Files
continuum-proxy/README.md
T
octoturge 305c41993d Update docs and prune examples superseded by real functionality
README/certs/README/.env.example/printers.example.toml were all still
describing this as a learning-stage stub with no real printer protocol
clients - rewritten to reflect the real Bambu MQTT client, cert
auto-pinning, and marlin serial connection that now exist.

- Remove examples/fetch_bambu_cert.rs: its manual fetch-and-save workflow
  is now what BambuPrinter::connect()'s ensure_trusted does automatically
  on every connect, so it has no remaining use case.
- Fix examples/printer_polymorphism.rs, which no longer compiled -
  dispatch_gcode was replaced by real methods earlier this session;
  swapped in print_status() as the vendor-only-extension example.
- Remove Config::bambu_ca_cert_overrides/bambu_require_valid_cert and the
  .env vars documenting them - confirmed dead (nothing read them),
  fully superseded by printers.toml's per-printer ca_cert_path/
  require_valid_cert plus automatic trust-on-first-connect pinning.
- Fix stale doc comments in printer/mod.rs and printer/bambu.rs that
  described certificate trust and MQTT as not built yet, or referencing
  the now-removed example.

No behavior change in the daemon itself - verified with cargo build
--examples and a live run of printer_polymorphism and auto_connect_bambu
against the real P1P/H2C printers.
2026-09-07 16:17:15 +00:00

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5.0 KiB
Markdown

# 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`).
## What's real right now
- **Bambu MQTT** - a real client for both protocol generations (MQTT
v3.1.1+BambuMQTT v1 on older firmware, MQTT v5+BambuMQTT v2 on current
firmware), auto-detected per printer on connect (a firmware update can
move the same physical printer between them, so this isn't something
config can hard-code once and forget - see `printer/bambu.rs`'s
`BambuProtocolPreference::Auto`). Request/reply correlation via
`sequence_id`, an in-memory `print.push_status` cache that merges v1's
partial updates and replaces on v2's full ones, and TLS trust that
auto-pins a printer's certificate via trust-on-first-connect the first
time the bundled CA doesn't verify (`printer/bambu.rs`'s
`ensure_trusted`) - see `printer/bambu_mqtt.rs`'s doc comment for the
full protocol write-up.
- **Marlin/RepRap serial** - a real held-open serial connection that paces
gcode lines by Marlin's own "ok" acknowledgment (`printer/marlin_serial.rs`).
- **Wire shapes from schemas, not hand duplication** - Bambu's raw MQTT
JSON is built straight from `continuum-schemas`' JSON Schema files via
`continuum-schema-instance`, instead of a second hand-written copy of
every request shape drifting out of sync with the schema.
- **Cloud uplink** - a WebSocket client to `continuum-backend` that
connects, sends a heartbeat on a timer, and reconnects on drop
(`src/uplink/`).
- **go2rtc watchdog** - restarts the camera-restreaming subprocess if it
dies (`src/go2rtc.rs`).
## What's still a stub
PrusaLink (REST) and Klipper/Moonraker (WebSocket) - `printer/prusa.rs`
and `printer/klipper.rs` just `println!` what they'd send. Also not built
yet: dispatching a cloud-issued command to a connected printer (the uplink
and the printer fleet run side by side in `main.rs`, but nothing routes
between them yet), local buffering for telemetry across connectivity gaps,
LAN printer discovery (SSDP/mDNS), and the mechanical plate-changer
interface.
## Getting started
```bash
cp .env.example .env
cargo run # the daemon: connects every configured printer, then runs the cloud uplink + go2rtc watchdog
cp printers.example.toml printers.toml # fill in your real printers (gitignored)
cargo run --example auto_connect_bambu # checks/auto-pins each Bambu printer's certificate, no MQTT needed
cargo run --example test_bambu_certs # narrower: just the raw TLS handshake, no auto-pinning
cargo run --example printer_polymorphism # standalone trait+enum demo, fake data, no network/env needed
cargo run --example bambu_commands_demo # round-trips hand-written structs against real captured Bambu JSON
```
## Structure
```
src/
main.rs Loads+connects the printer fleet, then runs the uplink and 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
go2rtc.rs Restarts the go2rtc camera-restreaming process if it dies
printer/
mod.rs GenericPrinter trait + PrinterBase + PrinterHandle enum - the trait+enum
"inheritance" pattern this project uses instead of class inheritance
bambu.rs The real Bambu printer type: cert trust, protocol version auto-detect, commands
bambu_mqtt.rs The real MQTT wiring underneath bambu.rs - see its doc comment for the protocol details
bambu_commands/ Hand-written serde structs mirroring continuum-schemas' bambulab/ shapes
marlin_serial.rs A real held-open Marlin/RepRap serial connection
prusa.rs, klipper.rs Still stubs - see "What's still a stub" above
examples/
auto_connect_bambu.rs Checks/auto-pins every Bambu printer's certificate (no MQTT)
test_bambu_certs.rs Narrower: just a raw TLS handshake per Bambu printer
printer_polymorphism.rs Standalone trait+enum demo, five fake printers, no network needed
bambu_commands_demo.rs Round-trips bambu_commands' structs against real captured Bambu JSON
```
`printers.toml` (gitignored - copy from `printers.example.toml`) holds real
per-printer connection details: host, access code/API key/serial port
depending on vendor, and - for Bambu - an optional per-printer CA
certificate override (see `certs/README.md`; most printers don't need one,
since `connect()` auto-pins automatically).
## Learning Rust through this repo
`src/printer/mod.rs`'s doc comment is where the "how do I do inheritance
without classes" question lives - trait (shared behavior) + struct
(shared fields) + enum (the closed set of concrete types), instead of
`GenericPrinter -> BambuPrinter/PrusaLinkPrinter/...` class inheritance.
Run `printer_polymorphism` to see it work end to end without needing any
real printer on the network.