pea2pea

pea2pea is a simple, low-level, and customizable implementation of a TCP P2P node.

The core library only provides the most basic functionalities like starting, ending and maintaining connections; the rest is up to a few low-level, opt-in protocols:

• Handshake requires connections to adhere to the given handshake logic before anything else can be done with them
• Reading enables the node to receive messages based on the user-supplied Decoder
• Writing enables the node to send messages based on the user-supplied Encoder
• OnDisconnect makes the node perform specified actions whenever a connection with a peer is severed
• OnConnect makes the node perform specified actions whenever a connection with a peer is fully established (post-handshake)

goals

• small, simple, non-framework codebase: the entire library is ~1k LOC and there are few dependencies
• ease of use: few objects and traits, no "turboeels" or generics/references that would force all parent objects to adapt
• correctness: builds with stable Rust, there is no unsafe code, there's more code in tests than in the actual library
• low-level: the user has full control over all connections and every byte sent or received
• good performance: over 10GB/s in favorable scenarios, small memory footprint

how to use it

1. define a clonable struct containing a Node and any extra state you'd like to carry alongside it
2. implement the trivial Pea2Pea trait for it
3. make it implement any/all of the protocols
4. create that struct (or as many of them as you like)
5. enable the protocols you'd like them to utilize

That's it!

examples

• including noise encryption, simple interop with libp2p, or TLS connections

status

• all the desired functionalities are complete
• the crate follows semver, and some API breakage is still possible before 1.0
• the project is actively developed, with all changes being recorded in the CHANGELOG
• some of the desired features that are not yet available in Rust include associated type defaults
• the project aims to always build with the current stable Rust compiler; legacy version support is not a goal, but they might also work