Spring Cloud Spring Cloud Gateway & Load Balancing 1 — Questions and Answers
Question 1: What replaces the deprecated Netflix Zuul as the recommended API gateway in Spring Cloud?
- Spring Cloud Consul Gateway
- Spring Cloud Gateway (Correct answer)
- Spring Cloud Router
- Spring Cloud Proxy
Correct answer: Spring Cloud Gateway
Spring Cloud Gateway, built on Spring WebFlux and Project Reactor, is the modern replacement for the deprecated Netflix Zuul API gateway.
Question 2: Which programming model does Spring Cloud Gateway use for reactive, non-blocking request processing?
- Spring MVC with Tomcat thread pool
- Spring WebFlux with Project Reactor (Correct answer)
- Netty with Vert.x event loop
- Akka HTTP with actor model
Correct answer: Spring WebFlux with Project Reactor
Spring Cloud Gateway is built on Spring WebFlux and Project Reactor, providing non-blocking, reactive request routing and filtering.
Question 3: In Spring Cloud Gateway, what is a 'Predicate' used for?
- Modifying the request or response headers
- Matching incoming requests to determine which route to apply (Correct answer)
- Performing authentication and authorization checks
- Balancing load across downstream service instances
Correct answer: Matching incoming requests to determine which route to apply
Predicates in Spring Cloud Gateway are conditions evaluated against incoming requests (path, headers, method, etc.) to determine if a route matches.
Question 4: What is the purpose of a 'Filter' in Spring Cloud Gateway?
- Selecting which downstream instance receives a request
- Modifying the incoming request or outgoing response before/after routing (Correct answer)
- Caching responses from downstream services
- Discovering available routes from the service registry
Correct answer: Modifying the incoming request or outgoing response before/after routing
Filters in Spring Cloud Gateway can inspect and modify HTTP requests and responses, enabling cross-cutting concerns like authentication, logging, and header manipulation.
Question 5: Which Spring Cloud Gateway predicate routes requests where the path matches `/api/orders/**`?
- PathVariable=/api/orders/**
- Path=/api/orders/** (Correct answer)
- Route=/api/orders/**
- Match=/api/orders/**
Correct answer: Path=/api/orders/**
The Path predicate factory in Spring Cloud Gateway routes requests whose URI path matches the specified Ant-style pattern.
Question 6: How does Spring Cloud Gateway integrate with service discovery to route requests to registered services by name?
- By hardcoding service IPs in route configuration
- Via the lb:// URI scheme which triggers client-side load balancing through DiscoveryClient (Correct answer)
- By querying the DNS server for service IP resolution
- Through a sidecar proxy that intercepts all traffic
Correct answer: Via the lb:// URI scheme which triggers client-side load balancing through DiscoveryClient
Using lb://service-name as the route URI instructs Spring Cloud Gateway to use the load balancer and service discovery to resolve the target service's instances.
Spring Cloud Spring Cloud Gateway & Load Balancing 1
What replaces the deprecated Netflix Zuul as the recommended API gateway in Spring Cloud?