# 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

```bash
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.