turcsanyip commented on code in PR #6225: URL: https://github.com/apache/nifi/pull/6225#discussion_r953145681
########## nifi-nar-bundles/nifi-mqtt-bundle/nifi-mqtt-processors/src/main/java/org/apache/nifi/processors/mqtt/adapters/HiveMqV5ClientAdapter.java: ########## @@ -0,0 +1,148 @@ +/* + * 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.nifi.processors.mqtt.adapters; + +import com.hivemq.client.mqtt.datatypes.MqttQos; +import com.hivemq.client.mqtt.mqtt5.Mqtt5BlockingClient; +import com.hivemq.client.mqtt.mqtt5.message.connect.Mqtt5Connect; +import com.hivemq.client.mqtt.mqtt5.message.connect.Mqtt5ConnectBuilder; +import com.hivemq.client.mqtt.mqtt5.message.subscribe.suback.Mqtt5SubAck; +import org.apache.nifi.logging.ComponentLog; +import org.apache.nifi.processors.mqtt.common.MqttCallback; +import org.apache.nifi.processors.mqtt.common.MqttClient; +import org.apache.nifi.processors.mqtt.common.MqttConnectionProperties; +import org.apache.nifi.processors.mqtt.common.MqttException; +import org.apache.nifi.processors.mqtt.common.ReceivedMqttMessage; +import org.apache.nifi.processors.mqtt.common.StandardMqttMessage; + +import java.nio.charset.StandardCharsets; +import java.util.Objects; +import java.util.concurrent.CompletableFuture; + +public class HiveMqV5ClientAdapter implements MqttClient { + + private final Mqtt5BlockingClient mqtt5BlockingClient; + private final ComponentLog logger; + + private MqttCallback callback; + + public HiveMqV5ClientAdapter(Mqtt5BlockingClient mqtt5BlockingClient, ComponentLog logger) { + this.mqtt5BlockingClient = mqtt5BlockingClient; + this.logger = logger; + } + + @Override + public boolean isConnected() { + return mqtt5BlockingClient.getState().isConnected(); + } + + @Override + public void connect(MqttConnectionProperties connectionProperties) { + logger.debug("Connecting to broker"); + + final Mqtt5ConnectBuilder connectBuilder = Mqtt5Connect.builder() + .keepAlive(connectionProperties.getKeepAliveInterval()); + + final boolean cleanSession = connectionProperties.isCleanSession(); + connectBuilder.cleanStart(cleanSession); + if (!cleanSession) { + connectBuilder.sessionExpiryInterval(connectionProperties.getSessionExpiryInterval()); + } + + final String lastWillTopic = connectionProperties.getLastWillTopic(); + if (lastWillTopic != null) { + connectBuilder.willPublish() + .topic(lastWillTopic) + .payload(connectionProperties.getLastWillMessage().getBytes()) + .retain(connectionProperties.getLastWillRetain()) + .qos(MqttQos.fromCode(connectionProperties.getLastWillQOS())) + .applyWillPublish(); + } + + final String username = connectionProperties.getUsername(); + final String password = connectionProperties.getPassword(); + if (username != null && password != null) { + connectBuilder.simpleAuth() + .username(connectionProperties.getUsername()) + .password(password.getBytes(StandardCharsets.UTF_8)) + .applySimpleAuth(); + } + + final Mqtt5Connect mqtt5Connect = connectBuilder.build(); + mqtt5BlockingClient.connect(mqtt5Connect); + } + + @Override + public void disconnect(long disconnectTimeout) { + logger.debug("Disconnecting client"); + // Currently it is not possible to set timeout for disconnect with HiveMQ Client. (Only connect timeout exists.) + mqtt5BlockingClient.disconnect(); + } + + @Override + public void close() { + // there is no paho's close equivalent in hivemq client + } + + @Override + public void publish(String topic, StandardMqttMessage message) { + logger.debug("Publishing message to {} with QoS: {}", topic, message.getQos()); + + mqtt5BlockingClient.publishWith() + .topic(topic) + .payload(message.getPayload()) + .retain(message.isRetained()) + .qos(Objects.requireNonNull(MqttQos.fromCode(message.getQos()))) + .send(); + } + + @Override + public void subscribe(String topicFilter, int qos) { + Objects.requireNonNull(callback, "callback should be set"); + + logger.debug("Subscribing to {} with QoS: {}", topicFilter, qos); + + CompletableFuture<Mqtt5SubAck> ack = mqtt5BlockingClient.toAsync().subscribeWith() + .topicFilter(topicFilter) + .qos(Objects.requireNonNull(MqttQos.fromCode(qos))) + .callback(mqtt5Publish -> { + final ReceivedMqttMessage receivedMessage = new ReceivedMqttMessage( + mqtt5Publish.getPayloadAsBytes(), + mqtt5Publish.getQos().getCode(), + mqtt5Publish.isRetain(), + mqtt5Publish.getTopic().toString()); + callback.messageArrived(receivedMessage); + }) + .send(); + + // Setting "listener" callback is only possible with async client, though sending subscribe message + // should happen in a blocking way to make sure the processor is blocked until ack is not arrived. + ack.whenComplete((mqtt5SubAck, throwable) -> { + logger.debug("Received mqtt5 subscribe ack: {}", mqtt5SubAck.toString()); + + if (throwable != null) { + throw new MqttException("An error has occurred during sending subscribe message to broker", throwable); + } + }); Review Comment: `whenComplete()` registers an async callback, it does not block. The blocking way would be to use `ack.get()`. `whenComplete()` can also work but in this case: - in case of error (`throwable != null`), `logger.error()` must be used instead of throwing an exception in order to put the error message on the processor's bulletin - please fix the comment because this approach does not block -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
