add self define config

[gy09535]

Which issue(s) this PR fixes:

Fixes #4259

Brief changelog

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[gy09535]

I have read the CLA Document and I hereby sign the CLA

[gy09535]

recheck

[nobodyiam]

It looks like self define discovery is very similar to KubernetesDiscoveryService, could we just reuse that instead?

[gy09535]

It looks like self define discovery is very similar to KubernetesDiscoveryService, could we just reuse that instead?

Functionally speaking, it is similar, but semantically it is different, k8s definition is through k8s service discovery to replace eureka, but in some non-k8s environments or complex deployment scenarios, we do not need to use k8s services as service discovery, then we need more flexible semantics to define this operation, if we use k8s service discovery, can cause semantic mixing, conceptually unclear.

[nobodyiam]

Then I suppose we could do like this, in which custom-defined is the profile to be activated for those non-kubernetes environment, but we could share the same implementation.

@Service
@Profile({"kubernetes", "custom-defined-discovery"})
public class KubernetesDiscoveryService implements DiscoveryService {
}

[gy09535]

Then I suppose we could do like this, in which custom-defined is the profile to be activated for those non-kubernetes environment, but we could share the same implementation.

@Service
@Profile({"kubernetes", "custom-defined-discovery"})
public class KubernetesDiscoveryService implements DiscoveryService {
}

Good idea 👍