[FLINK-10422] Follow AWS specs in Kinesis Consumer

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.6.1, 1.7.1
• Fix Version/s: 1.8.0
• Component/s: Connectors / Kinesis
• Labels: pull-request-available
• Assignee: eugen yushin
• Reporter: eugen yushin
• Created: 25/Sep/18 13:36
• Updated: 09/Feb/19 19:46
• Resolved: 09/Feb/19 19:46

Description

Related conversation in mailing list:

https://lists.apache.org/thread.html/96de3bac9761564767cf283b58d664f5ae1b076e0c4431620552af5b@%3Cdev.flink.apache.org%3E

Summary:

Flink Kinesis consumer checks shards id for a particular pattern:

"^shardId-\\d{12}"

https://github.com/apache/flink/blob/master/flink-connectors/flink-connector-kinesis/src/main/java/org/apache/flink/streaming/connectors/kinesis/model/StreamShardHandle.java#L132

While this inlines with current Kinesis streams server implementation (all streams follows this pattern), it confronts with AWS docs:

 

ShardId
 The unique identifier of the shard within the stream.
 Type: String
 Length Constraints: Minimum length of 1. Maximum length of 128.
Pattern: [a-zA-Z0-9_.-]+
 Required: Yes

 

https://docs.aws.amazon.com/kinesis/latest/APIReference/API_Shard.html

Intention:
We have no guarantees and can't rely on patterns other than provided in AWS manifest.
Any custom implementation of Kinesis mock should rely on AWS manifest which claims ShardID to be alfanums. This prevents anyone to use Flink with such kind of mocks.

The reason behind the scene to use particular pattern "^shardId-d12" is to create Flink's custom Shard comparator, filter already seen shards, and pass latest shard for client.listShards only to limit the scope for RPC call to AWS.

In the meantime, I think we can get rid of this logic at all. The current usage in project is:

• fix Kinesalite bug (I've already opened an issue to cover this:
  https://github.com/mhart/kinesalite/issues/76 and opened PR: https://github.com/mhart/kinesalite/pull/77). We can move this logic to test code base to keep production code clean for now
  https://github.com/apache/flink/blob/50d076ab6ad325907690a2c115ee2cb1c45775c9/flink-connectors/flink-connector-kinesis/src/main/java/org/apache/flink/streaming/connectors/kinesis/proxy/KinesisProxy.java#L464

• adjust last seen shard id. We can simply omit this cause' AWS client won't return already seen shards and we will have new ids only or nothing.
  https://github.com/apache/flink/blob/50d076ab6ad325907690a2c115ee2cb1c45775c9/flink-connectors/flink-connector-kinesis/src/main/java/org/apache/flink/streaming/connectors/kinesis/internals/KinesisDataFetcher.java#L475
  https://github.com/apache/flink/blob/50d076ab6ad325907690a2c115ee2cb1c45775c9/flink-connectors/flink-connector-kinesis/src/main/java/org/apache/flink/streaming/connectors/kinesis/proxy/KinesisProxy.java#L406

Issue Links

• links to: GitHub Pull Request #6760