown = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "MANIFEST_UNKNOWN",
 		Message: "manifest unknown",
 		Description: `This error is returned when the manifest, identified by
@@ -89,7 +91,7 @@ var (
 	// ErrorCodeManifestInvalid returned when an image manifest is invalid,
 	// typically during a PUT operation. This error encompasses all errors
 	// encountered during manifest validation that aren't signature errors.
-	ErrorCodeManifestInvalid = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeManifestInvalid = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "MANIFEST_INVALID",
 		Message: "manifest invalid",
 		Description: `During upload, manifests undergo several checks ensuring
@@ -101,7 +103,7 @@ var (
 
 	// ErrorCodeManifestUnverified is returned when the manifest fails
 	// signature verfication.
-	ErrorCodeManifestUnverified = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeManifestUnverified = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "MANIFEST_UNVERIFIED",
 		Message: "manifest failed signature verification",
 		Description: `During manifest upload, if the manifest fails signature
@@ -111,7 +113,7 @@ var (
 
 	// ErrorCodeManifestBlobUnknown is returned when a manifest blob is
 	// unknown to the registry.
-	ErrorCodeManifestBlobUnknown = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeManifestBlobUnknown = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "MANIFEST_BLOB_UNKNOWN",
 		Message: "blob unknown to registry",
 		Description: `This error may be returned when a manifest blob is 
@@ -122,7 +124,7 @@ var (
 	// ErrorCodeBlobUnknown is returned when a blob is unknown to the
 	// registry. This can happen when the manifest references a nonexistent
 	// layer or the result is not found by a blob fetch.
-	ErrorCodeBlobUnknown = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeBlobUnknown = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "BLOB_UNKNOWN",
 		Message: "blob unknown to registry",
 		Description: `This error may be returned when a blob is unknown to the
@@ -133,7 +135,7 @@ var (
 	})
 
 	// ErrorCodeBlobUploadUnknown is returned when an upload is unknown.
-	ErrorCodeBlobUploadUnknown = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeBlobUploadUnknown = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "BLOB_UPLOAD_UNKNOWN",
 		Message: "blob upload unknown to registry",
 		Description: `If a blob upload has been cancelled or was never
@@ -142,7 +144,7 @@ var (
 	})
 
 	// ErrorCodeBlobUploadInvalid is returned when an upload is invalid.
-	ErrorCodeBlobUploadInvalid = errcode.Register("registry.api.v2", errcode.ErrorDescriptor{
+	ErrorCodeBlobUploadInvalid = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:   "BLOB_UPLOAD_INVALID",
 		Message: "blob upload invalid",
 		Description: `The blob upload encountered an error and can no

docs/client/blob_writer_test.go

@@ -164,7 +164,10 @@ func TestUploadReadFrom(t *testing.T) {
 	} else if len(uploadErr) != 1 {
 		t.Fatalf("Unexpected number of errors: %d, expected 1", len(uploadErr))
 	} else {
-		v2Err := uploadErr[0]
+		v2Err, ok := uploadErr[0].(errcode.Error)
+		if !ok {
+			t.Fatalf("Not an 'Error' type: %#v", uploadErr[0])
+		}
 		if v2Err.Code != v2.ErrorCodeBlobUploadInvalid {
 			t.Fatalf("Unexpected error code: %s, expected %d", v2Err.Code.String(), v2.ErrorCodeBlobUploadInvalid)
 		}

docs/handlers/api_test.go

@@ -780,11 +780,15 @@ func checkBodyHasErrorCodes(t *testing.T, msg string, resp *http.Response, error
 		counts[code] = 0
 	}
 
-	for _, err := range errs {
+	for _, e := range errs {
-		if _, ok := expected[err.Code]; !ok {
+		err, ok := e.(errcode.ErrorCoder)
-			t.Fatalf("unexpected error code %v encountered during %s: %s ", err.Code, msg, string(p))
+		if !ok {
+			t.Fatalf("not an ErrorCoder: %#v", e)
 		}
-		counts[err.Code]++
+		if _, ok := expected[err.ErrorCode()]; !ok {
+			t.Fatalf("unexpected error code %v encountered during %s: %s ", err.ErrorCode(), msg, string(p))
+		}
+		counts[err.ErrorCode()]++
 	}
 
 	// Ensure that counts of expected errors were all non-zero

docs/handlers/app.go

@@ -346,9 +346,9 @@ func (app *App) dispatcher(dispatch dispatchFunc) http.Handler {
 
 				switch err := err.(type) {
 				case distribution.ErrRepositoryUnknown:
-					context.Errors = append(context.Errors, errcode.NewError(v2.ErrorCodeNameUnknown, err))
+					context.Errors = append(context.Errors, v2.ErrorCodeNameUnknown.WithDetail(err))
 				case distribution.ErrRepositoryNameInvalid:
-					context.Errors = append(context.Errors, errcode.NewError(v2.ErrorCodeNameInvalid, err))
+					context.Errors = append(context.Errors, v2.ErrorCodeNameInvalid.WithDetail(err))
 				}
 
 				serveJSON(w, context.Errors)
@@ -363,7 +363,7 @@ func (app *App) dispatcher(dispatch dispatchFunc) http.Handler {
 			context.Repository, err = applyRepoMiddleware(context.Repository, app.Config.Middleware["repository"])
 			if err != nil {
 				ctxu.GetLogger(context).Errorf("error initializing repository middleware: %v", err)
-				context.Errors = append(context.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+				context.Errors = append(context.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 
 				serveJSON(w, context.Errors)
 				return
@@ -383,10 +383,25 @@ func (app *App) dispatcher(dispatch dispatchFunc) http.Handler {
 }
 
 func (app *App) logError(context context.Context, errors errcode.Errors) {
-	for _, e := range errors {
+	for _, e1 := range errors {
-		c := ctxu.WithValue(context, "err.code", e.Code)
+		var c ctxu.Context
-		c = ctxu.WithValue(c, "err.message", e.Code.Message())
+
-		c = ctxu.WithValue(c, "err.detail", e.Detail)
+		switch e1.(type) {
+		case errcode.Error:
+			e, _ := e1.(errcode.Error)
+			c = ctxu.WithValue(context, "err.code", e.Code)
+			c = ctxu.WithValue(c, "err.message", e.Code.Message())
+			c = ctxu.WithValue(c, "err.detail", e.Detail)
+		case errcode.ErrorCode:
+			e, _ := e1.(errcode.ErrorCode)
+			c = ctxu.WithValue(context, "err.code", e)
+			c = ctxu.WithValue(c, "err.message", e.Message())
+		default:
+			// just normal go 'error'
+			c = ctxu.WithValue(context, "err.code", errcode.ErrorCodeUnknown)
+			c = ctxu.WithValue(c, "err.message", e1.Error())
+		}
+
 		c = ctxu.WithLogger(c, ctxu.GetLogger(c,
 			"err.code",
 			"err.message",
@@ -441,7 +456,7 @@ func (app *App) authorized(w http.ResponseWriter, r *http.Request, context *Cont
 			// proceed.
 
 			var errs errcode.Errors
-			errs = append(errs, errcode.NewError(v2.ErrorCodeUnauthorized))
+			errs = append(errs, v2.ErrorCodeUnauthorized)
 
 			serveJSON(w, errs)
 			return fmt.Errorf("forbidden: no repository name")
@@ -465,7 +480,7 @@ func (app *App) authorized(w http.ResponseWriter, r *http.Request, context *Cont
 			err.ServeHTTP(w, r)
 
 			var errs errcode.Errors
-			errs = append(errs, errcode.NewError(v2.ErrorCodeUnauthorized, accessRecords))
+			errs = append(errs, v2.ErrorCodeUnauthorized.WithDetail(accessRecords))
 			serveJSON(w, errs)
 		default:
 			// This condition is a potential security problem either in

docs/handlers/app_test.go

@@ -201,8 +201,12 @@ func TestNewApp(t *testing.T) {
 		t.Fatalf("error decoding error response: %v", err)
 	}
 
-	if errs[0].Code != v2.ErrorCodeUnauthorized {
+	err2, ok := errs[0].(errcode.ErrorCoder)
-		t.Fatalf("unexpected error code: %v != %v", errs[0].Code, v2.ErrorCodeUnauthorized)
+	if !ok {
+		t.Fatalf("not an ErrorCoder: %#v", errs[0])
+	}
+	if err2.ErrorCode() != v2.ErrorCodeUnauthorized {
+		t.Fatalf("unexpected error code: %v != %v", err2.ErrorCode(), v2.ErrorCodeUnauthorized)
 	}
 }
 

docs/handlers/blob.go

@@ -18,12 +18,12 @@ func blobDispatcher(ctx *Context, r *http.Request) http.Handler {
 
 		if err == errDigestNotAvailable {
 			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-				ctx.Errors = append(ctx.Errors, errcode.NewError(v2.ErrorCodeDigestInvalid, err))
+				ctx.Errors = append(ctx.Errors, v2.ErrorCodeDigestInvalid.WithDetail(err))
 			})
 		}
 
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			ctx.Errors = append(ctx.Errors, errcode.NewError(v2.ErrorCodeDigestInvalid, err))
+			ctx.Errors = append(ctx.Errors, v2.ErrorCodeDigestInvalid.WithDetail(err))
 		})
 	}
 
@@ -53,16 +53,16 @@ func (bh *blobHandler) GetBlob(w http.ResponseWriter, r *http.Request) {
 	desc, err := blobs.Stat(bh, bh.Digest)
 	if err != nil {
 		if err == distribution.ErrBlobUnknown {
-			bh.Errors = append(bh.Errors, errcode.NewError(v2.ErrorCodeBlobUnknown, bh.Digest))
+			bh.Errors = append(bh.Errors, v2.ErrorCodeBlobUnknown.WithDetail(bh.Digest))
 		} else {
-			bh.Errors = append(bh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+			bh.Errors = append(bh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 		}
 		return
 	}
 
 	if err := blobs.ServeBlob(bh, w, r, desc.Digest); err != nil {
 		context.GetLogger(bh).Debugf("unexpected error getting blob HTTP handler: %v", err)
-		bh.Errors = append(bh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+		bh.Errors = append(bh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 		return
 	}
 }

docs/handlers/blobupload.go

@@ -37,7 +37,7 @@ func blobUploadDispatcher(ctx *Context, r *http.Request) http.Handler {
 		if err != nil {
 			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 				ctxu.GetLogger(ctx).Infof("error resolving upload: %v", err)
-				buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeBlobUploadInvalid, err))
+				buh.Errors = append(buh.Errors, v2.ErrorCodeBlobUploadInvalid.WithDetail(err))
 			})
 		}
 		buh.State = state
@@ -45,14 +45,14 @@ func blobUploadDispatcher(ctx *Context, r *http.Request) http.Handler {
 		if state.Name != ctx.Repository.Name() {
 			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 				ctxu.GetLogger(ctx).Infof("mismatched repository name in upload state: %q != %q", state.Name, buh.Repository.Name())
-				buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeBlobUploadInvalid, err))
+				buh.Errors = append(buh.Errors, v2.ErrorCodeBlobUploadInvalid.WithDetail(err))
 			})
 		}
 
 		if state.UUID != buh.UUID {
 			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 				ctxu.GetLogger(ctx).Infof("mismatched uuid in upload state: %q != %q", state.UUID, buh.UUID)
-				buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeBlobUploadInvalid, err))
+				buh.Errors = append(buh.Errors, v2.ErrorCodeBlobUploadInvalid.WithDetail(err))
 			})
 		}
 
@@ -62,12 +62,12 @@ func blobUploadDispatcher(ctx *Context, r *http.Request) http.Handler {
 			ctxu.GetLogger(ctx).Errorf("error resolving upload: %v", err)
 			if err == distribution.ErrBlobUploadUnknown {
 				return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-					buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeBlobUploadUnknown, err))
+					buh.Errors = append(buh.Errors, v2.ErrorCodeBlobUploadUnknown.WithDetail(err))
 				})
 			}
 
 			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-				buh.Errors = append(buh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+				buh.Errors = append(buh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 			})
 		}
 		buh.Upload = upload
@@ -81,14 +81,14 @@ func blobUploadDispatcher(ctx *Context, r *http.Request) http.Handler {
 				defer upload.Close()
 				ctxu.GetLogger(ctx).Infof("error seeking blob upload: %v", err)
 				return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-					buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeBlobUploadInvalid, err))
+					buh.Errors = append(buh.Errors, v2.ErrorCodeBlobUploadInvalid.WithDetail(err))
 					upload.Cancel(buh)
 				})
 			} else if nn != buh.State.Offset {
 				defer upload.Close()
 				ctxu.GetLogger(ctx).Infof("seek to wrong offest: %d != %d", nn, buh.State.Offset)
 				return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-					buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeBlobUploadInvalid, err))
+					buh.Errors = append(buh.Errors, v2.ErrorCodeBlobUploadInvalid.WithDetail(err))
 					upload.Cancel(buh)
 				})
 			}
@@ -119,7 +119,7 @@ func (buh *blobUploadHandler) StartBlobUpload(w http.ResponseWriter, r *http.Req
 	blobs := buh.Repository.Blobs(buh)
 	upload, err := blobs.Create(buh)
 	if err != nil {
-		buh.Errors = append(buh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+		buh.Errors = append(buh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 		return
 	}
 
@@ -127,7 +127,7 @@ func (buh *blobUploadHandler) StartBlobUpload(w http.ResponseWriter, r *http.Req
 	defer buh.Upload.Close()
 
 	if err := buh.blobUploadResponse(w, r, true); err != nil {
-		buh.Errors = append(buh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+		buh.Errors = append(buh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 		return
 	}
 
@@ -138,7 +138,7 @@ func (buh *blobUploadHandler) StartBlobUpload(w http.ResponseWriter, r *http.Req
 // GetUploadStatus returns the status of a given upload, identified by id.
 func (buh *blobUploadHandler) GetUploadStatus(w http.ResponseWriter, r *http.Request) {
 	if buh.Upload == nil {
-		buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeBlobUploadUnknown))
+		buh.Errors = append(buh.Errors, v2.ErrorCodeBlobUploadUnknown)
 		return
 	}
 
@@ -146,7 +146,7 @@ func (buh *blobUploadHandler) GetUploadStatus(w http.ResponseWriter, r *http.Req
 	// resumable upload is supported. This will enable returning a non-zero
 	// range for clients to begin uploading at an offset.
 	if err := buh.blobUploadResponse(w, r, true); err != nil {
-		buh.Errors = append(buh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+		buh.Errors = append(buh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 		return
 	}
 
@@ -157,13 +157,13 @@ func (buh *blobUploadHandler) GetUploadStatus(w http.ResponseWriter, r *http.Req
 // PatchBlobData writes data to an upload.
 func (buh *blobUploadHandler) PatchBlobData(w http.ResponseWriter, r *http.Request) {
 	if buh.Upload == nil {
-		buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeBlobUploadUnknown))
+		buh.Errors = append(buh.Errors, v2.ErrorCodeBlobUploadUnknown)
 		return
 	}
 
 	ct := r.Header.Get("Content-Type")
 	if ct != "" && ct != "application/octet-stream" {
-		buh.Errors = append(buh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, fmt.Errorf("Bad Content-Type")))
+		buh.Errors = append(buh.Errors, errcode.ErrorCodeUnknown.WithDetail(fmt.Errorf("Bad Content-Type")))
 		// TODO(dmcgowan): encode error
 		return
 	}
@@ -173,12 +173,12 @@ func (buh *blobUploadHandler) PatchBlobData(w http.ResponseWriter, r *http.Reque
 	// Copy the data
 	if _, err := io.Copy(buh.Upload, r.Body); err != nil {
 		ctxu.GetLogger(buh).Errorf("unknown error copying into upload: %v", err)
-		buh.Errors = append(buh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+		buh.Errors = append(buh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 		return
 	}
 
 	if err := buh.blobUploadResponse(w, r, false); err != nil {
-		buh.Errors = append(buh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+		buh.Errors = append(buh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 		return
 	}
 
@@ -192,7 +192,7 @@ func (buh *blobUploadHandler) PatchBlobData(w http.ResponseWriter, r *http.Reque
 // url of the blob.
 func (buh *blobUploadHandler) PutBlobUploadComplete(w http.ResponseWriter, r *http.Request) {
 	if buh.Upload == nil {
-		buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeBlobUploadUnknown))
+		buh.Errors = append(buh.Errors, v2.ErrorCodeBlobUploadUnknown)
 		return
 	}
 
@@ -200,21 +200,21 @@ func (buh *blobUploadHandler) PutBlobUploadComplete(w http.ResponseWriter, r *ht
 
 	if dgstStr == "" {
 		// no digest? return error, but allow retry.
-		buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeDigestInvalid, "digest missing"))
+		buh.Errors = append(buh.Errors, v2.ErrorCodeDigestInvalid.WithDetail("digest missing"))
 		return
 	}
 
 	dgst, err := digest.ParseDigest(dgstStr)
 	if err != nil {
 		// no digest? return error, but allow retry.
-		buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeDigestInvalid, "digest parsing failed"))
+		buh.Errors = append(buh.Errors, v2.ErrorCodeDigestInvalid.WithDetail("digest parsing failed"))
 		return
 	}
 
 	// Read in the data, if any.
 	if _, err := io.Copy(buh.Upload, r.Body); err != nil {
 		ctxu.GetLogger(buh).Errorf("unknown error copying into upload: %v", err)
-		buh.Errors = append(buh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+		buh.Errors = append(buh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 		return
 	}
 
@@ -229,14 +229,14 @@ func (buh *blobUploadHandler) PutBlobUploadComplete(w http.ResponseWriter, r *ht
 	if err != nil {
 		switch err := err.(type) {
 		case distribution.ErrBlobInvalidDigest:
-			buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeDigestInvalid, err))
+			buh.Errors = append(buh.Errors, v2.ErrorCodeDigestInvalid.WithDetail(err))
 		default:
 			switch err {
 			case distribution.ErrBlobInvalidLength, distribution.ErrBlobDigestUnsupported:
-				buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeBlobUploadInvalid, err))
+				buh.Errors = append(buh.Errors, v2.ErrorCodeBlobUploadInvalid.WithDetail(err))
 			default:
 				ctxu.GetLogger(buh).Errorf("unknown error completing upload: %#v", err)
-				buh.Errors = append(buh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+				buh.Errors = append(buh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 			}
 
 		}
@@ -253,7 +253,7 @@ func (buh *blobUploadHandler) PutBlobUploadComplete(w http.ResponseWriter, r *ht
 	// Build our canonical blob url
 	blobURL, err := buh.urlBuilder.BuildBlobURL(buh.Repository.Name(), desc.Digest)
 	if err != nil {
-		buh.Errors = append(buh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+		buh.Errors = append(buh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 		return
 	}
 
@@ -266,14 +266,14 @@ func (buh *blobUploadHandler) PutBlobUploadComplete(w http.ResponseWriter, r *ht
 // CancelBlobUpload cancels an in-progress upload of a blob.
 func (buh *blobUploadHandler) CancelBlobUpload(w http.ResponseWriter, r *http.Request) {
 	if buh.Upload == nil {
-		buh.Errors = append(buh.Errors, errcode.NewError(v2.ErrorCodeBlobUploadUnknown))
+		buh.Errors = append(buh.Errors, v2.ErrorCodeBlobUploadUnknown)
 		return
 	}
 
 	w.Header().Set("Docker-Upload-UUID", buh.UUID)
 	if err := buh.Upload.Cancel(buh); err != nil {
 		ctxu.GetLogger(buh).Errorf("error encountered canceling upload: %v", err)
-		buh.Errors = append(buh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+		buh.Errors = append(buh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 	}
 
 	w.WriteHeader(http.StatusNoContent)

docs/handlers/helpers.go

@@ -16,9 +16,14 @@ func serveJSON(w http.ResponseWriter, v interface{}) error {
 	sc := http.StatusInternalServerError
 
 	if errs, ok := v.(errcode.Errors); ok && len(errs) > 0 {
-		sc = errs[0].Code.Descriptor().HTTPStatusCode
+		if err, ok := errs[0].(errcode.ErrorCoder); ok {
-		if sc == 0 {
+			if sc2 := err.ErrorCode().Descriptor().HTTPStatusCode; sc2 != 0 {
-			sc = http.StatusInternalServerError
+				sc = sc2
+			}
+		}
+	} else if err, ok := v.(errcode.ErrorCoder); ok {
+		if sc2 := err.ErrorCode().Descriptor().HTTPStatusCode; sc2 != 0 {
+			sc = sc2
 		}
 	}
 

docs/handlers/images.go

@@ -64,7 +64,7 @@ func (imh *imageManifestHandler) GetImageManifest(w http.ResponseWriter, r *http
 	}
 
 	if err != nil {
-		imh.Errors = append(imh.Errors, errcode.NewError(v2.ErrorCodeManifestUnknown, err))
+		imh.Errors = append(imh.Errors, v2.ErrorCodeManifestUnknown.WithDetail(err))
 		return
 	}
 
@@ -72,7 +72,7 @@ func (imh *imageManifestHandler) GetImageManifest(w http.ResponseWriter, r *http
 	if imh.Digest == "" {
 		dgst, err := digestManifest(imh, sm)
 		if err != nil {
-			imh.Errors = append(imh.Errors, errcode.NewError(v2.ErrorCodeDigestInvalid, err))
+			imh.Errors = append(imh.Errors, v2.ErrorCodeDigestInvalid.WithDetail(err))
 			return
 		}
 
@@ -93,13 +93,13 @@ func (imh *imageManifestHandler) PutImageManifest(w http.ResponseWriter, r *http
 
 	var manifest manifest.SignedManifest
 	if err := dec.Decode(&manifest); err != nil {
-		imh.Errors = append(imh.Errors, errcode.NewError(v2.ErrorCodeManifestInvalid, err))
+		imh.Errors = append(imh.Errors, v2.ErrorCodeManifestInvalid.WithDetail(err))
 		return
 	}
 
 	dgst, err := digestManifest(imh, &manifest)
 	if err != nil {
-		imh.Errors = append(imh.Errors, errcode.NewError(v2.ErrorCodeDigestInvalid, err))
+		imh.Errors = append(imh.Errors, v2.ErrorCodeDigestInvalid.WithDetail(err))
 		return
 	}
 
@@ -107,7 +107,7 @@ func (imh *imageManifestHandler) PutImageManifest(w http.ResponseWriter, r *http
 	if imh.Tag != "" {
 		if manifest.Tag != imh.Tag {
 			ctxu.GetLogger(imh).Errorf("invalid tag on manifest payload: %q != %q", manifest.Tag, imh.Tag)
-			imh.Errors = append(imh.Errors, errcode.NewError(v2.ErrorCodeTagInvalid))
+			imh.Errors = append(imh.Errors, v2.ErrorCodeTagInvalid)
 			return
 		}
 
@@ -115,11 +115,11 @@ func (imh *imageManifestHandler) PutImageManifest(w http.ResponseWriter, r *http
 	} else if imh.Digest != "" {
 		if dgst != imh.Digest {
 			ctxu.GetLogger(imh).Errorf("payload digest does match: %q != %q", dgst, imh.Digest)
-			imh.Errors = append(imh.Errors, errcode.NewError(v2.ErrorCodeDigestInvalid))
+			imh.Errors = append(imh.Errors, v2.ErrorCodeDigestInvalid)
 			return
 		}
 	} else {
-		imh.Errors = append(imh.Errors, errcode.NewError(v2.ErrorCodeTagInvalid, "no tag or digest specified"))
+		imh.Errors = append(imh.Errors, v2.ErrorCodeTagInvalid.WithDetail("no tag or digest specified"))
 		return
 	}
 
@@ -131,19 +131,19 @@ func (imh *imageManifestHandler) PutImageManifest(w http.ResponseWriter, r *http
 			for _, verificationError := range err {
 				switch verificationError := verificationError.(type) {
 				case distribution.ErrManifestBlobUnknown:
-					imh.Errors = append(imh.Errors, errcode.NewError(v2.ErrorCodeBlobUnknown, verificationError.Digest))
+					imh.Errors = append(imh.Errors, v2.ErrorCodeBlobUnknown.WithDetail(verificationError.Digest))
 				case distribution.ErrManifestUnverified:
-					imh.Errors = append(imh.Errors, errcode.NewError(v2.ErrorCodeManifestUnverified))
+					imh.Errors = append(imh.Errors, v2.ErrorCodeManifestUnverified)
 				default:
 					if verificationError == digest.ErrDigestInvalidFormat {
-						imh.Errors = append(imh.Errors, errcode.NewError(v2.ErrorCodeDigestInvalid))
+						imh.Errors = append(imh.Errors, v2.ErrorCodeDigestInvalid)
 					} else {
-						imh.Errors = append(imh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, verificationError))
+						imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown, verificationError)
 					}
 				}
 			}
 		default:
-			imh.Errors = append(imh.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+			imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 		}
 
 		return
@@ -172,7 +172,7 @@ func (imh *imageManifestHandler) DeleteImageManifest(w http.ResponseWriter, r *h
 	// tag index entries a serious problem in eventually consistent storage.
 	// Once we work out schema version 2, the full deletion system will be
 	// worked out and we can add support back.
-	imh.Errors = append(imh.Errors, errcode.NewError(v2.ErrorCodeUnsupported))
+	imh.Errors = append(imh.Errors, v2.ErrorCodeUnsupported)
 }
 
 // digestManifest takes a digest of the given manifest. This belongs somewhere

docs/handlers/tags.go

@@ -40,9 +40,9 @@ func (th *tagsHandler) GetTags(w http.ResponseWriter, r *http.Request) {
 	if err != nil {
 		switch err := err.(type) {
 		case distribution.ErrRepositoryUnknown:
-			th.Errors = append(th.Errors, errcode.NewError(v2.ErrorCodeNameUnknown, map[string]string{"name": th.Repository.Name()}))
+			th.Errors = append(th.Errors, v2.ErrorCodeNameUnknown.WithDetail(map[string]string{"name": th.Repository.Name()}))
 		default:
-			th.Errors = append(th.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+			th.Errors = append(th.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 		}
 		return
 	}
@@ -54,7 +54,7 @@ func (th *tagsHandler) GetTags(w http.ResponseWriter, r *http.Request) {
 		Name: th.Repository.Name(),
 		Tags: tags,
 	}); err != nil {
-		th.Errors = append(th.Errors, errcode.NewError(errcode.ErrorCodeUnknown, err))
+		th.Errors = append(th.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
 		return
 	}
 }