LambdaContainerHandler - Error while mapping object to RequestType class

Comece em LambdaContainerHandler.java:256 e acompanhe a chamada de mapeamento da requisição a partir de StreamLambdaHandler.java:42. Reproduza a requisição reportada do Spring Boot 2 com o payload fornecido do API Gateway e inspecione por que a entrada chega vazia ao Jackson; considera-se concluído quando o endpoint retorna o JSON esperado com HTTP 200 em vez de 502.

To help us debug your issue fill in the basic information below using the options provided

Serverless Java Container version: 1.9

Implementations: Spring Boot 2

Framework version: SpringBoot 2.7.6.RELEASE

Frontend service: REST API

Deployment method: Console

Scenario

Describe what you are trying to accomplish
I have created an AP Gateway REST API which proxies to a Springboot Java application exposing differnet endpoints, mostly returning Monos and Fluxes. Payload inputted is below.
{ "resource": "/{proxy+}", "path": "/capitals", "httpMethod": "GET", "headers": { "Accept": "application/json", "Accept-Encoding": "gzip, deflate", "Cache-Control": "no-cache", "Content-Type": "application/json", "Host": "xxxxxxx.execute-api.eu-north-1.amazonaws.com", "Postman-Token": "zzzzzzz-4c21-4a6b-a71a-b5d39ce42332", "User-Agent": "PostmanRuntime/7.28.4", "X-Amzn-Trace-Id": "Root=1-638f4d15-626c445233b14ceb2f567363", "X-BlueCoat-Via": "0drrr83fc54be448", "X-Forwarded-For": "1.2.3.4", "X-Forwarded-Port": "443", "X-Forwarded-Proto": "https" }, "multiValueHeaders": { "Accept": [ "application/json" ], "Accept-Encoding": [ "gzip, deflate" ], "Cache-Control": [ "no-cache" ], "Content-Type": [ "application/json" ], "Host": [ "ay9vitrep4.execute-api.eu-north-1.amazonaws.com" ], "Postman-Token": [ "zzzzzzz-4c21-4a6b-a71a-b5d39ce42332" ], "User-Agent": [ "PostmanRuntime/7.28.4" ], "X-Amzn-Trace-Id": [ "Root=1-638f4d15-626c445233b14ceb2f567363" ], "X-BlueCoat-Via": [ "ggg3fc54be448" ], "X-Forwarded-For": [ "1.2.3.4" ], "X-Forwarded-Port": [ "443" ], "X-Forwarded-Proto": [ "https" ] }, "queryStringParameters": null, "multiValueQueryStringParameters": null, "pathParameters": { "proxy": "capitals" }, "stageVariables": null, "requestContext": { "resourceId": "sm5w9j", "resourcePath": "/{proxy+}", "httpMethod": "GET", "extendedRequestId": "cuj7cEsTgi0FkCA=", "requestTime": "06/Dec/2022:14:09:25 +0000", "path": "/dev/capitals", "accountId": "123456789", "protocol": "HTTP/1.1", "stage": "dev", "domainPrefix": "ay9vitrep4", "requestTimeEpoch": 1670335765833, "requestId": "50facc59-b889-44a0-8a58-f86431bf0897", "identity": { "cognitoIdentityPoolId": null, "accountId": null, "cognitoIdentityId": null, "caller": null, "sourceIp": "1.2.3.4", "principalOrgId": null, "accessKey": null, "cognitoAuthenticationType": null, "cognitoAuthenticationProvider": null, "userArn": null, "userAgent": "PostmanRuntime/7.28.4", "user": null }, "domainName": "xxxxxxxxx.execute-api.eu-north-1.amazonaws.com", "apiId": "xxxxxxxx" }, "body": null, "isBase64Encoded": false }

Nevertheless, when executing the endpoint, the call fails as seems that above payload cannot be mapped into a RequestType class (which is an AWSProxyRequest)

[main] ERROR com.amazonaws.serverless.proxy.internal.LambdaContainerHandler - Error while mapping object to RequestType class
  | 2022-12-06T15:38:16.811+01:00 | com.fasterxml.jackson.databind.exc.MismatchedInputException: No content to map due to end-of-input

Expected behavior

Describe how you would expect the application to behave
Json Payload should be returned with 200 response

Actual behavior

Describe what you are seeing instead
Response returns 502 with this error inCloudwatch:

[main] ERROR com.amazonaws.serverless.proxy.internal.LambdaContainerHandler - Error while mapping object to RequestType class   | 2022-12-06T15:38:16.811+01:00 | com.fasterxml.jackson.databind.exc.MismatchedInputException: No content to map due to end-of-input

Steps to reproduce

Provide code samples we can use to reproduce the issue as part of our integration tests. If there is a public repository for the misbehaving application link to it here

1. Added aws-serverless-java-container springboot2 library in pom, version 1.9
   2)Added LambdaHandler as below

public class StreamLambdaHandler implements RequestStreamHandler {
    private static SpringBootLambdaContainerHandler<AwsProxyRequest, AwsProxyResponse> handler;
    static {
        try {
            handler = SpringBootLambdaContainerHandler.getAwsProxyHandler(Application.class);
            // If you are using HTTP APIs with the version 2.0 of the proxy model, use the getHttpApiV2ProxyHandler
            // method: handler = SpringBootLambdaContainerHandler.getHttpApiV2ProxyHandler(Application.class);
        } catch (ContainerInitializationException e) {
            // if we fail here. We re-throw the exception to force another cold start
            e.printStackTrace();
            throw new RuntimeException("Could not initialize Spring Boot application", e);
        }
    }

    @Override
    public void handleRequest(InputStream inputStream, OutputStream outputStream, Context context)
            throws IOException {
        handler.proxyStream(inputStream, outputStream, context);
    }
}

3)Add typical Application (annotated with @SpringBootpplication) + a RestController with this class:

@RestController
public class Resource {

    private AService service;

    public Resource1(AService service) {
        this.service = service;
    }
    
    @GetMapping("/capitals")
    public Mono<Capitals> getMono() {
        return service.serve()
                .collectList()
                .map(Capitals::new);
    }
    
    @Data
    private class Capitals {
        final List<String> values;
    }
}

Service class:

@Service
public class AService {

    public static final List<String> capitals = Arrays.asList("Copenhagen", "Rome", "Berlin", "Reykjavik");

    public Flux<String> serve() {
        return Flux.fromIterable(capitals);
    }
}
```



## Full log output
*Paste the full log output from the Lambda function's CloudWatch logs*

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2022-12-06T15:38:16.811+01:00 | 14:38:16.811 [main] ERROR com.amazonaws.serverless.proxy.internal.LambdaContainerHandler - Error while mapping object to RequestType class
-- | --
  | 2022-12-06T15:38:16.811+01:00 | com.fasterxml.jackson.databind.exc.MismatchedInputException: No content to map due to end-of-input
  | 2022-12-06T15:38:16.811+01:00 | at [Source: (ByteArrayInputStream); line: 1, column: 0]
  | 2022-12-06T15:38:16.811+01:00 | at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:59)
  | 2022-12-06T15:38:16.811+01:00 | at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1741)
  | 2022-12-06T15:38:16.811+01:00 | at com.fasterxml.jackson.databind.ObjectReader._initForReading(ObjectReader.java:359)
  | 2022-12-06T15:38:16.811+01:00 | at com.fasterxml.jackson.databind.ObjectReader._bindAndClose(ObjectReader.java:2041)
  | 2022-12-06T15:38:16.811+01:00 | at com.fasterxml.jackson.databind.ObjectReader.readValue(ObjectReader.java:1427)
  | 2022-12-06T15:38:16.811+01:00 | at com.amazonaws.serverless.proxy.internal.LambdaContainerHandler.proxyStream(LambdaContainerHandler.java:256)
  | 2022-12-06T15:38:16.811+01:00 | at com.nordea.ndf.lambda.StreamLambdaHandler.handleRequest(StreamLambdaHandler.java:42)
  | 2022-12-06T15:38:16.811+01:00 | at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  | 2022-12-06T15:38:16.811+01:00 | at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
  | 2022-12-06T15:38:16.811+01:00 | at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
  | 2022-12-06T15:38:16.811+01:00 | at java.base/java.lang.reflect.Method.invoke(Unknown Source)
  | 2022-12-06T15:38:16.811+01:00 | at lambdainternal.EventHandlerLoader$StreamMethodRequestHandler.handleRequest(EventHandlerLoader.java:375)
  | 2022-12-06T15:38:16.811+01:00 | at lambdainternal.EventHandlerLoader$2.call(EventHandlerLoader.java:899)
  | 2022-12-06T15:38:16.811+01:00 | at lambdainternal.AWSLambda.startRuntime(AWSLambda.java:268)
  | 2022-12-06T15:38:16.811+01:00 | at lambdainternal.AWSLambda.startRuntime(AWSLambda.java:206)
  | 2022-12-06T15:38:16.811+01:00 | at lambdainternal.AWSLambda.main(AWSLambda.java:200)
  | 2022-12-06T15:38:16.811+01:00 | 14:38:16.811 [main] ERROR com.amazonaws.serverless.proxy.AwsProxyExceptionHandler - Called exception handler for:
  | 2022-12-06T15:38:16.811+01:00 | com.fasterxml.jackson.databind.exc.MismatchedInputException: No content to map due to end-of-input
  | 2022-12-06T15:38:16.811+01:00 | at [Source: (ByteArrayInputStream); line: 1, column: 0]
  | 2022-12-06T15:38:16.811+01:00 | at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:59)
  | 2022-12-06T15:38:16.811+01:00 | at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1741)
  | 2022-12-06T15:38:16.811+01:00 | at com.fasterxml.jackson.databind.ObjectReader._initForReading(ObjectReader.java:359)
  | 2022-12-06T15:38:16.811+01:00 | at com.fasterxml.jackson.databind.ObjectReader._bindAndClose(ObjectReader.java:2041)
  | 2022-12-06T15:38:16.811+01:00 | at com.fasterxml.jackson.databind.ObjectReader.readValue(ObjectReader.java:1427)
  | 2022-12-06T15:38:16.811+01:00 | at com.amazonaws.serverless.proxy.internal.LambdaContainerHandler.proxyStream(LambdaContainerHandler.java:256)
  | 2022-12-06T15:38:16.811+01:00 | at com.nordea.ndf.lambda.StreamLambdaHandler.handleRequest(StreamLambdaHandler.java:42)
  | 2022-12-06T15:38:16.811+01:00 | at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  | 2022-12-06T15:38:16.811+01:00 | at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
  | 2022-12-06T15:38:16.811+01:00 | at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
  | 2022-12-06T15:38:16.811+01:00 | at java.base/java.lang.reflect.Method.invoke(Unknown Source)
  | 2022-12-06T15:38:16.811+01:00 | at lambdainternal.EventHandlerLoader$StreamMethodRequestHandler.handleRequest(EventHandlerLoader.java:375)
  | 2022-12-06T15:38:16.811+01:00 | at lambdainternal.EventHandlerLoader$2.call(EventHandlerLoader.java:899)
  | 2022-12-06T15:38:16.811+01:00 | at lambdainternal.AWSLambda.startRuntime(AWSLambda.java:268)
  | 2022-12-06T15:38:16.811+01:00 | at lambdainternal.AWSLambda.startRuntime(AWSLambda.java:206)
  | 2022-12-06T15:38:16.811+01:00 | at lambdainternal.AWSLambda.main(AWSLambda.java:200)
  | 2022-12-06T15:38:16.812+01:00 | com.fasterxml.jackson.databind.exc.MismatchedInputException: No content to map due to end-of-input
  | 2022-12-06T15:38:16.812+01:00 | at [Source: (ByteArrayInputStream); line: 1, column: 0]
  | 2022-12-06T15:38:16.812+01:00 | at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:59)
  | 2022-12-06T15:38:16.812+01:00 | at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1741)
  | 2022-12-06T15:38:16.812+01:00 | at com.fasterxml.jackson.databind.ObjectReader._initForReading(ObjectReader.java:359)
  | 2022-12-06T15:38:16.812+01:00 | at com.fasterxml.jackson.databind.ObjectReader._bindAndClose(ObjectReader.java:2041)
  | 2022-12-06T15:38:16.812+01:00 | at com.fasterxml.jackson.databind.ObjectReader.readValue(ObjectReader.java:1427)
  | 2022-12-06T15:38:16.812+01:00 | at com.amazonaws.serverless.proxy.internal.LambdaContainerHandler.proxyStream(LambdaContainerHandler.java:256)
  | 2022-12-06T15:38:16.812+01:00 | at com.nordea.ndf.lambda.StreamLambdaHandler.handleRequest(StreamLambdaHandler.java:42)
  | 2022-12-06T15:38:16.812+01:00 | at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  | 2022-12-06T15:38:16.812+01:00 | at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
  | 2022-12-06T15:38:16.828+01:00 | at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
  | 2022-12-06T15:38:16.848+01:00 | at java.base/java.lang.reflect.Method.invoke(Unknown Source)
  | 2022-12-06T15:38:16.848+01:00 | at lambdainternal.EventHandlerLoader$StreamMethodRequestHandler.handleRequest(EventHandlerLoader.java:375)
  | 2022-12-06T15:38:16.848+01:00 | at lambdainternal.EventHandlerLoader$2.call(EventHandlerLoader.java:899)
  | 2022-12-06T15:38:16.848+01:00 | at lambdainternal.AWSLambda.startRuntime(AWSLambda.java:268)
  | 2022-12-06T15:38:16.848+01:00 | at lambdainternal.AWSLambda.startRuntime(AWSLambda.java:206)

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