feat(routes): better error message in case of missing annotations (#1150)

putting this info into error detail would be ideal, but skopeo
doesn't print them, so overwrite the error message.

Signed-off-by: Petu Eusebiu <peusebiu@cisco.com>

pkg/extensions/lint/lint.go

@@ -5,10 +5,13 @@ package lint
 
 import (
 	"encoding/json"
+	"fmt"
 
 	godigest "github.com/opencontainers/go-digest"
 	ispec "github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/pkg/errors"
 
+	zerr "zotregistry.io/zot/errors"
 	"zotregistry.io/zot/pkg/extensions/config"
 	"zotregistry.io/zot/pkg/log"
 	"zotregistry.io/zot/pkg/storage"
@@ -98,10 +101,11 @@ func (linter *Linter) CheckMandatoryAnnotations(repo string, manifestDigest godi
 
 	missingAnnotations = getMissingAnnotations(mandatoryAnnotationsMap)
 	if len(missingAnnotations) > 0 {
-		linter.log.Error().Msgf("linter: manifest %s / config %s are missing annotations: %s",
+		msg := fmt.Sprintf("\nlinter: manifest %s\nor config %s\nis missing the next annotations: %s",
 			string(manifestDigest), string(configDigest), missingAnnotations)
+		linter.log.Error().Msg(msg)
 
-		return false, nil
+		return false, errors.WithMessage(zerr.ErrImageLintAnnotations, msg)
 	}
 
 	return true, nil

pkg/extensions/lint/lint_test.go

@@ -636,7 +636,7 @@ func TestVerifyMandatoryAnnotationsFunction(t *testing.T) {
 			log.NewLogger("debug", ""), monitoring.NewMetricsServer(false, log.NewLogger("debug", "")), linter, nil)
 
 		pass, err := linter.CheckMandatoryAnnotations("zot-test", digest, imgStore)
-		So(err, ShouldBeNil)
+		So(err, ShouldNotBeNil)
 		So(pass, ShouldBeFalse)
 	})