dahr / flask-app

flask-vote-app

A sample web poll application written in Python (Flask). Users will be prompted with a poll question and related options. They can vote preferred option(s) and see poll results as a chart. Poll results are then loaded into an internal DB based on sqlite. As alternative, the application can store poll results in an external MySQL database.

This application is intended for demo only.

Local deployment

This application can be deployed locally. On linux, install git and clone the reposistory

[root@centos]# yum install -y git
[root@centos]# git clone https://github.com/kalise/flask-vote-app
[root@centos]# cd flask-vote-app

Install the dependencies

pip install flask
pip install flask-sqlalchemy
pip install mysql-python

and start the application

python app.py
Check if a poll already exists into db
* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)

Poll question and options are loaded from a JSON file called seed_data.json under the ./seeds directory. This file is filled with default values, change it before to start the application.

The DB data file is called app.db and is located under the ./data directory. To use an external MySQL database, set the environment variables by editing the flask.rc file under the application directory

nano flask.rc
export PS1='[\u(flask)]\> '
export DB_HOST=centos
export DB_PORT=3306
export DB_NAME=votedb
export DB_USER=voteuser
export DB_PASS=password
export DB_TYPE=mysql

Source the file and restart the application

source flask.rc
python app.py

Make sure an external MySQL database server is running according with the parameters above.

Docker deployment

A Dockerfile is provided in the reposistory to build a docker image and run the application as linux container.

On Linux, install and start Docker

[root@centos ~]# yum install -y docker
[root@centos ~]# systemctl start docker

Install git and clone the reposistory

[root@centos]# yum install -y git
[root@centos]# git clone https://github.com/kalise/flask-vote-app
[root@centos]# cd flask-vote-app

Build a Docker image

[root@centos]# docker build -t flask-vote-app:latest .
[root@centos]# docker images
REPOSITORY            TAG                 IMAGE ID            CREATED             SIZE
flask-vote-app        latest              e6e0578f5f2d        2 minutes ago       695.4 MB

Start the container

docker run -d -p 80:5000 --name=vote flask-vote-app:latest

Seeds data directory containing the seed data file seed_data.json can be mounted as an external volume under the host /mnt directory

cp flask-vote-app/seeds/seed_data.json /mnt
docker run -d -p 80:5000 -v /mnt:/app/seeds --name=vote flask-vote-app:latest

An external MySQL database can be used instead of the internal sqlite by setting the desired env variables

docker run -e DB_HOST=centos \
           -e DB_PORT=3306 \
           -e DB_NAME=votedb \
           -e DB_USER=voteuser \
           -e DB_PASS=password \
           -e DB_TYPE=mysql \
           -d -p 80:5000  --name=vote flask-vote-app:latest

Happy polling!