Flask Extension¶

Dynaconf provides a drop in replacement for app.config.

As Flask encourages the composition by overriding the config_class attribute this extension follows the patterns of Flask and turns your Flask's app.config in to a dynaconf instance.

Initialize the extension¶

Initialize the FlaskDynaconf extension in your app

from flask import Flask
from dynaconf import FlaskDynaconf

app = Flask(__name__)
FlaskDynaconf(app)

You can optionally use init_app as well.

Use `FLASK_` environment variables¶

Then the app.config will work as a dynaconf.settings instance and FLASK_ will be the global prefix for exporting environment variables.

Example:

export FLASK_DEBUG=true              # app.config.DEBUG
export FLASK_INTVALUE=1              # app.config['INTVALUE']
export FLASK_MAIL_SERVER='host.com'  # app.config.get('MAIL_SERVER')

You can also leverage custom environment variables just as in the default Dynaconf class, like so:

Example:

from flask import Flask
from dynaconf import FlaskDynaconf

app = Flask(__name__)
FlaskDynaconf(app, envvar_prefix="PEANUT")

Now you can declare your variables with your custom prefix, and it will be normally available within Flask's native configuration app.config.

export PEANUT_DEBUG=true              # app.config.DEBUG
export PEANUT_INTVALUE=1              # app.config['INTVALUE']
export PEANUT_MAIL_SERVER='host.com'  # app.config.get('MAIL_SERVER')

Info

Version 3.1.7 backwards was case sensitive on defining ENVVAR_PREFIX and would only accept uppsercase kwargs (different from Dynaconf(envvar_prefix)). Starting from version X.X.X, kwargs should be case insensitive to improve consistency between Dynaconf and Flask/Django extensions, while keeping backwards compatibility.

Settings files¶

You can also have settings files for your Flask app, in the root directory (the same where you execute flask run) put your settings.toml and .secrets.toml files and then define your environments [default], [development] and [production].

To switch the working environment the FLASK_ENV variable can be used, so FLASK_ENV=development to work in development mode or FLASK_ENV=production to switch to production.

IMPORTANT: To use $ dynaconf CLI the FLASK_APP must be defined.

IF you don't want to manually create your config files take a look at the CLI

Loading Flask Extensions Dynamically¶

You can tell Dynaconf to load your Flask Extensions dynamically as long as the extensions follows the Patterns of Flask extensions.

The only requirement is that the extension must be a callable that accepts app as first argument. e.g: flask_admin:Admin or custom_extension.module:instance.init_app and of course the extension must be in Python namespace to be imported.

For extensions initialized just use an entry point object reference like: "flask_admin:Admin" or "extension.module:instance.init_app"

having a settings.toml

[default]
EXTENSIONS = [
  "flask_admin:Admin",
  "flask_bootstrap:Bootstrap",
  "custom_extension.module:init_app"
]

Considering an app.py like:

from flask import Flask
from dynaconf import FlaskDynaconf

app = Flask(__name__)
flask_dynaconf = FlaskDynaconf(app, extensions_list="EXTENSIONS")

The above will immediately load all flask extensions listed on EXTENSIONS key on settings.

You can also load it lazily.

# at any point in your app startup
app.config.load_extensions()

Optionally you can pass load_extensions(key="OTHER_NAME") pointing to your list of extensions.

It is also possible to use environment variables to set the extensions to be loaded.

# .env
export FLASK_EXTENSIONS="['flask_admin:Admin']"

The extensions will be loaded in order.

Development extensions¶

It is also possible to have extensions that loads only for development environment.

[default]
EXTENSIONS = [
  "flask_admin:Admin",
  "flask_bootstrap:Bootstrap",
  "custom_extension.module:init_app"
]

[development]
EXTENSIONS = [
  "dynaconf_merge",
  "flask_debugtoolbar:DebugToolbar"
]

Troubleshooting¶

If you find an issue regarding Flask not being able to load variables from .env file or not possible to import app or create_app please disable flask support for dotenv

export FLASK_SKIP_DOTENV=1