Want to call AWS lambda in VPC to another AWS lambda without VPC in same region and account using JAVA 8

Question

Want to connect one AWS lambda which is in VPC to another lambda which is not in VPC but in same region and account.

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• Code of caller lambda "lambda_1":

  @Override public String handleRequest(final Object input, final Context context) { logger.log(context.getFunctionName() + " invoked");

  final AWSLambda client = AWSLambdaClientBuilder.standard().withRegion(Regions.EU_WEST_2).build();
  final InvokeRequest request = new InvokeRequest();
  request.withFunctionName("lambda_2").withPayload("JSON data as String").withInvocationType(InvocationType.RequestResponse);
  
  logger.log("Lambda is about to invoke");
  final InvokeResult response = client.invoke(request);
  
  logger.log(context.getFunctionName() + " returned");
  
  return input.toString();
  

  }

AWS java sdk for lambda is used through maven dependency

<dependency>
      <groupId>com.amazonaws</groupId>
      <artifactId>aws-java-sdk-lambda</artifactId>
    <version>1.11.681</version>
    </dependency>

• Allow: lambda:InvokeFunction is given to lambda_1 for lambda_2

---

• Code of callee lambda "lambda_2":

@Override public String handleRequest(final Object input, final Context context) {

    logger.log(context.getFunctionName() + " invoked");

    logger.log(context.getFunctionName() + " returned");

    return input.toString();

}

• Logs get created for lambda_1 till Lambda is about to invoke line, execution doesn't go further and times up.
• Enough time and memory has been set for lambda_1, lambda_2 as 2 min 198 MB and 1 min 128 MB respectively.
• But Unable to call lambda_2 and even not getting any kind of error at runtime, kindly help thanks

Answer 1

Timeout with no further log output sounds like a typical networking-issue, I'd start looking there.

To reach the Lambda service, the calling Lambda (and with that your VPC) needs access to the Internet, have you got an Internet Gateway or NAT Interface/Gateway in the VPC?

Alternatively, instead of directly invoking the Lambda, you could go over SNS, that would allow you to add an SNS Interface endpoint in your VPC, if connecting your VPC to the Internet is not an option.