Github user markap14 commented on a diff in the pull request:
https://github.com/apache/nifi/pull/200#discussion_r51601774
--- Diff:
nifi-nar-bundles/nifi-amqp-bundle/nifi-amqp-processors/src/main/java/org/apache/nifi/amqp/processors/AMQPPublisher.java
---
@@ -0,0 +1,134 @@
+/*
+ * 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.amqp.processors;
+
+import java.io.IOException;
+
+import org.apache.nifi.logging.ProcessorLog;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.rabbitmq.client.AMQP.BasicProperties;
+import com.rabbitmq.client.Connection;
+import com.rabbitmq.client.ReturnListener;
+
+/**
+ * Generic publisher of messages to AMQP-based messaging system. It is
based on
+ * RabbitMQ client API (https://www.rabbitmq.com/api-guide.html)
+ */
+final class AMQPPublisher extends AMQPWorker {
+
+ private final static Logger logger =
LoggerFactory.getLogger(AMQPPublisher.class);
+
+ private final String exchangeName;
+
+ private final String routingKey;
+
+ private final ProcessorLog processLog;
+
+ /**
+ * Creates an instance of this publisher
+ *
+ * @param connection
+ * instance of AMQP {@link Connection}
+ * @param exchangeName
+ * the name of AMQP exchange to which messages will be
published.
+ * If not provided 'default' exchange will be used.
+ * @param routingKey
+ * (required) the name of the routingKey to be used by
AMQP-based
+ * system to route messages to its final destination
(queue).
+ */
+ AMQPPublisher(Connection connection, String exchangeName, String
routingKey, ProcessorLog processLog) {
+ super(connection);
+ this.processLog = processLog;
+ this.validateStringProperty("routingKey", routingKey);
+ this.exchangeName = exchangeName == null ? "" :
exchangeName.trim();
+ if (this.exchangeName.length() == 0) {
+ logger.info("The 'exchangeName' is not specified. Messages
will be sent to default exchange");
+ }
+
+ this.routingKey = routingKey;
+ this.channel.addReturnListener(new UndeliverableMessageLogger());
+ logger.info("Successfully connected AMQPPublisher to " +
connection.toString() + " and '" + this.exchangeName
+ + "' exchange with '" + routingKey + "' as a routing
key.");
+ }
+
+ /**
+ * Publishes message without any AMQP properties (see
+ * {@link BasicProperties}) to a pre-defined AMQP Exchange.
+ *
+ * @param bytes
+ * bytes representing a message.
+ */
+ void publish(byte[] bytes) {
+ this.publish(bytes, null);
+ }
+
+ /**
+ * Publishes message with provided AMQP properties (see
+ * {@link BasicProperties}) to a pre-defined AMQP Exchange.
+ *
+ * @param bytes
+ * bytes representing a message.
+ * @param properties
+ * instance of {@link BasicProperties}
+ */
+ void publish(byte[] bytes, BasicProperties properties) {
+ if (this.channel.isOpen()) {
+ try {
+ this.channel.basicPublish(this.exchangeName,
this.routingKey, true, properties, bytes);
+ } catch (Exception e) {
+ throw new IllegalStateException("Failed to publish to '" +
+ this.exchangeName + "' with '" + this.routingKey +
"'.", e);
+ }
+ } else {
+ throw new IllegalStateException("This instance of
AMQPPublisher is invalid since "
+ + "its publishigChannel is closed");
+ }
+ }
+
+ /**
+ *
+ */
+ @Override
+ public String toString() {
+ return super.toString() + ", EXCHANGE:" + this.exchangeName + ",
ROUTING_KEY:" + this.routingKey;
+ }
+
+ /**
+ * Listener to listen and WARN-log undeliverable messages which are
returned
--- End diff --
If I am understanding this comment correctly, it is possible, if the AMQP
Broker is not setup properly, to lose messages? Is that accurate? If so, I
think we need to be sure to explicitly state this in the PublishAMQP's
@CapabilityDescription
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