Library for signing grpc requests

Allows you to understand on the server side which service made the request. This is implemented through a pair of interceptors. The client writes the name of the application to the metadata, and the server reads this data and writes it to the context.

Usage

How to use interceptors

On client side

package main

import (
	"context"
	"github.com/tulzke/grpc_signature"
	"google.golang.org/grpc"
)

func main() {
	grpcClientDialOpts := []grpc.DialOption{
		grpc.WithChainUnaryInterceptor(
			grpc_signature.UnaryClientInterceptor("someApp"),
		),
		grpc.WithChainStreamInterceptor(
			grpc_signature.StreamClientInterceptor("someApp"),
		),
	}

	conn, err := grpc.DialContext(context.Background(), "", grpcClientDialOpts...)
}

On server side

package main

import (
    grpc_middleware "github.com/grpc-ecosystem/go-grpc-middleware"
	"github.com/tulzke/grpc_signature"
	"google.golang.org/grpc"
)

func main() {
	server := grpc.NewServer(
		grpc_middleware.WithUnaryServerChain(
			grpc_signature.UnaryServerInterceptor(),
		),
		grpc_middleware.WithStreamServerChain(
			grpc_signature.StreamServerInterceptor(),
		),
	)
}

How to get the client name on server side

package controller

import (
	"context"
	"examplev1"
	"github.com/tulzke/grpc_signature"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

type Server struct{}

func (s *Server) Example(ctx context.Context, r *examplev1.Request) (*examplev1.Response, error) {
	// First way
	clientName := grpc_signature.ClientName(ctx)
	
	// Second Way
	clientName = ctx.Value(grpc_signature.ContextKey).(string)
}