marker VS Protobuf

Check out this, which aims to implement said stable interface!

Hey, I might be able to give some input how I deal with it in [rust-linting](https://github.com/rust-linting/rust-linting). For some context, the project needs to load several dynamic libraries and provide each of them with an abstract syntax tree. Serializing and deserializing the types for every step would most likely be too expensive. That's why I opted for a Rust <-> Rust FFI. There are two parts of this: 1. The loaded libraries needed to accept data from a driver. For this, I generate functions in the library crates which are marked as `extern "C"` and only use FFI safe types. Passing information to the loaded crates then always calls the generated functions, which intern call access a thread local struct instance in the dynamic crate. It's important that the instance implement a specific trait. For the library creation, it seems like magic. 2. Callbacks. The loaded libraries need to pass information back to the driver. For this, I use a struct with function pointers. These are also marked as `extern "C"` and need to only use FFI safe types. The definition of FFI safe, is a bit difficult. Slices, `str`, `Option<>` and most of the rusts STD types don't have a stable layout to the point, that it can change between compilations with the same compiler. Therefore, it's required that each passed type is `#[repr(C)]`. Options are wrapped in an enum, which has `#[repr(C)]`, slices and strings are dismantled into a data pointer and a length. On the receiving and they're reconstructed again. A small warning. I'm not an expert on FFI interfaces. My implementation would probably have some problems with lifetimes, if I'd use a slightly different memory model. So far, this has worked well (Besides the required boilerplate). The project is currently sadly lacking documentation, as it's still under heavy development. If you want, feel free to lock around the code base. The stable types and most of the interface is inside the `linter_api` crate.

protobuf: go get -u google.golang.org/protobuf/proto

It's because they changed the versioning format: https://github.com/protocolbuffers/protobuf/releases?page=5

But I suppose old version still receive bugfixes.

For at least 4 years protobuf has had decent support for self-describing messages (very similar to avro) as well as reflection

https://github.com/protocolbuffers/protobuf/blob/main/src/go...

Xgooglers trying to make do on the cheap will just create a Union of all their messages and include the message def in a self-describing message pattern. Super-sensitive network I/O can elide the message def (empty buffer) and any for RecordIO clone well file compression takes care of the definition.

Definitely useful to be able to dig out old defs but protobuf maintainers have surprisingly added useful features so you don’t have to.

Bonus points tho for extracting the protobuf defs that e.g. Apple bakes into their binaries.

gRPC Gateway is a protoc plugin that reads gRPC service definitions and generates a reverse proxy server that translates a RESTful JSON API into gRPC.

To use more recent versions of protoc in future applications, you can download them from the Protobuf repository.

Use the Protobuf CLI protoc and the plugin protoc-gen-tonic.

> didn’t find any standard for separating protobuf messages

The fact that protobufs are not self-delimiting is an endless source of frustration, but I know of 2 standards:

- SerializeDelimited* is part of the protobuf library: https://github.com/protocolbuffers/protobuf/blob/main/src/go...

- Riegeli is "a file format for storing a sequence of string records, typically serialized protocol buffers. It supports dense compression, fast decoding, seeking, detection and optional skipping of data corruption, filtering of proto message fields for even faster decoding, and parallel encoding": https://github.com/google/riegeli

It looks like it is in fact universal. Just glancing at the code here, it looks like the tool searches any arbitrary file for bytes that look like encoded protobuf descriptors, specifically looking for bytes that are plausibly the beginning of a FileDescriptorProto message defined here:

https://github.com/protocolbuffers/protobuf/blob/main/src/go...

This takes advantage of the fact that such descriptors are commonly compiled into programs that use protobuf. The descriptors are usually embedded as constant byte arrays. That said, not all protobuf implementations embed the descriptors and those that do often have an option to inhibit such embedding (at the expense of losing some dynamic introspection features).