debian-django-tenant-schemas/docs/install.rst

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==================
Installation
==================
Assuming you have django installed, the first step is to install ``django-tenant-schemas``.
.. code-block:: bash
pip install django-tenant-schemas
Basic Settings
==============
You'll have to make the following modifications to your ``settings.py`` file.
Your ``DATABASE_ENGINE`` setting needs to be changed to
.. code-block:: python
DATABASES = {
'default': {
'ENGINE': 'tenant_schemas.postgresql_backend',
# ..
}
}
Add `tenant_schemas.routers.TenantSyncRouter` to your `DATABASE_ROUTERS` setting, so that the correct apps can be synced, depending on what's being synced (shared or tenant).
.. code-block:: python
DATABASE_ROUTERS = (
'tenant_schemas.routers.TenantSyncRouter',
)
Add the middleware ``tenant_schemas.middleware.TenantMiddleware`` to the top of ``MIDDLEWARE_CLASSES``, so that each request can be set to use the correct schema.
If the hostname in the request does not match a valid tenant ``domain_url``, a HTTP 404 Not Found will be returned.
If you'd like to raise ``DisallowedHost`` and a HTTP 400 response instead, use the ``tenant_schemas.middleware.SuspiciousTenantMiddleware``.
If you'd like to serve the public tenant for unrecognised hostnames instead, use ``tenant_schemas.middleware.DefaultTenantMiddleware``. To use a tenant other than the public tenant, create a subclass and register it instead.
If you'd like a different tenant selection technique (e.g. using an HTTP Header), you can define a custom middleware. See :ref:`Advanced Usage`.
.. code-block:: python
from tenant_schemas.middleware import DefaultTenantMiddleware
class MyDefaultTenantMiddleware(DefaultTenantMiddleware):
DEFAULT_SCHEMA_NAME = 'default'
.. code-block:: python
MIDDLEWARE_CLASSES = (
'tenant_schemas.middleware.TenantMiddleware',
# 'tenant_schemas.middleware.SuspiciousTenantMiddleware',
# 'tenant_schemas.middleware.DefaultTenantMiddleware',
# 'myproject.middleware.MyDefaultTenantMiddleware',
#...
)
Make sure you have ``django.template.context_processors.request`` (``django.core.context_processors.request`` if you're on Django 1.8) listed under ``TEMPLATE_CONTEXT_PROCESSORS`` else the tenant will not be available on ``request``.
.. code-block:: python
TEMPLATE_CONTEXT_PROCESSORS = (
'django.core.context_processors.request',
#...
)
The Tenant Model
================
Now we have to create your tenant model. Your tenant model can contain whichever fields you want, however, you **must** inherit from ``TenantMixin``. This Mixin only has two fields (``domain_url`` and ``schema_name``) and both are required. Here's an example, suppose we have an app named ``customers`` and we want to create a model called ``Client``.
.. code-block:: python
from django.db import models
from tenant_schemas.models import TenantMixin
class Client(TenantMixin):
name = models.CharField(max_length=100)
paid_until = models.DateField()
on_trial = models.BooleanField()
created_on = models.DateField(auto_now_add=True)
# default true, schema will be automatically created and synced when it is saved
auto_create_schema = True
Once you have defined your model, don't forget to create the migrations for it or otherwise Django >= 1.9 will not create its table. Replace ``customers`` with your app name.
.. code-block:: bash
python manage.py makemigrations customers
Configure Tenant and Shared Applications
========================================
To make use of shared and tenant-specific applications, there are two settings called ``SHARED_APPS`` and ``TENANT_APPS``. ``SHARED_APPS`` is a tuple of strings just like ``INSTALLED_APPS`` and should contain all apps that you want to be synced to ``public``. If ``SHARED_APPS`` is set, then these are the only apps that will be synced to your ``public`` schema! The same applies for ``TENANT_APPS``, it expects a tuple of strings where each string is an app. If set, only those applications will be synced to all your tenants. Here's a sample setting
.. code-block:: python
SHARED_APPS = (
'tenant_schemas', # mandatory, should always be before any django app
'customers', # you must list the app where your tenant model resides in
'django.contrib.contenttypes',
# everything below here is optional
'django.contrib.auth',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.messages',
'django.contrib.admin',
)
TENANT_APPS = (
'django.contrib.contenttypes',
# your tenant-specific apps
'myapp.hotels',
'myapp.houses',
)
INSTALLED_APPS = (
'tenant_schemas', # mandatory, should always be before any django app
'customers',
'django.contrib.contenttypes',
'django.contrib.auth',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.messages',
'django.contrib.admin',
'myapp.hotels',
'myapp.houses',
)
You also have to set where your tenant model is.
.. code-block:: python
TENANT_MODEL = "customers.Client" # app.Model
Now run ``migrate_schemas --shared`` to create the shared apps on the ``public`` schema. Note: your database should be empty if this is the first time you're running this command.
.. code-block:: bash
python manage.py migrate_schemas --shared
.. warning::
Never use ``migrate`` as it would sync *all* your apps to ``public``!
Lastly, you need to create a tenant whose schema is ``public`` and it's address is your domain URL. Please see the section on :doc:`use <use>`.
You can also specify extra schemas that should be visible to all queries using
``PG_EXTRA_SEARCH_PATHS`` setting.
.. code-block:: python
PG_EXTRA_SEARCH_PATHS = ['extensions']
``PG_EXTRA_SEARCH_PATHS`` should be a list of schemas you want to make visible
globally.
.. tip::
You can create a dedicated schema to hold postgresql extensions and make it
available globally. This helps avoid issues caused by hiding the public
schema from queries.
Optional Settings
=================
.. attribute:: PUBLIC_SCHEMA_NAME
:Default: ``'public'``
The schema name that will be treated as ``public``, that is, where the ``SHARED_APPS`` will be created.
Tenant View-Routing
-------------------
.. attribute:: PUBLIC_SCHEMA_URLCONF
:Default: ``None``
We have a goodie called ``PUBLIC_SCHEMA_URLCONF``. Suppose you have your main website at ``example.com`` and a customer at ``customer.example.com``. You probably want your user to be routed to different views when someone requests ``http://example.com/`` and ``http://customer.example.com/``. Because django only uses the string after the host name, this would be impossible, both would call the view at ``/``. This is where ``PUBLIC_SCHEMA_URLCONF`` comes in handy. If set, when the ``public`` schema is being requested, the value of this variable will be used instead of `ROOT_URLCONF <https://docs.djangoproject.com/en/dev/ref/settings/#std:setting-ROOT_URLCONF>`_. So for example, if you have
.. code-block:: python
PUBLIC_SCHEMA_URLCONF = 'myproject.urls_public'
When requesting the view ``/login/`` from the public tenant (your main website), it will search for this path on ``PUBLIC_SCHEMA_URLCONF`` instead of ``ROOT_URLCONF``.
Separate projects for the main website and tenants (optional)
-------------------------------------------------------------
In some cases using the ``PUBLIC_SCHEMA_URLCONF`` can be difficult. For example, `Django CMS <https://www.django-cms.org/>`_ takes some control over the default Django URL routing by using middlewares that do not play well with the tenants. Another example would be when some apps on the main website need different settings than the tenants website. In these cases it is much simpler if you just run the main website `example.com` as a separate application.
If your projects are ran using a WSGI configuration, this can be done by creating a filed called ``wsgi_main_website.py`` in the same folder as ``wsgi.py``.
.. code-block:: python
# wsgi_main_website.py
import os
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "project.settings_public")
from django.core.wsgi import get_wsgi_application
application = get_wsgi_application()
If you put this in the same Django project, you can make a new ``settings_public.py`` which points to a different ``urls_public.py``. This has the advantage that you can use the same apps that you use for your tenant websites.
Or you can create a completely separate project for the main website.
Caching
-------
To enable tenant aware caching you can set the `KEY_FUNCTION <https://docs.djangoproject.com/en/1.8/ref/settings/#std:setting-CACHES-KEY_FUNCTION>`_ setting to use the provided ``make_key`` helper function which
adds the tenants ``schema_name`` as the first key prefix.
.. code-block:: python
CACHES = {
"default": {
...
'KEY_FUNCTION': 'tenant_schemas.cache.make_key',
'REVERSE_KEY_FUNCTION': 'tenant_schemas.cache.reverse_key',
},
}
The ``REVERSE_KEY_FUNCTION`` setting is only required if you are using the `django-redis <https://github.com/niwinz/django-redis>`_ cache backend.
Configuring your Apache Server (optional)
=========================================
Here's how you can configure your Apache server to route all subdomains to your django project so you don't have to setup any subdomains manually.
.. code-block:: apacheconf
<VirtualHost 127.0.0.1:8080>
ServerName mywebsite.com
ServerAlias *.mywebsite.com mywebsite.com
WSGIScriptAlias / "/path/to/django/scripts/mywebsite.wsgi"
</VirtualHost>
`Django's Deployment with Apache and mod_wsgi <https://docs.djangoproject.com/en/dev/howto/deployment/wsgi/modwsgi/>`_ might interest you too.
Building Documentation
======================
Documentation is available in ``docs`` and can be built into a number of
formats using `Sphinx <http://pypi.python.org/pypi/Sphinx>`_. To get started
.. code-block:: bash
pip install Sphinx
cd docs
make html
This creates the documentation in HTML format at ``docs/_build/html``.