Wednesday, April 29, 2020

Reactjs


Hello and Welcome to this tutorial on Reactjs . Here , we are going to learn Reactjs and also create a simple application .


Table of Contents

  • Getting Started
  • Components
  • JSX
  • props
  • state



1. Getting Started

Finish up all the required software installation (nodejs , vscode..) and start with creating a simple application using the following command .

npx create-react-app your-app-name
start your app using the following command

npm start

2. Components

Components are basic building blocks of a React application . Let's create one .
Create a new  file , here is an example of a sample component . 


import React from 'react';
import './App.css';

function App() {
  return (
    <div  >
       Hello World !
    </div>
  );
}

export default App;

2.1  render()

returns the HTML part of the component .


3. JSX

JSX stands for Javascript XML . You would have notice that in the render function we return an HTML element , that's actually a JSX . A JSX should be a valid XML .It is translated to Javascript at runtime .You can use an expression {} in JSX .


4. props

We can access the data passed to a component using props .


5. state

A state can have multiple properties which will be used within an application . If any state property is changed the component is re rendered .



  6.LifeCycle : Mounting 

  • Constructor
  • static getDerivedStateFromProps
  • render
  • componentDidMount



AWS CloudFormation

CloudFormation is used to save the configuration ( as a JSON )which can be used to create a new service .

Service to provision resources using templates .

 CloudFormation Template is a JSON document .

CloudFormation Stack : Services that are created using CloudFormation Template .

CloudFormation Designer : used to create a CloudFormation Template using a drag and drop .

CloudFormer : creates a cloudFormation template based on existing infrastructure .

Elastic Beanstalk

Elastic Beanstack can be used to automate deployment and scaling .

Amazon Aurora and Dynamo DB

DynamoDB will throttle or deny requests that exceed the table's provisioned throughput capacity .

Provisioned Throughput Capacity
Read/Write Operations per second provisioned for your DynamoDB table .


1 Read /Write Unit is 4kb item .

AI

Workflow of a Machine Learning Project .

Example : Amazon Echo
1.collect data
2.Train Model : Iterate many times until good enough .
3. Deploy Model : get data back , maintain update model .

Workflow of a Data Science Project .
1.Collect Data
2. Analyze Data : Iterate many times to get good insight
3. Suggest hypothesis /action : Deploy changes / reanalyze new Data periodically .


Monday, April 27, 2020

Aws ElasticCache

Web application
Database type : radis

Aws database services

Aws database migration service

Redshirt data warehouse solution.

Petabyte scale .

Wide column storage
Graph database.
Neptune

RDS database snapshot is placed to S3.
This is an increment backup.

Aurora : reduce cost by 90%
Dynamo db runs on top of s3

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