BEP Gateway: Architecture Design for E-commerce Cloud Platform Service Integration

This article introduces the BEP (Business Extension Point) Gateway design for YouZan's e-commerce cloud platform. The e-commerce cloud provides a customized solution based on YouZan's SAAS product, offering APP runtime hosting, frontend visualization customization, and backend business process orchestration capabilities.

Core Concepts:

BEP (Business Extension Point) are extension point APIs defined by YouZan's core domain system, which are implemented by customized domain apps in the e-commerce cloud. Technically similar to SPI (Service Provider Interface), these business extension points are orchestrated by the core domain system to provide powerful runtime customization capabilities.

Design Challenges:

The main challenges include: 1) Adapting two completely different service governance solutions - the core domain uses Dubbo-based governance while the customized domain uses Kubernetes-based container scheduling; 2) Implementing network isolation between the strictly separated core domain and customized domain.

Technical Architecture:

The BEP Gateway uses a Service Mesh-like architecture where Sidecar proxies shield the gateway from customized domain service governance details. The gateway adopts Dubbo RPC protocol for internal requests but converts it to HTTP2 for better extensibility in headers. Network isolation is achieved through public LVS connecting to Edge Sidecar, with TLS encryption and authentication.

Key Components:

The SDK encapsulates core BEP calling logic, handling authorization verification between shop owners and apps. The gateway uses a generic Dubbo Provider to accept all extension point calls without restart when adding new points. Protocol conversion transforms Dubbo RPC to HTTP2 to leverage HTTP2's header extensibility for routing control.

Service Governance:

The customized domain uses Kubernetes for multi-tenant isolation and Istio-based Service Mesh architecture. YouZan's Tether middleware replaces Envoy for service discovery and routing control. Edge Sidecar serves as the critical bridge between the two isolated service governance domains.

Future Plans:

The gateway will support multi-language apps through protocol conversion and enhance general gateway capabilities including rate limiting, logging, and monitoring.