DVA-C02 Development with AWS Services Practice Question
A developer is building a microservice that needs to invoke another AWS Lambda function and wait for the result to continue processing. Which Lambda invocation type must the developer use to achieve synchronous invocation?
⚠ Common exam trap
Test-takers frequently confuse the Event invocation type (asynchronous) with synchronous behavior, or mistakenly think DryRun is a valid Lambda invocation type, leading them to select 'None of the above' when they don't recognize RequestResponse as the correct term.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
RequestResponse
The RequestResponse invocation type is the correct choice for synchronous invocation of a Lambda function, where the caller waits for the function to execute and receive a response. This is the default invocation type when using the Invoke API with InvocationType set to 'RequestResponse', and it is required for microservices that need to block until the downstream Lambda returns a result.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
RequestResponse
Why this is correct
When a microservice needs to invoke another AWS Lambda function synchronously, the RequestResponse invocation type is used. This causes the invoking client to pause its execution and wait for the target Lambda function to fully execute and return its response payload. The client receives the function's output, including any errors, directly, enabling real-time processing and decision-making based on the invoked function's result.
- ✗
Event
Why it's wrong here
The Event invocation type is designed for asynchronous processing, where the invoking microservice does not require an immediate response from the target Lambda function. Upon invocation, AWS Lambda queues the event and immediately returns a 202 Accepted status code to the client, allowing the invoker to continue its own processing without waiting. The invoked function executes independently, with its results not directly returned to the original caller, making it suitable for background tasks or event-driven architectures.
- ✗
DryRun
Why it's wrong here
The DryRun invocation type serves a specific diagnostic purpose: to test the invoking entity's permissions to execute a target Lambda function without actually running the function's code. When DryRun is specified, Lambda performs an authorization check against the caller's IAM permissions. It returns a 204 No Content status if the caller has sufficient permissions, or an error if not, thereby preventing unintended function executions while verifying access.
- ✗
None of the above
Why it's wrong here
This option is incorrect because RequestResponse is a valid and appropriate invocation type specifically designed for synchronous Lambda function calls. Since the question asks for a method to synchronously invoke another Lambda, and RequestResponse perfectly fulfills this requirement by making the client wait for the result, selecting 'None of the above' would be inaccurate. The existence of a direct solution negates the validity of this general negative choice.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DVA-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DVA-C02 exam.