fix(meshtastic): daemon survives an unreachable MQTT broker at startup (ref #897)

Deploy found a crash-loop: the shipped default config has [shared_grid] set, but
the opt-in mosquitto is not running, so Bridge.start()/the paho adapter's
synchronous connect() raised ConnectionRefusedError and killed the daemon.
Bridge.start() now skips an unreachable broker (log + continue); the paho adapter
uses connect_async + loop_start (non-blocking, auto-reconnect). +regression test.

Co-Authored-By: Gerald KERMA <devel@cybermind.fr>

packages/secubox-meshtastic/api/bridge.py

@@ -3,11 +3,14 @@
 """SecuBox-Deb :: meshtastic — host-side serial↔MQTT bridge (grid-policy driven)."""
 from __future__ import annotations
 import json
+import logging
 from typing import Callable
 from .config import Config
 from .gridpolicy import targets_for
 from .model import Packet
 
+_log = logging.getLogger("secubox.meshtastic.bridge")
+
 
 class Bridge:
     def __init__(self, cfg: Config, mqtt_factory: Callable[[str], object]) -> None:
@@ -25,7 +28,15 @@ class Bridge:
             except ValueError:
                 port_num = 1883
             cli = self._factory(tgt)
-            cli.connect(host, port_num)
+            try:
+                cli.connect(host, port_num)
+            except Exception as exc:
+                # A configured broker that is DOWN at startup (e.g. the opt-in
+                # private mosquitto not yet running) must NOT crash the daemon —
+                # skip this target; it can be reconnected when the broker is up.
+                _log.warning("bridge: %s broker %s:%s unreachable at start (%s); skipping",
+                             tgt, host, port_num, exc)
+                continue
             self._clients[tgt] = cli
 
     def publish(self, channel_name: str, p: Packet) -> None:

packages/secubox-meshtastic/api/daemon.py

@@ -70,7 +70,10 @@ class _PahoAdapter:
         self._client = client
 
     def connect(self, host: str, port: int) -> None:
-        self._client.connect(host, port)
+        # connect_async (not connect): a broker that is DOWN at startup must not
+        # raise/crash the daemon — loop_start's background thread establishes and
+        # auto-reconnects the connection when the broker becomes reachable.
+        self._client.connect_async(host, port)
         self._client.loop_start()
 
     def publish(self, topic: str, payload: str) -> None:

packages/secubox-meshtastic/debian/changelog

@@ -1,3 +1,14 @@
+secubox-meshtastic (0.1.1-1~bookworm1) bookworm; urgency=medium
+
+  * Fix daemon crash-loop when a configured MQTT broker is down at startup
+    (deploy #897): the opt-in private mosquitto is not running by default, and
+    Bridge.start() / the paho adapter's synchronous connect() raised
+    ConnectionRefusedError → the daemon died. Bridge.start() now skips an
+    unreachable broker (logs + continues), and the paho adapter uses
+    connect_async + loop_start (non-blocking, auto-reconnect).
+
+ -- Gerald KERMA <devel@cybermind.fr>  Tue, 22 Jul 2026 12:30:00 +0200
+
 secubox-meshtastic (0.1.0-1~bookworm1) bookworm; urgency=medium
 
   * Initial release: multi-grid Meshtastic LoRa node integration (ref #897).

packages/secubox-meshtastic/tests/test_bridge.py

@@ -36,3 +36,17 @@ def test_on_channel_publishes_only_when_enabled():
     made={}
     b=Bridge(_cfg(["off","on"], on=True), lambda k: made.setdefault(k, FakeMqtt())); b.start(); b.publish("fam", _p())
     assert "on" in made and made["on"].conn==("mqtt.x.org",8883)
+
+
+class RefusingMqtt(FakeMqtt):
+    def connect(self, host, port):
+        raise ConnectionRefusedError("broker down")
+
+
+def test_start_tolerates_unreachable_broker():
+    # A configured broker that is DOWN at startup must not crash Bridge.start()
+    # (the daemon's #897 deploy bug: opt-in mosquitto not running).
+    from api.bridge import Bridge
+    b = Bridge(_cfg(["off", "shared"]), lambda k: RefusingMqtt())
+    b.start()                          # must not raise
+    b.publish("fam", _p())             # no client registered → no-op, no crash