tap

Documentation

Overview

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

Experimental

Notice: This API is EXPERIMENTAL and may be changed or removed in a later release.

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

	// Header contains the header metadata received.
	Header metadata.MD
}

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 an error will be returned to the client. If the error returned is a status error, that status code and message will be used, otherwise PermissionDenied will be the code and err.Error() will be the message.

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). 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.