Github user olegz commented on a diff in the pull request: https://github.com/apache/nifi/pull/392#discussion_r63530121 --- Diff: nifi-nar-bundles/nifi-mqtt-bundle/nifi-mqtt-processors/src/main/java/org/apache/nifi/processors/mqtt/ConsumeMQTT.java --- @@ -0,0 +1,341 @@ +/* + * 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; + +import org.apache.nifi.annotation.behavior.InputRequirement; +import org.apache.nifi.annotation.behavior.TriggerSerially; +import org.apache.nifi.annotation.lifecycle.OnStopped; +import org.apache.nifi.components.PropertyDescriptor; +import org.apache.nifi.components.ValidationContext; +import org.apache.nifi.components.ValidationResult; +import org.apache.nifi.flowfile.FlowFile; +import org.apache.nifi.annotation.behavior.WritesAttribute; +import org.apache.nifi.annotation.behavior.WritesAttributes; +import org.apache.nifi.annotation.lifecycle.OnScheduled; +import org.apache.nifi.annotation.lifecycle.OnUnscheduled; +import org.apache.nifi.annotation.documentation.CapabilityDescription; +import org.apache.nifi.annotation.documentation.SeeAlso; +import org.apache.nifi.annotation.documentation.Tags; +import org.apache.nifi.processor.ProcessContext; +import org.apache.nifi.processor.ProcessorInitializationContext; +import org.apache.nifi.processor.Relationship; +import org.apache.nifi.processor.exception.ProcessException; +import org.apache.nifi.processor.ProcessSession; +import org.apache.nifi.processor.io.OutputStreamCallback; + +import org.apache.nifi.processor.util.StandardValidators; +import org.apache.nifi.processors.mqtt.common.AbstractMQTTProcessor; +import org.apache.nifi.processors.mqtt.common.MQTTQueueMessage; +import org.eclipse.paho.client.mqttv3.MqttCallback; +import org.eclipse.paho.client.mqttv3.MqttException; +import org.eclipse.paho.client.mqttv3.MqttMessage; +import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken; + +import java.util.Collection; +import java.util.Collections; +import java.util.HashMap; +import java.util.HashSet; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.concurrent.LinkedBlockingQueue; +import java.io.OutputStream; +import java.io.IOException; + +import static org.apache.nifi.processors.mqtt.ConsumeMQTT.BROKER_ATTRIBUTE_KEY; +import static org.apache.nifi.processors.mqtt.ConsumeMQTT.IS_DUPLICATE_ATTRIBUTE_KEY; +import static org.apache.nifi.processors.mqtt.ConsumeMQTT.IS_RETAINED_ATTRIBUTE_KEY; +import static org.apache.nifi.processors.mqtt.ConsumeMQTT.QOS_ATTRIBUTE_KEY; +import static org.apache.nifi.processors.mqtt.ConsumeMQTT.TOPIC_ATTRIBUTE_KEY; +import static org.apache.nifi.processors.mqtt.common.MqttConstants.ALLOWABLE_VALUE_QOS_0; +import static org.apache.nifi.processors.mqtt.common.MqttConstants.ALLOWABLE_VALUE_QOS_1; +import static org.apache.nifi.processors.mqtt.common.MqttConstants.ALLOWABLE_VALUE_QOS_2; + + +@Tags({"subscribe", "MQTT", "IOT", "consume", "listen"}) +@InputRequirement(InputRequirement.Requirement.INPUT_FORBIDDEN) +@TriggerSerially // we want to have a consistent mapping between clientID and MQTT connection +@CapabilityDescription("Subscribes to a topic and receives messages from an MQTT broker") +@SeeAlso({PublishMQTT.class}) +@WritesAttributes({ + @WritesAttribute(attribute=BROKER_ATTRIBUTE_KEY, description="MQTT broker that was the message source"), + @WritesAttribute(attribute=TOPIC_ATTRIBUTE_KEY, description="MQTT topic on which message was received"), + @WritesAttribute(attribute=QOS_ATTRIBUTE_KEY, description="The quality of service for this message."), + @WritesAttribute(attribute=IS_DUPLICATE_ATTRIBUTE_KEY, description="Whether or not this message might be a duplicate of one which has already been received."), + @WritesAttribute(attribute=IS_RETAINED_ATTRIBUTE_KEY, description="Whether or not this message was from a current publisher, or was \"retained\" by the server as the last message published " + + "on the topic.")}) +public class ConsumeMQTT extends AbstractMQTTProcessor { + public final static String BROKER_ATTRIBUTE_KEY = "mqtt.broker"; + public final static String TOPIC_ATTRIBUTE_KEY = "mqtt.topic"; + public final static String QOS_ATTRIBUTE_KEY = "mqtt.qos"; + public final static String IS_DUPLICATE_ATTRIBUTE_KEY = "mqtt.isDuplicate"; + public final static String IS_RETAINED_ATTRIBUTE_KEY = "mqtt.isRetained"; + + public static final PropertyDescriptor PROP_TOPIC_FILTER = new PropertyDescriptor.Builder() + .name("Topic Filter") + .description("The MQTT topic filter to designate the topics to subscribe to.") + .required(true) + .expressionLanguageSupported(false) + .addValidator(StandardValidators.NON_BLANK_VALIDATOR) + .build(); + + public static final PropertyDescriptor PROP_QOS = new PropertyDescriptor.Builder() + .name("Quality of Service(QoS)") + .description("The Quality of Service(QoS) to receive the message with. Accepts values '0', '1' or '2'; '0' for 'at most once', '1' for 'at least once', '2' for 'exactly once'.") + .required(true) + .defaultValue(ALLOWABLE_VALUE_QOS_0.getValue()) + .allowableValues( + ALLOWABLE_VALUE_QOS_0, + ALLOWABLE_VALUE_QOS_1, + ALLOWABLE_VALUE_QOS_2) + .build(); + + public static final PropertyDescriptor PROP_MAX_QUEUE_SIZE = new PropertyDescriptor.Builder() + .name("Max Queue Size") + .description("The MQTT messages are always being sent to subscribers on a topic. If the 'Run Schedule' is significantly behind the rate at which the messages are arriving to this " + + "processor then a back up can occur. This property specifies the maximum number of messages this processor will hold in memory at one time.") + .required(true) + .addValidator(StandardValidators.POSITIVE_INTEGER_VALIDATOR) + .build(); + + + private static int DISCONNECT_TIMEOUT = 5000; + private long maxQueueSize; --- End diff -- Hate to be picky, but given that this is set in @OnSchduled but used elsewhere (other threads) it needs to be _volatile_.
--- If your project is set up for it, you can reply to this email and have your reply appear on GitHub as well. If your project does not have this feature enabled and wishes so, or if the feature is enabled but not working, please contact infrastructure at infrastruct...@apache.org or file a JIRA ticket with INFRA. ---