No way to configure loadbalancer properties per client

[Aloren]

Is your feature request related to a problem? Please describe.
When migrating our integrations from ribbon to loadbalancer, we faced with an issue there is not possibility to configure spring.cloud.loadbalancer properties per client basis. Current LoadBalancerProperties gives an ability to configure loadbalancing for the whole application. In case application is integrated with multiple clients -- this is an issue.

Describe the solution you'd like
We would like to have an ability to configure spring.cloud.loadbalancer per client as it was previously done in ribbon.

Describe alternatives you've considered
There is no way to set specific properties for specific client.

[shsrams]

We are in the same boat, where we are migrating from Ribbon to LoadBalancer but there is no way to configure properties per client. More importantly, we want to turn on healthcheck only on certain clients but we could not find an option with 2020.0.1 version of spring cloud loadbalancer

[NeatGuyCoding]

In same boat too. Well, I have migrated from Ribbon to Loadbalancer last year. The way I migrated is using @LoadBalancerClient, for example:

@LoadBalancerClient(value = "service-1", configuration = Service1LoadBalancerConfig.class)
public class Service1LoadBalancerConfig {
    @Bean
    @Order(Integer.MIN_VALUE)
    public ServiceInstanceListSupplier discoveryClientServiceInstanceListSupplier(
            DiscoveryClient discoveryClient, Environment env,
            LoadBalancerZoneConfig zoneConfig,
            ApplicationContext context) {
        isValid = true;
        ServiceInstanceListSupplier delegate = new SameZoneOnlyServiceInstanceListSupplier(
                new DiscoveryClientServiceInstanceListSupplier(discoveryClient, env),
                zoneConfig
        );
        ObjectProvider<LoadBalancerCacheManager> cacheManagerProvider = context
                .getBeanProvider(LoadBalancerCacheManager.class);
        if (cacheManagerProvider.getIfAvailable() != null) {
            return new CachingServiceInstanceListSupplier(
                    delegate,
                    cacheManagerProvider.getIfAvailable()
            );
        }
        return delegate;
    }
}

In this way you can configuration customized specifications for each service.

And If you feel it is troublesome, I suggest you applying a default configuration using LoadBalancerClients. For example:

@LoadBalancerClients(defaultConfiguration = {DefaultLoadBalancerConfig.class})
public class DefaultLoadBalancerConfig {
//some default bean
}

And then, configure for some services using @LoadBalancerClient

[NeatGuyCoding]

And Based on my own comprehension, spring.cloud.loadbalancer is only used to configuration for common basic application. But for customization for each service RPC, it is another design and you should implement it based on @LoadBalancerClients and @LoadBalancerClient yourself. Or maybe the current design should be re-considerated. :-)
@OlgaMaciaszek @ryanjbaxter

[Ferioney]

@OlgaMaciaszek @ryanjbaxter @spencergibb
I prepared PR 942 with PoC (for BlockingLoadBalancedRetryFactory) how it can be done in the current design.
What do you think?

[NeatGuyCoding]

I vote for Ferioney's design

[OlgaMaciaszek]

@Ferioney Thanks for the PR. Continuing the discussion in the PR issue.

[OlgaMaciaszek]

We are considering moving adding this feature for 2021.0.0 release train in order to be able to build it on top of the following feature planned for Spring Boot: spring-projects/spring-boot#26144.