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https://issues.apache.org/jira/browse/FLINK-4582?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16698252#comment-16698252
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ASF GitHub Bot commented on FLINK-4582:
---------------------------------------
tweise commented on a change in pull request #6968: [FLINK-4582] [kinesis]
Consuming data from DynamoDB streams to flink
URL: https://github.com/apache/flink/pull/6968#discussion_r236085962
##########
File path:
flink-connectors/flink-connector-kinesis/src/main/java/org/apache/flink/streaming/connectors/kinesis/internals/DynamodbStreamsDataFetcher.java
##########
@@ -0,0 +1,126 @@
+/*
+ * 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.kinesis.internals;
+
+import org.apache.flink.api.common.functions.RuntimeContext;
+import org.apache.flink.streaming.api.functions.source.SourceFunction;
+import org.apache.flink.streaming.connectors.kinesis.KinesisShardAssigner;
+import
org.apache.flink.streaming.connectors.kinesis.metrics.ShardMetricsReporter;
+import
org.apache.flink.streaming.connectors.kinesis.model.DynamodbStreamsShardHandle;
+import org.apache.flink.streaming.connectors.kinesis.model.SequenceNumber;
+import org.apache.flink.streaming.connectors.kinesis.model.StreamShardHandle;
+import
org.apache.flink.streaming.connectors.kinesis.proxy.DynamodbStreamsProxy;
+import
org.apache.flink.streaming.connectors.kinesis.serialization.KinesisDeserializationSchema;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Properties;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static
org.apache.flink.streaming.connectors.kinesis.config.ConsumerConfigConstants.DEFAULT_DYNAMODB_STREAMS_SHARDID_FORMAT_CHECK;
+import static
org.apache.flink.streaming.connectors.kinesis.config.ConsumerConfigConstants.DYNAMODB_STREAMS_SHARDID_FORMAT_CHECK;
+
+/**
+ * Dynamodb streams data fetcher.
+ * @param <T> type of fetched data.
+ */
+public class DynamodbStreamsDataFetcher <T> extends KinesisDataFetcher<T> {
+ private boolean shardIdFormatCheck = false;
+
+ /**
+ * Constructor.
+ *
+ * @param streams list of streams to fetch data
+ * @param sourceContext source context
+ * @param runtimeContext runtime context
+ * @param configProps config properties
+ * @param deserializationSchema deserialization schema
+ * @param shardAssigner shard assigner
+ */
+ public DynamodbStreamsDataFetcher(List<String> streams,
+ SourceFunction.SourceContext<T> sourceContext,
+ RuntimeContext runtimeContext,
+ Properties configProps,
+ KinesisDeserializationSchema<T> deserializationSchema,
+ KinesisShardAssigner shardAssigner) {
+
+ super(streams,
+ sourceContext,
+ sourceContext.getCheckpointLock(),
+ runtimeContext,
+ configProps,
+ deserializationSchema,
+ shardAssigner,
+ null,
+ new AtomicReference<>(),
+ new ArrayList<>(),
+
createInitialSubscribedStreamsToLastDiscoveredShardsState(streams),
+ // use DynamodbStreamsProxy
+ DynamodbStreamsProxy::create);
+
+ shardIdFormatCheck = Boolean.valueOf(configProps.getProperty(
+ DYNAMODB_STREAMS_SHARDID_FORMAT_CHECK,
+ DEFAULT_DYNAMODB_STREAMS_SHARDID_FORMAT_CHECK));
+ }
+
+ /**
+ * Updates the last discovered shard of a subscribed stream; only
updates if the update is valid.
+ */
+ @Override
+ public void advanceLastDiscoveredShardOfStream(String stream, String
shardId) {
Review comment:
Rather than duplicating complete logic from the base class, can we just
extract what is unique to DynamoDB? That might also eliminate the need to
expose `subscribedStreamsToLastDiscoveredShardIds`?
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> Allow FlinkKinesisConsumer to adapt for AWS DynamoDB Streams
> ------------------------------------------------------------
>
> Key: FLINK-4582
> URL: https://issues.apache.org/jira/browse/FLINK-4582
> Project: Flink
> Issue Type: New Feature
> Components: Kinesis Connector, Streaming Connectors
> Reporter: Tzu-Li (Gordon) Tai
> Assignee: Ying Xu
> Priority: Major
> Labels: pull-request-available
>
> AWS DynamoDB is a NoSQL database service that has a CDC-like (change data
> capture) feature called DynamoDB Streams
> (http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Streams.html),
> which is a stream feed of item-level table activities.
> The DynamoDB Streams shard abstraction follows that of Kinesis Streams with
> only a slight difference in resharding behaviours, so it is possible to build
> on the internals of our Flink Kinesis Consumer for an exactly-once DynamoDB
> Streams source.
> I propose an API something like this:
> {code}
> DataStream dynamoItemsCdc =
> FlinkKinesisConsumer.asDynamoDBStream(tableNames, schema, config)
> {code}
> The feature adds more connectivity to popular AWS services for Flink, and
> combining what Flink has for exactly-once semantics, out-of-core state
> backends, and queryable state with CDC can have very strong use cases. For
> this feature there should only be an extra dependency to the AWS Java SDK for
> DynamoDB, which has Apache License 2.0.
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