Jiabao-Sun commented on code in PR #1: URL: https://github.com/apache/flink-connector-mongodb/pull/1#discussion_r1018113562
########## flink-connector-mongodb/src/main/java/org/apache/flink/connector/mongodb/sink/writer/MongoWriter.java: ########## @@ -0,0 +1,183 @@ +/* + * 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.connector.mongodb.sink.writer; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.api.common.functions.util.ListCollector; +import org.apache.flink.api.common.operators.MailboxExecutor; +import org.apache.flink.api.common.serialization.SerializationSchema; +import org.apache.flink.api.connector.sink2.Sink; +import org.apache.flink.api.connector.sink2.SinkWriter; +import org.apache.flink.connector.mongodb.common.config.MongoConnectionOptions; +import org.apache.flink.connector.mongodb.sink.config.MongoWriteOptions; +import org.apache.flink.connector.mongodb.sink.writer.context.DefaultMongoSinkContext; +import org.apache.flink.connector.mongodb.sink.writer.context.MongoSinkContext; +import org.apache.flink.connector.mongodb.sink.writer.serializer.MongoSerializationSchema; +import org.apache.flink.metrics.groups.SinkWriterMetricGroup; +import org.apache.flink.runtime.operators.util.metrics.CountingCollector; +import org.apache.flink.util.Collector; +import org.apache.flink.util.FlinkRuntimeException; + +import com.mongodb.MongoException; +import com.mongodb.client.MongoClient; +import com.mongodb.client.MongoClients; +import com.mongodb.client.model.WriteModel; +import org.bson.BsonDocument; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.List; + +import static org.apache.flink.util.Preconditions.checkNotNull; + +/** + * This class is responsible for writing records to a MongoDB collection. + * + * @param <IN> The type of the input elements. + */ +@Internal +public class MongoWriter<IN> implements SinkWriter<IN> { + + private static final Logger LOG = LoggerFactory.getLogger(MongoWriter.class); + + private final MongoConnectionOptions connectionOptions; + private final MongoWriteOptions writeOptions; + private final MongoSerializationSchema<IN> serializationSchema; + private final MongoSinkContext sinkContext; + private final MailboxExecutor mailboxExecutor; + private final boolean flushOnCheckpoint; + private final List<WriteModel<BsonDocument>> bulkRequests = new ArrayList<>(); + private final Collector<WriteModel<BsonDocument>> collector; + private final MongoClient mongoClient; + + private boolean checkpointInProgress = false; + private volatile long lastSendTime = 0L; + private volatile long ackTime = Long.MAX_VALUE; + + public MongoWriter( + MongoConnectionOptions connectionOptions, + MongoWriteOptions writeOptions, + boolean flushOnCheckpoint, + Sink.InitContext initContext, + MongoSerializationSchema<IN> serializationSchema) { + this.connectionOptions = checkNotNull(connectionOptions); + this.writeOptions = checkNotNull(writeOptions); + this.serializationSchema = checkNotNull(serializationSchema); + this.flushOnCheckpoint = flushOnCheckpoint; + + checkNotNull(initContext); + this.mailboxExecutor = checkNotNull(initContext.getMailboxExecutor()); + + SinkWriterMetricGroup metricGroup = checkNotNull(initContext.metricGroup()); + metricGroup.setCurrentSendTimeGauge(() -> ackTime - lastSendTime); + + this.collector = + new CountingCollector<>( + new ListCollector<>(this.bulkRequests), + metricGroup.getNumRecordsSendCounter()); + + // Initialize the serialization schema. + this.sinkContext = new DefaultMongoSinkContext(initContext, writeOptions); + try { + SerializationSchema.InitializationContext initializationContext = + initContext.asSerializationSchemaInitializationContext(); + serializationSchema.open(initializationContext, sinkContext, writeOptions); + } catch (Exception e) { + throw new FlinkRuntimeException("Failed to open the MongoEmitter", e); + } + + // Initialize the mongo client. + this.mongoClient = MongoClients.create(connectionOptions.getUri()); + } + + @Override + public void write(IN element, Context context) throws IOException, InterruptedException { + // do not allow new bulk writes until all actions are flushed + while (checkpointInProgress) { + mailboxExecutor.yield(); + } + collector.collect(serializationSchema.serialize(element, sinkContext)); + if (isOverMaxBatchSizeLimit() || isOverMaxBatchIntervalLimit()) { + doBulkWrite(); + } + } + + @Override + public void flush(boolean endOfInput) throws IOException { + checkpointInProgress = true; + while (!bulkRequests.isEmpty() && (flushOnCheckpoint || endOfInput)) { + doBulkWrite(); + } + checkpointInProgress = false; + } + + @Override + public void close() { + mongoClient.close(); + } + + @VisibleForTesting + void doBulkWrite() throws IOException { + if (bulkRequests.isEmpty()) { + // no records to write + return; + } + + int maxRetries = writeOptions.getMaxRetries(); Review Comment: Thanks @rozza When using Flink SQL, we will use the primary key of the Flink table schema as the _id of MongoDB. Then process upsert or delete operations by that key. I think it's idempotent in this case. When using Flink Streaming, how to convert record to `BsonDocument` and how to write to MongoDB will be decided by user. If the write method are non-idempotent, some problem may occur on retries. Thanks to suggest retryable writes feature that seems' to be able to give us a higher delivery guarantee. I'll try that. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
