database: Add StorageError type

database/database.go

@@ -17,7 +17,6 @@
 package database
 
 import (
-	"errors"
 	"fmt"
 	"time"
 
@@ -27,20 +26,20 @@ import (
 var (
 	// ErrBackendException is an error that occurs when the database backend
 	// does not work properly (ie. unreachable).
-	ErrBackendException = errors.New("database: an error occurred when querying the backend")
+	ErrBackendException = NewStorageError("an error occurred when querying the backend")
 
 	// ErrInconsistent is an error that occurs when a database consistency check
 	// fails (i.e. when an entity which is supposed to be unique is detected
 	// twice)
-	ErrInconsistent = errors.New("database: inconsistent database")
+	ErrInconsistent = NewStorageError("inconsistent database")
 
 	// ErrInvalidParameters is an error that occurs when the parameters are not valid.
-	ErrInvalidParameters = errors.New("database: parameters are not valid")
+	ErrInvalidParameters = NewStorageError("parameters are not valid")
 
 	// ErrMissingEntities is an error that occurs when an associated immutable
 	// entity doesn't exist in the database. This error can indicate a wrong
 	// implementation or corrupted database.
-	ErrMissingEntities = errors.New("database: associated immutable entities are missing in the database")
+	ErrMissingEntities = NewStorageError("associated immutable entities are missing in the database")
 )
 
 // RegistrableComponentConfig is a configuration block that can be used to

database/error.go

@@ -0,0 +1,35 @@
+// Copyright 2019 clair authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package database
+
+// StorageError is database error
+type StorageError struct {
+	reason   string
+	original error
+}
+
+func (e *StorageError) Error() string {
+	return e.reason
+}
+
+// NewStorageErrorWithInternalError creates a new database error
+func NewStorageErrorWithInternalError(reason string, originalError error) *StorageError {
+	return &StorageError{reason, originalError}
+}
+
+// NewStorageError creates a new database error
+func NewStorageError(reason string) *StorageError {
+	return &StorageError{reason, nil}
+}