flask-example-cicd

This is a simple python flask application to host a simple web app.

After starting the flask application you can access following URL's on the server:

Function	URL
index	`http://<server>:<port>/`
json	`http://<server>:<port>/json/`
hello	`http://<server>:<port>/hello/`
hello <name>	`http://<server>:<port>/hello/<name>`
primes 100	`http://<server>:<port>/primes/`
primes <count>	`http://<server>:<port>/primes/<count>`

How to run

You can run the application in 2 ways:

Build and run the docker image
Build and run the code from source

Docker instructions

Requirements:

Docker installed

Build the docker image in the project root folder with:

docker build . -t flask-example-cicd:latest

To run the docker image in interactive mode:

docker run --rm -it -p 8080:8080/tcp --name flask-example flask-example-cicd:latest

To run the docker image in detached mode:

docker run --rm -d -p 8080:8080/tcp --name flask-example flask-example-cicd:latest

You can change the environmental variable for flask in the Dockerfile, for example you can change the port by changing ENV FLASK_RUN_PORT=8080.

Stop the running container:

docker stop flask-example

Build from source

Requirements:

python3
python3-dev
python3-pip
gcc (to compile cython)
musl-dev (to compile cython)

Instructions for Debian/Ubuntu

Install requirements:

apt update
apt install gcc musl-dev python3 python3-dev python3-pip

Build/Install project:

. build.sh

Run the server on localhost:8080:

. run.sh

Development

Virtual Environment

For local development you can use a virtual environment → How to install virtualenv.

Create a virtual environment:

# linux example
python3 -m venv "venv"
source venv/bin/activate

With deactivate you can disable the virtual environment.

Debugging

Built-In flask debugger

You can debug the flask app by running following commands:

Linux (Bash)

export FLASK_APP=flaskr.app
export FLASK_ENV=development
flask run

Windows (CMD)

set FLASK_APP=flaskr.app
set FLASK_ENV=development
flask run

Windows (PowerShell)

$env:FLASK_APP = "flaskr.app"
$env:FLASK_ENV = "development"
flask run

External Debugger

When using an external debugger, the app should still be in debug mode, but it an be useful to disable the built-in debugger and reloader, which can interfere.

flask run --no-debugger
flask run --no-reload
flask run --no-debugger --no-reload

Example configuration for VS Code

.vscode/launch.json

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Python: Flask",
            "type": "python",
            "request": "launch",
            "module": "flask",
            "env": {
                "FLASK_APP": "flaskr/app.py",
                "FLASK_ENV": "development",
                "FLASK_RUN_PORT" : "8080",
                "FLASK_DEBUG": "1"
            },
            "args": [
                "run",
                "--no-debugger"
            ],
            "jinja": true
        }
    ]
}

Testing

To run unit tests:

# install pytest manually or use "reset-dev.sh"
pip3 install pytest 
pytest

Reset development environment

You can use the script reset-dev.sh to reset your development environment:

. reset-dev.sh

The script will do following:

(Re)create the virtual environment venv without dependencies installed
Activating venv in current terminal
Install development/testing tools in venv
- flake8 (Linting)
- pylint (Linting)
- autopep8 (Formatting)
- pytest (Testing)
Remove all folders created by build/install
- package info (*egg-info)
- build folder
- dist folder
- pycache folders
- built cython files (*.so, *.pyd)

Now you can build the project manually or with build.sh.

FlorianKutz/flask-example-cicd