How to install Flask – Python web development micro framework on Ubuntu 18.04 and 19.04

Go ahead and launch your terminal, run the following commands..

sudo apt update && upgrade

I assume that you already have python and pip installed on your Ubuntu Desktop/server. If not, you can install python3 and pip3 with the following commands.

Let’s Install python3 and pip3

sudo apt install python3

sudo apt install python3-pip

Now, let’s check python3 and pip3 version

python3 -V

pip3 -V

Install python virtual environment

We’ll create a directory/folder, where python virtual enviroment will be installed and activated.

cd Desktop && mkdir pybox && cd pybox

We just created a directory on the Desktop and changed directory, now, we are in pybox directory.

Let’s install venv and name it venv

python3 -m venv venv

Let’s activate the venv – The Python environment

source venv/bin/activate

Make sure you are in pybox direcetory, before start activating python virtual envorinment

Let’s install Flask

pip install flask

flask --version

pip lists

Let’s quickly create flask app

Create a folder/directory in the pybox directory/folder

mkdir demoapp && cd demoapp && touch app.py

In app.py file, put the following code

from flask import Flask
app = Flask(__name__)

@app.route("/")
def home():
	return "Hello from flask app.py file"

if __name__ == '__main__':
	app.run(debug=True)

Make sure you are in the flask app root directory and run the following command from the terminal

FLASK_APP=app.py

then

flask run

Now, go ahead and open your preferred browser and navigate to

http://127.0.0.1:5000/

How to install Flask on Ubuntu 18.04 Video