30 Days Of AWS (Day 8 and 9)
Tags: aws, challenge, 30daysofaws
Published: 2019-06-09 20:31:32

---
title: 30 Days Of AWS (Day 8 and 9)
published: true
description: 
tags: AWS, challenge, 30DaysOfAWS
cover_image: https://thepracticaldev.s3.amazonaws.com/i/xk3wcpnc2h8nk8oy9xh6.png
series: 30 Days of AWS
---

Hello guys! I've come back. I'm so sorry the last 3 days, I was sick but now I feel ready to share what I've studied those days.

## Day 8 - Resume.

I was practising a lot in the console using different services, VCP, S3, EC2 and RDS.  Besides I was reading about in AWS papers. It's important to mention that this challenge is part of my preparation to AWS Solution Architect Certified, I know that when you study to accomplish something like that, you should check more information than an essentials course.

Once I will have done this first course I gonna take another course specialized to this certification. Thank you to [Andrew Brown](https://dev.to/andrewbrown) that has been suggesting to me what other content I should study and he shared with me early access to his platform. Besides, [Walter Seun](https://dev.to/walterseun) Shared with me one page to practice the test. Thank you all.

## Day 9 - SNS.

Today I was learning about SNS, although it's one service I'm using every single day. Because we have a lot of notification, about, billing, health check and between lambdas (I gonna explain later).

## SNS.

From the Docs "Amazon Simple Notification Service (Amazon SNS) is a web service that coordinates and manages the delivery or sending of messages to subscribing endpoints or clients. In Amazon SNS, there are two types of clients—publishers and subscribers—also referred to as producers and consumers. Publishers communicate asynchronously with subscribers by producing and sending a message to a topic, which is a logical access point and communication channel. Subscribers (i.e., web servers, email addresses, Amazon SQS queues, AWS Lambda functions) consume or receive the message or notification over one of the supported protocols (i.e., Amazon SQS, HTTP/S, email, SMS, Lambda) when they are subscribed to the topic."

By default, the maximum number of SNS topics per account is 100,000 and By default, the maximum number of subscriptions per topic is 12,500,000.

![SNS](https://thepracticaldev.s3.amazonaws.com/i/3xpdl9rv94my7jjf02of.png)

## Real world example.

The following image is a diagram about how we are using the SNS, It couldn't be the best example but you can have an idea about how to use it.

![RWE](https://thepracticaldev.s3.amazonaws.com/i/8aw6ctnq0oxjkk2ofvg9.png)

Ok, the first service that we have is an API Gateway, immediately when the user makes a request, we send a response back to notify that the request has been processed. One thing that we are doing is to use the lambdas function as a microservice because our workflow has several possible options with different output.

Once the lambda function called *Process A* processes the message, we notify to an SNS. This will send a message to 2 different services, Process B and D. Here you can think why do you need to send the message to 2 different lambdas? Because we need the same info to different propose and each lambda should have its function.

After the lambda *Process B* processes the message, it has 2 different ways, If it's ok it will be sent a message to other lambdas and if it is not ok, it will be sent an email. So Basically what we are doing is to use the SNS to notify to other services depending on the case we have different output.

Besides I've taken a small exam about SNS And above the result. 

![Exam Result](https://thepracticaldev.s3.amazonaws.com/i/isq9swc5z4o7jmob2h7s.png)

OK, guys, that's all for today. 

Thanks for reading.