Environment variables and configuration in Azure - Mini Project: Build & Apply

Environment variables and configuration

📖 Scenario: You are setting up a simple Azure App Service application. You need to manage environment variables to store configuration settings securely and access them in your app.

🎯 Goal: Build an Azure App Service configuration that defines environment variables and accesses them in the app settings.

📋 What You'll Learn

Create an Azure App Service resource configuration dictionary

Add environment variables as app settings

Use a configuration variable to hold environment variable names

Apply environment variables in the app service configuration

💡 Why This Matters

🌍 Real World

Managing environment variables securely is essential for cloud applications to separate code from configuration and protect sensitive data.

💼 Career

Cloud engineers and developers often configure environment variables in Azure App Services to manage app settings and secrets without hardcoding them.

1

Create Azure App Service configuration dictionary

Create a dictionary called app_service_config with these exact entries: 'name': 'myappservice', 'location': 'eastus', and 'resource_group': 'myResourceGroup'.

Azure

# Create the app_service_config dictionary with name, location, and resource_group
# Your code here

Hint

Use a Python dictionary with keys 'name', 'location', and 'resource_group' and assign the exact string values.

2

Add environment variables as app settings

Add a key 'app_settings' to the app_service_config dictionary. Set its value to a dictionary with these exact environment variables: 'DATABASE_URL': 'mysql://user:pass@host/db' and 'API_KEY': '12345-abcde'.

Azure

app_service_config = {
    'name': 'myappservice',
    'location': 'eastus',
    'resource_group': 'myResourceGroup'
}
# Add 'app_settings' key with environment variables dictionary
# Your code here

Hint

Add a nested dictionary under the key 'app_settings' with the exact environment variable names and values.

3

Create configuration variable for environment variable names

Create a list called env_vars containing the exact strings 'DATABASE_URL' and 'API_KEY'.

Azure

app_service_config = {
    'name': 'myappservice',
    'location': 'eastus',
    'resource_group': 'myResourceGroup',
    'app_settings': {
        'DATABASE_URL': 'mysql://user:pass@host/db',
        'API_KEY': '12345-abcde'
    }
}
# Create a list called env_vars with 'DATABASE_URL' and 'API_KEY'
# Your code here

Hint

Use a Python list with the exact strings 'DATABASE_URL' and 'API_KEY'.

4

Apply environment variables in app service configuration

Add a new key 'environment_variables' to app_service_config. Set its value to a dictionary comprehension that includes keys and values from app_service_config['app_settings'] only for keys in the env_vars list.

Azure

app_service_config = {
    'name': 'myappservice',
    'location': 'eastus',
    'resource_group': 'myResourceGroup',
    'app_settings': {
        'DATABASE_URL': 'mysql://user:pass@host/db',
        'API_KEY': '12345-abcde'
    }
}
env_vars = ['DATABASE_URL', 'API_KEY']
# Add 'environment_variables' key with filtered app_settings using env_vars
# Your code here

Hint

Use a dictionary comprehension to filter app_settings by keys in env_vars and assign it to 'environment_variables'.

Practice

1. What is the main purpose of using environment variables in Azure web apps?

easy

A. To write application logic inside the environment

B. To separate configuration settings from the application code

C. To store large files for the application

D. To replace the need for a database

Solution

1. Step 1: Understand environment variables role

   Environment variables hold configuration data outside the code, making apps flexible and secure.

2. Step 2: Identify correct purpose in Azure context

   Azure web apps use environment variables to keep settings separate from code, allowing easy updates without code changes.

3. Final Answer:

   To separate configuration settings from the application code -> Option B

4. Quick Check:

   Environment variables separate config from code [OK]

Hint: Think: config outside code for easy updates [OK]

Common Mistakes:

• Confusing environment variables with code logic
• Using environment variables to store large files
• Assuming environment variables replace databases

2. Which Azure CLI command correctly sets an environment variable named API_KEY with value 12345 for a web app called myapp?

easy

A. az webapp config appsettings set --name myapp --resource-group mygroup --settings API_KEY=12345

B. az webapp set env --app myapp --key API_KEY --value 12345

C. az appservice env set --app myapp --name API_KEY --value 12345

D. az webapp config set --app myapp --env API_KEY=12345

Solution

1. Step 1: Recall Azure CLI syntax for setting app settings

   The correct command uses az webapp config appsettings set with --name, --resource-group, and --settings.

2. Step 2: Match command to given options

   az webapp config appsettings set --name myapp --resource-group mygroup --settings API_KEY=12345 matches the correct syntax exactly; others use incorrect commands or flags.

3. Final Answer:

   az webapp config appsettings set --name myapp --resource-group mygroup --settings API_KEY=12345 -> Option A

4. Quick Check:

   Use az webapp config appsettings set with correct flags [OK]

Hint: Remember: 'az webapp config appsettings set' sets env vars [OK]

Common Mistakes:

• Using wrong Azure CLI commands or flags
• Omitting resource group parameter
• Confusing appsettings with environment commands

3. Given this Azure web app environment variable setup:
API_URL=https://api.example.com
What will the following Python code print?

import os
print(os.getenv('API_URL'))

medium

A. os.getenv('API_URL')

B. API_URL

C. None

D. https://api.example.com

Solution

1. Step 1: Understand os.getenv behavior

   os.getenv('API_URL') fetches the value of environment variable 'API_URL' if set.

2. Step 2: Match environment variable value

   The environment variable 'API_URL' is set to 'https://api.example.com', so the print outputs this string.

3. Final Answer:

   https://api.example.com -> Option D

4. Quick Check:

   os.getenv returns env var value [OK]

Hint: os.getenv returns the variable's value, not the name [OK]

Common Mistakes:

• Expecting the variable name instead of its value
• Assuming None if variable is set
• Confusing function call with string output

4. You tried to update an environment variable in Azure CLI but the app still uses the old value. What is the most likely cause?

medium

A. Azure CLI does not support environment variable updates

B. You used the wrong variable name in the code

C. You forgot to restart the web app after updating the variable

D. Environment variables cannot be updated once set

Solution

1. Step 1: Understand environment variable update behavior

   After updating environment variables, Azure web apps often require a restart to apply changes.

2. Step 2: Identify common mistake

   Not restarting the app causes it to keep using old cached environment values.

3. Final Answer:

   You forgot to restart the web app after updating the variable -> Option C

4. Quick Check:

   Restart app to apply env var changes [OK]

Hint: Restart app after env var changes to apply them [OK]

Common Mistakes:

• Assuming variables update instantly without restart
• Confusing variable name errors with update issues
• Thinking Azure CLI cannot update variables

5. You want to securely store a database password as an environment variable in Azure App Service. Which approach is best practice?

hard

A. Use Azure Key Vault and reference the secret in the app settings

B. Store the password directly in the app settings as plain text

C. Hardcode the password inside your application code

D. Send the password as a query parameter in URLs

Solution

1. Step 1: Identify secure storage options

   Azure Key Vault is designed to securely store secrets like passwords and keys.

2. Step 2: Understand integration with app settings

   You can reference Key Vault secrets in Azure App Service app settings, avoiding plain text storage.

3. Step 3: Evaluate other options

   Storing passwords in plain text, code, or URLs exposes security risks and is not recommended.

4. Final Answer:

   Use Azure Key Vault and reference the secret in the app settings -> Option A

5. Quick Check:

   Use Key Vault for secure secret storage [OK]

Hint: Always use Key Vault for sensitive secrets [OK]

Common Mistakes:

• Storing passwords in plain text app settings
• Hardcoding secrets in code
• Exposing secrets in URLs