grpc-web VS buf

* Additionally, client can stream data to the backend server (if bidirectional GRPC streams are used). I.e. client sends WebSocket messages, those will be transformed to GRPC messages by WebSocket server and delivered to the application backend.

As a result we have a system which allows to quickly create individual streams by using strict GRPC contract but terminating connections over WebSocket transport. So it works well in web browsers. After that no need to write WebSocket protocol, client implementation, handle WebSocket connection. This all will be solved by a suggested WebSocket server and its client SDKs.

The mechanics is similar to Websocketd (https://github.com/joewalnes/websocketd), but instead of creating OS processes we create GRPC streams. The difference from grpc-web (https://github.com/grpc/grpc-web) is that we provide streaming capabilities but not exposing GRPC contract to the client - just allowing to stream any data as payload (both binary and text) with some wrappers from our client SDKs side for managing subscriptions. I.e. it's not native GRPC streams on the client side - we expose just Connection/Subscription object to stream in both directions. GRPC streams used only for communication between WebSocket server and backend. To mention - grpc-web does not support all kinds of streaming now (https://github.com/grpc/grpc-web#streaming-support) while proposed solution can. This all should provide a cross-platform way to quickly write streaming apps due to client SDKs and language-agnostic nature of GRPC.

I personally see both pros and cons in this scheme (without concentrating on both too much here to keep the question short). I spent some time thinking about this myself, already have some working prototypes – but turned out need more opinions before moving forward with the idea and releasing this, kinda lost in doubts.

My main question - whether this seems interesting for someone here? Do you find this useful and see practical value?

By default, web browsers do not support gRPC, but we will use gRPC-web to make it possible.

You just have to use a library implementation for JavaScript https://github.com/grpc/grpc-web

TypeScript support remains an experimental feature of gRPC.

The gRPC-Web protocol supports HTTP/1 and can be used from a browser.

-- grpc-web

gRPC is mainly used in server-to-server communication, but it can also be used in client-to-server communication. gRPC-web is a gRPC implementation for web browsers. It is a JavaScript library that allows you to call gRPC services from a web browser. It supports Unary and Streaming Server API calls.

Since we're using Envoy, there's one more neat trick that we can employ. It turns out that Envoy also support gRPC-Web out of the box, a JavaScript client designed to support gRPC communication from the browser! That means that we can send gRPC messages over HTTP/1.1 as base64 encoded strings or as binary protobufs. Messages will be sent through our proxy and on to our backend service. The advantage of this is smaller and more efficient wire communication which should lead to better performance.

protoc-gen-grpc-web — a plugin that allows our front end to communicate with the backend using gRPC calls. A separate blog post on this coming up in the future.

The Buf CLI is a versatile tool designed for handling Protocol Buffers (Protobuf), a method of serializing structured data. It offers several key features, including managing Protobuf assets through the Buf Schema Registry (BSR), providing a linter to enforce optimal API design and structure, and a breaking change detector to maintain compatibility either in source code or at the wire level. Additionally, the Buf CLI includes a generator that activates plugins based on user-defined templates and a formatter to standardize the formatting of Protobuf files according to industry norms. It also integrates seamlessly with the Buf Schema Registry, supporting comprehensive dependency management.

We'll use the Buf CLI as an alternative to protoc so that we can save our generation configuration as YAML. Buf is compatible with protoc plugins.

Not so much anymore! Take a look at buf.build, it makes the whole thing notoriously easy :)

In my opinion it's a good idea, it's the architecture we use at work, and it works well for us. The main limitation to be aware of is that many PaaS don't support gRPC traffic (because of the proxies used). For example, DigitalOcean App Platform or Heroku if I remember correctly. If the way you want to host your backend is OK with HTTP/2 and gRPC traffic, then it's not a limitation. One way around this limitation is to use the gRPC-Web protocol, or the Connect protocol (https://connect.build/). Unfortunately, Dart's gRPC client does not support the gRPC-Web protocol outside the web platform. So for a mobile application, it's not usable at the moment. (If this PR were accepted, it would solve the issue: https://github.com/grpc/grpc-dart/pull/557.) As for Connect, no client is currently offered by Buf for Dart. Don't hesitate if you want to know more. That said, I'd advise you to use the Connect implementation for Go to implement your backend. Connect will enable your server to speak all three protocols (gRPC, gRPC-Web and Connect), which is very useful in the long term. What's more, the code is cleaner, and you benefit from official support for observability with OpenTelemetry. If you don't know Buf (the creators of Connect),I suggest you visit their website: https://buf.build/. :-) Good luck!

As mentioned in the intro, we are going to use Buf and Connect as our tools. We’ll start by installing the dependencies.

gRPC itself is quite nice, especially with buf which makes generating Go code much easier. The rest of the code was in a bad state. Unmaintained router packages, repository pattern without any actual benefit or a repository pattern.

The second big difference is that we now have auto-generated client and server stubs. For this task, I chose to use buf and the protobuf-ts plugin in order to generate idiomatic Typescript classes and objects. Not only do these classes describe the types we'll use in the server and client, but also includes the actual gRPC implementations used to serialize and send messages back and forth across the wire.

Our team has been using Buf (https://buf.build) recently, and they have a nice solution for schema dependency management.

I've found that https://buf.build/ is easier to use than protoc directly.

Consider checking out https://connect.build from https://buf.build. Supports a simpler protocol than grpc-web. Includes a js/ts client for frontend. Then you don’t necessarily need a rest layer, but could leverage the proxy your building.