readme.md

gRPC Interceptor

What interceptor does? Obviously, it intercepts. What it intercepts? - intercepts the execution of each RPC call
can be configured independently on the client side and server side
types of interceptors
- Unary Interceptor
  - For Client
  - For Server
- Stream Interceptor
  - For Client
  - For Server
UnaryClientInterceptor
- how is it configured? as a DialOption using WithUnaryInterceptor(func) or WithChainUnaryInterceptor(func), when creating a ClientConn
- what is the function signature?
  - func(ctx context.Context, method string, req, reply interface{}, cc *ClientConn, invoker UnaryInvoker, opts ...CallOption) error
- stages
  - pre-processing
  - invoking the actual RPC
  - post-processing
- common use cases - authentication, metadata processing
UnaryServerInterceptor - intercepts the execution of RPC on the server side
- how is it configured? as a grpc.ServerOption using grpc.UnaryInterceptor
- what is the function signature for the interceptor? - func(ctx context.Context, req interface{}, info *UnaryServerInfo, handler UnaryHandler) (resp interface{}, err error)
- just like, interception is common to all unary RPCs defined in the service
- interceptor is responsible for invoking the handler
- common use cases - authentication, authorization, tracing, rate limiting etc