Github user MikeThomsen commented on a diff in the pull request: https://github.com/apache/nifi/pull/2614#discussion_r183234826 --- Diff: nifi-nar-bundles/nifi-pulsar-bundle/nifi-pulsar-processors/src/main/java/org/apache/nifi/processors/pulsar/pubsub/ConsumePulsar_1_X.java --- @@ -0,0 +1,206 @@ +/* + * 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.pulsar.pubsub; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashSet; +import java.util.List; +import java.util.Set; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.Future; + +import org.apache.nifi.annotation.behavior.InputRequirement; +import org.apache.nifi.annotation.documentation.CapabilityDescription; +import org.apache.nifi.annotation.documentation.Tags; +import org.apache.nifi.annotation.lifecycle.OnStopped; +import org.apache.nifi.components.PropertyDescriptor; +import org.apache.nifi.flowfile.FlowFile; +import org.apache.nifi.logging.ComponentLog; +import org.apache.nifi.processor.ProcessContext; +import org.apache.nifi.processor.ProcessSession; +import org.apache.nifi.processor.Relationship; +import org.apache.nifi.processor.exception.ProcessException; +import org.apache.nifi.processors.pulsar.AbstractPulsarConsumerProcessor; +import org.apache.nifi.pulsar.PulsarClientPool; +import org.apache.pulsar.client.api.Consumer; +import org.apache.pulsar.client.api.Message; +import org.apache.pulsar.client.api.PulsarClientException; + +@Tags({"Pulsar", "Get", "Ingest", "Ingress", "Topic", "PubSub", "Consume"}) +@CapabilityDescription("Consumes messages from Apache Pulsar " + + "The complementary NiFi processor for sending messages is PublishPulsar.") +@InputRequirement(InputRequirement.Requirement.INPUT_FORBIDDEN) +public class ConsumePulsar_1_X extends AbstractPulsarConsumerProcessor { + + private static final List<PropertyDescriptor> PROPERTIES; + private static final Set<Relationship> RELATIONSHIPS; + + static { + final List<PropertyDescriptor> properties = new ArrayList<>(); + properties.add(PULSAR_CLIENT_SERVICE); + properties.add(TOPIC); + properties.add(SUBSCRIPTION); + properties.add(ASYNC_ENABLED); + properties.add(MAX_ASYNC_REQUESTS); + properties.add(ACK_TIMEOUT); + properties.add(PRIORITY_LEVEL); + properties.add(RECEIVER_QUEUE_SIZE); + properties.add(SUBSCRIPTION_TYPE); + properties.add(MAX_WAIT_TIME); + + PROPERTIES = Collections.unmodifiableList(properties); + + final Set<Relationship> relationships = new HashSet<>(); + relationships.add(REL_SUCCESS); + RELATIONSHIPS = Collections.unmodifiableSet(relationships); + } + + @Override + public Set<Relationship> getRelationships() { + return RELATIONSHIPS; + } + + @Override + protected List<PropertyDescriptor> getSupportedPropertyDescriptors() { + return PROPERTIES; + } + + @Override + public void onTrigger(ProcessContext context, ProcessSession session) throws ProcessException { + + try { + if (context.getProperty(ASYNC_ENABLED).asBoolean()) { + // Launch consumers + consumeAsync(context, session); + + // Handle completed consumers + handleAsync(context, session); + + } else { + consume(context, session); + } + } catch (PulsarClientException e) { + getLogger().error("Unable to consume from Pulsar Topic ", e); + context.yield(); + throw new ProcessException(e); + } + + } + + private void handleAsync(ProcessContext context, ProcessSession session) { + + try { + Future<Message> done = consumerService.take(); + Message msg = done.get(); + + if (msg != null) { + FlowFile flowFile = null; + final byte[] value = msg.getData(); + if (value != null && value.length > 0) { + flowFile = session.create(); + flowFile = session.write(flowFile, out -> { + out.write(value); + }); + + session.getProvenanceReporter().receive(flowFile, "From " + getWrappedConsumer(context).getTransitURL()); + session.transfer(flowFile, REL_SUCCESS); + session.commit(); + getWrappedConsumer(context).getConsumer().acknowledgeAsync(msg); + } + } + + } catch (InterruptedException | ExecutionException | PulsarClientException e) { + getLogger().error("Trouble consuming messages ", e); + } + + } + + @OnStopped + public void close(final ProcessContext context) { + + getLogger().info("Disconnecting Pulsar Consumer"); + if (consumer != null) { + + context.getProperty(PULSAR_CLIENT_SERVICE) + .asControllerService(PulsarClientPool.class) + .getConsumerPool().evict(consumer); + } + + consumer = null; + } + + /* + * When this Processor expects to receive many small files, it may + * be advisable to create several FlowFiles from a single session + * before committing the session. Typically, this allows the Framework + * to treat the content of the newly created FlowFiles much more efficiently. + */ + private void consume(ProcessContext context, ProcessSession session) throws PulsarClientException { + + Consumer consumer = getWrappedConsumer(context).getConsumer(); + + final ComponentLog logger = getLogger(); + final Message msg; + FlowFile flowFile = null; + + try { + + msg = consumer.receive(); + final byte[] value = msg.getData(); + + if (value != null && value.length > 0) { + flowFile = session.create(); + flowFile = session.write(flowFile, out -> { + out.write(value); + }); + + session.getProvenanceReporter().receive(flowFile, "From " + context.getProperty(TOPIC).getValue()); + session.transfer(flowFile, REL_SUCCESS); + logger.info("Created {} from {} messages received from Pulsar Server and transferred to 'success'", --- End diff -- Let's do this as debug and wrap with an if statement because this will get called a lot.
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