Apply Venus OS best practices across all services

- Standardize multilog to s25000 n4 (~100KB cap) to prevent filling /data
- Use VeDbusService register=False + deferred register() in dbus-generator-ramp and dbus-vrm-history
- Add @exit_on_error decorator to template GLib callback
- Document best practices in README and template README

Made-with: Cursor

README.md

@@ -74,6 +74,22 @@ Some projects require API keys or credentials. These are excluded from version c
 - `dbus-windy-station/station_config.example.json` --> `station_config.json`
 - `watermaker/ui/.env.example` --> `.env`
 
+## Venus OS Best Practices
+
+These projects follow guidelines from the [Venus OS wiki](https://github.com/victronenergy/venus/wiki):
+
+**D-Bus Service Registration** -- Create `VeDbusService` with `register=False`, add all paths and populate initial values, then call `register()`. This prevents consumers from querying the service before it is fully initialized ([details](https://github.com/victronenergy/venus/wiki/dbus-api)).
+
+**Mandatory D-Bus Paths** -- Every service must publish: `/Mgmt/ProcessName`, `/Mgmt/ProcessVersion`, `/Mgmt/Connection`, `/DeviceInstance`, `/ProductId`, `/ProductName`, `/FirmwareVersion`, `/Connected`.
+
+**Stability and Exception Handling** -- Don't code too defensively. If something goes wrong, let the process exit cleanly and let daemontools restart it. For `GLib.timeout_add` callbacks in Python, an unhandled exception silently drops the callback without exiting; use `exit_on_error()` from `ve_utils.py` to ensure crashes propagate. Background threads should always set `daemon=True` ([details](https://github.com/victronenergy/venus/wiki/howto-add-a-driver-to-Venus#4-stability---exceptions-handling)).
+
+**Logging** -- Use `multilog t s25000 n4` in `service/log/run` to cap log storage at ~100KB per service (4 files x 25KB). This matches the Victron v2.23 standard and prevents filling the `/data` partition on space-constrained devices.
+
+**Service Directory** -- Symlink services to `/opt/victronenergy/service` (not `/service`, which is a tmpfs overlay). The `install.sh` scripts handle this with fallback logic.
+
+**Persistence** -- Install code under `/data/` so it survives firmware updates. Add an entry in `/data/rc.local` to restore the service symlink after updates.
+
 ## New Project Template
 
 See [`_template/`](_template/) for a skeleton D-Bus service with all the boilerplate: main script, config, daemontools service, install/uninstall scripts, and build packaging.

_template/README.md

@@ -34,6 +34,15 @@ Update these for your service:
 | `/Connected` | int | Connection status (0/1) |
 | `/Settings/Template/Enabled` | int | Enable/disable via settings |
 
+## Venus OS Best Practices
+
+The template follows these [Venus OS wiki](https://github.com/victronenergy/venus/wiki) guidelines:
+
+- **`register=False`** -- `VeDbusService` is created with `register=False`, paths are added, then `register()` is called to prevent race conditions with consumers.
+- **`@exit_on_error`** -- Applied to the `GLib.timeout_add` callback so unhandled exceptions crash the process instead of silently dropping the callback.
+- **`daemon=True`** -- Set on background threads so they don't prevent process exit.
+- **multilog** -- Log size capped at `s25000 n4` (~100KB) to avoid filling the `/data` partition.
+
 ## Checklist
 
 - [ ] Unique service name in `config.py` (`com.victronenergy.yourservice`)
@@ -41,4 +50,6 @@ Update these for your service:
 - [ ] All file references updated in `service/run`, `install.sh`, `build-package.sh`
 - [ ] Custom D-Bus paths added
 - [ ] Settings paths updated
+- [ ] `@exit_on_error` on all `GLib.timeout_add` callbacks
+- [ ] Background threads use `daemon=True`
 - [ ] README replaced with your own documentation

_template/dbus-template.py

@@ -20,6 +20,7 @@ import time
 sys.path.insert(1, os.path.join(os.path.dirname(__file__), 'ext', 'velib_python'))
 
 from vedbus import VeDbusService  # noqa: E402
+from ve_utils import exit_on_error  # noqa: E402
 from settingsdevice import SettingsDevice  # noqa: E402
 import dbus  # noqa: E402
 from gi.repository import GLib  # noqa: E402
@@ -84,6 +85,7 @@ class TemplateService:
         self._running = True
         GLib.timeout_add(MAIN_LOOP_INTERVAL_MS, self._update)
 
+    @exit_on_error
     def _update(self):
         """Called every MAIN_LOOP_INTERVAL_MS. Return True to keep running."""
         if not self._running:

_template/service/log/run

@@ -1,2 +1,2 @@
 #!/bin/sh
-exec multilog t s99999 n8 /var/log/dbus-template
+exec multilog t s25000 n4 /var/log/dbus-template

axiom-nmea/examples/dbus-raymarine-publisher/service/log/run

@@ -1,2 +1,2 @@
 #!/bin/sh
-exec multilog t s99999 n8 /var/log/dbus-raymarine-publisher
+exec multilog t s25000 n4 /var/log/dbus-raymarine-publisher

dbus-generator-ramp/dbus-generator-ramp.py

@@ -157,7 +157,7 @@ class GeneratorRampController:
 
         for attempt in range(max_retries):
             try:
-                self.dbus_service = VeDbusService(SERVICE_NAME, self.bus)
+                self.dbus_service = VeDbusService(SERVICE_NAME, self.bus, register=False)
                 break  # Success
             except dbus.exceptions.NameExistsException:
                 if attempt < max_retries - 1:
@@ -317,6 +317,7 @@ class GeneratorRampController:
                                    onchangecallback=self._on_setting_changed,
                                    gettextcallback=lambda p, v: f"{v} min")
 
+        self.dbus_service.register()
         self.logger.info("D-Bus service created")
     
     def _generator_state_text(self, path, value):

dbus-generator-ramp/service-webui/log/run

@@ -1,2 +1,2 @@
 #!/bin/sh
-exec multilog t s99999 n8 /var/log/dbus-generator-ramp-webui
+exec multilog t s25000 n4 /var/log/dbus-generator-ramp-webui

dbus-generator-ramp/service/log/run

@@ -5,4 +5,4 @@
 # Logs service output using multilog
 #
 
-exec multilog t s99999 n8 /var/log/dbus-generator-ramp
+exec multilog t s25000 n4 /var/log/dbus-generator-ramp

dbus-lightning/service/log/run

@@ -1,2 +1,2 @@
 #!/bin/sh
-exec multilog t s99999 n8 /var/log/dbus-lightning
+exec multilog t s25000 n4 /var/log/dbus-lightning

dbus-meteoblue-forecast/service/log/run

@@ -1,2 +1,2 @@
 #!/bin/sh
-exec multilog t s99999 n8 /var/log/dbus-meteoblue-forecast
+exec multilog t s25000 n4 /var/log/dbus-meteoblue-forecast

dbus-no-foreign-land/service/log/run

@@ -5,4 +5,4 @@
 # Logs service output using multilog
 #
 
-exec multilog t s99999 n8 /var/log/dbus-no-foreign-land
+exec multilog t s25000 n4 /var/log/dbus-no-foreign-land

dbus-tides/service/log/run

@@ -1,2 +1,2 @@
 #!/bin/sh
-exec multilog t s99999 n8 /var/log/dbus-tides
+exec multilog t s25000 n4 /var/log/dbus-tides

dbus-vrm-history/dbus-vrm-history.py

@@ -93,7 +93,7 @@ class VrmHistoryService:
 
         for attempt in range(max_retries):
             try:
-                self.dbus_service = VeDbusService(SERVICE_NAME, self.bus)
+                self.dbus_service = VeDbusService(SERVICE_NAME, self.bus, register=False)
                 break
             except dbus.exceptions.NameExistsException:
                 if attempt < max_retries - 1:
@@ -135,6 +135,9 @@ class VrmHistoryService:
         svc.add_path('/History/GeneratorRuntime', '')
         svc.add_path('/History/BatteryCycles', '')
 
+        # Register service after all paths added (Venus OS best practice)
+        svc.register()
+
     def _setup_settings(self):
         try:
             base = DBUS_CONFIG['settings_path']

dbus-vrm-history/service/log/run

@@ -1,2 +1,2 @@
 #!/bin/sh
-exec multilog t s99999 n8 /var/log/dbus-vrm-history
+exec multilog t s25000 n4 /var/log/dbus-vrm-history

dbus-windy-station/service/log/run

@@ -1,2 +1,2 @@
 #!/bin/sh
-exec multilog t s99999 n8 /var/log/dbus-windy-station
+exec multilog t s25000 n4 /var/log/dbus-windy-station