Secrets management in Apache Airflow - Mini Project: Build & Apply

Secrets Management in Apache Airflow

📖 Scenario: You are setting up Apache Airflow to securely manage sensitive information like database passwords and API keys. Instead of hardcoding secrets in your DAGs, you will use Airflow's built-in secrets backend to fetch secrets at runtime.

🎯 Goal: Build a simple Airflow DAG that retrieves a secret value from Airflow's Variable store using the secrets backend and prints it. This will demonstrate how to manage secrets securely in Airflow.

📋 What You'll Learn

Create a dictionary to simulate Airflow Variables with secret values

Add a configuration variable to specify the secret key to fetch

Write a function to retrieve the secret from the dictionary using the key

Print the retrieved secret value

💡 Why This Matters

🌍 Real World

In real Airflow setups, secrets like passwords and API keys are stored securely and accessed at runtime to avoid exposing sensitive data in code.

💼 Career

Understanding secrets management is crucial for DevOps roles to maintain security and compliance when deploying workflows and applications.

1

Create a dictionary to simulate Airflow Variables

Create a dictionary called airflow_variables with these exact entries: 'db_password': 'SuperSecret123', 'api_key': 'XYZ-987654'

Apache Airflow

# Create the airflow_variables dictionary with secrets
# Your code here

Hint

Use curly braces {} to create a dictionary with the exact keys and values.

2

Add a configuration variable for the secret key

Create a variable called secret_key and set it to the string 'db_password'

Apache Airflow

airflow_variables = {'db_password': 'SuperSecret123', 'api_key': 'XYZ-987654'}
# Create the secret_key variable with the value 'db_password'
# Your code here

Hint

Assign the string 'db_password' to the variable secret_key.

3

Write a function to retrieve the secret

Define a function called get_secret that takes a parameter key and returns the value from airflow_variables for that key

Apache Airflow

airflow_variables = {'db_password': 'SuperSecret123', 'api_key': 'XYZ-987654'}
secret_key = 'db_password'
# Define get_secret(key) to return airflow_variables[key]
# Your code here

Hint

Use def to define the function and return the dictionary value for the given key.

4

Print the retrieved secret value

Write a print statement that calls get_secret(secret_key) and prints the result

Apache Airflow

airflow_variables = {'db_password': 'SuperSecret123', 'api_key': 'XYZ-987654'}
secret_key = 'db_password'

def get_secret(key):
    return airflow_variables[key]

# Print the secret value using get_secret(secret_key)
# Your code here

Hint

Use print(get_secret(secret_key)) to display the secret.

Practice

1. What is the main purpose of secrets management in Apache Airflow?

easy

A. To keep sensitive information like passwords out of the code

B. To speed up DAG execution

C. To store large datasets

D. To monitor task progress visually

Solution

1. Step 1: Understand what secrets management means

   Secrets management is about protecting sensitive data such as passwords or API keys from being exposed in code.

2. Step 2: Identify the main goal in Airflow context

   Airflow uses secrets management to keep such sensitive info safe and separate from DAG code.

3. Final Answer:

   To keep sensitive information like passwords out of the code -> Option A

4. Quick Check:

   Secrets management = protect sensitive info [OK]

Hint: Secrets management means hiding passwords from code [OK]

Common Mistakes:

• Confusing secrets management with data storage
• Thinking it speeds up DAGs
• Assuming it monitors tasks

2. Which of the following is the correct way to retrieve a secret stored as an Airflow Variable in a DAG?

easy

A. get_variable('my_secret')

B. Variable.get('my_secret')

C. Variable.fetch('my_secret')

D. fetch_variable('my_secret')

Solution

1. Step 1: Recall Airflow's Variable API

   Airflow provides a Variable class with a get() method to access stored variables or secrets.

2. Step 2: Match the correct syntax

   The correct method call is Variable.get('variable_name'), so Variable.get('my_secret') is correct.

3. Final Answer:

   Variable.get('my_secret') -> Option B

4. Quick Check:

   Use Variable.get() to access secrets [OK]

Hint: Use Variable.get() to fetch secrets in Airflow [OK]

Common Mistakes:

• Using non-existent methods like fetch or get_variable
• Confusing function names
• Missing the Variable class prefix

3. Given this Airflow DAG snippet, what will be the output if the secret 'db_password' is stored as 'mypassword123' in Airflow Variables?

from airflow.models import Variable

password = Variable.get('db_password')
print(password)

medium

A. Error: Variable not found

B. db_password

C. Variable.get('db_password')

D. mypassword123

Solution

1. Step 1: Understand Variable.get() behavior

   Variable.get('db_password') fetches the value stored under 'db_password' key, which is 'mypassword123'.

2. Step 2: Predict the print output

   Printing the variable will output the string 'mypassword123'.

3. Final Answer:

   mypassword123 -> Option D

4. Quick Check:

   Variable.get() returns stored secret value [OK]

Hint: Variable.get() returns the secret's stored value [OK]

Common Mistakes:

• Thinking it prints the key name
• Expecting the method call as output
• Assuming an error without checking storage

4. You wrote this code in your Airflow DAG to get a secret:

from airflow.models import Variable

api_key = Variable.get('api_key')

But you get an error: "KeyError: 'api_key' not found". What is the best way to fix this?

medium

A. Add a default value like Variable.get('api_key', default_var='default')

B. Change Variable.get to Variable.fetch

C. Remove the import statement

D. Rename 'api_key' to 'API_KEY'

Solution

1. Step 1: Understand the error cause

   The error means 'api_key' variable does not exist in Airflow Variables, so Variable.get() fails.

2. Step 2: Use default_var to avoid error

   Adding default_var='default' returns 'default' if the variable is missing, preventing the error.

3. Final Answer:

   Add a default value like Variable.get('api_key', default_var='default') -> Option A

4. Quick Check:

   Use default_var to handle missing secrets safely [OK]

Hint: Use default_var to avoid missing variable errors [OK]

Common Mistakes:

• Using non-existent Variable.fetch method
• Removing imports breaks code
• Changing variable name without updating storage

5. You want to securely store and access AWS credentials in Airflow using AWS Secrets Manager. Which approach correctly integrates this with Airflow's secrets backend?

hard

A. Hardcode AWS credentials in DAG files for faster access

B. Store credentials in Airflow Variables and access with Variable.get() only

C. Configure airflow.cfg with [secrets] backend = airflow.providers.amazon.aws.secrets.secrets_manager.SecretsManagerBackend

D. Use environment variables without any Airflow configuration

Solution

1. Step 1: Identify how Airflow integrates with AWS Secrets Manager

   Airflow supports multiple secrets backends configured in airflow.cfg under the [secrets] section.

2. Step 2: Correctly configure the secrets backend

   Setting backend to airflow.providers.amazon.aws.secrets.secrets_manager.SecretsManagerBackend enables Airflow to fetch secrets from AWS Secrets Manager securely.

3. Final Answer:

   Configure airflow.cfg with [secrets] backend = airflow.providers.amazon.aws.secrets.secrets_manager.SecretsManagerBackend -> Option C

4. Quick Check:

   Configure secrets backend for AWS Secrets Manager [OK]

Hint: Set secrets backend in airflow.cfg for AWS Secrets Manager [OK]

Common Mistakes:

• Hardcoding credentials in DAGs (unsafe)
• Using Variables only without backend config
• Ignoring Airflow secrets backend configuration