Files
continuum-proxy/README.md
T
octoturgeandClaude Opus 5 d25614b313 Route telemetry up and commands down over the cloud uplink
The proxy did not actually proxy. `fleet` was loaded and connected in
main.rs and then never touched again, while the uplink said hello and sent
heartbeats into the void - two halves of the program running side by side
with nothing between them. Both directions are wired now.

Up: every 5s, one vendor-neutral `PrinterTelemetry` snapshot per printer
that has reported, batched into a single `Telemetry` message. The snapshot
is a translation rather than a forwarded `print.push_status`, because it
has to describe a Prusa too, and because Bambu's wire format has traps
(0-15 fan gears, ints-or-floats temperatures) that should not reach the
rest of the system.

Down: a `Command` is looked up by our own printer id, executed, and
answered with a `CommandResult`. `PrinterCommand` is deliberately small and
deliberately has no "start a print" variant - `start_uploaded_file` has
never been run against hardware, and the first thing to exercise it should
be a human watching the machine, not a message from the internet.

The fleet becomes `Arc<Mutex<Vec<PrinterHandle>>>` so main and the uplink
can share it. One lock for the whole Vec is coarse - a slow command to one
printer stalls telemetry for all of them - which is fine at a handful of
printers and is the shape to revisit (a lock per printer, or an actor task
each) before a farm gets large.

Two things found by running this against the live P1P and H2C:

- A v1 Bambu reached the cloud as a row of nulls with one real bed
  temperature in it, while the v2 H2C beside it was fully populated. v1
  only sends a *complete* status when asked, and `pushall`'s own doc
  comment said to call it periodically - nothing ever did. Each telemetry
  tick now collects, then requests the next refresh, so v1 telemetry runs
  one tick behind instead of staying stuck on fragments. The quirk lives in
  `PrinterHandle::refresh_status` so the uplink does not have to know it.
- The third instance of the silent-swallow parse bug, at the old
  uplink/mod.rs:63: `if let Ok(server_msg) = serde_json::from_str(..)` with
  no else. Same shape that hid broken `print.push_status` parsing for
  weeks, except here it would mean commands vanishing with the cloud never
  being told. Now a `match` with a loud `Err` arm.

Verified end to end against both printers with a throwaway WebSocket
server: H2C `RUNNING 88% layer 48/50 13min nozzle 230/230 bed 35/35`, P1P
`IDLE 0% nozzle 23.5/0 bed 22.5/0`, both fan commands `ok=true`, zero
warnings over 24s.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-10-03 10:22:22 +00:00

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7.1 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`).
- **Bambu file upload** - implicit FTPS (port 990) into the printer's own
`cache/` directory (`src/printer/bambu_ftps.rs`, via
`BambuPrinter::upload_file`). **Confirmed live against a P1P on
2026-10-03**: login, binary mode, and the transfer all work, byte count
matched exactly.
- **Print status** - `print.push_status` parsed into `PrintReport` with real
job progress, temperatures, fans and HMS entries. Confirmed live on both
generations (idle P1P on v1, H2C 20% into a job on v2); regression
fixtures from those captures are in `tests/fixtures/`.
## Examples worth knowing
- `cargo run --example live_reports [printer-id]` - **read-only**, safe
against a printer that is mid-print. Connects, reports firmware, and
watches the status stream. Redirect stderr to capture raw payloads.
- `cargo run --example bambu_idle_checks -- <printer-id>` - **writes**
(FTPS upload, fan speed). Requires an explicit printer id and refuses to
run unless that printer reports `gcode_state: "IDLE"`.
## What routes between the cloud and the printers
The uplink and the printer fleet are wired together, in both directions
(`uplink/mod.rs`):
- **Up:** every 5s, one `PrinterTelemetry` snapshot per printer that has
reported, batched into a single `Telemetry` message. Verified live against
a P1P and an H2C.
- **Down:** a `Command` from the cloud is looked up by our own printer id,
executed, and answered with a `CommandResult`. The set of commands is
deliberately small - a fan speed and a single gcode line - and deliberately
has no "start a print" variant; see `PrinterCommand`.
One quirk worth knowing: a Bambu on protocol v1 only sends a *complete*
status when asked, so each telemetry tick also fires a `pushing.pushall` for
the next one. A v1 printer's telemetry is therefore one tick behind, which
is why it shows up on the second frame rather than the first.
## What's still a stub
`start_uploaded_file` - the MQTT command that actually *starts* a print from
an uploaded file - is written but has deliberately never been fired, since
that commits a machine to hours of work. Its doc comment lists the three
details to confirm on the first real attempt. `upload_file` is proven, but
only with a small text file, not a multi-megabyte sliced `.3mf`.
PrusaLink (REST) and Klipper/Moonraker (WebSocket) - `printer/prusa.rs`
and `printer/klipper.rs` just `println!` what they'd send. Also not built
yet: local buffering for telemetry across connectivity gaps (so telemetry
produced while the uplink is down is simply lost), 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.