[Rate limiting] Configure Rate limit policies in Choreo Connect components

[renuka-fernando]

Description

Rate limit policies are configured in the Control Plane or defined using Ratelimit CRD with API, HTTP Route, Application and Subscription CRDs. Once Ratelimits are in an internal Data Structure (Ratelimits got from CP or CRDs) to the Agent, the Agent should configure Enforcer, Router, and Ratelimit service with Ratelimit policies.

• [Rate limiting]Design Configuring Rate limit policies in Choreo Connect components #118
• Implementation API level policies with conditional policy support.
  • Configure Router
  • Configure Enforcer
  • Configure Rate Limit Service
• Configure Application level and Subscription level Rate limits.

[renuka-fernando]

Drafted Ratelimit config format in Ratelimit service: https://github.com/renuka-fernando/ratelimit/blob/cc-k8s/examples/ratelimit/config/example.yaml

Drafted HTTP header names (and basic conditional rate limit handle): Header names that enforcer is setting: https://github.com/renuka-fernando/ratelimit/blob/cc-k8s/ext-auth-server/auth.go

Drafted Router, envoy config: https://github.com/renuka-fernando/ratelimit/blob/cc-k8s/examples/envoy/envoy.yaml
https://github.com/renuka-fernando/ratelimit/blob/cc-k8s/kubernetes/gateway-runtime/envoy/envoy-config.yaml

[renuka-fernando]

For inline rate limits (Ratelimits are defined by the API creator by just typing the number of requests in an input box and selecting the unit time from a selection with conditional rate limits) it is able to use the same name for the same limits (to reuse the same policy, otherwise the rate limit config will be larger).

For example 10 req/min: "$_10_per_min"

But there could be cases something like the following.
The same 10 per min policy with different conditional policies.
Eg:

• Policy1: 10 per min, c1 - IP Range(1,2)
• Policy2: 10 per min, c1 - IP Range (2,3)).

Append UUIDs of conditions to the name ("$_10_per_min_UUID1", "$_10_per_min_UUID2", "$_10_per_min_default"). This has to be decided.

[renuka-fernando]

Rate limit policies including conditional policies (this should be clearly identified): https://docs.google.com/document/d/1ttOTjbNPWUM9Em4vQAK1KW5wdcVXK6Z51jBgI2Rr5vI/edit#heading=h.emcc7kx7gf6i

• Header equals a value
• Header matches for given regex pattern
• IP in "X-Forwarded-For" header equals the defined IP
• IP in "X-Forwarded-For" header is within the defined IP range
• Time the request is made is within the given time range (Cron format with duration - or duration) (eg: Peak/Off Peak)