Configuration management in Flask - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Flask app configuration code?

Consider this Flask app setup. What will be the value of app.config['DEBUG'] after running this code?

Flask

from flask import Flask
app = Flask(__name__)
app.config.from_mapping(DEBUG=True)
app.config['DEBUG'] = False
print(app.config['DEBUG'])

A False

B True

C None

D Raises KeyError

💡 Hint

Remember that later assignments overwrite earlier ones.

The app config is first set with DEBUG=True, but then immediately set to False. So the final value is False.

📝 Syntax

intermediate

Which option correctly loads configuration from a Python file in Flask?

You want to load configuration from a file named config.py. Which code snippet correctly does this?

A app.load_config('config.py')

B app.config.load_pyfile('config.py')

C app.config.from_pyfile('config.py')

D app.config.from_file('config.py')

💡 Hint

Check Flask's official method for loading config from a Python file.

The correct method is from_pyfile. Other options are invalid method names.

🔧 Debug

advanced

What error does this Flask config code raise?

What error occurs when running this code snippet?

Flask

from flask import Flask
app = Flask(__name__)
app.config.from_pyfile('missing_config.py')

A FileNotFoundError

B KeyError

C TypeError

D No error, loads default config

💡 Hint

The file does not exist in the directory.

Trying to load a missing config file raises a FileNotFoundError.

❓ state_output

advanced

What is the value of app.config['SECRET_KEY'] after this code runs?

Given this Flask app configuration, what is the final value of app.config['SECRET_KEY']?

Flask

from flask import Flask
app = Flask(__name__)
app.config['SECRET_KEY'] = 'first'
app.config.from_mapping(SECRET_KEY='second')
app.config.update({'SECRET_KEY': 'third'})
print(app.config['SECRET_KEY'])

A 'first'

B KeyError

C 'second'

D 'third'

💡 Hint

Later config updates overwrite earlier ones.

The last update sets SECRET_KEY to 'third', so that is the final value.

🧠 Conceptual

expert

Which method is best to load environment-specific config in Flask?

You want to load different configurations for development and production environments without changing code. Which approach is best?

A Hardcode config values directly in the Flask app file

B Use <code>app.config.from_object()</code> with different config classes for each environment

C Manually edit <code>app.config</code> dictionary in code before running

D Use <code>app.config.from_pyfile()</code> with the same file for all environments

💡 Hint

Think about clean separation and easy switching of configs.

Using from_object() with different classes allows clean, maintainable environment-specific configs.