Spring Cloud Case Studies & Practical Application 4

Question 1

A company's Spring Cloud Gateway is overwhelmed by a single client making thousands of requests per second. Which built-in filter should be applied to protect backend services?

Accepted Answer

RequestRateLimiter filter with Redis backend

Answer

The RequestRateLimiter GatewayFilter uses Redis and a token bucket algorithm to enforce per-client rate limits, returning 429 when exceeded.

Question 2

A team's Circuit Breaker opens even during normal operations, causing unnecessary fallbacks. Which configuration change would reduce false positives?

Accepted Answer

Increase the slidingWindowSize and failure rate threshold in Resilience4j configuration

Answer

Increasing the sliding window size and raising the failure rate threshold requires more evidence of real failures before the circuit opens, reducing false positives from small sample noise.

Question 3

A platform team needs to route requests to different microservice versions based on a custom HTTP header (X-Version: v2). Which Spring Cloud Gateway feature supports this?

Accepted Answer

Header-based RoutePredicateFactory matching on the X-Version header

Answer

Spring Cloud Gateway's Header RoutePredicateFactory matches routes based on the presence and value of specific HTTP headers, enabling header-driven version routing.

Question 4

After deploying a Config Server with a Vault backend, services cannot start because Vault is sealed. What is the correct handling strategy?

Accepted Answer

Mark config as optional so services start with defaults when Vault is unavailable

Answer

Using spring.config.import=optional:configserver: or fail-fast=false lets services start with local defaults when the config source is unavailable, preventing a startup deadlock.

Question 5

A team wants to test their Feign clients against a WireMock stub server in CI without spinning up real microservices. Which Spring Cloud project provides stub generation from contracts?

Accepted Answer

Spring Cloud Contract WireMock stub runner

Answer

Spring Cloud Contract's WireMock Stub Runner automatically starts stubs generated from producer contracts, letting consumers test against realistic stubs without live services.

Spring Cloud Practice Test

Spring Cloud Practice Test

Spring Cloud Case Studies & Practical Application 4