cookiecutter-django/docs/developing-locally-docker.rst
Nikita P. Shupeyko 3ac9902670 Rename project template Docker Compose volumes
Rationale: consistent image, volume etc. naming conventions
2018-06-27 19:52:06 +03:00

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Getting Up and Running Locally With Docker
==========================================
.. index:: Docker
The steps below will get you up and running with a local development environment.
All of these commands assume you are in the root of your generated project.
Prerequisites
-------------
* Docker; if you don't have it yet, follow the `installation instructions`_;
* Docker Compose; refer to the official documentation for the `installation guide`_.
.. _`installation instructions`: https://docs.docker.com/install/#supported-platforms
.. _`installation guide`: https://docs.docker.com/compose/install/
Attention, Windows Users
------------------------
Currently PostgreSQL (``psycopg2`` python package) is not installed inside Docker containers for Windows users, while it is required by the generated Django project. To fix this, add ``psycopg2`` to the list of requirements inside ``requirements/base.txt``::
# Python-PostgreSQL Database Adapter
psycopg2==2.6.2
Doing this will prevent the project from being installed in an Windows-only environment (thus without usage of Docker). If you want to use this project without Docker, make sure to remove ``psycopg2`` from the requirements again.
Build the Stack
---------------
This can take a while, especially the first time you run this particular command on your development system::
$ docker-compose -f local.yml build
Generally, if you want to emulate production environment use ``production.yml`` instead. And this is true for any other actions you might need to perform: whenever a switch is required, just do it!
Run the Stack
-------------
This brings up both Django and PostgreSQL. The first time it is run it might take a while to get started, but subsequent runs will occur quickly.
Open a terminal at the project root and run the following for local development::
$ docker-compose -f local.yml up
You can also set the environment variable ``COMPOSE_FILE`` pointing to ``local.yml`` like this::
$ export COMPOSE_FILE=local.yml
And then run::
$ docker-compose up
To run in a detached (background) mode, just::
$ docker-compose up -d
Execute Management Commands
---------------------------
As with any shell command that we wish to run in our container, this is done using the ``docker-compose -f local.yml run --rm`` command: ::
$ docker-compose -f local.yml run --rm django python manage.py migrate
$ docker-compose -f local.yml run --rm django python manage.py createsuperuser
Here, ``django`` is the target service we are executing the commands against.
(Optionally) Designate your Docker Development Server IP
--------------------------------------------------------
When ``DEBUG`` is set to ``True``, the host is validated against ``['localhost', '127.0.0.1', '[::1]']``. This is adequate when running a ``virtualenv``. For Docker, in the ``config.settings.local``, add your host development server IP to ``INTERNAL_IPS`` or ``ALLOWED_HOSTS`` if the variable exists.
.. _envs:
Configuring the Environment
---------------------------
This is the excerpt from your project's ``local.yml``: ::
# ...
postgres:
build:
context: .
dockerfile: ./compose/production/postgres/Dockerfile
volumes:
- local_postgres_data:/var/lib/postgresql/data
- local_postgres_data_backups:/backups
env_file:
- ./.envs/.local/.postgres
# ...
The most important thing for us here now is ``env_file`` section enlisting ``./.envs/.local/.postgres``. Generally, the stack's behavior is governed by a number of environment variables (`env(s)`, for short) residing in ``envs/``, for instance, this is what we generate for you: ::
.envs
├── .local
│   ├── .django
│   └── .postgres
└── .production
├── .caddy
├── .django
└── .postgres
By convention, for any service ``sI`` in environment ``e`` (you know ``someenv`` is an environment when there is a ``someenv.yml`` file in the project root), given ``sI`` requires configuration, a ``.envs/.e/.sI`` `service configuration` file exists.
Consider the aforementioned ``.envs/.local/.postgres``: ::
# PostgreSQL
# ------------------------------------------------------------------------------
POSTGRES_HOST=postgres
POSTGRES_DB=<your project slug>
POSTGRES_USER=XgOWtQtJecsAbaIyslwGvFvPawftNaqO
POSTGRES_PASSWORD=jSljDz4whHuwO3aJIgVBrqEml5Ycbghorep4uVJ4xjDYQu0LfuTZdctj7y0YcCLu
The three envs we are presented with here are ``POSTGRES_DB``, ``POSTGRES_USER``, and ``POSTGRES_PASSWORD`` (by the way, their values have also been generated for you). You might have figured out already where these definitions will end up; it's all the same with ``django`` and ``caddy`` service container envs.
One final touch: should you ever need to merge ``.envs/production/*`` in a single ``.env`` run the ``merge_production_dotenvs_in_dotenv.py``: ::
$ python merge_production_dotenvs_in_dotenv.py
The ``.env`` file will then be created, with all your production envs residing beside each other.
Tips & Tricks
-------------
Activate a Docker Machine
~~~~~~~~~~~~~~~~~~~~~~~~~
This tells our computer that all future commands are specifically for the dev1 machine. Using the ``eval`` command we can switch machines as needed.::
$ eval "$(docker-machine env dev1)"
Debugging
~~~~~~~~~
ipdb
"""""
If you are using the following within your code to debug: ::
import ipdb; ipdb.set_trace()
Then you may need to run the following for it to work as desired: ::
$ docker-compose -f local.yml run --rm --service-ports django
django-debug-toolbar
""""""""""""""""""""
In order for ``django-debug-toolbar`` to work designate your Docker Machine IP with ``INTERNAL_IPS`` in ``local.py``.
Mailhog
~~~~~~~
When developing locally you can go with MailHog_ for email testing provided ``use_mailhog`` was set to ``y`` on setup. To proceed,
#. make sure ``mailhog`` container is up and running;
#. open up ``http://127.0.0.1:8025``.
.. _Mailhog: https://github.com/mailhog/MailHog/
.. _`CeleryFlower`:
Celery Flower
~~~~~~~~~~~~~
`Flower`_ is a "real-time monitor and web admin for Celery distributed task queue".
Prerequisites:
* ``use_docker`` was set to ``y`` on project initialization;
* ``use_celery`` was set to ``y`` on project initialization.
By default, it's enabled both in local and production environments (``local.yml`` and ``production.yml`` Docker Compose configs, respectively) through a ``flower`` service. For added security, ``flower`` requires its clients to provide authentication credentials specified as the corresponding environments' ``.envs/.local/.django`` and ``.envs/.production/.django`` ``CELERY_FLOWER_USER`` and ``CELERY_FLOWER_PASSWORD`` environment variables. Check out ``localhost:5555`` and see for yourself.
.. _`Flower`: https://github.com/mher/flower