How to configure Flask to handle different configuration files based on environment variables. Having specific configuration files for production and development.
Separated configurations for Development and Production
In most situations, applications would need different configurations for each environment: Production, Staging, Development, etc.
Load default config and an environment specific one
The easiest way to have multiple configurations is to:
- use a default configuration that is always loaded and
- the default configuration is under version control (e.g.: part of the git project repo) and
- Use an environment variable to switch between the configurations that overrides the values as needed in each environment
Having a configuration that loads configuration values from the
specified config environment
app = Flask(__name__) app.config.from_object('yourapplication.default_settings') app.config.from_envvar('YOURAPPLICATION_SETTINGS')
Then we create a separate config.py for each env and export the configuration path:
$ export YOURAPPLICATION_SETTINGS=/path/to/config.py
This way it will always load the default configs and then our custom
From Flask 0.8, there is the concept of instance folders. The instance folder is a good fit for configuration files because it is designed to not be under version control and be deployment specific.
To keep the instance folder out of versioning in Git add
By default, Flask looks for a folder named
instance in the same
level of your main file or the package.
Using this folder and having environment specific configuration files
config folder we end up having the following directory structure:
... config/ __init__.py default.py development.py production.py instance/ config.py myapp/ __init__.py myapp.py ..
To have the configurations loaded we have to:
- load the default config in
- load configuration from instance folder
- Load the file specified by the
myapp/__init__.py we load them:
# myapp/__init__.py app = Flask(__name__, instance_relative_config=True) app.config.from_object('config.default') app.config.from_pyfile('config.py') app.config.from_envvar('APP_CONFIG_FILE')
Then set the environment variable depending on the server we are invoking the app:
$ export APP_CONFIG_FILE=/var/www/yourapp/config/production.py
Now your folder structure should look like:
myapp ├── config │ ├── __init__.py # empty │ ├── development.py │ ├── default.py │ └── production.py ├── instance │ └── config.py └── myapp ├── __init__.py └── myapp.py
It can be useful to also add support for
dotenv to handle sensitive
variables when deploying to Heroku.
- Explore flask book http://explore-flask.readthedocs.io/en/latest/configuration.html
- Non existing path when setting up Flask to have separated configurations for each environment
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