What is gRPC Mate?

This introduction describe briefly what is gRPC Mate, why it is useful, and how to deploy it.

gRPC Mate is a light weight reverse proxy server that translates JSON HTTP requests into gRPC calls without the need of code generation. It reads protobuf service definitions through accessing reflection API exposed by the gRPC service, and converts HTTP and JSON requests to gRPC invocations dynamically.

The purpose that gRPC Mate is created is to provide a way to serve HTTP and JSON from a gRPC server very easily, without protobuf definition files sharing, without protobuf directives, and without any Service Discovery system integration.

As its name gRPC Mate suggestes, the reverse proxy server is designed to be a sidecar, and is expected to run beside the proxied gRPC server. In a development or testing scenario, it can be dropped with mere configuration in front of the target gRPC service. In a production environment, instead of running a single gRPC Mate server in front all gRPC services, it is better to be deployed alongside each gRPC server instances, for example, as another container in the same pod if running within Kubernetes cluster.

The key features of gRPC Mate are:

• HTTP to gRPC Translation - Translates gRPC services into HTTP JSON endpoints.
• Independent Reverse Proxy - Runs as an independent proxy server against upstream gRPC service, and evolving of the underlying gRPC service does not require an upgrade or rebuild of gRPC Mate server.
• Easy to Setup - Requires only 1) the upstream gRPC server enabling gRPC reflection service, and 2) the gRPC listening address and port passing to gRPC Mate.
• Management Endpoints - Provides basic management endpoints, such as /actuator/health telling if the service is healthy, and /actuator/services introspecting all services, methods, their HTTP route mappings and request/response schema example.