Development

Our development process is focused on high quality and development comfort. We use tools that are proven to be the best in class.

There are two possible ways to develop your apps.

  1. local development
  2. development inside docker

You can choose one or use both at the same time. How to choose what method should you use?

Local development is much easier and much faster. You can choose it if you don’t have too many infrastructure dependencies. That’s a default option for the new projects.

Choosing docker development means that you already have a complex setup of different technologies, containers, networks, etc. This is a default option for older and more complicated projects.

Dependencies

We use poetry to manage dependencies. So, please do not use virtualenv or pip directly. Before going any further, please, take a moment to read the official documentation about poetry to know some basics.

If you are using docker then prepend docker-compose run --rm web before any of those commands to execute them.

Please, note that you don’t need almost all of them with docker. You can just skip this sub-section completely. Go right to Development with docker.

Installing dependencies

You do not need to run any of these command for docker based development, since it is already executed inside Dockerfile.

Please, note that poetry will automatically create a virtualenv for this project. It will use you current python version. To install all existing dependencies run:

poetry install

To install dependencies for production use, you will need to run:

poetry install --no-dev

And to activate virtualenv created by poetry run:

poetry shell

Adding new dependencies

To add a new dependency you can run:

  • poetry add django to install django as a production dependency
  • poetry add --dev pytest to install pytest as a development dependency

This command might be used with docker.

Dependencies security

We use safety to validate that we use only secure releases. To validate that all dependencies are secure, run:

safety check

This command might be used with docker.

Updating poetry version

Package managers should also be pinned very strictly. We had a lot of problems in production because we were not pinning package manager versions.

This can result in broken lock files, inconsistent installation process, bizarre bugs, and missing packages. You do not want to experience that!

How can we have the same poetry version for all users in a project? That’s where [build-system] tag shines. It specifies the exact version of your poetry installation that must be used for the project. Version mismatch will fail your build.

When you to update poetry, you have to bump it in several places:

  1. pyproject.toml
  2. docker/django/Dockerfile

Then you are fine!

Development with docker

To start development server inside docker you will need to run:

docker-compose build
docker-compose run --rm web python manage.py migrate
docker-compose up

Running scripts inside docker

As you have already mentioned inside the previous section we use docker-compose run to run scripts inside docker.

What do you need to know about it?

  1. You can run anything you want: poetry, python, sh, etc
  2. Most likely it will have a permanent effect, due to docker volumes
  3. You need to use --rm to automatically remove this container afterward

Extra configuration

You might want to tweak INTERNAL_IPS django setting to include your docker container address into it. Otherwise django-debug-toolbar might not show up.

To get your docker ip run:

docker inspect your-container-name | grep -e '"Gateway"'

You can also configure a permanent hostname inside your /etc/hosts to access your docker containers with a permanent hostname.

Local development

When cloning a project for the first time you may need to configure it properly, see Django section for more information.

Note, that you only need to run these commands once per project.

Local database

When using local development environment without docker, you will need a postgres up and running. To create new development database run:

psql postgres -f sql/create_database.sql

Then migrate your database:

python manage.py migrate

Running project

If you have reached this point, you should be able to run the project.

python manage.py runserver