utility-meter: wait for the configured broker under ebus-service-discovery 0.5.0

CHANGELOG.md

@@ -4,16 +4,16 @@ All notable changes to `ebus-sdk` are recorded here. Format follows [Keep a Chan
 
 ## [Unreleased]
 
-Adopts [`ebus-service-discovery`](https://github.com/electrification-bus/python-service-discovery) 0.4.0 for mDNS ([#100](https://github.com/electrification-bus/python-sdk/issues/100)).
+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)).
 
 ### Added
 
 - `utility-meter` advertises `_ebus._tcp` and `_device-info._tcp` (framework.md requirement 6) with the library's `Advertiser` when the `mdns` extra is installed, from the meter config's `info`, under the device id as the instance name. `--no-advertise` turns it off.
 
 ### Changed
 
-- The `mdns` extra installs `ebus-service-discovery[zeroconf]>=0.4.0` in place of `zeroconf>=0.131.0`. zeroconf still comes with it, as a dependency of that package.
-- `utility-meter --discover` finds the broker with `ebus-service-discovery` (`mdns.browse_many()`, `ebus.rank_brokers()`, `ebus.select_broker()`). A plain (non-TLS) broker config now also accepts `_mqtt._tcp`; a TLS config still accepts only `_secure-mqtt._tcp`. `use_tls` follows the discovered service type, and when the config names a `host`, a discovered broker with that host is preferred among several. The fallback to the config's `host` after `--discover-timeout` seconds is unchanged.
+- The `mdns` extra installs `ebus-service-discovery[zeroconf]>=0.5.0` in place of `zeroconf>=0.131.0`. zeroconf still comes with it, as a dependency of that package.
+- `utility-meter --discover` finds the broker with `ebus-service-discovery` (`mdns.browse_many()`, `ebus.rank_brokers()`, `ebus.match_configured()`). A plain (non-TLS) broker config now also accepts `_mqtt._tcp`; a TLS config still accepts only `_secure-mqtt._tcp`. `use_tls` follows the discovered service type, and when the config names a `host`, only a discovered broker that is that host is used, so another broker never receives the config's credentials. The fallback to the config's `host` after `--discover-timeout` seconds is unchanged.
 - `simple-span-controller` accepts only the `_secure-mqtt._tcp` advertisement whose SRV target is `span-<serial>.local` (it matched a substring of the target before, and also browsed `_mqtt._tcp`), and connects by that host name instead of the first IPv4 address. When this host cannot resolve `.local` names, it connects to the panel's most-preferred advertised address.
 
 ## [0.25.0] — 2026-10-08

examples/README.md

@@ -31,7 +31,7 @@ Publishes a single eBus utility-meter device (`energy.ebus.device.utility-meter`
 
 **Need a broker to run against?** [`broker-quickstart`](https://github.com/electrification-bus/broker-quickstart) brings up a local eBus broker on macOS with one command (`python -m laptop.run`), including the mDNS advertisement that `--discover` (below) resolves. Its `scripts/laptop-bench.sh` runs this simulator against that broker with `--discover`, end to end; see the [laptop quickstart](https://github.com/electrification-bus/broker-quickstart/blob/main/docs/laptop-quickstart.md).
 
-Add `--discover` to find the broker over mDNS, with [`ebus-service-discovery`](https://github.com/electrification-bus/python-service-discovery), instead of using the `host`/`port` in the broker config; the broker config still supplies the TLS material and credentials. A TLS broker config accepts only `_secure-mqtt._tcp`; a plain one accepts `_secure-mqtt._tcp` or `_mqtt._tcp`. When the config also names a `host`, a discovered broker with that host is preferred, and the config's `host` is the fallback after `--discover-timeout` seconds. Needs the `mdns` extra (`pip install 'ebus-sdk[mdns]'`):
+Add `--discover` to find the broker over mDNS, with [`ebus-service-discovery`](https://github.com/electrification-bus/python-service-discovery), instead of using the `host`/`port` in the broker config; the broker config still supplies the TLS material and credentials. A TLS broker config accepts only `_secure-mqtt._tcp`; a plain one accepts `_secure-mqtt._tcp` or `_mqtt._tcp`. When the config also names a `host`, only a discovered broker that is that host is used, so another broker never receives the config's credentials, and the config's `host` is the fallback after `--discover-timeout` seconds. When you know where the broker is, leave out `--discover`. Needs the `mdns` extra (`pip install 'ebus-sdk[mdns]'`):
 
 ```bash
 ./utility-meter --config ./utility-meter-cfg.example.json --broker-config /path/to/broker-cfg.json --discover

examples/utility-meter

@@ -714,17 +714,19 @@ def _discover_broker(mqtt_cfg: Dict[str, Any], timeout: float, log: logging.Logg
     `use_tls` (the host is the advertised `broker` TXT value, the name the
     broker's certificate covers, else the SRV target), or None when no broker
     is found within `timeout` seconds. A TLS config accepts only
-    `_secure-mqtt._tcp`. When the config names a `host`, a discovered broker
-    with that host is preferred among several. Requires the `mdns` extra.
+    `_secure-mqtt._tcp`. When the config names a `host`, only a discovered
+    broker that is that host is used (another broker never receives this
+    config's credentials); otherwise the first ranked broker. Requires the
+    `mdns` extra.
     """
     try:
         from ebus_service_discovery import mdns
         from ebus_service_discovery.ebus import (
             SECURE_MQTT_SERVICE,
             TCP_BROKER_TYPES,
             BrokerEndpoint,
+            match_configured,
             rank_brokers,
-            select_broker,
         )
     except ImportError:
         log.error("discovery needs the 'mdns' extra: pip install 'ebus-sdk[mdns]'")
@@ -740,8 +742,11 @@ def _discover_broker(mqtt_cfg: Dict[str, Any], timeout: float, log: logging.Logg
         while (remaining := deadline - time.monotonic()) > 0:
             found = mdns.browse_many(accept, min(3.0, remaining), zc)
             usable = rank_brokers((BrokerEndpoint.from_instance(i) for i in found), accept=accept)
-            if usable:
-                return select_broker("discovery-with-fallback", configured, usable).mqtt_cfg(mqtt_cfg)
+            chosen = usable[0] if configured is None and usable else None
+            if configured is not None:
+                chosen = match_configured(configured, usable)
+            if chosen is not None:
+                return chosen.mqtt_cfg(mqtt_cfg)
     finally:
         zc.close()
     return None

pyproject.toml

@@ -67,7 +67,7 @@ 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]>=0.4.0"]
+mdns = ["ebus-service-discovery[zeroconf]>=0.5.0"]
 # 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