utility-meter: advertise the Homie keys on _ebus._tcp

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to `ebus-sdk` are recorded here. Format follows [Keep a Chan
 
 ## [Unreleased]
 
+### Changed
+
+- `utility-meter` adds `homie_domain`, `homie_version` and `homie_roles` to its `_ebus._tcp` advertisement, from the domain its Homie device publishes under. The `mdns` extra requires `ebus-service-discovery[zeroconf]>=0.5.1`, which added those keys (electrification-bus/python-service-discovery#8).
+
 ## [0.26.0] — 2026-10-09
 
 Adopts [`ebus-service-discovery`](https://github.com/electrification-bus/python-service-discovery) 0.5.0 for mDNS ([#100](https://github.com/electrification-bus/python-sdk/issues/100)); requires ebus-mqtt-client 0.8.0.

examples/README.md

@@ -37,7 +37,7 @@ Add `--discover` to find the broker over mDNS, with [`ebus-service-discovery`](h
 ./utility-meter --config ./utility-meter-cfg.example.json --broker-config /path/to/broker-cfg.json --discover
 ```
 
-With the `mdns` extra installed, the meter also advertises `_ebus._tcp` and `_device-info._tcp` (role `device`; manufacturer, model, serial number and firmware version from the config's `info`), as the eBus framework requires of every entity. `--no-advertise` turns this off. On a host with several network interfaces, see [electrification-bus/python-service-discovery#3](https://github.com/electrification-bus/python-service-discovery/issues/3).
+With the `mdns` extra installed, the meter also advertises `_ebus._tcp` and `_device-info._tcp` (role `device`; manufacturer, model, serial number and firmware version from the config's `info`; `homie_domain`, `homie_version` and `homie_roles` from its Homie device), as the eBus framework requires of every entity. `--no-advertise` turns this off. On a host with several interfaces on one subnet, the advertisement uses one of them and moves to another if that one goes down (ebus-service-discovery's default `interfaces="one-per-subnet"`).
 
 Set a DOE envelope at runtime. The body is a single envelope object or an array of them (the retained schedule); it is set atomically as one `json` value:
 

examples/utility-meter

@@ -463,6 +463,10 @@ class UtilityMeterAdapter:
         if self._homie_device is not None:
             self._homie_device.stop()
 
+    def homie_domain(self) -> str:
+        """The Homie domain the meter publishes under."""
+        return self._homie_device.homie_domain()
+
     @staticmethod
     def load_broker_config(config_file: str) -> Dict[str, Any]:
         with open(config_file, "r") as fp:
@@ -752,8 +756,11 @@ def _discover_broker(mqtt_cfg: Dict[str, Any], timeout: float, log: logging.Logg
     return None
 
 
-def _identity_from_info(device_id: str, info: Dict[str, Any]):
-    """The `_ebus._tcp` / `_device-info._tcp` identity from the meter's `info` config."""
+def _identity_from_info(device_id: str, info: Dict[str, Any], homie_domain: str):
+    """The `_ebus._tcp` / `_device-info._tcp` identity from the meter's `info` config.
+
+    `homie_domain` adds the `homie_domain`, `homie_version` and `homie_roles` TXT keys.
+    """
     from ebus_service_discovery.ebus import Identity
 
     return Identity(
@@ -764,10 +771,11 @@ def _identity_from_info(device_id: str, info: Dict[str, Any]):
         serial_number=str(info.get("serial-number") or device_id),
         fw_version=str(info["firmware-version"]) if info.get("firmware-version") else None,
         device_type=DEVICE_TYPE,
+        homie_domain=homie_domain,
     )
 
 
-def _start_advertiser(device_id: str, info: Dict[str, Any], log: logging.Logger):
+def _start_advertiser(device_id: str, info: Dict[str, Any], homie_domain: str, log: logging.Logger):
     """Advertise `_ebus._tcp` and `_device-info._tcp` (framework.md requirement 6).
 
     Returns the running `mdns.Advertiser`, or None when the `mdns` extra is not
@@ -779,9 +787,7 @@ def _start_advertiser(device_id: str, info: Dict[str, Any], log: logging.Logger)
         log.warning("reason=advertiseSkipped,detail=mdns extra not installed (pip install 'ebus-sdk[mdns]')")
         return None
     try:
-        # Named for the device: on macOS the OS already advertises a
-        # `_device-info._tcp` instance under the host label, the default name.
-        advertiser = mdns.Advertiser(_identity_from_info(device_id, info), instance_name=device_id).start()
+        advertiser = mdns.Advertiser(_identity_from_info(device_id, info, homie_domain)).start()
     except Exception as exc:
         log.warning("reason=advertiseFailed,error=%s", exc)
         return None
@@ -894,7 +900,11 @@ def main():
     )
     start_doe_endpoint(meter, args.doe_port)
     start_tick_thread(meter, args.tick_interval)
-    advertiser = None if args.no_advertise else _start_advertiser(device_id, meter_cfg.get("info", {}), log)
+    advertiser = (
+        None
+        if args.no_advertise
+        else _start_advertiser(device_id, meter_cfg.get("info", {}), adapter.homie_domain(), log)
+    )
 
     log.info(
         "reason=utilityMeterReady,deviceId=%s,deviceType=%s",

pyproject.toml

@@ -72,7 +72,7 @@ dependencies = [
 [project.optional-dependencies]
 # mDNS broker discovery and _ebus._tcp advertising for the examples, through
 # ebus-service-discovery (which brings zeroconf).
-mdns = ["ebus-service-discovery[zeroconf]>=0.5.0"]
+mdns = ["ebus-service-discovery[zeroconf]>=0.5.1"]
 # Optional: JSONSchema validation of `json`-datatype property `$format`. Absent
 # it, the SDK still runs and $format validation is gracefully skipped (with a
 # one-time warning). Kept optional so a constrained build (e.g. Yocto) can omit