DevOps Apprenticeship: Project Exercise

If you are using GitPod for the project exercise (i.e. you cannot use your local machine) then you'll want to launch a VM using the following link. Note this VM comes pre-setup with Python & Poetry pre-installed.

System Requirements

The project uses poetry for Python to create an isolated environment and manage package dependencies. To prepare your system, ensure you have an official distribution of Python version 3.7+ and install Poetry using one of the following commands (as instructed by the poetry documentation):

Poetry installation (Bash)

curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/install.python-poetry.org | python -

Poetry installation (PowerShell)

(Invoke-WebRequest -Uri https://raw.githubusercontent.com/python-poetry/poetry/master/install.python-poetry.org -UseBasicParsing).Content | python -

Dependencies

The project uses a virtual environment to isolate package dependencies. To create the virtual environment and install required packages, run the following from your preferred shell:

$ poetry install

You'll also need to clone a new .env file from the .env.template to store local configuration options. This is a one-time operation on first setup:

$ cp .env.template .env  # (first time only)

The .env file is used by flask to set environment variables when running flask run. This enables things like development mode (which also enables features like hot reloading when you make a file change). There's also a SECRET_KEY variable which is used to encrypt the flask session cookie.

Trello integration

This app uses a Trello board to store the items. You should set up a Trello board, with three lists for 'To Do', 'Doing' and 'Done'. Update your .env file with the board and list id's, as well as your Trello API Key and Token.

Running the App locally

Once the all dependencies have been installed, start the Flask app in development mode within the Poetry environment by running:

$ poetry run flask run

You should see output similar to the following:

 * Serving Flask app "app" (lazy loading)
 * Environment: development
 * Debug mode: on
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
 * Restarting with fsevents reloader
 * Debugger is active!
 * Debugger PIN: 226-556-590

Now visit http://localhost:5000/ in your web browser to view the app.

Running the App on the VM

Run the following command on the control node:

ansible-playbook ansible-playbook.yml -i ansible-inventory

Running the App in a Docker Container - Development mode

To create the image, run the command:

docker build --target development --tag todo-app:dev .

Then to run the container, run:

docker run --env-file .env -p 8080:5000 --mount type=bind,source="$(pwd)"/todo_app,target=/app/todo_app todo-app:dev

You can then find the app on http://localhost:8080/

Running the App in a Docker Container - Production mode

To create the image, run the command:

docker build --target production --tag todo-app:prod .

Then to run the container, run:

docker run -p 8080:8000 --env-file .env todo-app:prod

You can then find the app on http://localhost:8080/

Running the Tests

Once the all dependencies have been installed, you can run all tests with:

$ poetry run pytest

Running the tests in Docker

To create the image, run

$ docker build --target test --tag my-test-image .

then to run the tests, run

$ docker run my-test-image