Invoking a Lambda function from within another Lambda function not getting invoked

Question

How can I invoke a Lambda function within a Lambda function?

for example,

in function 1, it will be triggered by an API Gateway request and will invoke a second lambda function as an event (InvocationType = Event).

in function 2, it will do an http request to an endpoint.

also, am I going to code in serverless.yml? or code only on index/app/handler.js?

I tried the link here on stackoverflow -> Nodejs - Invoke an AWS.Lambda function from within another lambda function but it's not working.

var AWS = require('aws-sdk'); AWS.config.region = 'eu-west-1'; var lambda = new AWS.Lambda(); //LAMBDA A exports.handler = function(event, context) { var params = { FunctionName: 'Lambda_B', // the lambda function we are going to invoke InvocationType: 'RequestResponse', LogType: 'Tail', Payload: '{ "name" : "Yza" }' }; lambda.invoke(params, function(err, data) { if (err) { context.fail(err); } else { context.succeed('Lambda_B said '+ data.Payload); } }) }; //LAMBDA B exports.handler = function(event, context) { console.log('Lambda B Received event:', JSON.stringify(event, null, 2)); context.succeed('Hello ' + event.name); };

Daniel Vassallo · Accepted Answer · 2019-02-07 08:15:23Z

Your problem is that the lambda.invoke() function is non-blocking, so Lambda_A is finishing its execution before it gets to call Lambda_B. You can use promises to deal with that. If you're using Node.js 8.10+, you can do this:

Lambda_A:

let AWS = require('aws-sdk'); let lambda = new AWS.Lambda(); exports.handler = async (event) => { let params = { FunctionName: 'Lambda_B', InvocationType: 'RequestResponse', Payload: '{ "foo" : "bar" }' }; return await lambda.invoke(params, function(err, data) { if (err) { throw err; } else { console.log('LambdaB invoked: ' + data.Payload); } }).promise(); };

Lambda_B:

exports.handler = async (event) => { return { statusCode: 200, body: JSON.stringify('Hello from Lambda_B!'), }; };

Response when Lambda_A invoked:

{ "StatusCode": 200, "ExecutedVersion": "$LATEST", "Payload": "{\"statusCode\":200,\"body\":\"\\\"Hello from Lambda_B!\\\"\"}" }

Console output from Lambda_A when invoked:

START RequestId: 016a763d-c79e-4d72-bd44-0aaa89a5efaf Version: $LATEST 2019-02-07T08:07:11.154Z 016a763d-c79e-4d72-bd44-0aaa89a5efaf LambdaB invoked: {"statusCode":200,"body":"\"Hello from Lambda_B!\""} END RequestId: 016a763d-c79e-4d72-bd44-0aaa89a5efaf REPORT RequestId: 016a763d-c79e-4d72-bd44-0aaa89a5efaf Duration: 717.40 ms Billed Duration: 800 ms Memory Size: 128 MB Max Memory Used: 30 MB

I'm not very familiar with the serverless project, but I assume the code should just go in handler.js
I tried your code but it gives me an error Serverless Error --------------------------------------- Stack:arn:aws:cloudformation:us-east-1:376014394890:stack/lambda-test-dev/be4e1a40-29c0-11e9-8b17-0a9ef6cbb06a is in UPDATE_IN_PROGRESS state and can not be updated.

Mesut Yilmes · Accepted Answer · 2020-12-15 22:41:06Z

You can add an user which has policy includes LambdaInvoke then add below configuration

enter code var credentials = { accessKeyId : process.env.ACCESS_KEY, secretAccessKey : process.env.SECRET_KEY}; AWS.config.update( { "credentials":credentials, "region":"eu-central-1" });

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