feat: Add build flag to build w/o messging capability

Signed-off-by: Leonard Goodell <[email protected]>

Author: Leonard Goodell

messaging/factory.go

@@ -1,5 +1,8 @@
+//go:build !no_messagebus
+// +build !no_messagebus
+
 //
-// Copyright (c) 2019 Intel Corporation
+// Copyright (c) 2021 Intel Corporation
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

messaging/factory_noop.go

@@ -0,0 +1,33 @@
+//go:build no_messagebus
+// +build no_messagebus
+
+//
+// Copyright (c) 2021 Intel Corporation
+//
+// 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 messaging
+
+import (
+	"errors"
+
+	"github.com/edgexfoundry/go-mod-messaging/v2/pkg/types"
+)
+
+// NewMessageClient is noop implementation when service doesn't need the message bus.
+// This is need when this module is included in the common go-mod-bootstrap, but some service
+// such as security service have no need for messaging.
+func NewMessageClient(msgConfig types.MessageBusConfig) (MessageClient, error) {
+	return nil, errors.New("messaging was disabled during build with the no_messagebus build flag")
+}