continuum-proxy

Edge gateway daemon for the Continuum print farm platform. Runs on a Linux SBC on-site, talks to printers over the LAN, and keeps a connection to the cloud control plane (continuum-backend).

This is a learning-stage boilerplate

This repo is deliberately minimal right now — real printer protocol clients (Bambu MQTT+FTPS, PrusaLink REST, Klipper/Moonraker WebSocket) are not implemented yet. Each vendor is a stub that just prints what it would do (src/printer/bambu.rs, prusa.rs, klipper.rs). The idea is to learn Rust's polymorphism pattern (trait + enum, since Rust has no class inheritance) on something simple before adding real networking on top.

Getting started

cp .env.example .env
cargo run                                  # the daemon: cloud uplink + go2rtc watchdog
cargo run --example printer_polymorphism   # standalone demo, no network/env needed

cp printers.example.toml printers.toml     # fill in your real printers (gitignored)
cargo run --example test_bambu_certs       # real TLS handshake test against each Bambu printer

Structure

src/
  main.rs      Runs the uplink and the go2rtc watchdog side by side
  config.rs    Loads settings from environment variables
  fleet.rs     Loads printers.toml into ready-to-use PrinterHandles
  uplink/      WebSocket client to continuum-backend: connect, heartbeat, reconnect on drop
  printer/     GenericPrinter trait + PrinterBase + PrinterHandle enum + one stub per vendor
  go2rtc.rs    Restarts the go2rtc camera-restreaming process if it dies
examples/
  printer_polymorphism.rs   Runs all five printer stubs through one `connect()` call site
  test_bambu_certs.rs       Loads printers.toml, does a real TLS handshake to each Bambu printer

src/printer/ is where the "inheritance" question lives — see that module's doc comment for the trait+enum pattern this project uses instead of class inheritance, and run printer_polymorphism to see it work.

printers.toml (gitignored — copy from printers.example.toml) holds real per-printer connection details: host, access code, and — since not every Bambu printer trusts the same certificate (see certs/README.md) — an optional per-printer CA override. src/fleet.rs loads it; nothing in main.rs uses it yet, but test_bambu_certs does, as a real (if narrow — just the TLS handshake, no MQTT) way to check a printer's certificate without needing the full MQTT client built yet.

What's not here yet (on purpose)

• Real MQTT/FTPS/HTTP/WebSocket printer clients — src/printer/*.rs has a println! where each of these will go.
• Local SQLite buffering for telemetry across connectivity gaps.
• LAN printer discovery (SSDP/mDNS).
• The mechanical plate-changer interface (serial/GPIO).

Add these back in one at a time as you get comfortable with the Rust underneath them — each is its own small lesson (async I/O, a new crate's API, error handling for a real protocol) rather than something to absorb all at once.