如何判断Kinesis碎片的状态？

Question

Is there a way to tell what a shard's status is, whether it's OPEN, CLOSED, or EXPIRED? The only way I've been able to determine this information seems to be attempting an operation on the shard.

Answer 1

You can use Amazon Web Services Java SDK: https://github.com/aws/aws-sdk-java

There are a lot of useful methods for accessing your resources.

Edit: Sorry, I misunderstood the question. You cannot access a shard's status directly (yet). But there is a trick: A Closed shard always has an "Ending Sequence Number" defined. You can hack this way.

Excerpt from Javadoc;

public String getEndingSequenceNumber ()

The ending sequence number for the range. Shards that are in the OPEN state have an ending sequence number of null.

http://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/services/kinesis/model/SequenceNumberRange.html#getEndingSequenceNumber()

import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.services.kinesis.AmazonKinesis;
import com.amazonaws.services.kinesis.AmazonKinesisClient;
import com.amazonaws.services.kinesis.model.DescribeStreamRequest;
import com.amazonaws.services.kinesis.model.DescribeStreamResult;
import com.amazonaws.services.kinesis.model.ListStreamsResult;

public class KinesisSandbox {

    public static void main(String[] args) {
        try {
            String amazonKey = "x";
            String amazonSecret = "y";
            AmazonKinesis client = new AmazonKinesisClient(new BasicAWSCredentials(amazonKey, amazonSecret));

            ListStreamsResult listStreamsResult = client.listStreams();
            System.out.println("\nlistStreamsResult: " + listStreamsResult);

            String streamName = listStreamsResult.getStreamNames().get(0);

            DescribeStreamRequest describeStreamRequest = new DescribeStreamRequest();
            describeStreamRequest.setStreamName(streamName);
            DescribeStreamResult describeStreamResult = client.describeStream(describeStreamRequest);
            System.out.println("\n describeStreamResult.getStreamDescription().getStreamStatus(): "
                    + describeStreamResult.getStreamDescription().getStreamStatus());
                // System.out.println("\ndescribeStreamResult: " + describeStreamResult);

            List<Shard> shards = describeStreamResult.getStreamDescription().getShards();
            for (int i = 0; i < shards.size(); i++) {
                Shard shard = shards.get(i);
                if (shard.getSequenceNumberRange().getEndingSequenceNumber() == null) {
                    System.out.println("shard(" + i + "): " + shard.getShardId() + " is OPEN.");
                } else {
                    System.out.println("shard(" + i + "): " + shard.getShardId() + " is CLOSED.");
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

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