elphastori opened a new pull request, #21238:
URL: https://github.com/apache/flink/pull/21238
## What is the purpose of the change
This pull request makes the Kinesis DynamoDB Streams Consumer close shards
that are no longer valid rather than throwing an irrecoverable exceptions. This
is because the `DescribeStream` API can return shards that are no longer valid
and expects the client to handle them.
## Brief change log
- `ResourceNotFoundException` thrown in `getShardIterator` for DynamoDB
streams consumer is now swallowed
- A `null` `shardIterator` is returned which is an existing signal to
close a shard
- Added an `INFO` log to explain that the shard has been closed
## Verifying this change
This change added tests and can be verified as follows:
- Added a unit test that validates that a `ResourceNotFoundException`
thrown in `getShardIterator` is caught and a `null` is returned
- Manually verified the change by running the ConsumeFromDyanamoDB
example, updating records in a DDB table every 10 ms and pausing for updates to
re-produce a shard that is no longer valid. Shards that threw a
`NoResourceFoundException` were closed.
```python
dyn_resource = boto3.resource('dynamodb')
users = Users(dyn_resource)
users.table = dyn_resource.Table("UsersExample")
while True:
users.update_user(random.randint(0, 999), names.get_first_name())
time.sleep(1)
```
- Manually introduced random failures by changing the last digit of a
`shardId` to a 0 and this also resulted in a `NoResourceFoundException` that
was handled correctly
```java
public String getShardIterator(
StreamShardHandle shard, String shardIteratorType, @Nullable
Object startingMarker)
throws InterruptedException {
...
if (random.nextInt(10) == 0) {
char[] shardIdChars =
shard.getShard().getShardId().toCharArray();
shardIdChars[shardIdChars.length - 1] = '0';
shard =
new StreamShardHandle(
shard.getStreamName(),
new Shard().withShardId(new
String(shardIdChars)));
}
...
}
```
## Does this pull request potentially affect one of the following parts:
- Dependencies (does it add or upgrade a dependency): (no)
- The public API, i.e., is any changed class annotated with
`@Public(Evolving)`: (no)
- The serializers: (no)
- The runtime per-record code paths (performance sensitive): (no)
- Anything that affects deployment or recovery: JobManager (and its
components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (no)
- The S3 file system connector: (no)
## Documentation
- Does this pull request introduce a new feature? (no)
- If yes, how is the feature documented? (not applicable)
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