Merge pull request #711 from stevvooe/errors-marshaling

Initial implementation of API errors data structure
This commit is contained in:
Olivier Gambier 2014-11-10 16:54:12 -08:00
commit 7f75e6368d
2 changed files with 254 additions and 0 deletions

177
errors.go Normal file
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package registry
import (
"fmt"
"strings"
)
// 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
const (
ErrorCodeUnknown ErrorCode = iota
// The following errors can happen during a layer upload.
ErrorCodeInvalidChecksum
ErrorCodeInvalidLength
ErrorCodeInvalidTarsum
// The following errors can happen during manifest upload.
ErrorCodeInvalidName
ErrorCodeInvalidTag
ErrorCodeUnverifiedManifest
ErrorCodeUnknownLayer
ErrorCodeUntrustedSignature
)
var errorCodeStrings = map[ErrorCode]string{
ErrorCodeUnknown: "UNKNOWN",
ErrorCodeInvalidChecksum: "INVALID_CHECKSUM",
ErrorCodeInvalidLength: "INVALID_LENGTH",
ErrorCodeInvalidTarsum: "INVALID_TARSUM",
ErrorCodeInvalidName: "INVALID_NAME",
ErrorCodeInvalidTag: "INVALID_TAG",
ErrorCodeUnverifiedManifest: "UNVERIFIED_MANIFEST",
ErrorCodeUnknownLayer: "UNKNOWN_LAYER",
ErrorCodeUntrustedSignature: "UNTRUSTED_SIGNATURE",
}
var errorCodesMessages = map[ErrorCode]string{
ErrorCodeUnknown: "unknown error",
ErrorCodeInvalidChecksum: "provided checksum did not match uploaded content",
ErrorCodeInvalidLength: "provided length did not match content length",
ErrorCodeInvalidTarsum: "provided tarsum did not match binary content",
ErrorCodeInvalidName: "Manifest name did not match URI",
ErrorCodeInvalidTag: "Manifest tag did not match URI",
ErrorCodeUnverifiedManifest: "Manifest failed signature validation",
ErrorCodeUnknownLayer: "Referenced layer not available",
ErrorCodeUntrustedSignature: "Manifest signed by untrusted source",
}
var stringToErrorCode map[string]ErrorCode
func init() {
stringToErrorCode = make(map[string]ErrorCode, len(errorCodeStrings))
// Build up reverse error code map
for k, v := range errorCodeStrings {
stringToErrorCode[v] = k
}
}
// ParseErrorCode attempts to parse the error code string, returning
// ErrorCodeUnknown if the error is not known.
func ParseErrorCode(s string) ErrorCode {
ec, ok := stringToErrorCode[s]
if !ok {
return ErrorCodeUnknown
}
return ec
}
// String returns the canonical identifier for this error code.
func (ec ErrorCode) String() string {
s, ok := errorCodeStrings[ec]
if !ok {
return errorCodeStrings[ErrorCodeUnknown]
}
return s
}
func (ec ErrorCode) Message() string {
m, ok := errorCodesMessages[ec]
if !ok {
return errorCodesMessages[ErrorCodeUnknown]
}
return m
}
func (ec ErrorCode) MarshalText() (text []byte, err error) {
return []byte(ec.String()), nil
}
func (ec *ErrorCode) UnmarshalText(text []byte) error {
*ec = stringToErrorCode[string(text)]
return nil
}
type Error struct {
Code ErrorCode `json:"code,omitempty"`
Message string `json:"message,omitempty"`
Detail interface{} `json:"detail,omitempty"`
}
// Error returns a human readable representation of the error.
func (e Error) Error() string {
return fmt.Sprintf("%s: %s",
strings.Title(strings.Replace(e.Code.String(), "_", " ", -1)),
e.Message)
}
// Errors provides the envelope for multiple errors and a few sugar methods
// for use within the application.
type Errors struct {
Errors []error `json:"errors,omitempty"`
}
// Push pushes an error on to the error stack, with the optional detail
// argument. It is a programming error (ie panic) to push more than one
// detail at a time.
func (errs *Errors) Push(code ErrorCode, details ...interface{}) {
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]
}
errs.PushErr(Error{
Code: code,
Message: code.Message(),
Detail: detail,
})
}
// PushErr pushes an error interface onto the error stack.
func (errs *Errors) PushErr(err error) {
errs.Errors = append(errs.Errors, err)
}
func (errs *Errors) Error() string {
switch len(errs.Errors) {
case 0:
return "<nil>"
case 1:
return errs.Errors[0].Error()
default:
msg := "errors:\n"
for _, err := range errs.Errors {
msg += err.Error() + "\n"
}
return msg
}
}
// detailUnknownLayer provides detail for unknown layer errors, returned by
// image manifest push for layers that are not yet transferred. This intended
// to only be used on the backend to return detail for this specific error.
type DetailUnknownLayer struct {
// Unknown should contain the contents of a layer descriptor, which is a
// single json object with the key "blobSum" currently.
Unknown struct {
// BlobSum contains the uniquely identifying tarsum of the layer.
BlobSum string `json:"blobSum"`
} `json:"unknown"`
}

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errors_test.go Normal file
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package registry
import (
"encoding/json"
"testing"
)
// TestErrorCodes ensures that error code format, mappings and
// marshaling/unmarshaling. round trips are stable.
func TestErrorCodes(t *testing.T) {
for ec, _ := range errorCodeStrings {
if ec.String() != errorCodeStrings[ec] {
t.Fatalf("error code string incorrect: %q != %q", ec.String(), errorCodeStrings[ec])
}
if ec.Message() != errorCodesMessages[ec] {
t.Fatalf("incorrect message for error code %v: %q != !q", ec, ec.Message(), errorCodesMessages[ec])
}
// Serialize the error code using the json library to ensure that we
// get a string and it works round trip.
p, err := json.Marshal(ec)
if err != nil {
t.Fatalf("error marshaling error code %v: %v", ec, err)
}
if len(p) <= 0 {
t.Fatalf("expected content in marshaled before for error code %v: %v", ec)
}
// First, unmarshal to interface and ensure we have a string.
var ecUnspecified interface{}
if err := json.Unmarshal(p, &ecUnspecified); err != nil {
t.Fatalf("error unmarshaling error code %v: %v", ec, err)
}
if _, ok := ecUnspecified.(string); !ok {
t.Fatalf("expected a string for error code %v on unmarshal got a %T", ec, ecUnspecified)
}
// Now, unmarshal with the error code type and ensure they are equal
var ecUnmarshaled ErrorCode
if err := json.Unmarshal(p, &ecUnmarshaled); err != nil {
t.Fatalf("error unmarshaling error code %v: %v", ec, err)
}
if ecUnmarshaled != ec {
t.Fatalf("unexpected error code during error code marshal/unmarshal: %v != %v", ecUnmarshaled, ec)
}
}
}
// TestErrorsManagement does a quick check of the Errors type to ensure that
// members are properly pushed and marshaled.
func TestErrorsManagement(t *testing.T) {
var errs Errors
errs.Push(ErrorCodeInvalidChecksum)
var detail DetailUnknownLayer
detail.Unknown.BlobSum = "sometestblobsumdoesntmatter"
errs.Push(ErrorCodeUnknownLayer, detail)
p, err := json.Marshal(errs)
if err != nil {
t.Fatalf("error marashaling errors: %v", err)
}
expectedJSON := "{\"errors\":[{\"code\":\"INVALID_CHECKSUM\",\"message\":\"provided checksum did not match uploaded content\"},{\"code\":\"UNKNOWN_LAYER\",\"message\":\"Referenced layer not available\",\"detail\":{\"unknown\":{\"blobSum\":\"sometestblobsumdoesntmatter\"}}}]}"
if string(p) != expectedJSON {
t.Fatalf("unexpected json: %q != %q", string(p), expectedJSON)
}
}