Add message queue service factory (#1537)

pkg/mqtrigger/validator/validator.go

@@ -0,0 +1,59 @@
+/*
+Copyright 2020 The Fission 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 validator
+
+import (
+	"sync"
+)
+
+var (
+	topicValidators = make(map[string]TopicValidator)
+	lock            = sync.Mutex{}
+)
+
+type (
+	TopicValidator func(topic string) bool
+)
+
+func Register(mqType string, validator TopicValidator) {
+	lock.Lock()
+	defer lock.Unlock()
+
+	if validator == nil {
+		panic("Nil message queue topic validator")
+	}
+
+	_, registered := topicValidators[mqType]
+	if registered {
+		panic("Message queue topic validator already register")
+	}
+
+	topicValidators[mqType] = validator
+}
+
+func IsValidTopic(mqType string, topic string) bool {
+	validator, registered := topicValidators[mqType]
+	if !registered {
+		return false
+	}
+	return validator(topic)
+}
+
+func IsValidMessageQueue(mqType string) bool {
+	_, registered := topicValidators[mqType]
+	return registered
+}