How to trigger one lambda function from multiple lambdas at the same time

Question

I want to trigger a lambda function from multiple lambdas at the same time. The architecture i am following is lambda -- > Step Function--> parallel execution of 2 lambdas --> these two lambda should trigger one lambda. the event from these two lambda should be passed to one lambda.

Till the triggering of two lambda function from step function i have already achieved. to Trigger the lambda function i have written the below code. but only on lambda event is passed to the next lambda.

from boto3 import client as botoClient
import json
lambdas = botoClient("lambda")

def lambda_handler(event, context):

    response = lambdas.invoke(FunctionName="lambda-name", 
                              InvocationType="RequestResponse", 
                               Payload=json.dumps(event))
    return {
        'statusCode': 200,
        'body': json.dumps('Hello from Lambda!')
    }

Answer 1

Here's a snippet to invoke a Lambda function, from another Lambda function -

let AWS = require('aws-sdk');
let util = require('util');

module.exports.proxyAPIRequest = async () => {

    let client = new AWS.Lambda({
        region: "us-east-1"
    });

    let requestPayload = {
        'someKey' : 'someValue'
    };

    requestPayload = JSON.stringify(requestPayload);
    console.log("Payload => ", requestPayload);

    let params = {
        FunctionName: functionName,
        InvocationType: "RequestResponse", 
        Payload: requestPayload
    };

    let lambda = util.promisify(client.invoke).bind(client);
    let response = await lambda(params);

    console.log(response.Payload);

    return response.Payload;
};

Ensure your caller Lambda function has permission to invoke another function -

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "Lambda permission",
      "Action": [
        "lambda:InvokeFunction"
      ],
      "Effect": "Allow",
      "Resource": "arn:aws:lambda:awsRegion:awsAccountId:function:functionName"
    }
  ]
}