nielsbasjes 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_r232681463
########## File path: flink-connectors/flink-connector-pubsub/src/main/java/org/apache/flink/streaming/connectors/pubsub/PubSubSink.java ########## @@ -0,0 +1,283 @@ +/* + * 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.serialization.SerializationSchema; +import org.apache.flink.configuration.Configuration; +import org.apache.flink.streaming.api.functions.sink.RichSinkFunction; +import org.apache.flink.streaming.api.functions.sink.SinkFunction; +import org.apache.flink.streaming.connectors.pubsub.common.SerializableCredentialsProvider; + +import com.google.api.gax.core.CredentialsProvider; +import com.google.api.gax.grpc.GrpcTransportChannel; +import com.google.api.gax.rpc.FixedTransportChannelProvider; +import com.google.api.gax.rpc.TransportChannel; +import com.google.auth.Credentials; +import com.google.cloud.pubsub.v1.Publisher; +import com.google.protobuf.ByteString; +import com.google.pubsub.v1.ProjectTopicName; +import com.google.pubsub.v1.PubsubMessage; +import io.grpc.ManagedChannel; +import io.grpc.ManagedChannelBuilder; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.util.concurrent.TimeUnit; + +/** + * A sink function that outputs to PubSub. + * + * @param <IN> type of PubSubSink messages to write + */ +public class PubSubSink<IN> extends RichSinkFunction<IN> { + private static final Logger LOG = LoggerFactory.getLogger(PubSubSink.class); + + private SerializableCredentialsProvider serializableCredentialsProvider; + private SerializationSchema<IN> serializationSchema; + private String projectName; + private String topicName; + private String hostAndPort = null; + + private transient Publisher publisher; + + private PubSubSink() { + } + + void setSerializableCredentialsProvider(SerializableCredentialsProvider serializableCredentialsProvider) { + this.serializableCredentialsProvider = serializableCredentialsProvider; + } + + void setSerializationSchema(SerializationSchema<IN> serializationSchema) { + this.serializationSchema = serializationSchema; + } + + void setProjectName(String projectName) { + this.projectName = projectName; + } + + void setTopicName(String topicName) { + this.topicName = topicName; + } + + /** + * 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") + */ + void withHostAndPort(String hostAndPort) { + this.hostAndPort = hostAndPort; + } + + void initialize() throws IOException { + if (serializableCredentialsProvider == null) { + serializableCredentialsProvider = SerializableCredentialsProvider.credentialsProviderFromEnvironmentVariables(); + } + if (serializationSchema == null) { + throw new IllegalArgumentException("The serializationSchema has not been specified."); + } + if (projectName == null) { + throw new IllegalArgumentException("The projectName has not been specified."); + } + if (topicName == null) { + throw new IllegalArgumentException("The topicName has not been specified."); + } + } + + + private transient ManagedChannel managedChannel = null; + private transient TransportChannel channel = null; + + @Override + public void open(Configuration configuration) throws Exception { + Publisher.Builder builder = Publisher + .newBuilder(ProjectTopicName.of(projectName, topicName)) + .setCredentialsProvider(serializableCredentialsProvider); + + if (hostAndPort != null) { + managedChannel = ManagedChannelBuilder + .forTarget(hostAndPort) + .usePlaintext(true) // This is 'Ok' because this is ONLY used for testing. + .build(); + channel = GrpcTransportChannel.newBuilder().setManagedChannel(managedChannel).build(); + builder.setChannelProvider(FixedTransportChannelProvider.create(channel)); + } + + publisher = builder.build(); + } + + @Override + public void close() throws Exception { + super.close(); + shutdownPublisher(); + shutdownTransportChannel(); + shutdownManagedChannel(); + } + + private void shutdownPublisher() { + try { + publisher.shutdown(); + } catch (Exception e) { + LOG.info("Shutting down Publisher failed: " + e.getMessage()); + } + } + + private void shutdownTransportChannel() { + if (channel == null) { + return; + } + try { + channel.close(); + } catch (Exception e) { + LOG.info("Shutting down TransportChannel failed: " + e.getMessage()); + } + } + + private void shutdownManagedChannel() { + if (managedChannel == null) { + return; + } + try { + managedChannel.shutdownNow(); + managedChannel.awaitTermination(1000L, TimeUnit.MILLISECONDS); + } catch (Exception e) { + LOG.info("Shutting down ManagedChannel failed: " + e.getMessage()); + } + } + + @Override + public void invoke(IN message, SinkFunction.Context context) { + PubsubMessage pubsubMessage = PubsubMessage + .newBuilder() + .setData(ByteString.copyFrom(serializationSchema.serialize(message))) + .build(); + publisher.publish(pubsubMessage); + publisher.publishAllOutstanding(); + } + + /** + * Create a builder for a new PubSubSink. + * + * @param <IN> The generic of the type that is to be written into the sink. + * @return a new PubSubSinkBuilder instance + */ + public static <IN> PubSubSinkBuilder<IN, ? extends PubSubSink<IN>, ? extends PubSubSinkBuilder<IN, ?, ?>> newBuilder() { + return new PubSubSinkBuilder<>(new PubSubSink<>()); + } + + /** + * PubSubSinkBuilder to create a PubSubSink. + * + * @param <IN> Type of PubSubSink to create. + */ + @SuppressWarnings("unchecked") + public static class PubSubSinkBuilder<IN, PSS extends PubSubSink<IN>, BUILDER extends PubSubSinkBuilder<IN, PSS, BUILDER>> { + protected PSS sinkUnderConstruction; + + private PubSubSinkBuilder(PSS sinkUnderConstruction) { + this.sinkUnderConstruction = sinkUnderConstruction; + } + + /** + * 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 PubSubSinkBuilder instance + */ + public BUILDER withCredentials(Credentials credentials) { + sinkUnderConstruction.setSerializableCredentialsProvider(new SerializableCredentialsProvider(credentials)); Review comment: Fixed ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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