README.md

IMAGE FILTERING MICROSERVICE with NODEJS

"Image Filtering Microservice" with NodeJs is a simple cloud application developed and hosted on AWS ElasticBeanstalk alongside the Udacity Cloud Engineering Nanodegree. It allows users to download images from a public accessible address. It validate the public accessibility of the URL with queries, post photos to the feed, and process photos using an image filtering microservice.

The Steps below is targeted towards readers with knowledge of Git, AWS ElasticBeanstalk, Typescript programming, NodeJs, Node Package Manager (npm), Linux, and DevOps principles.

Image Filter Microservice App

The image-filter url app is built with express web framework on nodejs.

See the code

Engineering Process and Quality

Following good cloud practices, development and production environment created for this project. All code written, build processes and deployment were done on Dev environment. The Git & GitHub Dev environment served as the working, testing, staging and deployment env before merging the updated working code to main branch. The main branch contains the most recent working and tested solution.

Development Server

• Install the dependencies npm i

Fig 1.0: Installing Dependencies

• Switched to dev branch to commit and test the node server for dev environment

npm run dev

Fig 2.0: Dev Server Running

• The API design and Implementation

IMPLEMENT A RESTFUL ENDPOINT GET /filteredimage?image_url={{URL}} endpoint to filter an image from a public url. IT SHOULD

1. validate the image_url query
2. call filterImageFromURL(image_url) to filter the image
3. send the resulting file in the response
4. deletes any files on the server on finish of the response QUERY PARAMATERS image_url: URL of a publicly accessible image RETURNS the filtered image file [!!TIP res.sendFile(filteredpath); might be useful] /**************************************************************************** */

see the code here

Image Url Validator

//Image Url validator code
const url_regex    = new RegExp(/([a-z]+\:\/+)([^\/\s]+)([a-z0-9\-@\^=%&;\/~\+]*)[\?]?([^ \#\r\n]*)#?([^ \#\r\n]*)\.(?:jpeg|jpg|gif|png|svg|bpm|tiff)/ig);
    const is_Valid_url  = url_regex.test(image_url);

Testing The API with POSTMAN

• Status Code 422 Testing the API with POSTMAN for graceful failure.

  catch(error) {
        return res.status(422)
                  .send(`${image_url} format not supported! See Supported formats: jpg, png, bmp, tiff, or gif`);
      }

  It failed as expected. The url validator only checks for a valid url with condition; publicly accessible and image file type. While the image filter checks if this is a supported format.

Fig 3.0: Status Code 422

• Status Code 200

try {
      //2.  calling the filterImageFromUrl function to validate the image
      const filter_image_file: string = await filterImageFromURL(image_url);
      
      //3.  sending the resulting file from filterImageFromUrl function
      res.status(200).sendFile(filter_image_file);
      
      //4. Deleting the file from the local tmp/filtered directory
      res.on('finish', () => deleteLocalFiles([filter_image_file]));
    }

It passed the testing as expected

Fig 4.0: Status Code 200

ElasticBeanStalk Deployment

• Build the Application

npm run build

Fig 5.0: Build the Application

• Initiate the ElasticBeanstalk Application

eb init --platform node.js --region us-east-1

Fig 6.0: Initialised ElasticBeanstalk

• Create the ElasticBeanstalk Environment

eb create --sample full-stack

Fig 7.1: Create ElasticBeanstalk

• ElasticBeanstalk Dashboard

Fig 7.2: ElasticBeanstalk Dashboard

• Testing Full-Stack Endpoint

Fig 8.0: Full-Stack Endpoint

• Deployment

eb deploy

Fig 8.0: ElasticBaeanstalk Deployment

Fig 9.1: ElasticBeanstalk Deployment

Fig 9.2: ElasticBeanstalk Deployment - Dashboard

• Response to Public URL

Fig 10.1: Filteredimeage download the public image

• filteredimage Endpoint

Fig 10.2: filteredimage

![filteredimage]http://full-stack.eba-3tfrxr3e.us-east-1.elasticbeanstalk.com/filteredimage?image_url=https://bs-uploads.toptal.io/blackfish-uploads/blog/post/seo/og_image_file/og_image/15921/secure-rest-api-in-nodejs-18f43b3033c239da5d2525cfd9fdc98f.png

Fig 11.1: Cat

Public URL

https://upload.wikimedia.org/wikipedia/commons/b/bd/Golden_tabby_and_white_kitten_n01.jpg

ElasticBeanstalk Public URL

http://full-stack.eba-3tfrxr3e.us-east-1.elasticbeanstalk.com/filteredimage?image_url=https://upload.wikimedia.org/wikipedia/commons/b/bd/Golden_tabby_and_white_kitten_n01.jpg

Public URL

http://full-stack.eba-3tfrxr3e.us-east-1.elasticbeanstalk.com

The ElasticBeanstalk Public URL

http://full-stack.eba-3tfrxr3e.us-east-1.elasticbeanstalk.com/filteredimage?image_url=https://upload.wikimedia.org/wikipedia/commons/b/bd/Golden_tabby_and_white_kitten_n01.jpg

Problems Encounter and Solution

To be written later

Summary

The ImageFilter App is an application developed with express framework hosted on elasticbeanstalk. Code written for this work were structured into directories. The API is written with Typescript in server.ts file which is located at the image-filter-starter-code/src directory.