Lambda layers for shared code in AWS - Mini Project: Build & Apply

Lambda layers for shared code

📖 Scenario: You are building two AWS Lambda functions that both need to use the same helper code. Instead of copying the helper code into each function, you will use a Lambda layer to share the code.

🎯 Goal: Create a Lambda layer with shared helper code, then configure two Lambda functions to use this layer.

📋 What You'll Learn

Create a Lambda layer named shared_helpers with a Python helper function

Create two Lambda functions named function_one and function_two

Configure both Lambda functions to use the shared_helpers layer

💡 Why This Matters

🌍 Real World

Sharing common code across multiple Lambda functions reduces duplication and simplifies maintenance.

💼 Career

Understanding Lambda layers is important for AWS developers and cloud engineers to build efficient serverless applications.

1

Create the shared helper code for the Lambda layer

Create a folder named python and inside it create a file named helper.py with a function def greet(name): that returns the string f"Hello, {name}!".

AWS

# Create the folder 'python' and inside it create 'helper.py' with the greet function
# Your code here

Need a hint?

Remember, the Lambda layer code must be inside a folder named python at the root of the zip file.

2

Create the Lambda layer configuration

Create a variable named layer_name and set it to the string 'shared_helpers' to name your Lambda layer.

AWS

python/helper.py

def greet(name):
    return f"Hello, {name}!"

# Create a variable 'layer_name' with value 'shared_helpers'
# Your code here

Need a hint?

Use a simple assignment to create the layer_name variable.

3

Create two Lambda functions that use the shared layer

Create two variables named function_one and function_two. Assign each a dictionary with keys 'FunctionName' set to 'function_one' and 'function_two' respectively, and 'Layers' set to a list containing layer_name.

AWS

python/helper.py

def greet(name):
    return f"Hello, {name}!"

layer_name = 'shared_helpers'

# Create 'function_one' and 'function_two' dictionaries with 'FunctionName' and 'Layers' keys
# Your code here

Need a hint?

Each function configuration must include the Layers key with a list containing the layer_name.

4

Add the layer ARN to the Lambda functions

Create a variable named layer_arn and set it to the string 'arn:aws:lambda:us-east-1:123456789012:layer:shared_helpers:1'. Then update the 'Layers' list in both function_one and function_two to contain only layer_arn.

AWS

python/helper.py

def greet(name):
    return f"Hello, {name}!"

layer_name = 'shared_helpers'

function_one = {'FunctionName': 'function_one', 'Layers': [layer_name]}
function_two = {'FunctionName': 'function_two', 'Layers': [layer_name]}

# Create 'layer_arn' variable and update 'Layers' in both functions
# Your code here

Need a hint?

The layer ARN is a string that uniquely identifies the Lambda layer version.