Retrieving Function parameters values in aws lambda using node.js

Question

I have 2 aws lambda functions i.e. "LambdaChain1" and "LambdaChain2" i am calling aws lambda function "LambdaChain2" from aws lambda function "LambdaChain1" as follows :

enter code here var start=new Date(); enter code hereconsole.log('Loading function');

exports.handler = function(event, context) {
    //console.log('Received event:', JSON.stringify(event, null, 2));
    event.Records.forEach(function(record) {
        // Kinesis data is base64 encoded so decode here
        var payload = new Buffer(record.kinesis.data, 'base64').toString('ascii');
        console.log('Decoded payload:', payload);
    });
    context.succeed("Successfully processed " + event.Records.length + " records.");
    var params = {
  FunctionName: 'LambdaChain2', /* required */
  InvokeArgs: start.getTime() /* required */
};
lambda.invokeAsync(params, function(err, data) {
  if (err) console.log(err, err.stack); // an error occurred
  else     console.log(data);           // successful response
});
};

Now we can see from the code that I have passed "start.getTime()" as parameter to aws lambda function "LambdaChain2"....

I want to know that in aws lambda function LambdaChain2 how can I retrieve or use the parameter that I have passed to the function "LambdaChain2" from lambda function "LambdaChain1".....Can you please provide an example

James · Accepted Answer · 2015-11-02 17:01:52Z

2

It looks like invokeAsync is deprecated, so I used invoke for this example, but it is fairly similar.

The Payload argument in the invoke params becomes the event parameter in ChainFunc2.

ChainFunc1

var AWS = require("aws-sdk");

exports.handler = function(event, context) {
    console.log('Received event:', JSON.stringify(event, null, 2));
    var params = {
        FunctionName: "ChainFunc2",
        InvocationType: "RequestResponse",
        Payload: JSON.stringify({"greeting": "Hello, Lambda"})
    };
    var lambdaClient = new AWS.Lambda();
    lambdaClient.invoke(params, function(err, data) {
        if (err) {
            console.log("invoke failed:" + err, err.stack);
            context.fail(err);
        } else {
            console.log("invoke succeeded", data);
            context.succeed(data);
        }
    });
};

ChainFunc2

exports.handler = function(event, context) {
    console.log("Received event:", JSON.stringify(event, null, 2));
    console.log("Greeting:", event.greeting);
    context.succeed({"message": "ChainFunc2 processed this", "payload": event});
};

answered Nov 2, 2015 at 17:01

James

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8 Comments

AKSHAY SHINGOTE Over a year ago

Your solution is working when i am using the parameter of ChainFunc1 in ChainFunc2....But now I am not able to use the same in ChainFunc3,4,5...Basically I want to use the same parameter with same value in other functions also....I can see from the logs that JSON.stringify(event,null,2) returns null from ChainFunc3 & returns not null in 1 & 2.....How can I be able to use the parameter greeting in another lambda functions?? Do I have to make separate approach if I am using Long or Integer values in node js

James Over a year ago

How did you pass the parameter from ChainFunc2 to ChainFunc3, 4, etc? You will have to keep passing the same values along.

AKSHAY SHINGOTE Over a year ago

I want to pass milliseconds throughout my lambda function. This is my code for ChainFunc1 :: var AWS = require("aws-sdk"); var starttime=new Date().getTime(); exports.handler=function(event,context) { var payload=new Buffer(record.kinesis.data, 'base64').toString('ascii'); var params = { FunctionName: "ChainFunc2", InvocationType: "RequestResponse", Payload: JSON.stringify({"starttime": start.getTime()}) }; var lambdaClient = new AWS.Lambda();

AKSHAY SHINGOTE Over a year ago

lambdaClient.invoke(params, function(err, data) { if (err) { console.log("invoke failed:" + err, err.stack); context.fail(err); } else { console.log("invoke succeeded", data); context.succeed(data); } }); }); };

AKSHAY SHINGOTE Over a year ago

Now this the code for my lambda function ChainFunc2 :: var AWS = require("aws-sdk"); console.log("Received event:", JSON.stringify(event, null, 2)); exports.handler = function(event, context) { console.log("Received event:", JSON.stringify(event, null, 2)); var startTime = event.starttime; var params = { FunctionName: "ChainFunc3", InvocationType: "RequestResponse", Payload: JSON.stringify({"starttime": starttime}) }; var lambdaClient = new AWS.Lambda();

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