AWS SNS Multiple notifications received

Question

I have an API Gateway method calling a Lambda Node.js function. The Lambda function calls SNS and posts an APNS notification to my iPhone. When I invoke the API gateway or the Lambda function in the AWS console, I get one notification as expected. I also get one notification when running the Lambda code on the command line (Grunt and Node.js). I also get one notification when running the javascript from eclipse.

However, when I POST to the API gateway, I get 2-5 notifications. Every thing looks the same. I checked the Cloudwatch logs and it seems only one request is sent each time. Anybody have any idea how to debug this?

Answer 1

I figured it out. I had my function outside the exports.handler function:

var AWS = require('aws-sdk');
var sns = new AWS.SNS();

var myAlerter = function(){

    var numSent = 0;
    var callback;
    var arn = "arn:aws:sns:us-west-2:45435475457:endpoint/APNS/MyAlerter/5a11c61f-1122-3344-5566-656845463";

    var sendNotification = function(messageText){

            var apns = {
                    aps : {
                        alert : messageText,
                        sound : 'default'
                    }
            };
            var message = {
                    "APNS" : JSON.stringify(apns)
            };
            message = JSON.stringify(message);

            var params = {
                    Message: message, 
                    MessageStructure: 'json',
                    TargetArn: arn
            };

            numSent++;
            sns.publish(params, function(err, data){
                if (err){
                    callback(err, err.stack);
                }else {
                    var result = {
                            error: false,
                            numSent : numSent,
                            data: data
                    };              

                    callback(false,result);
                }
            });            
    };

    return {

        alert : function(message, cb){
            callback = cb;
            sendNotification(message);
        }

    }

}();

exports.handler = function(event, context){

    var alertedCallback = function(error, data){
        if (error){
            context.done(error);
        } else {
            context.succeed(data);
        }
    };          

    myAlerter.alert(event.message, alertedCallback);

};

Everytime I called the API Gateway and invoked my Lambda function, the numSent variable would increment. I guess putting my function inside the exports.handler ensured that my function wasn't global or something.