Question

我有几个lambda通过SNS一起工作。一个lambda接收请求并将数据发送到SNS。另一个lambda订阅了SNS。在JavaScript中很容易做，因为传入的消息只是一个JS对象。现在我将lambda重写为Java。我正在寻找在处理程序中使用的类型。

这就是lambda的样子。 SNSMessage是该类型的占位符。

public class ArchiveRequestHandler implements RequestHandler<SNSMessage?, Void> {

    @Override public Void handleRequest(SNSMessage? input, Context context) {
        // do something with the message
        return null;
    }
}

这是示例消息的样子：

{
  "Records": [
    {
      "EventVersion": "1.0",
      "EventSubscriptionArn": "arn:aws:sns:EXAMPLE",
      "EventSource": "aws:sns",
      "Sns": {
        "SignatureVersion": "1",
        "Timestamp": "1970-01-01T00:00:00.000Z",
        "Signature": "EXAMPLE",
        "SigningCertUrl": "EXAMPLE",
        "MessageId": "1234567-ee98-5cb9-9903-4c221d41eb5e",
        "Message": "Hello from SNS!",
        "MessageAttributes": {
          "Test": {
            "Type": "String",
            "Value": "TestString"
          },
          "TestBinary": {
            "Type": "Binary",
            "Value": "TestBinary"
          }
        },
        "Type": "Notification",
        "UnsubscribeUrl": "EXAMPLE",
        "TopicArn": "arn:aws:sns:EXAMPLE",
        "Subject": "TestInvoke"
      }
    }
  ]
}

现在我确信我可以创建自己的类型来解析它，但我希望有更标准的方法来做到这一点。但是我没有在lambda和SNS SDK依赖项中找到任何看起来像这个对象的东西。

Answer 1

感谢@dnault和@notionquest的评论，我发现这个对象是aws-lambda-java-events库的一部分。我添加了依赖项：

compile 'com.amazonaws:aws-lambda-java-events:1.3.0'

现在我可以做到：

public class ArchiveRequestHandler implements RequestHandler<SNSEvent, Void> {

    @Override public Void handleRequest(SNSEvent input, Context context) {
        // do something with the message
        return null;
    }
}

Answer 2

以下Lambda代码处理SNS输入消息：

import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.LambdaLogger;
import com.amazonaws.services.lambda.runtime.RequestHandler;
import com.amazonaws.services.lambda.runtime.events.SNSEvent;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;

public class LogEvent implements RequestHandler<SNSEvent, Object> {

    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd_HH:mm:ss");

    public Object handleRequest(SNSEvent request, Context context){

        String timeStamp = sdf.format(new Date());
        LambdaLogger logger = context.getLogger();

        logger.log("-------------------------Invocation started: --------------" + timeStamp);
        List<SNSEvent.SNSRecord> snsRecordList = request.getRecords();
        if ( snsRecordList != null ){
            SNSEvent.SNS recordSNS = null;
            for ( SNSEvent.SNSRecord snsRecord : snsRecordList ) {
                recordSNS = snsRecord.getSNS();
                logger.log(
                     "Subject:[" + recordSNS.getSubject() + "]" +
                            "Arn:[" + recordSNS.getTopicArn() + "]" +
                             "attribs:[" + recordSNS.getMessageAttributes() + "]" +
                             "message:[" + recordSNS.getMessage() + "]" );
            }//for
        }

        timeStamp = sdf.format(new Date());
        logger.log("-------------------------Invocation completed: -------------" + timeStamp);
        return null;
    }
}

如何在用Java编写的AWS Lambda中处理SNS消息？

2 个答案: