Building and Deploying a simple Cloud-Native Web App

This article outlines the steps and choice of programming language in the development of our cloud-native web app. In this capstone project, we would use Flask (Python) web framework to build our application backend.

Web frameworks are software libraries that provide a structured way to build and develop web applications. Their set of pre-defined functions, templates, and tools simplify the process of creating dynamic and interactive websites or web applications.

Phase 2 - Writing the application code using python-flask

Create a VENV: (optional but great for multiple projects)

Three simple steps to set up venv on your machine

        //Install venv to host python using the cmd
        $ pip install virtualenv

        //Create a project folder in your terminal 
        $ python<version> -m venv <virtual-environment-name>

        //Activate your venv for windows with the cmd
        $ <virtual-env-name>/Scripts/Activate.ps1

        //Activete your venv for mac with the cmd
        $ source <virtual-env-name>/bin/activate

Install Flask using the command:

        $ pip install Flask

        //Check to see all dependecies installed alongside flask
        $ pip list
        Package      Version
        ------------ -------
        blinker      1.6.2  
        click        8.1.7  
        colorama     0.4.6  
        Flask        2.3.3  
        itsdangerous 2.1.2  
        Jinja2       3.1.2  
        MarkupSafe   2.1.3  
        pip          22.3.1 
        psutil       5.9.5  
        setuptools   65.5.0 
        Werkzeug     2.3.7

```bash from flask import Flask, jsonify, render_template import socket, psutil

app = Flask(name)

@app.route("/") def hello_world(): return "
Hello, I am Nelson Osagie, a Cloud / DevOps Engineer.
"

#Function that get system cpu and memory usage def app_health(): cpu_percent = psutil.cpu_percent() mem_percent = psutil.virtual_memory().percent message = None if cpu_percent > 85 or mem_percent > 70: message = "High CPU and Memory utilization, scale up" return str(cpu_percent), (mem_percent)

@app.route("/details") def details(): cpu_percent, mem_percent = app_health() hostname, ip_address = get_host_details() return render_template('index.html', HOSTNAME=hostname, IP=ip_address, CPU=cpu_percent, MEM=mem_percent)

if name == 'main': app.run(host="localhost", port=5000, debug=True)



index.html

```xml
<html>
<head>
    <title>
        A cloud-native-monitoring-web-app
    </title>
</head>
<body>
    <h2> Building and deploying a simple monitoring app, using python flask web framework</h2>
    <h2> Details of Host machine: {{ HOSTNAME }} and IP address {{ IP }}</h2>
    <h3> Details of CPU and Memory Utilization:</h3>
    <h1> CPU Usage {{ CPU }} and Memory Usage: {{ MEM }}</h1>
</body>
</html>

You are free to build any sort of dynamics to the project, check the repo for updates, and feel free to make contributions: https://github.com/Nelgit007/cloud-native-monitoring-web-app

Use pip to freeze all dependecise in your venv:
```
  $ pip freeze > requirements.txt
```

Building and Deploying a simple Cloud-Native Web App - Part 2

Table of contents

Phase 2 - Writing the application code using python-flask