[Enhancement request] ability to configure custom TTL per token

[patpatpat123]

Context

How has this issue affected you?
I would end up DDOS the token provider service

What are you trying to accomplish?
I hope to be able to cache the token based on a custom configurable TTL

What other alternatives have you considered?
Are you aware of any workarounds?
Not that I am aware of, but please let me know

I have a straighfoward code such as:

spring:
  application:
    name: client-application
  security:
    oauth2:
      client:
        registration:
          hello-client:
            provider: hello-provider
            client-id: someusername
            client-secret: somepassword
            authorization-grant-type: client_credentials
            scope: resolve
          hi-client:
            provider: hi-provider
            client-id: anotherusername
            client-secret: anotherpassword
            authorization-grant-type: client_credentials
            scope: download
        provider:
          hello-provider:
            token-uri: https://tokenprovider.com/token
          hi-provider:
            token-uri: https://secureservice.com/token

application:
  url:
    hello: https://somecoolcompany.com/api/v1.0/hello
    hi: https://veryawsomeendpoint.com/v2/hi

@Service
public class HelloServiceClient {

    private static final Logger log = LoggerFactory.getLogger(HelloServiceClient.class);

    private final RestClient restClient;

    public HelloServiceClient(RestClient.Builder builder, @Value("${application.url.hello}") String urlHello) {
        this.restClient = builder
                .baseUrl(urlHello)
                .requestInterceptor(
                        (request, body, execution) -> {
                            log.info("Lambda Interceptor: modifying before sending request");
                            ClientHttpResponse response = execution.execute(request, body);
                            log.info("Lambda Interceptor: modifying after receiving response");
                            return response;
                        }
                )
                .build();
    }

    public String hello() {
        return this.restClient.get()
                .uri("/hello")
                .attributes(clientRegistrationId("hello-client"))
                .retrieve()
                .body(String.class);
    }

}

package vn.cloud.restclientdemo.service;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestClient;

import static org.springframework.security.oauth2.client.web.client.RequestAttributeClientRegistrationIdResolver.clientRegistrationId;

@Service
public class HiServiceClient {

    private final RestClient restClient;

    public HiServiceClient(RestClient.Builder builder, @Value("${application.url.hi}") String urlHi) {
        this.restClient = builder
                .baseUrl(urlHi)
                .build();
    }

    public String hi() {
        return this.restClient.get()
                .uri("/hi")
                .attributes(clientRegistrationId("hi-client"))
                .retrieve()
                .body(String.class);
    }

}

Please note there are 4 different URLs here

The business logic is simple, call an endpoint A, but this endpoint A needs a token from token provider B.
Then call a resource endpoint C, which also needs another token from token provider D.
4 in total.

The app in under high load. And the token policies are different.
For instance, the first token is valid 9 minutes, while the second token is valid only 30 seconds.
Caching here is crucial, since under high load, we would like to avoid making unnecessary requests to get a token while it is still active. It would be great to cache it.

But not only to cache it, it would be amazing if we could configure the cache time.

Expected Behavior

Something like this would be great:

spring:
  application:
    name: client-application
  security:
    oauth2:
      client:
        registration:
          hello-client:
            provider: hello-provider
            client-id: someusername
            client-secret: somepassword
            authorization-grant-type: client_credentials
            scope: resolve
            TTL: 100000s
          hi-client:
            provider: hi-provider
            client-id: anotherusername
            client-secret: anotherpassword
            authorization-grant-type: client_credentials
            scope: download
            TTL: 50s
        provider:
          hello-provider:
            token-uri: https://tokenprovider.com/token
          hi-provider:
            token-uri: https://secureservice.com/token

application:
  url:
    hello: https://somecoolcompany.com/api/v1.0/hello
    hi: https://veryawsomeendpoint.com/v2/hi

Current Behavior

This is strange, since many token provider works on their own token "alive" time
As of now, it seems there are no easy ways to configure custom TTL.

Would it be possible to get some help on that?

Thank you