Lambda Layers と環境変数
依存関係には Lambda Layers、構成には環境変数を使用して、コードのデプロイと管理を効率化します。
「Lambda Layers と環境変数」はCoddyKit上の無料AWS for Backend Developers (EC2, S3, RDS, Lambda)レッスンです。 これはレッスン2/4です。 下記で完全なレッスンを無料で読むことができます。その後、ブラウザ内の組み込みコードエディタと24時間対応のAIチューターでハンズオン演習できます。 これはAWS for Backend Developers (EC2, S3, RDS, Lambda)学習パスの一部であり、ウェブとCoddyKitアプリ全体で進捗が同期されます。 AWS for Backend Developers (EC2, S3, RDS, Lambda)コースには全4レッスンが含まれています。
このレッスンの一部はまだ翻訳されておらず、英語で表示されています。
What are Lambda Layers?
AWS Lambda Layers help you manage common dependencies and custom runtimes more efficiently. Think of them as shared libraries for your functions.
Instead of bundling all your code and dependencies with every function deployment, you can package reusable components into a Layer.
Why Use Lambda Layers?
Layers offer several benefits for your serverless applications:
- Smaller Deployment Packages: Keep your function code lean by separating dependencies.
- Code Reusability: Share common code (e.g., utility functions, database connectors) across multiple Lambda functions.
- Faster Deployments: Smaller packages upload quicker.
- Easier Updates: Update a dependency once in a layer, and all functions using it benefit.
How Layers are Structured
A Lambda Layer is essentially a .zip file archive containing library code, custom runtimes, or other dependencies.
When you attach a layer to a function, Lambda extracts its content to the /opt directory in the function's execution environment. Your function code can then import modules from /opt.
Imagining a Simple Layer
Let's say you have a common logging utility or a specific SDK version you want to use. Instead of including it in every Lambda function's deployment package, you'd put it in a layer.
The layer's ZIP file structure might look like this for Python:
python/mylogger.pyYour Lambda function would then simply import it as import mylogger.
Attaching a Layer to Lambda
You can attach up to 5 layers to a single Lambda function. This is typically done through the AWS Management Console, AWS CLI, or Infrastructure as Code tools like SAM or CloudFormation.
When attaching, you specify the Layer ARN (Amazon Resource Name) which uniquely identifies the layer and its specific version.
Layer Demo: Shared Utility
Imagine we have a layer containing a utils.py with a greet function. Here's how a Lambda function would use it. (We simulate the layer's presence for this runnable demo):
import json
# In a real Lambda, 'utils' would be imported
# from a layer mounted at /opt/python/utils.py
# For this demo, we simulate the 'utils' module.
class Utils:
@staticmethod
def greet(name):
return f"Hello, {name} from Layer!"
utils = Utils() # Make it available as 'utils'
def lambda_handler(event, context):
name = event.get('name', 'World')
message = utils.greet(name)
return {
'statusCode': 200,
'body': json.dumps(message)
}
if __name__ == "__main__":
# Simulate a test event
test_event = {'name': 'Coddy'}
result = lambda_handler(test_event, None)
print(result['body'])
test_event_default = {}
result_default = lambda_handler(test_event_default, None)
print(result_default['body'])What are Env Variables?
Environment variables allow you to pass configuration settings to your Lambda function without changing its underlying code.
They are key-value pairs that are available to your function's code at runtime. This is ideal for settings that vary between environments (e.g., development, test, production) or for non-sensitive configuration data.
Setting Env Variables in Lambda
You can define environment variables when you create or update your Lambda function. This is typically done via:
- AWS Management Console: Under the function's "Configuration" tab, then "Environment variables".
- AWS CLI: Using the
--environment "Variables={KEY=VALUE}"parameter. - Infrastructure as Code: For example, in a SAM template, under the function's
Environment: Variables:section.
Important: For highly sensitive data like database passwords or API keys, always use AWS Secrets Manager instead of environment variables.
Env Variables Demo: Config
Let's say you have an environment variable named GREETING_PREFIX set to "Welcome". Your Lambda function can easily access its value using the os module in Python:
import os
import json
def lambda_handler(event, context):
# Access environment variables
# os.environ.get('KEY', 'default_value')
prefix = os.environ.get('GREETING_PREFIX', 'Hello')
name = event.get('name', 'User')
message = f"{prefix}, {name}!"
return {
'statusCode': 200,
'body': json.dumps(message)
}
if __name__ == "__main__":
# Simulate setting an environment variable locally
os.environ['GREETING_PREFIX'] = 'Hola'
test_event = {'name': 'Amigo'}
result = lambda_handler(test_event, None)
print(result['body'])
# Clean up and test default behavior
del os.environ['GREETING_PREFIX']
test_event_default = {'name': 'World'}
result_default = lambda_handler(test_event_default, None)
print(result_default['body'])Check Your Knowledge
Which of the following are valid reasons to use AWS Lambda Layers?
Recap: Layers & Env Vars
Today, you learned about two powerful tools for managing your Lambda functions more effectively:
- Lambda Layers: Used for packaging shared code, libraries, and dependencies, which reduces deployment package size and promotes code reusability across functions.
- Environment Variables: Used for passing configuration settings to your function at runtime, making your code more flexible and easier to manage across different deployment environments.
Mastering these features will help you build more organized, efficient, and maintainable serverless applications!
よくある質問
「Lambda Layers と環境変数」レッスンは無料ですか？
はい。「Lambda Layers と環境変数」の完全なテキストはこのウェブで無料で読めます。インタラクティブに演習し（組み込みコードエディタと24時間対応のAIチューター）、AWS for Backend Developers (EC2, S3, RDS, Lambda)コースの残りをアンロックするには、CoddyKit PROにアップグレードしてください。 AWS for Backend Developers (EC2, S3, RDS, Lambda)コースには全4レッスンが含まれています。
「Lambda Layers と環境変数」で何を学びますか？
依存関係には Lambda Layers、構成には環境変数を使用して、コードのデプロイと管理を効率化します。 ブラウザで直接実行するハンズオンコードでAWS for Backend Developers (EC2, S3, RDS, Lambda)を演習し、24時間対応のAIチューターがレッスンを進める中での質問に答えます。
AWS for Backend Developers (EC2, S3, RDS, Lambda)を始めるのに経験は必要ですか？
事前経験は必要ありません。CoddyKitのAWS for Backend Developers (EC2, S3, RDS, Lambda)は初級者から上級者向けに構成されているため、ここから始めるか最初から始めて、自分のペースで進むことができます。 これはレッスン2/4です。
「Lambda Layers と環境変数」レッスンにはどのくらい時間がかかりますか？
ほとんどのCoddyKitレッスンは約5～10分かかります。各レッスンはコンパクトでインタラクティブなので、着実に進歩し、ウェブとアプリ全体で正確に前回の場所から再開できます。
このAWS for Backend Developers (EC2, S3, RDS, Lambda)レッスンでコードを書いて実行できますか？
はい。すべてのAWS for Backend Developers (EC2, S3, RDS, Lambda)レッスンに組み込みコードエディタが含まれているため、ブラウザでリアルコードを書いて実行し、即座のAIフィードバックを取得できます。ローカル設定は不要です。