Cannot invoke my lambda function

Question

I'm trying to unterstand how aws lambda works but i have to admit that i have not totally catch the utility of this aws module. So, from what i know lambda allow to start a script after a event pre-specified ? Ok so i'm trying since a couple of days to build a simple case.

When i upload or delete something from S3, i want my lambda function send me a push notification by Using SNS. Unfortunately, i can't get this work. I don't know how to proceed. I followed the AWS getting started tutorial form lambda, i configured roles and all these stuffs, then i create a node.js function (deployment function) , installed dependencies and zipped all these stuffs then upload this to Aws lambda.

I also configured the event in aws S3, but when i upload or delete a file from S3 i never received any push notification. I just want to know the simplest way to test AWS Lambda because even the amazon sample test lambda function (S3 upload image, resizing and copy to another bucket) doesn't work when i test it.

Here is the code i'm trying to get it works

var async = require('async');
var AWS = require('aws-sdk');


// get reference to S3 client 
var s3 = new AWS.S3();
var sns = new AWS.SNS();

exports.handler = function(event, context, callback) {
	var params = {
	  Message: 'STRING_VALUE', /* required */
	  MessageAttributes: {
	    someKey: {
	      DataType: 'raw', /* required */
	      BinaryValue: new Buffer('...') || 'STRING_VALUE',
	      StringValue: 'STRING_VALUE'
	    },
	    /* anotherKey: ... */
	  },
	  MessageStructure: 'Hello from lambda',
	  Subject: 'STRING_VALUE',
	  TargetArn: 'XXXXXXX', //my target arn
	  TopicArn: 'XXXXX' //my topic arn
	};
	async.waterfall([
			sns.publish(params, function(err, data) {
			  if (err) console.log(err, err.stack); // an error occurred
			  else     console.log(data);           // successful response
			})
		],function(error){
		if (error) throw err;
	})
	
};

Any help will be highly appreciated. Thanks

cjwfuller · Accepted Answer · 2016-04-22 11:17:02Z

3

Couple things to check:

Are you subscribed to the SNS topic? SNS is just a notification so you need to be subscribed to the topic to get a notification e.g. an email subscription. Docs: http://docs.aws.amazon.com/sns/latest/dg/SubscribeTopic.html
Have you set up an event source mapping? Docs: http://docs.aws.amazon.com/lambda/latest/dg/intro-core-components.html
Check that you're using waterfall properly: http://docs.aws.amazon.com/lambda/latest/dg/with-s3-example-deployment-pkg.html

edited Apr 22, 2016 at 11:17

answered Apr 22, 2016 at 11:07

cjwfuller

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Lucifer · Accepted Answer · 2016-04-29 14:41:38Z

1

Also check your CloudWatch logs for the Lambda function, if it is being triggered you'll have a log entry. This is also your way of producing a debug trace from your function and will show any errors.

I'm developing in Java, so Serverless is no help to me, but as a Node developer you might also find this set of tools useful. https://github.com/serverless/serverless

answered Apr 29, 2016 at 14:41

Lucifer

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