Send pushnote to device with AWS Lambda Nodejs

var params = {'PlatformApplicationArn':platformApplicationArn,'Token': token};

sns.createPlatformEndpoint(params,function(err,EndPointResult)
    {
        if(EndPointResult != null){
          var clientArn = EndPointResult["EndpointArn"];
          sns.publish(
            {
              TargetArn: clientArn,
              Message: JSON.stringify(clientMessage),
              Subject: JSON.stringify(subject),
              MessageStructure: 'json'
            },
            function(err,data){
              if (err) {
                  console.log("Error sending a message "+err+JSON.stringify(params.Token));
                  if(err == "EndpointDisabled: Endpoint is disabled"){
                    sns.deleteEndpoint({'EndpointArn': clientArn}, function(err, data) {
                      if (err) console.log("Error removing Endpoint Arn: "+err);
                    });
                    message.deleteMessage(function(err, data) {
                      if(err){
                        console.log("Error deleting message: "+err);
                      }
                      message.next();
                    });
                  }
                  message.next();
              } else {
                  var messagedate = new Date();
                  console.log("Sent message: "+data.MessageId+messagedate+JSON.stringify(params));
                  sns.deleteEndpoint({'EndpointArn': clientArn}, function(err, data) {
                    if (err) console.log("Error removing Endpoint Arn: "+err);
                  });
                  message.deleteMessage(function(err, data) {
                    if(err){
                      console.log("Error deleting message: "+err);
                    }
                    message.next();
                  });
              }
            }
          );
        }
        if(EndPointResult == null){
          message.next();
        }
       
    });

Send message to a queue with AWS Lambda Nodejs

Following parameters need to be passed.
var params = {
            MessageBody: JSON.stringify({"platformApplicationArn":arn,
              'token':token_id,
              'message': messageBody,
              'subject':subject,
             }),
            QueueUrl: "https://sqs.ap-region-x.amazonaws.com/xxxxxxxxxxxx/2ndqueue"
      };

Send message to the queue.
sqs.sendMessage(params, function(err, data) {
    if (err){
      console.log(err, err.stack);
     
    }
    else {
      console.log(data);
    }
});

Connection pool and query within Lambda nodejs runtime

var pool = openConnectionToDB(host,username,password,database);

pool.getConnection(function(err,connection){
console.log('connected as id ' + connection.threadId);
        //Query
connection.query("SELECT * FROM ?? WHERE ?? = ? AND deleted_at IS NULL",['table_name','id',subject],function(err,rows){
           if(!err) {
             if(typeof rows[0] == 'undefined'){
               connection.release();
               connection.destroy();
             }
           }
 });
});

Using SqsQueueParallel to receive messages parallaly from a queue

var queue = new SqsQueueParallel({
      name: "queue1",
      region:process.env.REGION,
      accessKeyId:process.env.ACCESS_KEY_ID,
      secretAccessKey:process.env.SECRET_ACCESS_KEY,
      maxNumberOfMessages: 10,
      concurrency: 10
});

queue.on('message', function (message)
{
//more code
});

Lambda Function Basic

Create serverless function.
serverless function create functions/Function1/func1 (This command should be given within the project folder)

Within Function1 folder it creates
func1 folder and package.json file

Within func1 folder it creates following files.
event.json
handler.js
s-function.json

In handler.js file, we can include all the functions.

First we need to get required packages as below.

var aws = require('aws-sdk');
var SqsQueueParallel = require('sqs-queue-parallel');
var sqs = new aws.SQS({"accessKeyId":process.env.ACCESS_KEY_ID, "secretAccessKey": process.env.SECRET_ACCESS_KEY, "region": process.env.REGION});

Within handler function we can include the logic we want.

module.exports.handler = function(event, context, cb) {
};

s-function.json structure will be like
{
  "name": "func1",
  "runtime": "nodejs4.3",
  "description": "Serverless Lambda function for project: XXXXX",
  "customName": "func1",
  "customRole": "arn:aws:iam::xxxxxxxxxxxx:role/role",
  "handler": "func1/handler.handler",
  "timeout": 300,
  "memorySize": 128,
  "authorizer": {},
  "custom": {
    "excludePatterns": []
  },
  "endpoints": [],
  "events": [
    {
      "name": "V1Schedule",
      "type": "schedule",
      "config": {
        "schedule": "rate(5 minutes)",
        "enabled": true
      }
    }
  ],
  "environment": {
    "SERVERLESS_PROJECT": "${project}",
    "SERVERLESS_STAGE": "${stage}",
    "SERVERLESS_REGION": "${region}",
    "ACCESS_KEY_ID": "AWSKEYHERE",
    "SECRET_ACCESS_KEY": "AWSSECRETHERE",
    "REGION": "ap-southeast-1",
    "LIMIT": "300"
  },
  "vpc": {
    "securityGroupIds": [],
    "subnetIds": []
  }
}

package.json structure will be like,
{
  "name": "LambdaFunction",
  "version": "0.0.1",
  "description": "A Serverless Project and its Serverless Plugin dependencies.",
  "author": "ishara",
  "license": "MIT",
  "private": false,
  "repository": {
    "type": "git",
    "url": "git://github.com/"
  },
  "dependencies": {
    "async-foreach": "^0.1.3",
    "mysql": "^2.11.1",
    "object-sizeof": "^1.0.10",
    "sqs-queue-parallel": "^0.1.6"
  }
}

Pushnotification proceesor with AWS Lambda

Push Notification Processor is a microservice developed using AWS Lambda Node.js 4.3 runtime. To deploy the Lambda functions to AWS, the serverless framework is used.

Process:
To send bulk pushnotes, we use two SQS queues.
Platform -> 1st queue -> Execute 1st Lambda function -> 2nd queue -> Execute 2nd Lambda function to send pushnote to device

To execute lambda functions, we need a Role that has permission AmazonSQSFullAccess,AmazonSNSFullAccess

We can assign permissions to a role through AWS IAM (Identity Access Management).

In handler.js file, we can include all the functions.