zentol commented on a change in pull request #6594: [FLINK-9311] [pubsub] Added PubSub source connector with support for checkpointing (ATLEAST_ONCE) URL: https://github.com/apache/flink/pull/6594#discussion_r233826562
########## File path: flink-connectors/flink-connector-pubsub/src/main/java/org/apache/flink/streaming/connectors/pubsub/PubSubSource.java ########## @@ -0,0 +1,315 @@ +/* + * 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.flink.streaming.connectors.pubsub; + +import org.apache.flink.api.common.functions.RuntimeContext; +import org.apache.flink.api.common.functions.StoppableFunction; +import org.apache.flink.api.common.serialization.DeserializationSchema; +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.api.java.typeutils.ResultTypeQueryable; +import org.apache.flink.configuration.Configuration; +import org.apache.flink.streaming.api.functions.source.MultipleIdsMessageAcknowledgingSourceBase; +import org.apache.flink.streaming.api.functions.source.ParallelSourceFunction; +import org.apache.flink.streaming.api.operators.StreamingRuntimeContext; +import org.apache.flink.streaming.connectors.pubsub.common.PubSubSubscriberFactory; +import org.apache.flink.streaming.connectors.pubsub.common.SerializableCredentialsProvider; + +import com.google.api.gax.core.CredentialsProvider; +import com.google.auth.Credentials; +import com.google.cloud.pubsub.v1.AckReplyConsumer; +import com.google.cloud.pubsub.v1.Subscriber; +import com.google.pubsub.v1.ProjectSubscriptionName; +import com.google.pubsub.v1.PubsubMessage; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.util.List; +import java.util.Optional; + +/** + * PubSub Source, this Source will consume PubSub messages from a subscription and Acknowledge them as soon as they have been received. + */ +public class PubSubSource<OUT> extends MultipleIdsMessageAcknowledgingSourceBase<OUT, String, AckReplyConsumer> + implements ResultTypeQueryable<OUT>, ParallelSourceFunction<OUT>, StoppableFunction { + private static final Logger LOG = LoggerFactory.getLogger(PubSubSource.class); + protected DeserializationSchema<OUT> deserializationSchema; + protected SubscriberWrapper subscriberWrapper; + + protected boolean running = true; + protected transient volatile SourceContext<OUT> sourceContext = null; + + protected PubSubSource() { + super(String.class); + } + + protected void setDeserializationSchema(DeserializationSchema<OUT> deserializationSchema) { + this.deserializationSchema = deserializationSchema; + } + + protected void setSubscriberWrapper(SubscriberWrapper subscriberWrapper) { + this.subscriberWrapper = subscriberWrapper; + } + + @Override + public void open(Configuration configuration) throws Exception { + super.open(configuration); + subscriberWrapper.initialize(); + if (hasNoCheckpointingEnabled(getRuntimeContext())) { + throw new IllegalArgumentException("The PubSubSource REQUIRES Checkpointing to be enabled and " + + "the checkpointing frequency must be MUCH lower than the PubSub timeout for it to retry a message."); + } + + getRuntimeContext().getMetricGroup().gauge("PubSubMessagesProcessedNotAcked", this::getOutstandingMessagesToAck); + getRuntimeContext().getMetricGroup().gauge("PubSubMessagesReceivedNotProcessed", subscriberWrapper::amountOfMessagesInBuffer); + } + + private boolean hasNoCheckpointingEnabled(RuntimeContext runtimeContext) { + return !(runtimeContext instanceof StreamingRuntimeContext && ((StreamingRuntimeContext) runtimeContext).isCheckpointingEnabled()); + } + + @Override + protected void acknowledgeSessionIDs(List<AckReplyConsumer> ackReplyConsumers) { + ackReplyConsumers.forEach(AckReplyConsumer::ack); + } + + @Override + public void run(SourceContext<OUT> sourceContext) throws Exception { + this.sourceContext = sourceContext; + subscriberWrapper.start(); + + while (subscriberWrapper.isRunning()) { + try { + Optional.ofNullable(subscriberWrapper.take()) + .ifPresent(this::processMessage); + } catch (InterruptedException e) { + LOG.debug("Interrupted - stop or cancel called?"); + } + } + + nackOutstandingMessages(); + + LOG.debug("Waiting for PubSubSubscriber to terminate."); + subscriberWrapper.awaitTerminated(); + } + + void processMessage(Tuple2<PubsubMessage, AckReplyConsumer> input) { + PubsubMessage message = input.f0; + AckReplyConsumer ackReplyConsumer = input.f1; + if (sourceContext == null) { + ackReplyConsumer.nack(); + return; + } + + synchronized (sourceContext.getCheckpointLock()) { + boolean alreadyProcessed = !addId(message.getMessageId()); + if (alreadyProcessed) { + return; + } + + sessionIds.add(ackReplyConsumer); + sourceContext.collect(deserializeMessage(message)); + } + } + + private Integer getOutstandingMessagesToAck() { + return this.sessionIdsPerSnapshot + .stream() + .mapToInt(tuple -> tuple.f1.size()) + .sum() + this.sessionIds.size(); + } + + private void nackOutstandingMessages() { + LOG.debug("Going to nack {} processed but not checkpointed pubsub messages.", getOutstandingMessagesToAck()); + this.sessionIdsPerSnapshot.stream() + .flatMap(tuple -> tuple.f1.stream()) + .forEach(AckReplyConsumer::nack); + this.sessionIds.forEach(AckReplyConsumer::nack); + LOG.debug("Finished nacking pubsub messages."); + } + + @Override + public void cancel() { + sourceContext = null; + subscriberWrapper.stop(); + running = false; + } + + @Override + public void stop() { + subscriberWrapper.stop(); + running = false; + } + + private OUT deserializeMessage(PubsubMessage message) { + try { + return deserializationSchema.deserialize(message.getData().toByteArray()); + } catch (IOException e) { + throw new RuntimeException(e); + } + } + + @Override + public TypeInformation<OUT> getProducedType() { + return deserializationSchema.getProducedType(); + } + + public static <OUT> PubSubSourceBuilder<OUT, ? extends PubSubSource<OUT>, ? extends PubSubSourceBuilder<OUT, ?, ?>> newBuilder() { + return new PubSubSourceBuilder<>(new PubSubSource<>()); + } + + /** + * Builder to create PubSubSource. + * + * @param <OUT> The type of objects which will be read + * @param <PSS> The type of PubSubSource + * @param <BUILDER> The type of Builder to create the PubSubSource + */ + @SuppressWarnings("unchecked") + public static class PubSubSourceBuilder<OUT, PSS extends PubSubSource<OUT>, BUILDER extends PubSubSourceBuilder<OUT, PSS, BUILDER>> { + protected PSS sourceUnderConstruction; + + private PubSubSubscriberFactory pubSubSubscriberFactory; + private SerializableCredentialsProvider serializableCredentialsProvider; + private DeserializationSchema<OUT> deserializationSchema; + private String projectName; + private String subscriptionName; + private String hostAndPort; + + protected PubSubSourceBuilder(PSS sourceUnderConstruction) { + this.sourceUnderConstruction = sourceUnderConstruction; + } + + /** + * Set the credentials. + * If this is not used then the credentials are picked up from the environment variables. + * + * @param credentials the Credentials needed to connect. + * @return The current PubSubSourceBuilder instance + */ + public BUILDER withCredentials(Credentials credentials) { + this.serializableCredentialsProvider = new SerializableCredentialsProvider(credentials); + return (BUILDER) this; + } + + /** + * Set the CredentialsProvider. + * If this is not used then the credentials are picked up from the environment variables. + * + * @param credentialsProvider the custom SerializableCredentialsProvider instance. + * @return The current PubSubSourceBuilder instance + */ + public BUILDER withCredentialsProvider(CredentialsProvider credentialsProvider) throws IOException { + return withCredentials(credentialsProvider.getCredentials()); + } + + /** + * Set the credentials to be absent. + * This means that no credentials are to be used at all. + * + * @return The current PubSubSourceBuilder instance + */ + public BUILDER withoutCredentials() { + this.serializableCredentialsProvider = SerializableCredentialsProvider.withoutCredentials(); + return (BUILDER) this; + } + + /** + * @param deserializationSchema Instance of a DeserializationSchema that converts the OUT into a byte[] + * @return The current PubSubSourceBuilder instance + */ + public BUILDER withDeserializationSchema(DeserializationSchema<OUT> deserializationSchema) { + this.deserializationSchema = deserializationSchema; + return (BUILDER) this; + } + + /** + * @param projectName The name of the project in GoogleCloudPlatform + * @param subscriptionName The name of the subscription in PubSub + * @return The current PubSubSourceBuilder instance + */ + public BUILDER withProjectSubscriptionName(String projectName, String subscriptionName) { + this.projectName = projectName; + this.subscriptionName = subscriptionName; + return (BUILDER) this; + } + + /** + * Set the custom hostname/port combination of PubSub. + * The ONLY reason to use this is during tests with the emulator provided by Google. + * + * @param hostAndPort The combination of hostname and port to connect to ("hostname:1234") + * @return The current PubSubSourceBuilder instance + */ + public BUILDER withHostAndPort(String hostAndPort) { + this.hostAndPort = hostAndPort; + return (BUILDER) this; + } + + /** + * Set a PubSubSubscriberFactory + * This allows for custom Subscriber options to be set. + * Cannot be used in combination with withHostAndPort(). + * + * @param pubSubSubscriberFactory A factory to create a {@link Subscriber} + * @return The current PubSubSourceBuilder instance + */ + public BUILDER withPubSubSubscriberFactory(PubSubSubscriberFactory pubSubSubscriberFactory) { + this.pubSubSubscriberFactory = pubSubSubscriberFactory; + return (BUILDER) this; + } + + /** + * Actually build the desired instance of the PubSubSourceBuilder. + * + * @return a brand new SourceFunction + * @throws IOException incase of a problem getting the credentials + * @throws IllegalArgumentException incase required fields were not specified. + */ + public PSS build() throws IOException { + if (serializableCredentialsProvider == null) { + serializableCredentialsProvider = SerializableCredentialsProvider.credentialsProviderFromEnvironmentVariables(); + } + if (deserializationSchema == null) { + throw new IllegalArgumentException("The deserializationSchema has not been specified."); + } + + if (pubSubSubscriberFactory != null && hostAndPort != null) { + throw new IllegalArgumentException(("withPubSubSubscriberFactory() and withHostAndPort() both called, only one may be called.")); + } + + if (projectName == null || subscriptionName == null) { + throw new IllegalArgumentException("ProjectName or SubscriptionName has not been specified."); + } + + if (pubSubSubscriberFactory == null) { + pubSubSubscriberFactory = new DefaultPubSubSubscriberFactory(); + if (hostAndPort != null) { + ((DefaultPubSubSubscriberFactory) pubSubSubscriberFactory).withHostAndPort(hostAndPort); + } + } + + SubscriberWrapper subscriberWrapper = new SubscriberWrapper(serializableCredentialsProvider, ProjectSubscriptionName.of(projectName, subscriptionName), pubSubSubscriberFactory); + sourceUnderConstruction.setSubscriberWrapper(subscriberWrapper); + sourceUnderConstruction.setDeserializationSchema(deserializationSchema); Review comment: This issue still remains. It's the same issue that existed for the sink builder. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
