Environment variables and configuration in Azure - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are environment variables in cloud applications?

Environment variables are key-value pairs stored outside the application code. They provide configuration settings like database URLs or API keys, allowing apps to change behavior without changing code.

beginner

Why use environment variables instead of hardcoding settings?

Using environment variables keeps sensitive data like passwords safe and lets you change settings easily across different environments (development, testing, production) without changing the app code.

intermediate

How do Azure App Services manage environment variables?

Azure App Services let you set environment variables in the Application Settings section. These variables are injected into your app at runtime and override any default settings.

intermediate

What is the benefit of using Azure Key Vault with environment variables?

Azure Key Vault securely stores secrets like passwords or certificates. Your app can fetch these secrets at runtime, keeping sensitive info out of environment variables and code.

intermediate

How can you update environment variables without redeploying your Azure app?

You can update environment variables directly in Azure Portal under Application Settings. The app will use the new values on next restart or automatically if supported, avoiding full redeployment.

Where do environment variables typically store sensitive information in Azure apps?

A In user input forms

B In the application code files

C In Azure Application Settings

D In the app's UI

Environment variables are set in Azure Application Settings to keep sensitive info out of code.

What is a key advantage of using Azure Key Vault over environment variables for secrets?

A It stores secrets securely and separately from app settings

B It makes the app run faster

C It automatically writes code for you

D It replaces environment variables completely

Azure Key Vault securely stores secrets, reducing risk compared to environment variables.

How can you change an environment variable in Azure App Service without redeploying the app?

A Change the variable in Application Settings in Azure Portal

B Edit the code and redeploy

C Restart the computer

D Change the variable in the app's UI

Changing variables in Application Settings updates them without redeployment.

Why should sensitive data not be hardcoded in cloud apps?

A It makes the app slower

B It uses more memory

C It is required by law

D It risks exposing secrets and makes updates harder

Hardcoding secrets risks exposure and complicates updates.

What happens if an environment variable is set both in code and Azure Application Settings?

A The code value is used

B The Azure Application Settings value overrides the code

C The app crashes

D Both values are combined

Azure Application Settings override code values at runtime.

Explain how environment variables help manage configuration in Azure cloud apps.

Think about how apps can use settings that change by environment.

Describe the role of Azure Key Vault in securing application configuration.

Consider how to keep passwords and keys safe in the cloud.

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