Skip json.decoder.JSONDecodeError caused by OpenMHz (#79)

signal_scanner_bot/transport.py

@@ -1,5 +1,6 @@
 """Main module."""
 import asyncio
+import json
 import logging
 import subprocess
 from datetime import date, datetime, timedelta
@@ -158,6 +159,11 @@ async def radio_monitor_alert_transport() -> None:
                 f"Sleeping for {env.RADIO_MONITOR_LOOKBACK}s before checking for monitored unit alerts again."
             )
             await asyncio.sleep(env.RADIO_MONITOR_LOOKBACK)
+        except json.decoder.JSONDecodeError:
+            # Sometimes OpenMHz doesn't return properly and the Python json library throws this error.
+            # It is transient and so doesn't really need to panic or throw an exception, so we will
+            # ignore it.
+            pass
         except Exception as err:
             log.exception(err)
             signal.panic(err)