This guide gets you started with gRPC-Web with a simple working example from the browser.

Prerequisites

  • docker and docker-compose

This demo requires Docker Compose file version 3. Please refer to Docker website on how to install Docker.

Run an Echo example from the browser!

$ git clone https://github.com/grpc/grpc-web
$ cd grpc-web
$ docker-compose pull prereqs common node-server envoy commonjs-client
$ docker-compose up -d node-server envoy commonjs-client

Open a browser tab, and go to:

http://localhost:8081/echotest.html

To shutdown, run docker-compose down.

What is Happening?

In this demo, there are three key components:

  1. node-server: This is a standard gRPC Server, implemented in Node. This server listens at port :9090 and implements the service’s business logic.

  2. envoy: This is the Envoy proxy. It listens at :8080 and forwards the browser’s gRPC-Web requests to port :9090. This is done via a config file envoy.yaml.

  3. commonjs-client: This component generates the client stub class using the protoc-gen-grpc-web protoc plugin, compiles all the JS dependencies using webpack, and hosts the static content echotest.html and dist/main.js using a simple web server at port :8081. Once the user interacts with the webpage, it sends a gRPC-Web request to the Envoy proxy endpoint at :8080.

What’s next