Sample gRPC backend for CoreDNS

Generate the gRPC stubs

This is only needed if dns.proto is updated:

cd proto
protoc dns.proto --go_out=plugins=grpc:.

Run the server

This will start the backend on port 8053 (udp/tcp):

go build -o main
./main

Start CoreDNS

This will start coredns using the Corefile on port 1053 (udp/tcp) and proxy requests to the backend over gRPC:

coredns

Try it out

$ dig +short @localhost -p 1053 A foo.example.com
127.0.0.1

$ dig +short @localhost -p 1053 AAAA foo.example.com
::1