[jasperchan]

Fixes #47 (the "subscription never retries" half; the logger half overlaps with #48, happy to rebase on it if that lands first).

Problem

subscribe_mqtt runs a single aiomqtt.Client session. Any MqttError is logged and the task simply ends, and nothing re-establishes the subscription until schedule_reauthorization fires (~2 h 55 min later) or the user reloads the config entry. In the meantime Home Assistant silently stops receiving activity_state pushes (entities look available but freeze) and every command raises after the 30 s wait in send_command.

Seen today on HA 2026.10.4 / python-snoo 0.8.3: one MQTT connection for <serial> failed: Disconnected during message iteration at 13:31 and then total silence until a manual reload at 13:44. The code path is unchanged in 0.11.0.

Change

• subscribe_mqtt now loops. Each attempt runs one session (_run_mqtt_session); a connect failure or a dropped connection is retried with exponential backoff (1 s → 300 s), and the backoff resets once a connection has stayed up for 60 s.
• Each attempt reads the current tokens.aws_id, so a token refreshed by schedule_reauthorization is used on the next connect. Cancellation (from disconnect / the refresh path) still ends the task as before.
• _client_map bookkeeping is unchanged in spirit: the entry is removed whenever the session ends and re-added on reconnect, so send_command waits for a live client instead of publishing into a dead one.
• A failing callback or an unparsable payload is logged instead of tearing the connection down.
• Lifecycle logging goes through the module logger (python_snoo.snoo) instead of the root logger, so logger: python_snoo: debug in HA actually shows it.

Tests

Added tests/test_mqtt_reconnect.py with a scripted fake aiomqtt.Client covering: connect failure then success, mid-stream disconnect, _client_map state across a drop, cancellation stopping the loop, and a refreshed token being picked up by the next attempt. pytest and pre-commit run --all-files pass locally.

https://claude.ai/code/session_01Kjt2zjjJbbcYXsbXpzBUQk