`Retry` Filter

The Retry filter supports the following parameters:

retries: The number of retries that should be attempted.
methods: The HTTP methods that should be retried, represented by using org.springframework.http.HttpMethod.
series: The series of status codes to be retried, represented by using org.springframework.http.HttpStatus.Series.
exceptions: A list of thrown exceptions that should be retried.

The following defaults are configured for Retry filter, if enabled:

retries: Three times
series: 5XX series
methods: GET method
exceptions: IOException, TimeoutException and RetryException

The following listing configures a Retry filter:

application.yml

spring:
  cloud:
    gateway:
      mvc:
        routes:
        - id: retry_test
          uri: http://localhost:8080/flakey
          predicates:
          - Host=*.retry.com
          filters:
          - name: Retry
            args:
              retries: 3
              series: SERVER_ERROR
              methods: GET,POST

GatewaySampleApplication.java

import static org.springframework.cloud.gateway.server.mvc.filter.RetryFilterFunctions.retry;
import static org.springframework.cloud.gateway.server.mvc.handler.GatewayRouterFunctions.route;
import static org.springframework.cloud.gateway.server.mvc.handler.HandlerFunctions.http;
import static org.springframework.cloud.gateway.server.mvc.predicate.GatewayRequestPredicates.host;

@Configuration
class RouteConfiguration {

    @Bean
    public RouterFunction<ServerResponse> gatewayRouterFunctionsAddReqHeader() {
		return route("add_request_parameter_route")
			.route(host("*.retry.com"), http("https://example.org"))
				.filter(retry(config -> config.setRetries(3).setSeries(Set.of(HttpStatus.Series.SERVER_ERROR)).setMethods(Set.of(HttpMethod.GET, HttpMethod.POST))))
			.build();
    }
}

When using the retry filter with a forward: prefixed URL, the target endpoint should be written carefully so that, in case of an error, it does not do anything that could result in a response being sent to the client and committed. For example, if the target endpoint is an annotated controller, the target controller method should not return ResponseEntity with an error status code. Instead, it should throw an Exception or signal an error (for example, through a Mono.error(ex) return value), which the retry filter can be configured to handle by retrying.

A simplified "shortcut" notation can be added with a single status and method.

The following two examples are equivalent:

application.yml

spring:
  cloud:
    gateway:
      routes:
      - id: retry_route
        uri: https://example.org
        filters:
        - name: Retry
          args:
            retries: 3
            statuses: INTERNAL_SERVER_ERROR
            methods: GET
      - id: retryshortcut_route
        uri: https://example.org
        filters:
        - Retry=3,INTERNAL_SERVER_ERROR,GET

Retry Filter

`Retry` Filter