AWS Certified Developer – Associate (DVA-C02)Development with AWS ServicesMedium
A developer is creating an AWS Lambda function that needs to interact with Amazon S3. The Lambda function will be invoked frequently, and the developer wants to minimize latency by ensuring the S3 client is initialized only once across multiple invocations, rather than on every invocation. How can the developer achieve this?
- AInitialize the S3 client within the Lambda handler function.
- BConfigure AWS Lambda Provisioned Concurrency for the function.
- CUse AWS Step Functions to manage the S3 client state.
- DInitialize the S3 client as a global variable outside the handler function.
Show answer & explanationAnswer & explanation
Correct answer: D. Initialize the S3 client as a global variable outside the handler function.
Initializing the S3 client as a global variable (outside the handler function) leverages the Lambda execution environment's lifecycle. The client is initialized once when the execution environment is created and then reused for subsequent invocations of the same environment, significantly reducing initialization overhead and latency.
Why the other options are wrong
- A. Initializing within the handler means it's re-initialized on every invocation, increasing latency.
- B. Provisioned Concurrency keeps execution environments warm, which helps with this pattern, but the actual initialization reuse is achieved by placing the client outside the handler.
- C. AWS Step Functions orchestrates workflows and does not directly manage client initialization within a Lambda function.
Lambda Global Initialization
Initializing resources (like database connections or AWS SDK clients) as global variables outside the handler function in AWS Lambda to reuse them across multiple invocations of a warm execution environment.
- Reduces cold start times.
- Optimizes resource utilization.
- Improves performance for frequently invoked functions.
Memory trick: Global initialization makes Lambda's first use a sensation.