svc-core/README.md

---
type: reference
---
# Core services

Part of **Project Yukart**, making an old 2008 Mitsubishi Z27AG a bit smarter with modern technologies.  
This file serves as the minimalist portal to other docs


## What this repo is about

The acquisition and processing cluster on the Orin, developed and deployed as one
unit: `recorder`, `decoder`, `orin-status` and `obd-poller` now; `can-bridge` and `gnss` as they are
needed.

| Binary | Installed as | Does |
|---|---|---|
| `recorder` | `yukart-recorder.service` | Raw CAN + GNSS to disk, in sessions, under a storage bound; OBD-II values from the bus beside them |
| `decoder` | `yukart-decoder.service` | The car's own broadcast frames to named signals (`yukart/vehicle/*`): every `z27ag` signal in contracts' `signals.json`, laid out by its `can` block. Booleans on change, numbers ≤ 20/s, each refreshed once a second; reads only |
| `bus-bench` | not installed: a test tool | Raw CAN and decoded-signal load over MQTT, measured: loss, latency, broker CPU ([report](docs/impl/reports/BUS-BENCH.md)) |
| `obd-poller` | `yukart-obd-poller.service` | OBD-II mode 01 polling, the single CAN writer; **disabled**, the Z27AG has no OBD-II on CAN: speed, throttle, load, MAP, MAF ~10 Hz; temperatures and fuel 1 Hz (`yukart/vehicle/*`) |
| `orin-status` | `yukart-orin-status.service` | The Orin's health on the bus, once a second: temperatures, CPU/GPU load, memory, power, fan, WiFi (with SSID)/LTE/tablet links, the CAN interface, UPS battery (`yukart/host/*`) |

```bash
scripts/deploy-recorder.sh                 # build, glibc check, install on the car Orin
scripts/deploy-orin-status.sh              # build on the development Orin, glibc check, install
scripts/deploy-decoder.sh                  # same, for the decoder (after any signals.json change)
yukart-decoder --list                      # the signals it decodes, and where
zstdcat can-*.log.zst | yukart-decoder --replay   # what it would publish for a recording
scripts/deploy-obd-poller.sh               # build, glibc check, install on the car Orin
yukart-obd-poller --once                   # on the Orin, service stopped: what the ECU answers
yukart-orin-status --once                  # on an Orin: one reading as JSON, no broker
yukart-recorder ctl status                 # on the Orin
yukart-recorder ctl start "cold start"     # manual session, ends only on stop
yukart-recorder ctl mark "indicator left on"
yukart-recorder ctl stop
```

Recordings live in `/var/lib/yukart/recordings/`, one directory per session —
layout in [the initial plan](docs/impl/plans/INITIAL.md#session-layout).

- For implementation practice guidelines, refer to the [guidelines](docs/GUIDELINES.md);  
- For implementation plans and history, refer to [them](docs/impl/);