Implement token-bucket algorithm

[marcosbarbero]

@lchayoun I'm thinking about to change our main implementation to use a token-bucket instead.
Here's a link to take a look https://github.com/bbeck/token-bucket.

WDYT?

[lchayoun]

I think it is a good direction, not sure about this implementation.
bucket4j has good integration with spring and is out there for quite a while

[marcosbarbero]

Good to know.
I’ll take a look ASAP.

[marcosbarbero]

@lchayoun did you see those examples?

[lchayoun]

Saw them, I think the main issue is the configuration required because it is not zuul specific.
I think we should support it as backend, we'll gain the support for all the backends supported by bucket4j

[marcosbarbero]

Don't you think it would be better to entirely move the ratelimit algorithm to a bucket based one? Doesn't necessarily needs to be bucket4j.

[lchayoun]

Well, since buckets doesn't work natively with time limitation, the filters are still required.
Also redis is a very good backend and I think it need to remain.
Adding bucket4j as RateLimiter implementation will give us the logic of it with the backends supported without losing any capability.

[marcosbarbero]

Actually that's the main idea, I'm not planning to remove any supported backend just to move the logic towards a bucked based algorithm.

[lchayoun]

not sure I understood, maybe we are saying the same.
I think that it should be added first as another backend without modifying the existing ones and later on change merge them.

[marcosbarbero]

I think we are actually saying the same thing :D