envoy-demo

Connect-gRPC Envoy Bridge Demo

This repository contains a small demo of how to use the Connect-gRPC Envoy bridge.

Try it out!

To run locally, clone this repository:

git clone https://github.com/connectrpc/envoy-demo
cd envoy-demo

Then run docker-compose up to start the demo:

docker-compose up

After a minute or two, there should be a server listening on port 8080.

It's possible to browse to it directly, taking advantage of Connect's HTTP GET support:

Note: The Connect-gRPC filter requires the Connect protocol version to be set in the request to have any effect. For GET requests, this means including connect=v1 as a query parameter in the URL. For POST requests, this means including Connect-Protocol-Version: 1 in the HTTP request headers. Official Connect clients will do this automatically.

It's also possible to interact using buf curl. Since our Envoy configuration has both the Envoy gRPC Web filter and the Connect-gRPC bridge filter setup, we can use any of the available protocols:

$ buf curl http://localhost:8080/ping.v1.PingService/Ping --http2-prior-knowledge --schema . -d '{"number":2}' --protocol grpc
{"number":"2"}
$ buf curl http://localhost:8080/ping.v1.PingService/Ping --http2-prior-knowledge --schema . -d '{"number":2}' --protocol grpcweb
{"number":"2"}
$ buf curl http://localhost:8080/ping.v1.PingService/Ping --http2-prior-knowledge --schema . -d '{"number":2}' --protocol connect
{"number":"2"}

How it works

The gRPC server included in this repository is a typical gRPC-Go server with one simple addition—it includes a JSON codec. This makes it a lot simpler to interact with directly without the use of a Connect or gRPC client, though this is by no means required.

Then we have our Envoy configuration. The most important snippet is this part:

http_filters:
- name: envoy.filters.http.connect_grpc_bridge
  typed_config:
    "@type": type.googleapis.com/envoy.extensions.filters.http.connect_grpc_bridge.v3.FilterConfig
- name: envoy.filters.http.grpc_web
  typed_config:
    "@type": type.googleapis.com/envoy.extensions.filters.http.grpc_web.v3.GrpcWeb

These two filters will convert from the Connect and gRPC-Web protocols down to native gRPC for the upstream server.

Finally, to show all of this off in a contained environment, a Docker Compose manifest is included. It is trivial, containing only the Envoy container and the upstream vanilla gRPC server.

Try it with your server!

If you already use Envoy, please update to Envoy v1.26 and give the new Connect-gRPC bridge filter a try. Let us know how it works, and if you find any issues!