This document discusses Spring Cloud Gateway, a new API gateway solution that is part of the Spring Cloud family. It provides routing capabilities and filters that can route, filter, and secure requests to microservices. Spring Cloud Gateway is non-blocking, supports HTTP/2 and WebSockets, and routes can be configured using Java, YAML, or dynamically using repositories. It also includes out-of-the-box filters for request/response rewriting, rate limiting, and more. Routes are defined either through Java configuration or YAML files.

1. Craig Walls
Twitter: @habuma
Spring Cloud
Gateway

2. Who is Craig?

3. API Gateway Pattern

4. The Mighty Monolith

5. The Monolithic API

6. Busting the Monolith

7. The Gateway

8. Gateway
Responsibilities
Routing
Surgical Routing
Canary Routing
Monolith Strangling
Security
Resiliency
Monitoring
Flexibility

9. What about Zuul?
Zuul 1
Based on blocking servlet API
Unable to do SSE or WebSocket
Limited to path-based routing
Proprietary features

10. What about Zuul?
Zuul 2
Non-blocking I/O based on RxNetty
Supports HTTP/2 and WebSocket
Not backward compatible with Zuul 1
Proprietary features

11. Spring Cloud
Gateway

12. Spring Cloud Gateway
Based on Spring 5, Reactor, Boot 2
Routes can be configured in Java, configuration,
or with repositories
Can route on path, host, headers, parameters, or
anything in the request
Filters
Born in Colorado!

13. Out-of-the-Box Filters
Rewrite Path
Add/Remove Request/Response Headers
Rate Limiting
Hystrix
Spring Cloud LoadBalancerClient*
WebSocket*
Netty Routing*
* Global

14. Simple Filter
@Slf4j
public class SimpleFilter implements GatewayFilter {
@Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
log.info("BEFORE");
return chain.filter(exchange)
.then(Mono.fromRunnable(() -> {
log.info("AFTER");
}));
}
}

15. Route Config: YAML
spring:
cloud:
gateway:
- id: foo_route
uri: lb://foo
predicates:
- Host=**.foo.org
- Path=/headers
- Method=GET
- Header=X-Request-Id, d+
- Query=foo, ba.
- Query=baz
- Cookie=chocolate, ch.p
- After=1900-01-20T17:42:47.789-07:00[America/Denver]
filters:
- AddRequestHeader=X-Request-Foo, Bar
- AddResponseHeader=X-Response-Foo, Bar
- Hystrix=foo
- SecureHeaders
- RewritePath=/foo/(?<segment>.*), /${segment}

16. Route Config: Java
@Bean
public RouteLocator customRouteLocator(RouteLocatorBuilder builder,
ThrottleGatewayFilterFactory throttle) {
return builder.routes()
.route(r -> r.host("**.abc.org").and().path("/image/png")
.filters(f -> f.addResponseHeader("X-TestHeader", "foobar"))
.uri("http://httpbin.org:80")
)
.route(r -> r.path("/image/webp")
.filters(f -> f.addResponseHeader("X-AnotherHeader", "baz"))
.uri("http://httpbin.org:80")
)
.route(r -> r.order(-1)
.host("**.throttle.org").and().path("/get")
.filters(f -> f.filter(throttle.apply(1, 1, 10,
TimeUnit.SECONDS)))
.uri("http://httpbin.org:80")
)
.build();
}

17. DEMO

18. Thank you!
Craig Walls
Twitter: @habuma