Global rate limiting

Envoy integrates directly with a global gRPC rate limiting service. Although any service that implements the defined RPC/IDL protocol can be used, Envoy provides a reference implementation written in Go which uses a Redis backend. Envoy’s rate limit integration has the following features:

Note that Envoy also supports . Local rate limiting can be used in conjunction with global rate limiting to reduce load on the global rate limit service. For example, a local token bucket rate limit can absorb very large bursts in load that might otherwise overwhelm a global rate limit service. Thus, the rate limit is applied in two stages. The initial coarse grained limiting is performed by the token bucket limit before a fine grained global limit finishes the job.