protosocket-rpc

For making RPC servers and clients.

This crate provides an rpc-style client and server for protosocket connections. If you have very special requirements, like an ordered response requirement, you might need to use protosocket directly.

• See example-proto for an example of how to use this crate with protocol buffers.
• See example-messagepack for an example of how to use this crate with messagepack.

Main features

• It does as little as it can
  • What you encode is what is on the wire
  • You do not have to spawn if you don't have to
  • You can output messages with zero-copy serialization with zero copies
• It does not require Send
• RPC cancellation
• Response streaming
• Unopinionated about serialization format: You can do RPC with any format you want.

About

You can use whatever encoding you want, but you must provide both an Encoder and a Decoder for your messages. If you use prost, you can use the protosocket-prost crate to provide these implementations. There's also a protosocket-messagepack available, and other encodings are similarly straightforward to add.

Messages must provide a Message implementation, which includes a message_id and a control_code. The message_id is used to correlate requests and responses, while the control_code is used to provide special handling for RPC messages, like cancellation.

This RPC layer is medium-low level wrapper around the low level protosocket crate. You are expected to write a wrapper with the functions that make sense for your application, and use this client as the transport layer.

Clients and servers need to agree about the request and response semantics. While it is supported to have dynamic streaming/unary response types, it is recommended to instead use separate rpc-initiating request messages for streaming and unary responses.

Protosocket rpc lets you choose any encoding and does not wrap your messages at all. The bytes you encode are the bytes which are sent.