1. docker
  2. Commit 7d4b7883815d45a0b4e1f4c50ec566e24040cb2a
Browse code

errdefs: remove "ErrAlreadyExists" because it's not an error

The `ErrAlreadyExists` error is used for 304 statuses, which
is not an error-condition, so should probably not be defined
as part of the errdefs package.

This patch removes the `ErrAlreadyExists` interface, and related
helpers, as it was currently not used.

Note that a 304 status can fulfil certain use-cases, but (refering
to https://www.codetinkerer.com/2015/12/04/choosing-an-http-status-code.html)
could probably be handled by a 200 OK, unless we want to perform
caching in the client.

If we do want to use 304 statuses, perhaps we need a separate class
of "errors" for this (?).

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Sebastiaan van Stijn authored on 2018/12/31 21:10:29
Showing 5 changed files
errdefs/defs.go
History View file @ 7d4b788
... ... 
@@ -43,11 +43,6 @@ type ErrNotModified interface {
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 	NotModified()
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 }
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-// ErrAlreadyExists is a special case of ErrConflict which signals that the desired object already exists
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-type ErrAlreadyExists interface {
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-	AlreadyExists()
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-}
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-
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 // ErrNotImplemented signals that the requested action/feature is not implemented on the system as configured.
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 type ErrNotImplemented interface {
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 	NotImplemented()
errdefs/helpers.go
History View file @ 7d4b788
... ... 
@@ -130,22 +130,6 @@ func NotModified(err error) error {
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 	return errNotModified{err}
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 }
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-type errAlreadyExists struct{ error }
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-
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-func (errAlreadyExists) AlreadyExists() {}
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-
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-func (e errAlreadyExists) Cause() error {
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-	return e.error
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-}
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-
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-// AlreadyExists is a helper to create an error of the class with the same name from any error type
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-func AlreadyExists(err error) error {
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-	if err == nil || IsAlreadyExists(err) {
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-		return err
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-	}
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-	return errAlreadyExists{err}
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-}
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-
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 type errNotImplemented struct{ error }
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 func (errNotImplemented) NotImplemented() {}
errdefs/helpers_test.go
History View file @ 7d4b788
... ... 
@@ -89,19 +89,6 @@ func TestNotModified(t *testing.T) {
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 	}
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 }
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-func TestAlreadyExists(t *testing.T) {
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-	if IsAlreadyExists(errTest) {
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-		t.Fatalf("did not expect already exists error, got %T", errTest)
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-	}
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-	e := AlreadyExists(errTest)
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-	if !IsAlreadyExists(e) {
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-		t.Fatalf("expected already exists error, got %T", e)
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-	}
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-	if cause := e.(causal).Cause(); cause != errTest {
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-		t.Fatalf("causual should be errTest, got: %v", cause)
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-	}
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-}
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-
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 func TestUnauthorized(t *testing.T) {
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 	if IsUnauthorized(errTest) {
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 		t.Fatalf("did not expect unauthorized error, got %T", errTest)
errdefs/http_helpers.go
History View file @ 7d4b788
... ... 
@@ -28,7 +28,7 @@ func GetHTTPErrorStatusCode(err error) int {
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 		statusCode = http.StatusNotFound
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 	case IsInvalidParameter(err):
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 		statusCode = http.StatusBadRequest
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-	case IsConflict(err) || IsAlreadyExists(err):
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+	case IsConflict(err):
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 		statusCode = http.StatusConflict
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 	case IsUnauthorized(err):
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 		statusCode = http.StatusUnauthorized
errdefs/is.go
History View file @ 7d4b788
... ... 
@@ -15,7 +15,6 @@ func getImplementer(err error) error {
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 		ErrForbidden,
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 		ErrSystem,
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 		ErrNotModified,
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-		ErrAlreadyExists,
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 		ErrNotImplemented,
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 		ErrCancelled,
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 		ErrDeadline,
... ... 
@@ -77,12 +76,6 @@ func IsNotModified(err error) bool {
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 	return ok
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 }
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-// IsAlreadyExists returns if the passed in error is a AlreadyExists error
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-func IsAlreadyExists(err error) bool {
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-	_, ok := getImplementer(err).(ErrAlreadyExists)
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-	return ok
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-}
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-
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 // IsNotImplemented returns if the passed in error is an ErrNotImplemented
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 func IsNotImplemented(err error) bool {
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 	_, ok := getImplementer(err).(ErrNotImplemented)