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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.spark.streaming.mqtt
import java.io.IOException
import java.util.concurrent.Executors
import java.util.Properties
import scala.collection.JavaConversions._
import scala.collection.Map
import scala.collection.mutable.HashMap
import scala.reflect.ClassTag
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken
import org.eclipse.paho.client.mqttv3.MqttCallback
import org.eclipse.paho.client.mqttv3.MqttClient
import org.eclipse.paho.client.mqttv3.MqttClientPersistence
import org.eclipse.paho.client.mqttv3.MqttException
import org.eclipse.paho.client.mqttv3.MqttMessage
import org.eclipse.paho.client.mqttv3.MqttTopic
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence
import org.apache.spark.Logging
import org.apache.spark.storage.StorageLevel
import org.apache.spark.streaming.StreamingContext
import org.apache.spark.streaming.dstream._
import org.apache.spark.streaming.receiver.Receiver
/**
* Input stream that subscribe messages from a Mqtt Broker.
* Uses eclipse paho as MqttClient http://www.eclipse.org/paho/
* @param brokerUrl Url of remote mqtt publisher
* @param topic topic name to subscribe to
* @param storageLevel RDD storage level.
*/
private[streaming]
class MQTTInputDStream(
@transient ssc_ : StreamingContext,
brokerUrl: String,
topic: String,
storageLevel: StorageLevel
) extends ReceiverInputDStream[String](ssc_) {
def getReceiver(): Receiver[String] = {
new MQTTReceiver(brokerUrl, topic, storageLevel)
}
}
private[streaming]
class MQTTReceiver(
brokerUrl: String,
topic: String,
storageLevel: StorageLevel
) extends Receiver[String](storageLevel) {
def onStop() {
}
def onStart() {
// Set up persistence for messages
val persistence = new MemoryPersistence()
// Initializing Mqtt Client specifying brokerUrl, clientID and MqttClientPersistance
val client = new MqttClient(brokerUrl, MqttClient.generateClientId(), persistence)
// Callback automatically triggers as and when new message arrives on specified topic
val callback = new MqttCallback() {
// Handles Mqtt message
override def messageArrived(topic: String, message: MqttMessage) {
store(new String(message.getPayload(),"utf-8"))
}
override def deliveryComplete(token: IMqttDeliveryToken) {
}
override def connectionLost(cause: Throwable) {
restart("Connection lost ", cause)
}
}
// Set up callback for MqttClient. This needs to happen before
// connecting or subscribing, otherwise messages may be lost
client.setCallback(callback)
// Connect to MqttBroker
client.connect()
// Subscribe to Mqtt topic
client.subscribe(topic)
}
}
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