tap

Documentation

Overview

Package tap defines the function handles which are executed on the transport layer of gRPC-Go and related information. Everything here is EXPERIMENTAL.

Index

• type Info
• type ServerInHandle

Types

type Info

type Info struct {
	// FullMethodName is the string of grpc method (in the format of
	// /package.service/method).
	FullMethodName string
}

Info defines the relevant information needed by the handles.

type ServerInHandle

type ServerInHandle func(ctx context.Context, info *Info) (context.Context, error)

ServerInHandle defines the function which runs before a new stream is created on the server side. If it returns a non-nil error, the stream will not be created and a RST_STREAM will be sent back to the client with REFUSED_STREAM. The client will receive an RPC error "code = Unavailable, desc = stream terminated by RST_STREAM with error code: REFUSED_STREAM".

It's intended to be used in situations where you don't want to waste the resources to accept the new stream (e.g. rate-limiting). And the content of the error will be ignored and won't be sent back to the client. For other general usages, please use interceptors.

Note that it is executed in the per-connection I/O goroutine(s) instead of per-RPC goroutine. Therefore, users should NOT have any blocking/time-consuming work in this handle. Otherwise all the RPCs would slow down. Also, for the same reason, this handle won't be called concurrently by gRPC.