AWS Lambda：Java：运动事件

Question

我无法找到我正在尝试做的事情的示例...

我想在 Java 中创建一个 Lambda 函数。我原以为我会一直对 Lambda 函数使用 Javascript，但在这种情况下，我最终会重新使用已经在 Java 中编写的应用程序逻辑，所以这是有道理的。

过去我写过 Java脚本 Lambda 函数，由 Kinesis 事件触发。超级简单，函数接收事件作为参数，做点什么，瞧。我想对 Java 做同样的事情。真的很简单:

Kinesis 事件 -> 触发函数 -> (Java) 接收 Kinesis 事件，用它们做一些事情

有人有过这种用例的经验吗？

Answer 1

这是我编写的一些示例代码，用于在内部演示相同的概念。此代码将事件从一个流转发到另一个流。

请注意，如果转发中出现错误，此代码不会处理重试，也不意味着在生产环境中具有高性能，但它确实演示了如何处理来自发布流的记录。

import com.amazonaws.regions.Region;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.kinesis.AmazonKinesisClient;
import com.amazonaws.services.kinesis.model.PutRecordsRequest;
import com.amazonaws.services.kinesis.model.PutRecordsRequestEntry;
import com.amazonaws.services.kinesis.model.PutRecordsResult;
import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.LambdaLogger;
import com.amazonaws.services.lambda.runtime.events.KinesisEvent;

import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class KinesisToKinesis {

    private LambdaLogger logger;
    final private AmazonKinesisClient kinesisClient = new AmazonKinesisClient();

    public PutRecordsResult eventHandler(KinesisEvent event, Context context) {
        logger = context.getLogger();
        if (event == null || event.getRecords() == null) {
            logger.log("Event contains no data" + System.lineSeparator());
            return null;
        } else {
            logger.log("Received " + event.getRecords().size() +
                " records from " + event.getRecords().get(0).getEventSourceARN() + System.lineSeparator());
        }

        final Long startTime = System.currentTimeMillis();

        // set up the client
        Region region;
        final Map<String, String> environmentVariables = System.getenv();
        if (environmentVariables.containsKey("AWS_REGION")) {
            region = Region.getRegion(Regions.fromName(environmentVariables.get("AWS_REGION")));
        } else {
            region = Region.getRegion(Regions.US_WEST_2);
            logger.log("Using default region: " + region.toString() + System.lineSeparator());
        }
        kinesisClient.setRegion(region);

        Long elapsed = System.currentTimeMillis() - startTime;
        logger.log("Finished setup in " + elapsed + " ms" + System.lineSeparator());

        PutRecordsRequest putRecordsRequest = new PutRecordsRequest().withStreamName("usagecounters-global");
        List<PutRecordsRequestEntry> putRecordsRequestEntryList = event.getRecords().parallelStream()
            .map(r -> new PutRecordsRequestEntry()
                    .withData(ByteBuffer.wrap(r.getKinesis().getData().array()))
                    .withPartitionKey(r.getKinesis().getPartitionKey()))
            .collect(Collectors.toList());

        putRecordsRequest.setRecords(putRecordsRequestEntryList);

        elapsed = System.currentTimeMillis() - startTime;
        logger.log("Processed " + putRecordsRequest.getRecords().size() +
            " records in " + elapsed + " ms" + System.lineSeparator());

        PutRecordsResult putRecordsResult = kinesisClient.putRecords(putRecordsRequest);
        elapsed = System.currentTimeMillis() - startTime;
        logger.log("Forwarded " + putRecordsRequest.getRecords().size() +
                " records to Kinesis " + putRecordsRequest.getStreamName() +
                " in " + elapsed + " ms" + System.lineSeparator());
        return putRecordsResult;
    }
}

AWS Lambda：Java：运动事件

AWS Lambda : Java : Kinesis Events

java

amazon-kinesis

aws-lambda