Django：如何管理开发和生产设置？

I have been developing a basic app. Now at the deployment stage it has become clear I have need for both a local settings and production settings.

It would be great to know the following:

• How best to deal with development and production settings.
• How to keep apps such as django-debug-toolbar only in a development environment.
• Any other tips and best practices for development and deployment settings.

The DJANGO_SETTINGS_MODULE environment variable controls which settings file Django will load.

You therefore create separate configuration files for your respective environments (note that they can of course both import * from a separate, “shared settings” file), and use DJANGO_SETTINGS_MODULE to control which one to use.

Here’s how:

As noted in the Django documentation:

The value of DJANGO_SETTINGS_MODULE should be in Python path syntax, e.g. mysite.settings. Note that the settings module should be on the Python import search path.

So, let’s assume you created myapp/production_settings.py and myapp/test_settings.py in your source repository.

In that case, you’d respectively set DJANGO_SETTINGS_MODULE=myapp.production_settings to use the former and DJANGO_SETTINGS_MODULE=myapp.test_settings to use the latter.

From here on out, the problem boils down to setting the DJANGO_SETTINGS_MODULE environment variable.

Setting DJANGO_SETTINGS_MODULE using a script or a shell

You can then use a bootstrap script or a process manager to load the correct settings (by setting the environment), or just run it from your shell before starting Django: export DJANGO_SETTINGS_MODULE=myapp.production_settings.

Note that you can run this export at any time from a shell — it does not need to live in your .bashrc or anything.

Setting DJANGO_SETTINGS_MODULE using a Process Manager

If you’re not fond of writing a bootstrap script that sets the environment (and there are very good reasons to feel that way!), I would recommend using a process manager:

• Supervisor lets you pass environment variables to managed processes using a program’s environment configuration key.
• Honcho (a pure-Python equivalent of Ruby’s Foreman) lets you define environment variables in an “environment” (.env) file.

Finally, note that you can take advantage of the PYTHONPATH variable to store the settings in a completely different location (e.g. on a production server, storing them in /etc/). This allows for separating configuration from application files. You may or may not want that, it depends on how your app is structured.

By default use production settings, but create a file called settings_dev.py in the same folder as your settings.py file. Add overrides there, such as DEBUG=True.

On the computer that will be used for development, add this to your ~/.bashrc file:

export DJANGO_DEVELOPMENT=true

At the bottom of your settings.py file, add the following.

# Override production variables if DJANGO_DEVELOPMENT env variable is set
if os.environ.get('DJANGO_DEVELOPMENT'):
    from settings_dev import *  # or specific overrides

(Note that importing * should generally be avoided in Python)

By default the production servers will not override anything. Done!

Compared to the other answers, this one is simpler because it doesn’t require updating PYTHONPATH, or setting DJANGO_SETTINGS_MODULE which only allows you to work on one django project at a time.

I usually have one settings file per environment, and a shared settings file:

/myproject/
  settings.production.py
  settings.development.py
  shared_settings.py

Each of my environment files has:

try:
    from shared_settings import *
except ImportError:
    pass

This allows me to override shared settings if necessary (by adding the modifications below that stanza).

I then select which settings files to use by linking it in to settings.py:

ln -s settings.development.py settings.py

This is how I do it in 6 easy steps:

1. Create a folder inside your project directory and name it settings.

   Project structure:

   myproject/
          myapp1/
          myapp2/              
          myproject/
                 settings/
   

2. Create four python files inside of the settings directory namely __init__.py, base.py, dev.py and prod.py

   Settings files:

   settings/
        __init__.py
        base.py
        prod.py
        dev.py 
   

3. Open __init__.py and fill it with the following content:

   init.py:

   from .base import *
   # you need to set "myproject = 'prod'" as an environment variable
   # in your OS (on which your website is hosted)
   if os.environ['myproject'] == 'prod':
      from .prod import *
   else:
      from .dev import *
   

4. Open base.py and fill it with all the common settings (that will be used in both production as well as development.) for example:

   base.py:

   import os
   ...
   INSTALLED_APPS = [...]
   MIDDLEWARE = [...]
   TEMPLATES = [{...}]
   ...
   STATIC_URL = '/static/'
   STATIC_ROOT = os.path.join(BASE_DIR, 'staticfiles')
   MEDIA_ROOT = os.path.join(BASE_DIR, '/path/')
   MEDIA_URL = '/path/'
   

5. Open dev.py and include that stuff which is development specific for example:

   dev.py:

   DEBUG = True
   ALLOWED_HOSTS = ['localhost']
   ...
   

6. Open prod.py and include that stuff which is production specific for example:

   prod.py:

   DEBUG = False
   ALLOWED_HOSTS = ['www.example.com']
   LOGGING = [...]
   ...
   

Create multiple settings*.py files, extrapolating the variables that need to change per environment. Then at the end of your master settings.py file:

try:
  from settings_dev import *
except ImportError:
  pass

You keep the separate settings_* files for each stage.

At the top of your settings_dev.py file, add this:

import sys
globals().update(vars(sys.modules['settings']))

To import variables that you need to modify.

This wiki entry has more ideas on how to split your settings.

I use the awesome django-configurations, and all the settings are stored in my settings.py:

from configurations import Configuration

class Base(Configuration):
    # all the base settings here...
    BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
    ...

class Develop(Base):
    # development settings here...
    DEBUG = True 
    ...

class Production(Base):
    # production settings here...
    DEBUG = False

To configure the Django project I just followed the docs.

Here is the approach we use :

• a settings module to split settings into multiple files for readability ;
• a .env.json file to store credentials and parameters that we want excluded from our git repository, or that are environment specific ;
• an env.py file to read the .env.json file

Considering the following structure :

...
.env.json           # the file containing all specific credentials and parameters
.gitignore          # the .gitignore file to exclude `.env.json`
project_name/       # project dir (the one which django-admin.py creates)
  accounts/         # project's apps
    __init__.py
    ...
  ...
  env.py            # the file to load credentials
  settings/
    __init__.py     # main settings file
    database.py     # database conf
    storage.py      # storage conf
    ...
venv                # virtualenv
...

With .env.json like :

{
    "debug": false,
    "allowed_hosts": ["mydomain.com"],
    "django_secret_key": "my_very_long_secret_key",
    "db_password": "my_db_password",
    "db_name": "my_db_name",
    "db_user": "my_db_user",
    "db_host": "my_db_host",
}

And project_name/env.py :

<!-- language: lang-python -->
import json
import os


def get_credentials():
    env_file_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
    with open(os.path.join(env_file_dir, '.env.json'), 'r') as f:
        creds = json.loads(f.read())
    return creds


credentials = get_credentials()

We can have the following settings:

<!-- language: lang-py -->
# project_name/settings/__init__.py
from project_name.env import credentials
from project_name.settings.database import *
from project_name.settings.storage import *
...

SECRET_KEY = credentials.get('django_secret_key')

DEBUG = credentials.get('debug')

ALLOWED_HOSTS = credentials.get('allowed_hosts', [])

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',

    ...
]

if DEBUG:
    INSTALLED_APPS += ['debug_toolbar']

...

# project_name/settings/database.py
from project_name.env import credentials

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'NAME': credentials.get('db_name', ''),
        'USER': credentials.get('db_user', ''),
        'HOST': credentials.get('db_host', ''),
        'PASSWORD': credentials.get('db_password', ''),
        'PORT': '5432',
    }
}

the benefits of this solution are :

• user specific credentials and configurations for local development without modifying the git repository ;
• environment specific configuration, you can have for example three different environments with three different .env.json like dev, stagging and production ;
• credentials are not in the repository

I hope this helps, just let me know if you see any caveats with this solution.

I use the folloring file structure:

project/
   ...
   settings/
   settings/common.py
   settings/local.py
   settings/prod.py
   settings/__init__.py -> local.py

So __init__.py is a link (ln in unix or mklink in windows) to local.py or can be to prod.py so the configuration is still in the project.settings module is clean and organized, and if you want to use a particular config you can use the environment variable DJANGO_SETTINGS_MODULE to project.settings.prod if you need to run a command for production environment.

In the files prod.py and local.py:

from .shared import *

DATABASE = {
    ...
}

and the shared.py file keeps as global without specific configs.

building off cs01’s answer:

if you’re having problems with the environment variable, set its value to a string (e.g. I did DJANGO_DEVELOPMENT="true").

I also changed cs01’s file workflow as follows:

#settings.py
import os
if os.environ.get('DJANGO_DEVELOPMENT') is not None:
    from settings_dev import * 
else:
    from settings_production import *
#settings_dev.py
development settings go here
#settings_production.py
production settings go here

This way, Django doesn’t have to read through the entirety of a settings file before running the appropriate settings file. This solution comes in handy if your production file needs stuff that’s only on your production server.

Note: in Python 3, imported files need to have a . appended (e.g. from .settings_dev import *)

If you want to keep 1 settings file, and your development operating system is different than your production operating system, you can put this at the bottom of your settings.py:

from sys import platform
if platform == "linux" or platform == "linux2":
    # linux
    # some special setting here for when I'm on my prod server
elif platform == "darwin":
    # OS X
    # some special setting here for when I'm developing on my mac
elif platform == "win32":
    # Windows...
    # some special setting here for when I'm developing on my pc

Read more: How do I check the operating system in Python?

This seems to have been answered, however a method which I use as combined with version control is the following:

Setup a env.py file in the same directory as settings on my local development environment that I also add to .gitignore:

env.py:

#!usr/bin/python

DJANGO_ENV = True
ALLOWED_HOSTS = ['127.0.0.1', 'dev.mywebsite.com']

.gitignore:

mywebsite/env.py

settings.py:

if os.path.exists(os.getcwd() + '/env.py'):
    #env.py is excluded using the .gitignore file - when moving to production we can automatically set debug mode to off:
    from env import *
else:
    DJANGO_ENV = False

DEBUG = DJANGO_ENV

I just find this works and is far more elegant – with env.py it is easy to see our local environment variables and we can handle all of this without multiple settings.py files or the likes. This methods allows for all sorts of local environment variables to be used that we wouldn’t want set on our production server. Utilising the .gitignore via version control we are also keeping everything seamlessly integrated.

Use settings.py for production. In the same directory create settings_dev.py for overrides.

# settings_dev.py

from .settings import * 

DEBUG = False

On a dev machine run your Django app with:

DJANGO_SETTINGS_MODULE=<your_app_name>.settings_dev python3 manage.py runserver

On a prod machine run as if you just had settings.py and nothing else.

ADVANTAGES

1. settings.py (used for production) is completely agnostic to the fact that any other environments even exist.
2. To see the difference between prod and dev you just look into a single location – settings_dev.py. No need to gather configurations scattered across settings_prod.py, settings_dev.py and settings_shared.py.
3. If someone adds a setting to your prod config after troubleshooting a production issue you can rest assured that it will appear in your dev config as well (unless explicitly overridden). Thus the divergence between different config files will be minimized.

For the problem of setting files, I choose to copy

Project
   |---__init__.py   [ write code to copy setting file from subdir to current dir]
   |---settings.py  (do not commit this file to git)
   |---setting1_dir
   |         |--  settings.py
   |---setting2_dir
   |         |--  settings.py

When you run django, __init__py will be ran. At this time , settings.py in setting1_dir will replace settings.py in Project.

How to choose different env?

• modify __init__.py directly.
• make a bash file to modify __init__.py.
• modify env in linux, and then let __init__.py read this variable.

Why use to this way?

Because I don’t like so many files in the same directory, too many files will confuse other partners and not very well for IDE.(IDE cannot find what file we use)

If you do not want to see all these details, you can divide project into two part.

1. make your small tool like Spring Initializr, just for setup your project.(do sth like copy file)
2. your project code

I’m using different app.yaml file to change configuration between environments in google cloud app engine.

You can use this to create a proxy connection in your terminal command:

./cloud_sql_proxy -instances=<INSTANCE_CONNECTION_NAME>=tcp:1433

https://cloud.google.com/sql/docs/sqlserver/connect-admin-proxy#macos-64-bit

File: app.yaml

# [START django_app]
service: development
runtime: python37

env_variables:
  DJANGO_DB_HOST: '/cloudsql/myproject:myregion:myinstance'
  DJANGO_DEBUG: True

handlers:
# This configures Google App Engine to serve the files in the app's static
# directory.
- url: /static
  static_dir: static/

# This handler routes all requests not caught above to your main app. It is
# required when static routes are defined, but can be omitted (along with
# the entire handlers section) when there are no static files defined.
- url: /.*
  script: auto
# [END django_app]

This is my solution, with different environements for dev, test and prod

import socket

[...]

DEV_PC = 'PC059'
host_name = socket.gethostname()

if host_name == DEV_PC:
   #do something
   pass
elif [...]