simon-engledew / twirpmock

Create mock twirp services powered by Starlark scripts

twirpmock

Mock out any server that speaks Twirp (a simple RPC framework built on protobuf).

All you need is the protobuf definition of your service, e.g:

...
service Example {
  rpc Echo(EchoRequest) returns (EchoResponse);
}

message EchoRequest {
  string name = 1;
}

message EchoResponse {
  string message = 1;
  google.protobuf.Timestamp timestamp = 2;
}

and a script for the fake service to follow when any of the endpoints are called. This is written in Starlark, the Bazel configuration language:

def Echo(request, response):
    response.message = "Hello " + request.name + "!"
    response.timestamp = now()
    return response

Now when a client connects twirpmock will follow the script to create a response!

The generate function from gofakeit is also available to allow you to create a range of fake data:

def Echo(request, response):
    response.message = generate('here is a uuid {uuid} for you ') + request.name + '!'
    response.timestamp = now()
    return response

Twirpmock can be run standalone or as a Docker container:

docker run \
  -p 8888:8888 \
  -v "$(pwd):/workspace" \
  -w /workspace \
  ghcr.io/simon-engledew/twirpmock:latest example/service.proto.pb example/service.star