Durch die Nutzung von AWS re:Post stimmt du den AWS re:Post Nutzungsbedingungen

Lambda function with SQS trigger / Lambda Event JSON payload

0

I am receiving the error below when I am testing with lambda function via the AWS Console > Lambda > Specific Lambda Function > Test tab

Or within my IDE, VS Comm 2022 when I am invoking/testing the lambda function there as well.

What is perplexing is when I use 'Mock Lambda Test Tool' and pass in that same JSON there is no error and I get the expected output....

The error is listed below. I have also listed my code and the JSON that I am sending to it.

Amazon.Lambda.Serialization.SystemTextJson.JsonSerializerException: Error converting the Lambda event JSON payload to type System.String: The JSON value could not be converted to System.String. Path: $ | LineNumber: 0 | BytePositionInLine: 1.

JSON:

{ "FirstName": "JTran"
}

Function Code

using Amazon.Lambda.Core;
using Amazon.Lambda.SQSEvents;

// Assembly attribute to enable the Lambda function's JSON input to be converted into a .NET class.
[assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer))]

namespace Test_function
{
    public class Function
    {

        public string FunctionHandler(ApiHeader input, ILambdaContext context)
        {           

            return $"Additional text added as a test {input.FirstName}";

        }
    }
}

Class to be associated with it when the JSON object is deserialized:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Test_function
{
    public class ApiHeader
    {
        public string ApiID { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string Body { get; set; }

    }
}
1 Antwort
0

Hello,

I deployed your Lambda and it worked with the testevent you provided using the Lambda-Test-tab in the console:

{ "FirstName": "JTran" }

Result: "Additional text added as a test JTran"

Are you sure that you not accidently saved a faulty testevent and lambda is using that always instead of your input?

Handlername differs in my case (because I used hello-world-sam application as a template): HelloWorld::HelloWorld.Function::FunctionHandler

Using: .NET 6 (C#/PowerShell) & x86_64

using Amazon.Lambda.Core;
//using Amazon.Lambda.SQSEvents;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

// Assembly attribute to enable the Lambda function's JSON input to be converted into a .NET class.
[assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer))]

namespace HelloWorld
{
    public class Function
    {

        public string FunctionHandler(ApiHeader input, ILambdaContext context)
        {           

            return $"Additional text added as a test {input.FirstName}";

        }
    }
}

namespace HelloWorld
{
    public class ApiHeader
    {
        public string ApiID { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string Body { get; set; }

    }
}
profile picture
beantwortet vor einem Jahr
  • Hello! Thank you for responding, I don't believe I saved a faulty testevent. I do have to inquire, the lambda is part of a CDK CloudFormation stack. With the Lambda function being in a separate file, if I were to update the function code itself, can I just save it or do I need to run cdk deploy again?

  • Hey, you can just change/update the lambda directly. And as long as you don't change the lambdaname, cloudformation itself shouldn't detect a drift so its ok imo.

Du bist nicht angemeldet. Anmelden um eine Antwort zu veröffentlichen.

Eine gute Antwort beantwortet die Frage klar, gibt konstruktives Feedback und fördert die berufliche Weiterentwicklung des Fragenstellers.

Richtlinien für die Beantwortung von Fragen