factory.go

//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 (
	"fmt"
	"strings"

	"github.com/edgexfoundry/go-mod-messaging/v3/internal/pkg/mqtt"
	"github.com/edgexfoundry/go-mod-messaging/v3/internal/pkg/nats"
	"github.com/edgexfoundry/go-mod-messaging/v3/internal/pkg/nats/jetstream"
	"github.com/edgexfoundry/go-mod-messaging/v3/internal/pkg/redis"
	"github.com/edgexfoundry/go-mod-messaging/v3/pkg/types"
)

const (
	// MQTT messaging implementation
	MQTT = "mqtt"

	// Redis Pub/Sub messaging implementation
	Redis = "redis"

	// NatsCore implementation
	NatsCore = "nats-core"

	// NatsJetStream implementation
	NatsJetStream = "nats-jetstream"
)

// NewMessageClient is a factory function to instantiate different message client depending on
// the "Type" from the configuration
func NewMessageClient(msgConfig types.MessageBusConfig) (MessageClient, error) {

	if msgConfig.Broker.IsHostInfoEmpty() {
		return nil, fmt.Errorf("unable to create messageClient: Broker info not set")
	}

	switch lowerMsgType := strings.ToLower(msgConfig.Type); lowerMsgType {
	case MQTT:
		return mqtt.NewMQTTClient(msgConfig)
	case Redis:
		return redis.NewClient(msgConfig)
	case NatsCore:
		return nats.NewClient(msgConfig)
	case NatsJetStream:
		return jetstream.NewClient(msgConfig)
	default:
		return nil, fmt.Errorf("unknown message type '%s' requested", msgConfig.Type)
	}
}