How to Build Config Files in python? - json

Question

As I'm new and learning python, exploring different ways to build a config file for python based framework.
I have come across using-built-in-data-structure-complicated-py , couldn't understand main.py . Could you help me with how main.py should look like and how the variables from config.py can be accessed in main.py.
# config.py
class Config:
APP_NAME = 'myapp'
SECRET_KEY = 'secret-key-of-myapp'
ADMIN_NAME = 'administrator'
AWS_DEFAULT_REGION = 'ap-northeast-2'
STATIC_PREFIX_PATH = 'static'
ALLOWED_IMAGE_FORMATS = ['jpg', 'jpeg', 'png', 'gif']
MAX_IMAGE_SIZE = 5242880 # 5MB
class DevelopmentConfig(Config):
DEBUG = True
AWS_ACCESS_KEY_ID = 'aws-access-key-for-dev'
AWS_SECERT_ACCESS_KEY = 'aws-secret-access-key-for-dev'
AWS_S3_BUCKET_NAME = 'aws-s3-bucket-name-for-dev'
DATABASE_URI = 'database-uri-for-dev'
class TestConfig(Config):
DEBUG = True
TESTING = True
AWS_ACCESS_KEY_ID = 'aws-access-key-for-test'
AWS_SECERT_ACCESS_KEY = 'aws-secret-access-key-for-test'
AWS_S3_BUCKET_NAME = 'aws-s3-bucket-name-for-test'
DATABASE_URI = 'database-uri-for-dev'
class ProductionConfig(Config):
DEBUG = False
AWS_ACCESS_KEY_ID = 'aws-access-key-for-prod'
AWS_SECERT_ACCESS_KEY = 'aws-secret-access-key-for-prod'
AWS_S3_BUCKET_NAME = 'aws-s3-bucket-name-for-prod'
DATABASE_URI = 'database-uri-for-dev'
class CIConfig:
SERVICE = 'travis-ci'
HOOK_URL = 'web-hooking-url-from-ci-service'
# main.py
import sys
import config
...
if __name__ == '__main__':
env = sys.argv[1] if len(sys.argv) > 2 else 'dev'
if env == 'dev':
app.config = config.DevelopmentConfig
elif env == 'test':
app.config = config.TestConfig
elif env == 'prod':
app.config = config.ProductionConfig
else:
raise ValueError('Invalid environment name')
app.ci = config.CIConfig
What is app.config and app.ci ? How is it being used ?
And also, what all other best possible pythonic way to manage config files ?
If I have multiple set of profiles/credentials (username-password), how do i manage them ?
Any possible encryption to files containing credentials ?
Will be of great learning to me.

Answer 1

Here is a small example of how you could use config files
class Config:
APP_NAME='myapp'
ADMIN='admin'
class DevelopmentConfig(Config):
DEBUG = True
ADMIN = 'dev_admin'
class ProductionConfig(Config):
DEBUG = False
def main():
config = ProductionConfig # Change to DevelopmentConfig to experiment
# You may now use your config where you want
print(config.DEBUG)
print(config.ADMIN)
if __name__ == "__main__":
main()
This example does not use command line arguments like your example but should give you a good idea of building config files and using them.
In your example app.ci refers to configuration for continuous integration(CI) environment.