NYU DevOps lab showing a very simple REST API all on one Python module app.py

This lab demonstrates how to create a simple REST service using Python Flask and SQLite. The resource model is persistenced using SQLAlchemy to keep the application simple. SQLAlchemy is an Object Relational Mapper (ORM) that will allow you to work with classes instead of database records.

This projects purpose is to show the correct API and return codes that should be used for a REST API. Everything is contained ina single

The easiest way to use this lab is with Vagrant and VirtualBox. if you don't have this software the first step is down download and install it.

Download VirtualBox

Download Vagrant

Then all you have to do is clone this repo and invoke vagrant:

    git clone https://github.com/nyu-devops/lab-flask-rest.git
    cd lab-flask-rest
    vagrant up
    vagrant ssh
    cd /vagrant
    FLASK_APP=service:app flask run -h 0.0.0.0

You can also automatically set the environment variable FLASK_APP using a .env file. There is an example in this repo called .env-example that you can simply copy.

    cp .env .env-example

The .env file will be loaded when you do flask run so that you don't have to specify any environment variables.

If you have Python 3 installed on your computer you can make a virtual environment and run the code locally with:

    python3 -m venv venv
    source venv/bin/activate
    pip install -r requirements.txt
    FLASK_APP=service:app flask run

Run the tests using nose

    nosetests

Nose is configured to automatically include the flags --with-spec --spec-color so that red-green-refactor is meaningful. If you are in a command shell that supports colors, passing tests will be green while failing tests will be red. It also has --with-coverage specified so that code coverage is included in the tests.

The Code Coverage tool runs with nosetests so to see how well your test cases exercise your code just run the report:

    coverage report -m

This is particularly useful because it reports the line numbers for the code that is not covered so that you can write more test cases.

To run the service use flask run (Press Ctrl+C to exit):

    FLASK_APP=service:app flask run -h 0.0.0.0

You must pass the parameters -h 0.0.0.0 to have it listed on all network adapters to that the post can be forwarded by vagrant to your host computer so that you can open the web page in a local browser at: http://localhost:5000

When you are done, you can exit and shut down the vm with:

    exit
    vagrant halt

If the VM is no longer needed you can remove it with:

    vagrant destroy

This repo is part of the DevOps course CSCI-GA.2820-001/002 at NYU taught by John Rofrano.