Chathura Widanage chathurawidanage

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Working from home

chathurawidanage / AWS DynamoDB partition formula

Created February 21, 2018 08:25

	initialPartitions = roundUp(( readCapacityUnits / 3,000 ) + ( writeCapacityUnits / 1,000 ))
	= roundUp((5000 / 3000) + (1000 / 1000))
	= 1.667 + 1
	= 2.667
	= 3

chathurawidanage / Local Lambda Init.sh

Last active February 21, 2018 08:47

	npm init
	npm install --save validate.js

chathurawidanage / Contact Us Write Lambda With Validation.js

Last active February 21, 2018 08:50

	let AWS = require('aws-sdk');
	const ddb = new AWS.DynamoDB.DocumentClient();
	const validate = require("validate.js");

	exports.handler = function (event, context, callback) {
	//validating email and name
	var constraints = {
	email: {
	presence: true,
	email: true

chathurawidanage / index.js

Last active February 24, 2018 04:06

	const { execSync } = require('child_process');
	const fs = require("fs");

	let read = fs.readFileSync('index.js'); //reading myself
	let code = read.toString();

	let requireRegex = /=\srequire\s$['\"](.+)['\"]$/g;
	let match = requireRegex.exec(code);

	while (match != null) {

chathurawidanage / npmi.sh

Created February 23, 2018 11:14

npm install --prefix /tmp <library_name> --save

chathurawidanage / lambda_dynamic_module_load.js

Last active June 18, 2019 13:23

	const { execSync } = require('child_process');

	let oldRequire = require;
	require = function(module) {
	try{
	oldRequire.resolve(`/tmp/node_modules/${module}`);
	}catch(e){
	execSync(`npm install --prefix /tmp --save ${module}`);
	}
	return oldRequire(`/tmp/node_modules/${module}`);

chathurawidanage / lambda_dyn_dep_load_branch.js

Created February 24, 2018 11:51

	const { execSync } = require('child_process');

	let oldRequire = require;
	require = function(module) {
	try{
	oldRequire.resolve(`/tmp/node_modules/${module}`);
	}catch(e){
	execSync(`npm install --prefix /tmp --save ${module}`);
	}
	return oldRequire(`/tmp/node_modules/${module}`);

chathurawidanage / cloudformation_contact_us.json

Last active March 1, 2018 05:30

	{
	"AWSTemplateFormatVersion": "2010-09-09",
	"Description": "This template creates the stack for project PJ-1-0-0. Generated by Sigma",
	"Outputs": {
	"apigcontactuscontactPOST": {
	"Description": "POST endpoint for resource /contact on API contact_us",
	"Value": {
	"Fn::Join": [
	"",
	[

chathurawidanage / before-promises.js

Created March 24, 2018 08:00

	//Old Fashion 1 - Two callback functions
	oldFashionOne(function(error){
	//handle error
	},function(data){
	//handle data
	});

	//Old Fashion 2 - One callback function with two arguements
	oldFashionTwo(function(err,data){
	if(!err){

chathurawidanage / twocallbacks.js

Created March 30, 2018 05:39

Using two callbacks to handle success and failure

	function task(onSuccess,onError){
	//do task
	if(failed){
	onError(error);
	}else{
	onSuccess(data);
	}
	}

	//calling task