| /* |
| * 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.source.reader.split; |
| |
| import org.apache.flink.annotation.Internal; |
| import org.apache.flink.connector.base.source.reader.RecordsBySplits; |
| import org.apache.flink.connector.base.source.reader.RecordsWithSplitIds; |
| import org.apache.flink.connector.base.source.reader.splitreader.SplitReader; |
| import org.apache.flink.connector.base.source.reader.splitreader.SplitsAddition; |
| import org.apache.flink.connector.base.source.reader.splitreader.SplitsChange; |
| import org.apache.flink.connector.mongodb.common.config.MongoConnectionOptions; |
| import org.apache.flink.connector.mongodb.source.config.MongoReadOptions; |
| import org.apache.flink.connector.mongodb.source.reader.MongoSourceReaderContext; |
| import org.apache.flink.connector.mongodb.source.split.MongoScanSourceSplit; |
| import org.apache.flink.connector.mongodb.source.split.MongoSourceSplit; |
| import org.apache.flink.util.CollectionUtil; |
| |
| import com.mongodb.MongoException; |
| import com.mongodb.client.FindIterable; |
| import com.mongodb.client.MongoClient; |
| import com.mongodb.client.MongoClients; |
| import com.mongodb.client.MongoCursor; |
| import org.bson.BsonDocument; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import javax.annotation.Nullable; |
| |
| import java.io.IOException; |
| import java.util.List; |
| |
| import static org.apache.flink.connector.mongodb.common.utils.MongoUtils.project; |
| |
| /** An split reader implements {@link SplitReader} for {@link MongoScanSourceSplit}. */ |
| @Internal |
| public class MongoScanSourceSplitReader implements MongoSourceSplitReader<MongoSourceSplit> { |
| |
| private static final Logger LOG = LoggerFactory.getLogger(MongoScanSourceSplitReader.class); |
| |
| private final MongoConnectionOptions connectionOptions; |
| private final MongoReadOptions readOptions; |
| private final MongoSourceReaderContext readerContext; |
| @Nullable private final List<String> projectedFields; |
| |
| private boolean closed = false; |
| private boolean finished = false; |
| private MongoClient mongoClient; |
| private MongoCursor<BsonDocument> currentCursor; |
| private MongoScanSourceSplit currentSplit; |
| |
| public MongoScanSourceSplitReader( |
| MongoConnectionOptions connectionOptions, |
| MongoReadOptions readOptions, |
| @Nullable List<String> projectedFields, |
| MongoSourceReaderContext readerContext) { |
| this.connectionOptions = connectionOptions; |
| this.readOptions = readOptions; |
| this.projectedFields = projectedFields; |
| this.readerContext = readerContext; |
| } |
| |
| @Override |
| public RecordsWithSplitIds<BsonDocument> fetch() throws IOException { |
| if (closed) { |
| throw new IllegalStateException("Cannot fetch records from a closed split reader"); |
| } |
| |
| RecordsBySplits.Builder<BsonDocument> builder = new RecordsBySplits.Builder<>(); |
| |
| // Return when no split registered to this reader. |
| if (currentSplit == null) { |
| return builder.build(); |
| } |
| |
| // Return when current read count is over limit. |
| if (readerContext.isOverLimit()) { |
| builder.addFinishedSplit(currentSplit.splitId()); |
| currentSplit = null; |
| finished = true; |
| return builder.build(); |
| } |
| |
| currentCursor = getOrCreateCursor(); |
| int fetchSize = readOptions.getFetchSize(); |
| |
| try { |
| for (int recordNum = 0; recordNum < fetchSize; recordNum++) { |
| if (currentCursor.hasNext()) { |
| builder.add(currentSplit, currentCursor.next()); |
| readerContext.getReadCount().incrementAndGet(); |
| if (readerContext.isOverLimit()) { |
| builder.addFinishedSplit(currentSplit.splitId()); |
| finished = true; |
| break; |
| } |
| } else { |
| builder.addFinishedSplit(currentSplit.splitId()); |
| finished = true; |
| break; |
| } |
| } |
| return builder.build(); |
| } catch (MongoException e) { |
| throw new IOException("Scan records form MongoDB failed", e); |
| } finally { |
| if (finished) { |
| closeCursor(); |
| } |
| } |
| } |
| |
| @Override |
| public void handleSplitsChanges(SplitsChange<MongoSourceSplit> splitsChanges) { |
| LOG.debug("Handle split changes {}", splitsChanges); |
| |
| if (!(splitsChanges instanceof SplitsAddition)) { |
| throw new UnsupportedOperationException( |
| String.format( |
| "The SplitChange type of %s is not supported.", |
| splitsChanges.getClass())); |
| } |
| |
| MongoSourceSplit sourceSplit = splitsChanges.splits().get(0); |
| if (!(sourceSplit instanceof MongoScanSourceSplit)) { |
| throw new UnsupportedOperationException( |
| String.format( |
| "The SourceSplit type of %s is not supported.", |
| sourceSplit.getClass())); |
| } |
| |
| this.currentSplit = (MongoScanSourceSplit) sourceSplit; |
| this.finished = false; |
| } |
| |
| @Override |
| public void wakeUp() { |
| // Close current cursor to cancel blocked hasNext(), next(). |
| closeCursor(); |
| } |
| |
| @Override |
| public void close() { |
| if (!closed) { |
| closed = true; |
| closeCursor(); |
| } |
| } |
| |
| private MongoCursor<BsonDocument> getOrCreateCursor() { |
| if (currentCursor == null) { |
| LOG.debug("Opened cursor for partitionId: {}", currentSplit); |
| mongoClient = MongoClients.create(connectionOptions.getUri()); |
| |
| // Using MongoDB's cursor.min() and cursor.max() to limit an index bound. |
| // When the index range is the primary key, the bound is (min <= _id < max). |
| // Compound indexes and hash indexes bounds can also be supported in this way. |
| // Please refer to https://www.mongodb.com/docs/manual/reference/method/cursor.min/ |
| FindIterable<BsonDocument> findIterable = |
| mongoClient |
| .getDatabase(connectionOptions.getDatabase()) |
| .getCollection(connectionOptions.getCollection(), BsonDocument.class) |
| .find() |
| .min(currentSplit.getMin()) |
| .max(currentSplit.getMax()) |
| .hint(currentSplit.getHint()) |
| .noCursorTimeout(readOptions.isNoCursorTimeout()); |
| |
| // Current split was partially read and recovered from checkpoint |
| if (currentSplit.getOffset() > 0) { |
| findIterable.skip(currentSplit.getOffset()); |
| } |
| |
| // Push limit down |
| if (readerContext.isLimitPushedDown()) { |
| findIterable.limit(readerContext.getLimit()); |
| } |
| |
| // Push projection down |
| if (!CollectionUtil.isNullOrEmpty(projectedFields)) { |
| findIterable.projection(project(projectedFields)); |
| } |
| |
| currentCursor = findIterable.cursor(); |
| } |
| return currentCursor; |
| } |
| |
| private void closeCursor() { |
| if (currentCursor != null) { |
| LOG.debug("Closing cursor for split: {}", currentSplit); |
| try { |
| currentCursor.close(); |
| } finally { |
| currentCursor = null; |
| try { |
| mongoClient.close(); |
| } finally { |
| mongoClient = null; |
| } |
| } |
| } |
| } |
| } |