[Feature] Istio v1 Mixer quota management service integration

[sczyh30]

Issue Description

Type: feature request

Describe what feature you want

Istio’s Mixer component is responsible for policy controls and telemetry collection. Currently Istio performs rate-limiting for services in the Mixer. Istio provides mechanisms to add customized adapters to the Mixer, so that Istio could leverage external components to do policy controls. There're several kinds of adapters in Istio, and the quota management adapter is designed for flow control. The related template:

• Quota Management Template
• adapter.Handler and quota.Handler

Istio supports Mixer Out Of Process Adapter, which uses gRPC server as the adapter implementation. For qouta management:

// HandleQuotaService is implemented by backends that wants to handle request-time 'quota' instances.
service HandleQuotaService {
    // HandleQuota is called by Mixer at request-time to deliver 'quota' instances to the backend.
    rpc HandleQuota(HandleQuotaRequest) returns (istio.mixer.adapter.model.v1beta1.QuotaResult);

}

We may leverage the quota management gRPC service to do flow control and adaptive traffic shaping for the Istio service mesh with Sentinel. Discussions are welcomed!

[sczyh30]

The Mixer might have been deprecated since Istio 1.5.x, so we'll not work on this issue. We may leverage Sentinel Go version to develop Envoy WASM plugin to provide flow control support for Istio+Envoy. Refer alibaba/sentinel-golang#104