Gossipsub Interoperability: py-libp2p ↔ go-libp2p

Description

We need to ensure that the py-libp2p Gossipsub implementation can interoperate seamlessly with other libp2p implementations, starting with go-libp2p.

This will help us verify that:

• ✅ Message propagation works consistently
• ✅ Topic subscription is aligned across stacks
• ✅ Peer scoring and mesh formation behave as expected
• ✅ Protocol negotiation correctly follows the spec

Achieving this will build confidence that py-libp2p nodes can participate in heterogeneous libp2p networks.

Motivation

• Real-world networks are multi-language. Interoperability ensures py-libp2p nodes can join production libp2p swarms alongside go, js, and rust implementations.
• go-libp2p is the reference implementation. Compatibility here gives us a solid foundation.
• Future-proofing. This work lays the groundwork for supporting GossipSub 1.2 / 2.0 and strengthens cross-stack testing coverage.
• Ecosystem growth. Developers can confidently build applications with mixed libp2p stacks.

Current Implementation Plan

1. Minimal Interop Test Environment

• Run one py-libp2p Gossipsub node
• Run one go-libp2p Gossipsub node
• Establish a connection and exchange messages across a shared topic

2. Protocol Negotiation

• Confirm py-libp2p correctly negotiates /meshsub/1.1.0 (or later) with go-libp2p

3. Message Propagation & Subscription Validation

• Ensure py-libp2p nodes can subscribe, publish, and receive messages from go-libp2p nodes
• Verify peer discovery and mesh formation across both stacks

4. Cross-Implementation Testing Framework

• Add automated interop tests that can later be extended to js-libp2p and rust-libp2p
• Consider adding CI jobs that spin up minimal multi-language clusters

5. Documentation & Reporting

• Write clear instructions for running interop tests locally
• Track and document any inconsistencies in protocol behavior or message handling

Next Steps

• Kick off the initial py-libp2p ↔ go-libp2p interop test
• Collect findings and fix any compatibility issues
• Expand coverage to js-libp2p and rust-libp2p after baseline validation
• Add test artifacts (scripts, Docker configs, logs) for reproducibility

Are you planning to do it yourself in a pull request?

Maybe. Open to collaboration and contributions from others who want to join this effort.

No files or existing tests are identified. Begin with the proposed minimal py-libp2p and go-libp2p environment, then verify protocol negotiation, shared-topic subscription, publishing, receiving, peer discovery, and mesh formation. Done requires reproducible automated interop tests, CI coverage if feasible, and documented setup and findings.