Intent to discuss: GraphQL support?

[snowmantw]

WHAT

GraphQL is used by query-oriented apps and even is the basic method for mtc2018. Since this project already proxies the RESTful request to gRPC calls, to add one more API protocol could be in parallel components by following the similar pattern.

WHY

For frontend side GraphQL provides a way to support query-oriented apps and have several benefits. And although GraphQL is more like a thin layer that directly link to database via like Prisma, but for existing microservices and by requirements there would be some data from services, not directly from database. Therefore, if grpc-http-proxy can support GraphQL, it would help both frontend and backend to adapt the API protocol more easily.

Possible Strategies:

It seems possible to extend the http handler to call the module of GraphQL. GraphQL module could be a totally standalone component to handle schema and only when resolvers need, to call upstream gRPC services follow the same path as http handler (these code may be encapsulated as callable to be used in both places, to reduce the duplication), and then respond.