signalk-watch-schedule

A SignalK plugin + webapp for running a crew watch schedule on offshore or overnight passages. The captain defines watch teams and picks a rotation; the plugin tracks whether the boat is on watch, when it started, and shows a clean, color-coded, responsive schedule on any device.

Features

• Watch teams configured in the plugin settings — name each for the watch or the crew standing it.
• Built-in rotation systems: 4-on/4-off, 3-on/3-off, 6-on/6-off, and Royal Navy dog watches.
• Whole-hour starts — the schedule always begins on a clean clock hour, with a start-time picker covering ±12 hours so you can sync a watch that began earlier or schedule one ahead.
• Pick who's first — drag (or nudge with ▲/▼) the watch teams into order; the team on top starts at the chosen time, the rest follow.
• Live, color-coded schedule starting with the active shift, highlighted and counting down.
• Auth-aware UI — anyone can view the schedule; logged-in users get start/stop control.
• Everything published under watch.* so other SignalK consumers can use it too.

How it works

src/core/    Shared, dependency-free schedule logic — the single source of truth.
             Imported unchanged by both the server plugin and the webapp.
index.js     Plugin: holds state, publishes watch.*, exposes the REST API.
webapp/      React + Vite UI, builds into public/.

The core module turns a time-agnostic rotation definition (segments as minute offsets + durations) plus an absolute start time into concrete shifts. The server publishes the inputs (watch.state.*, watch.system, watch.teams) and the webapp re-runs the same core function each second, so the displayed schedule, countdowns, and the server's published watch.schedule can never disagree.

Install

From the SignalK App Store, search for signalk-watch-schedule. Or manually:

cd ~/.signalk/node_modules
git clone https://github.com/hoeken/signalk-watch-schedule.git
cd signalk-watch-schedule && npm install && npm run build:webapp

Then enable the plugin in Server → Plugin Config and open it from Webapps.

Configuration

| Setting | Description | |---|---| | Watch Teams | One entry per watch, in rotation order. Name it for the watch (e.g. Port Watch) or the crew member(s) standing it. | | Default Watch System | Rotation pre-selected when starting a watch. | | Start-time rounding | How the start snaps to the hour: nearest / up / down. | | Shifts to publish | How many upcoming shifts to publish and show. |

Only systems whose required team count fits your configured teams are offered (e.g. a three-team rotation appears once you have three teams).

SignalK paths

| Path | Description | |---|---| | watch.state.onWatch | Watch active flag. | | watch.state.startedAt | Epoch ms the watch began (whole hour). | | watch.state.systemId | Active rotation id. | | watch.system | Full active system definition. | | watch.teams | Configured watch teams, in rotation order. | | watch.current / watch.next | Active and upcoming shift. | | watch.schedule | Ordered upcoming shifts, current first. |

REST API

Base: /plugins/signalk-watch-schedule/api

| Method | Path | Auth | Description | |---|---|---|---| | GET | /state | read | Current state + resolved schedule. | | GET | /config | read | Teams + defaults. | | GET | /systems | read | Available watch systems. | | POST | /watch/start | write | Body { systemId, startAt?, teamOrder? }. startAt (epoch ms) snaps to the hour and defaults to now; teamOrder is a permutation of team indices putting one team first. | | POST | /watch/stop | write | Stops the watch. |

Write endpoints require an authenticated SignalK user when server security is enabled.

Development

npm install
npm test                 # core + server unit tests (node:test)
npm run dev:webapp       # Vite dev server, proxies to SignalK on :3000
npm run build:webapp     # build the UI into public/

The dev server proxies /plugins, /skServer, and /signalk (incl. WebSocket) to a SignalK server on localhost:3000.

License

Apache-2.0 © Zach Hoeken