support exclude default-filters by route specific

[wendell-dev]

Example:

spring:
  cloud:
    gateway:
      default-filters:
      - StripPrefix=1
      routes:
      - id: example-service
        uri: lb://example-service
        predicates: 
        - Path=/example-service/**

some routes do not require a default filter...

can add the excludeDefaultFilters attribute to support it, such as:

spring:
  cloud:
    gateway:
      default-filters:
      - StripPrefix=1
      routes:
      - id: example-service
        uri: lb://example-service
        predicates: 
        - Path=/example-service/**
        exclude-default-filters: StripPrefix

[wendell-dev]

the following changes should support it

change the source code: org.springframework.cloud.gateway.route.RouteDefinition

private List<String> excludeDefaultFilters = new ArrayList<>();
// setter and getter

change the source code: org.springframework.cloud.gateway.route.RouteDefinitionRouteLocator#getFilters

private List<GatewayFilter> getFilters(RouteDefinition routeDefinition) {
	List<GatewayFilter> filters = new ArrayList<>();

	if (!this.gatewayProperties.getDefaultFilters().isEmpty()) {
		List<FilterDefinition> defaultFilters = new ArrayList<>(this.gatewayProperties.getDefaultFilters());
		if (!CollectionUtils.isEmpty(routeDefinition.getExcludeDefaultFilters())) {
			defaultFilters.removeIf(filter -> routeDefinition.getExcludeDefaultFilters().contains(filter.getName()));
		}
		if (!CollectionUtils.isEmpty(defaultFilters)) {
			filters.addAll(loadGatewayFilters(routeDefinition.getId(), new ArrayList<>(defaultFilters)));
		}
	}

	if (!routeDefinition.getFilters().isEmpty()) {
		filters.addAll(loadGatewayFilters(routeDefinition.getId(), new ArrayList<>(routeDefinition.getFilters())));
	}

	AnnotationAwareOrderComparator.sort(filters);
	return filters;
}

[spencergibb]

I don't like RouteDefinition knowing about default filters. I'd prefer something in metadata like other things, but let's see if others want this.

[akcodian]

I am in the same situation. There are a few endpoints for which I don't want to apply the retry filter. @spencergibb do you have any other suggestion in addition to custom RouteDefinitionRouteLocator?