我应该将新的还是旧的Context对象发送到自己的gRPC服务器中的第三方gRPC API？

Question

We have a gRPC server written in golang. For one of the RPCs, we request data from the Google Maps gRPC API. Once we receive a response from the Google Maps RPC, we do some calculations and return a response to the enclosing RPC (defined by our server).

Naturally, we receive a Context object when the RPC is called on our server.

My question is: Should we pass this same Context object to the Google Maps RPC? Or, should we instead create a new Context object (using context.Background()), and then pass this to the Google Maps API?

Answer 1

The context you received contains the cancellation and timeout, so it would be good to use the same context to make the new RPC. Otherwise you need to manually pass these signals.

A side on the metadata, metadata in the received context will not be automatically forwarded to the new RPC, see:

https://github.com/grpc/grpc-go/issues/1148

https://github.com/grpc/grpc-go/pull/1157