Release 2.1.1

core/cleanup.py

@@ -34,6 +34,10 @@ class CleanupTimer:
         """Stop any threads and prepare for application shutdown"""
 
         self._stop_event.set()
+        if self._thread:
+            self._thread.join(timeout=15)
+            if self._thread.is_alive():
+                logger.warning("Cleanup worker thread did not exit on time and will be killed.")
 
     def _run(self):
         while not self._stop_event.wait(timeout=self._cleanup_interval):

core/constants.py

@@ -4,7 +4,7 @@ from data.band import Band
 from data.sig import SIG
 
 # General software
-SOFTWARE_VERSION = "2.1-pre"
+SOFTWARE_VERSION = "2.1.1"
 
 # HTTP headers used for spot providers that use HTTP
 HTTP_HEADERS = {"User-Agent": f"Spothole v{SOFTWARE_VERSION} (operated by {SERVER_OWNER_CALLSIGN})"}
@@ -263,6 +263,16 @@ SIGS = [
         region_flag="🇮🇪",
         refs_globally_unique=False,
     ),
+    SIG(
+        name="DMF",
+        comment_names=["DMF"],
+        description="Diplôme des Moulins de France",
+        sig_type=SIGType.REGIONAL,
+        ref_type=SIGRefType.MILL,
+        icon="fa-fan",
+        region_flag="🇫🇷",
+        refs_globally_unique=False,
+    ),
     SIG(
         name="DME",
         comment_names=["DME"],

core/data_providers.py

@@ -1,5 +1,6 @@
 import logging
 import threading
+import time
 
 from core.config import config, create_provider_from_config
 
@@ -16,6 +17,7 @@ class DataProviders:
         self.static_data_providers = []
         self.sig_ref_data_providers = []
         self.callsign_data_providers = []
+        self._startup_timers = []
 
     def setup(self):
         for entry in config["spot_providers"]:
@@ -43,41 +45,58 @@ class DataProviders:
     def start(self):
         # Start data providers before spot/alert providers so the lookup data is there already for incoming spots.
         # Each category is fired off after a small delay to give the rest of Spothole chance to start up.
-        threading.Timer(5.0, lambda: self.start_providers(self.static_data_providers, "static data")).start()
+        self._startup_timers = [
-        threading.Timer(
+            threading.Timer(5.0, lambda: self.start_providers(self.static_data_providers, "static data")),
-            10.0,
+            threading.Timer(10.0, lambda: self.start_providers(self.callsign_data_providers, "callsign data")),
-            lambda: self.start_providers(self.callsign_data_providers, "callsign data"),
+            threading.Timer(15.0, lambda: self.start_providers(self.spot_providers, "spot")),
-        ).start()
+            threading.Timer(20.0, lambda: self.start_providers(self.alert_providers, "alert")),
-        threading.Timer(15.0, lambda: self.start_providers(self.spot_providers, "spot")).start()
-        threading.Timer(20.0, lambda: self.start_providers(self.alert_providers, "alert")).start()
             threading.Timer(
                 25.0,
                 lambda: self.start_providers(self.solar_condition_providers, "solar condition"),
-        ).start()
+            ),
-        threading.Timer(
+            threading.Timer(30.0, lambda: self.start_providers(self.sig_ref_data_providers, "SIG ref data")),
-            30.0,
+        ]
-            lambda: self.start_providers(self.sig_ref_data_providers, "SIG ref data"),
+        for t in self._startup_timers:
-        ).start()
+            t.daemon = True
+            t.start()
 
     def stop(self):
-        for sp in self.spot_providers:
+        # Cancel any startup timers that haven't fired yet
-            if sp.enabled:
+        for t in self._startup_timers:
-                sp.stop()
+            t.cancel()
-        for ap in self.alert_providers:
+
-            if ap.enabled:
+        # Stop all providers
-                ap.stop()
+        all_providers = [
-        for scp in self.solar_condition_providers:
+            p
-            if scp.enabled:
+            for p in (
-                scp.stop()
+                self.spot_providers
-        for srdp in self.sig_ref_data_providers:
+                + self.alert_providers
-            if srdp.enabled:
+                + self.solar_condition_providers
-                srdp.stop()
+                + self.sig_ref_data_providers
-        for sdp in self.static_data_providers:
+                + self.static_data_providers
-            if sdp.enabled:
+                + self.callsign_data_providers
-                sdp.stop()
+            )
-        for cdp in self.callsign_data_providers:
+            if p.enabled
-            if cdp.enabled:
+        ]
-                cdp.stop()
+        if not all_providers:
+            return
+
+        def stop_provider(p):
+            try:
+                p.stop()
+            except Exception:
+                logger.exception("Exception stopping provider")
+
+        threads = [threading.Thread(target=stop_provider, args=(p,), daemon=True) for p in all_providers]
+        for t in threads:
+            t.start()
+
+        deadline = time.monotonic() + 40
+        for t in threads:
+            t.join(timeout=max(0.0, deadline - time.monotonic()))
+        still_running = [t for t in threads if t.is_alive()]
+        if still_running:
+            logger.warning("Some threads did not stop in time!")
 
 
 # Global object

core/data_store.py

@@ -106,6 +106,7 @@ class DataStore:
         and testing the callsign every time is expensive. So instead we build a separate in-memory lookup of compiled
         regex against DXCC entity code, as a list of tuples we can iterate through."""
 
+        self.dxcc_lookup_by_call_regex = []
         for entry in [DATA_STORE.dxcc_data[key] for key in DATA_STORE.dxcc_data]:
             self.dxcc_lookup_by_call_regex.append((re.compile(entry["prefixRegex"]), entry["entityCode"]))
 

core/live_data_cache.py

@@ -22,6 +22,8 @@ class LiveDataCache:
         self._listeners_lock = threading.Lock()
         self._snapshot_dir = snapshot_dir
         self._disk_cache = diskcache.Cache(str(snapshot_dir))
+        self._stop_event = threading.Event()
+        self._snapshot_thread = None
         self._load_snapshot()
         self._start_periodic_snapshot(snapshot_interval_sec)
 
@@ -89,13 +91,19 @@ class LiveDataCache:
 
     def _start_periodic_snapshot(self, interval):
         def loop():
-            while True:
+            while not self._stop_event.wait(timeout=interval):
-                time.sleep(interval)
                 self.save_snapshot()
 
-        t = threading.Thread(target=loop, name=f"LiveDataCache-Snapshot-{self._snapshot_dir}")
+        self._snapshot_thread = threading.Thread(
-        t.start()
+            target=loop, name=f"LiveDataCache-Snapshot-{self._snapshot_dir}", daemon=True
+        )
+        self._snapshot_thread.start()
 
     def close(self):
+        self._stop_event.set()
+        if self._snapshot_thread:
+            self._snapshot_thread.join(timeout=15)
+            if self._snapshot_thread.is_alive():
+                logger.warning(f"LiveDataCache snapshot thread for {self._snapshot_dir} did not exit on time.")
         self.save_snapshot()
         self._disk_cache.close()

core/sig_lookup_helper.py

@@ -24,7 +24,7 @@ def get_sig_ref_info(sig_name, ref_id):
 
     # Sometimes we allow spaces instead of dashes in references due to common usage that way, but official reference
     # lists never do, so convert them here.
-    ref_id.replace(" ", "-")
+    ref_id = ref_id.replace(" ", "-")
 
     # Prepare the object to be returned
     sig_ref = SIGRef(sig=sig_name, id=ref_id)
@@ -114,17 +114,24 @@ def get_sig_ref_info(sig_name, ref_id):
         # OK, this is something we have to look up. Now check to see if our data store contains reference data and if
         # so, copy the data into the sig_ref object
         key = f"{sig_name}:{ref_id}"
+        try:
             lookup_data = DATA_STORE.sigrefs.get(key) if key in DATA_STORE.sigrefs else None
             if lookup_data:
-            for key, value in lookup_data.__dict__.items():
+                for attr, value in lookup_data.__dict__.items():
-                if value is not None and sig_ref.__dict__.get(key) is None:
+                    if value is not None and sig_ref.__dict__.get(attr) is None:
-                    sig_ref.__dict__[key] = value
+                        sig_ref.__dict__[attr] = value
 
             else:
                 # Maybe a super new reference we don't know about yet, but more likely a typo or a test reference,
                 # just silently ignore it.
                 logger.debug(f"{sig_name} database did not contain data for ref {ref_id}")
 
+        except (ValueError, KeyError):
+            # Catch exceptions due to e.g. old versions of objects in the cache that are no longer compatible,
+            # and remove them from the cache.
+            del DATA_STORE.sigrefs[key]
+            return None
+
     except Exception:
         logger.exception(f"Exception when looking up sig_ref info for {sig_name} ref {ref_id}")
     return sig_ref

core/status_reporter.py

@@ -1,3 +1,4 @@
+import logging
 import os
 from datetime import datetime
 from threading import Event, Thread
@@ -14,6 +15,8 @@ from core.prometheus_metrics_handler import alerts_gauge, memory_use_gauge, spot
 from telnetserver.telnetserver import TELNET_SERVER
 from webserver.webserver import WEB_SERVER
 
+logger = logging.getLogger(__name__)
+
 
 class StatusReporter:
     """Provides a timed update of the application's status data."""
@@ -33,13 +36,17 @@ class StatusReporter:
     def start(self):
         """Start the reporter thread"""
 
-        self._thread = Thread(target=self._run, name="StatusReporter")
+        self._thread = Thread(target=self._run, name="StatusReporter", daemon=True)
         self._thread.start()
 
     def stop(self):
         """Stop any threads and prepare for application shutdown"""
 
         self._stop_event.set()
+        if self._thread:
+            self._thread.join(timeout=15)
+            if self._thread.is_alive():
+                logger.warning("Status reporter worker thread did not exit on time and will be killed.")
 
     def _run(self):
         """Thread entry point: report immediately on startup, then on each interval until stopped"""

core/url_data_cache.py

@@ -14,14 +14,13 @@ class URLDataCache(CachedSession):
     used across multiple threads, though note that URL lookups will block each other this way, so it is still better to
     create one of these objects per thread if possible."""
 
-    _lock = threading.Lock()
-
     def __init__(self, name):
         super().__init__(
             f"{CACHE_DIR}urls/{name}",
             expire_after=timedelta(days=1),
             allowable_codes=(200, 400, 401, 403, 404),
         )
+        self._lock = threading.Lock()
 
     def get(self, *args, **kwargs):
         with self._lock:

data/alert.py

@@ -158,7 +158,7 @@ class Alert:
                 self.icon = "fa-globe-africa"
             elif self.alert_type == AlertType.CONTEST:
                 self.icon = "fa-trophy"
-            elif self.alert_type == AlertType.CONTEST:
+            elif self.alert_type == AlertType.SATELLITE:
                 self.icon = "fa-satellite"
             elif self.sig_refs and self.sig_refs[0].icon:
                 self.icon = self.sig_refs[0].icon

data/spot.py

@@ -12,6 +12,7 @@ from pyhamtools.locator import latlong_to_locator, locator_to_latlong
 from core.call_lookup_helper import get_call_info
 from core.config import MAX_SPOT_AGE
 from core.constants import PROPAGATION_MODES, SIGS
+from core.data_store import DATA_STORE
 from core.enums import Continent, LocationSourceForSpot, Mode, ModeSource, ModeType
 from core.geo_utils import lat_lon_to_cq_zone, lat_lon_to_itu_zone
 from core.sig_lookup_helper import populate_missing_sig_ref_info
@@ -363,10 +364,12 @@ class Spot:
             if self.propagation_mode == "Satellite":
                 if not self.sig:
                     self.sig = "AMSAT"
+                if not any(sig_ref.sig == "AMSAT" for sig_ref in self.sig_refs):
                     self.sig_refs.append(SIGRef(sig="AMSAT"))
             if self.propagation_mode == "Earth-Moon-Earth":
                 if not self.sig:
                     self.sig = "EME"
+                if not any(sig_ref.sig == "EME" for sig_ref in self.sig_refs):
                     self.sig_refs.append(SIGRef(sig="EME"))
 
             # Parse "de_grid -> dx_grid" structures from the comment
@@ -445,6 +448,15 @@ class Spot:
                 elif self.dx_call:
                     self.dx_itu_zone = dx_call_info.itu_zone
 
+            # DXCC lookup from callsign if nothing else has provided it
+            if self.dx_call and not self.dx_dxcc_id:
+                for regex, entity_code in DATA_STORE.dxcc_lookup_by_call_regex:
+                    if regex.pattern and regex.match(self.dx_call):
+                        self.dx_dxcc_id = entity_code
+                        break
+            if self.dx_dxcc_id and not self.dx_flag:
+                self.dx_flag = get_flag_for_dxcc(self.dx_dxcc_id)
+
             # DX Location is "good" if it is from a spot, or from QRZ if the callsign doesn't contain a slash, so the operator
             # is likely at home.
             self.dx_location_good = bool(

providers/alert/http_alert_provider.py

@@ -27,11 +27,15 @@ class HTTPAlertProvider(AlertProvider):
         # Fire off the polling thread. It will poll immediately on startup, then sleep for poll_interval between
         # subsequent polls, so start() returns immediately and the application can continue starting.
         logger.info(f"Set up query of {self.name} alert API every {self._poll_interval!s} seconds.")
-        self._thread = Thread(target=self._run, name=f"HTTPAlertProvider-{self.name}")
+        self._thread = Thread(target=self._run, name=f"HTTPAlertProvider-{self.name}", daemon=True)
         self._thread.start()
 
     def stop(self):
         self._stop_event.set()
+        if self._thread:
+            self._thread.join(timeout=35)
+            if self._thread.is_alive():
+                logger.warning(f"{self.name} alert worker thread did not exit on time and will be killed.")
 
     def _run(self):
         while True:

providers/callsigndata/callsign_data_provider.py

@@ -42,7 +42,13 @@ class CallsignDataProvider:
 
         if self.enabled:
             if callsign in self._storage:
+                try:
                     return self._storage[callsign]
+                except (ValueError, KeyError):
+                    # Catch exceptions due to e.g. old versions of objects in the cache that are no longer compatible,
+                    # and remove them from the cache.
+                    del self._storage[callsign]
+                    return None
             else:
                 c = self._perform_new_lookup(callsign, lookup_credentials)
                 if c:

providers/callsigndata/file_download_callsign_data_provider.py

@@ -32,11 +32,15 @@ class FileDownloadCallsignDataProvider(CallsignDataProvider):
         # Fire off the polling thread. It will poll immediately on startup, then sleep for poll_interval between
         # subsequent polls, so start() returns immediately and the application can continue starting.
         logger.info(f"Set up query of {self.name} callsign reference data every {self._poll_interval!s} days.")
-        self._thread = Thread(target=self._run, name=f"FileDownloadCallsignDataProvider-{self.name}")
+        self._thread = Thread(target=self._run, name=f"FileDownloadCallsignDataProvider-{self.name}", daemon=True)
         self._thread.start()
 
     def stop(self):
         self._stop_event.set()
+        if self._thread:
+            self._thread.join(timeout=35)
+            if self._thread.is_alive():
+                logger.warning(f"{self.name} callsign data worker thread did not exit on time and will be killed.")
 
     def _run(self):
         while True:

providers/callsigndata/hamqth.py

@@ -124,8 +124,8 @@ class HamQTH(APIQueryCallsignDataProvider):
         lat = None
         lon = None
         if (
-            "latitude" in data
+            data.get("latitude") is not None
-            and "longitude" in data
+            and data.get("longitude") is not None
             and (float(data["latitude"]) != 0 or float(data["longitude"]) != 0)
             and -89.9 < float(data["latitude"]) < 89.9
         ):
@@ -134,7 +134,7 @@ class HamQTH(APIQueryCallsignDataProvider):
 
         # Check for sensible grids
         grid = None
-        if "grid" in data and not data["grid"].startswith("AA00"):
+        if data.get("grid") and not data["grid"].startswith("AA00"):
             grid = data["grid"]
 
         return Callsign(
@@ -147,8 +147,8 @@ class HamQTH(APIQueryCallsignDataProvider):
             latitude=lat,
             longitude=lon,
             grid=grid,
-            dxcc_id=int(data["adif"]) if "adif" in data else None,
+            dxcc_id=int(data["adif"]) if data.get("adif") is not None else None,
-            cq_zone=int(data["cq"]) if "cq" in data else None,
+            cq_zone=int(data["cq"]) if data.get("cq") is not None else None,
-            itu_zone=int(data["itu"]) if "itu" in data else None,
+            itu_zone=int(data["itu"]) if data.get("itu") is not None else None,
             location_source=LocationSourceForCallsign.HOME_QTH,
         )

providers/callsigndata/qrz.py

@@ -150,8 +150,8 @@ class QRZ(APIQueryCallsignDataProvider):
         lat = None
         lon = None
         if (
-            "latitude" in data
+            data.get("latitude") is not None
-            and "longitude" in data
+            and data.get("longitude") is not None
             and (float(data["latitude"]) != 0 or float(data["longitude"]) != 0)
             and -89.9 < float(data["latitude"]) < 89.9
         ):
@@ -160,7 +160,7 @@ class QRZ(APIQueryCallsignDataProvider):
 
         # Check for sensible grids
         grid = None
-        if "grid" in data and not data["grid"].startswith("AA00"):
+        if data.get("grid") and not data["grid"].startswith("AA00"):
             grid = data["grid"]
 
         return Callsign(
@@ -173,8 +173,8 @@ class QRZ(APIQueryCallsignDataProvider):
             latitude=lat,
             longitude=lon,
             grid=grid,
-            dxcc_id=int(data["adif"]) if "adif" in data else None,
+            dxcc_id=int(data["adif"]) if data.get("adif") is not None else None,
-            cq_zone=int(data["cqzone"]) if "cqzone" in data else None,
+            cq_zone=int(data["cqzone"]) if data.get("cqzone") is not None else None,
-            itu_zone=int(data["ituzone"]) if "ituzone" in data else None,
+            itu_zone=int(data["ituzone"]) if data.get("ituzone") is not None else None,
             location_source=LocationSourceForCallsign.HOME_QTH,
         )

providers/sigrefdata/dme.py

@@ -53,7 +53,7 @@ class DME(LocalFileSIGRefDataProvider):
 
                 # Bail out if a stop has been requested, i.e. the program is shutting down - no need to parse the rest
                 # of the data in this case
-                if self._stop:
+                if self._stop_event.is_set():
                     break
 
                 # Very short pause. This will extend the time to handle sig refs by a few seconds but will ensure some time

providers/sigrefdata/file_download_sig_ref_data_provider.py

@@ -1,6 +1,6 @@
 import logging
 from datetime import datetime
-from threading import Event, Thread
+from threading import Thread
 
 import pytz
 from requests.exceptions import ConnectionError, ConnectTimeout, ReadTimeout
@@ -21,19 +21,21 @@ class FileDownloadSIGRefDataProvider(SIGRefDataProvider):
         self._url = url
         self._poll_interval = poll_interval
         self._thread = None
-        self._stop_event = Event()
         self._url_data_cache = URLDataCache(f"sigrefdata_{sig_name}")
 
     def start(self):
         # Fire off the polling thread. It will poll immediately on startup, then sleep for poll_interval between
         # subsequent polls, so start() returns immediately and the application can continue starting.
         logger.info(f"Set up query of {self.sig_name} SIG ref data every {self._poll_interval!s} days.")
-        self._thread = Thread(target=self._run, name=f"FileDownloadSIGRefDataProvider-{self.sig_name}")
+        self._thread = Thread(target=self._run, name=f"FileDownloadSIGRefDataProvider-{self.sig_name}", daemon=True)
         self._thread.start()
 
     def stop(self):
         super().stop()
-        self._stop_event.set()
+        if self._thread:
+            self._thread.join(timeout=35)
+            if self._thread.is_alive():
+                logger.warning(f"{self.sig_name} SIG ref data worker thread did not exit on time and will be killed.")
 
     def _run(self):
         while True:

providers/sigrefdata/sig_ref_data_provider.py

@@ -1,5 +1,6 @@
 import logging
 from datetime import datetime
+from threading import Event
 
 import pytz
 
@@ -19,7 +20,7 @@ class SIGRefDataProvider:
         self.last_update_time = datetime.min.replace(tzinfo=pytz.UTC)
         self.status = "Not Started" if self.enabled else "Disabled"
         self.reference_count = 0
-        self._stop = False
+        self._stop_event = Event()
 
     def start(self):
         """Start the provider. This should return immediately after spawning threads to access the remote resources"""
@@ -30,20 +31,22 @@ class SIGRefDataProvider:
         """Stop any threads and prepare for application shutdown. Subclasses should implement this method and call
         super()."""
 
-        self._stop = True
+        self._stop_event.set()
 
     def _add_data(self, new_data):
         """Add all the provided reference data objects to the data store."""
 
-        # with transact() batches all writes together to save making thousands of individual sqlite writes
+        # with transact() batches all writes together to save making thousands of individual sqlite writes. However,
-        with DATA_STORE.sigrefs.transact():
+        # that means that each provider holds the lock while it writes, and the default behaviour for other attempted
+        # transact()s is to fail if they can't get the lock (?!). This behaviour is fixed by retry=True.
+        with DATA_STORE.sigrefs.transact(retry=True):
             for d in new_data:
                 DATA_STORE.sigrefs.set(f"{self.sig_name}:{d.id}", d)
 
                 # For the big data sources, loading will take a few minutes. If we want to shut down the software neatly
                 # within the first few minutes of startup, we need a way to abort this expensive process of filling up the
                 # disk cache.
-                if self._stop:
+                if self._stop_event.is_set():
                     break
 
         self.reference_count = len(new_data)

providers/sigrefdata/toilets.py

@@ -35,7 +35,7 @@ class Toilets(LocalFileSIGRefDataProvider):
 
                 # Bail out if a stop has been requested, i.e. the program is shutting down - no need to parse the rest
                 # of the data in this case
-                if self._stop:
+                if self._stop_event.is_set():
                     break
 
         return new_data

providers/solarconditions/giroionosonde.py

@@ -67,11 +67,15 @@ class GIROIonosonde(SolarConditionsProvider):
 
     def start(self):
         logger.info(f"Set up query of GIRO ionosonde data API every {POLL_INTERVAL} seconds.")
-        self._thread = Thread(target=self._run, name="GIROIonosondeDataProvider")
+        self._thread = Thread(target=self._run, name="GIROIonosondeDataProvider", daemon=True)
         self._thread.start()
 
     def stop(self):
         self._stop_event.set()
+        if self._thread:
+            self._thread.join(timeout=35)
+            if self._thread.is_alive():
+                logger.warning("GIRO ionosonde worker thread did not exit on time and will be killed.")
 
     def _run(self):
         # Real interval at which we poll is the "once per hour" divided by the number of stations, so each one gets

providers/solarconditions/http_solar_conditions_provider.py

@@ -25,11 +25,15 @@ class HTTPSolarConditionsProvider(SolarConditionsProvider):
 
     def start(self):
         logger.info(f"Set up query of {self.name} solar conditions API every {self._poll_interval!s} seconds.")
-        self._thread = Thread(target=self._run, name=f"HTTPSolarConditionsProvider-{self.name}")
+        self._thread = Thread(target=self._run, name=f"HTTPSolarConditionsProvider-{self.name}", daemon=True)
         self._thread.start()
 
     def stop(self):
         self._stop_event.set()
+        if self._thread:
+            self._thread.join(timeout=35)
+            if self._thread.is_alive():
+                logger.warning(f"{self.name} solar conditions worker thread did not exit on time and will be killed.")
 
     def _run(self):
         while True:

providers/solarconditions/kc2gprop.py

@@ -32,11 +32,15 @@ class KC2GProp(SolarConditionsProvider):
 
     def start(self):
         logger.info(f"Set up query of KC2G ionosonde data API every {POLL_INTERVAL} seconds.")
-        self._thread = Thread(target=self._run, name="KC2GPropProvider")
+        self._thread = Thread(target=self._run, name="KC2GPropProvider", daemon=True)
         self._thread.start()
 
     def stop(self):
         self._stop_event.set()
+        if self._thread:
+            self._thread.join(timeout=35)
+            if self._thread.is_alive():
+                logger.warning("KC2G ionosonde worker thread did not exit on time and will be killed.")
 
     def _run(self):
         while True:

providers/spot/aprsis.py

@@ -1,6 +1,6 @@
 import logging
 from datetime import datetime
-from threading import Thread
+from threading import Event, Thread
 
 import aprslib
 import pytz
@@ -17,27 +17,44 @@ class APRSIS(SpotProvider):
 
     def __init__(self, provider_config):
         super().__init__("APRS-IS", provider_config)
-        self._thread = Thread(target=self._connect, name="APRSISSpotProvider")
+        self._thread = None
-        self._thread.daemon = True
         self._aprsis = None
+        self._stop_event = Event()
 
     def start(self):
+        self._thread = Thread(target=self._run, name="APRSISSpotProvider", daemon=True)
         self._thread.start()
 
-    def _connect(self):
+    def _run(self):
+        while not self._stop_event.is_set():
+            try:
                 self._aprsis = aprslib.IS(SERVER_OWNER_CALLSIGN)
                 self.status = "Connecting"
                 logger.info("APRS-IS connecting...")
                 self._aprsis.connect()
-        self._aprsis.consumer(self._handle)
                 logger.info("APRS-IS connected.")
+                self._aprsis.consumer(self._handle, immortal=True)
+
+            except Exception:
+                if not self._stop_event.is_set():
+                    self.status = "Error"
+                    logger.exception("Exception in APRS-IS provider")
+
+            if not self._stop_event.is_set():
+                self._stop_event.wait(timeout=5)
 
     def stop(self):
         self.status = "Shutting down"
+        self._stop_event.set()
+        if self._aprsis:
             self._aprsis.close()
-        self._thread.join()
+        if self._thread:
+            self._thread.join(timeout=15)
+            if self._thread.is_alive():
+                logger.warning("APRS-IS worker thread did not exit on time and will be killed.")
 
     def _handle(self, data):
+        try:
             # Split SSID in "from" call and store separately
             from_parts = str(data["from"]).split("-")
             dx_call = from_parts[0].upper()
@@ -52,8 +69,8 @@ class APRSIS(SpotProvider):
                 de_call=de_call,
                 de_ssid=de_ssid,
                 comment=str(data["comment"]) if "comment" in data else None,
-            dx_latitude=float(data["latitude"]) if "latitude" in data else None,
+                dx_latitude=float(data["latitude"]) if data.get("latitude") is not None else None,
-            dx_longitude=float(data["longitude"]) if "longitude" in data else None,
+                dx_longitude=float(data["longitude"]) if data.get("longitude") is not None else None,
                 time=datetime.now(pytz.UTC).timestamp(),
             )  # APRS-IS spots are live so we can assume spot time is "now"
 
@@ -63,3 +80,6 @@ class APRSIS(SpotProvider):
             self.status = "OK"
             self.last_update_time = datetime.now(pytz.UTC)
             logger.debug("Data received from APRS-IS.")
+
+        except Exception:
+            logger.exception("Exception handling APRS-IS packet")

providers/spot/dxcluster.py

@@ -1,8 +1,7 @@
 import logging
 import re
 from datetime import datetime
-from threading import Thread
+from threading import Event, Thread
-from time import sleep
 
 import pytz
 import telnetlib3
@@ -41,23 +40,26 @@ class DXCluster(SpotProvider):
             self._LINE_PATTERN_ALLOW_RBN if self._allow_rbn_spots else self._LINE_PATTERN_EXCLUDE_RBN
         )
         self._telnet = None
-        self._thread = Thread(target=self._handle, name=f"DXClusterSpotProvider-{self.name}")
+        self._thread = None
-        self._thread.daemon = True
+        self._stop_event = Event()
-        self._running = True
 
     def start(self):
+        self._thread = Thread(target=self._handle, name=f"DXClusterSpotProvider-{self.name}", daemon=True)
         self._thread.start()
 
     def stop(self):
-        self._running = False
+        self._stop_event.set()
         if self._telnet:
             self._telnet.close()
-        self._thread.join()
+        if self._thread:
+            self._thread.join(timeout=15)
+            if self._thread.is_alive():
+                logger.warning(f"DX Cluster {self._hostname} worker thread did not exit on time and will be killed.")
 
     def _handle(self):
-        while self._running:
+        while not self._stop_event.is_set():
             connected = False
-            while not connected and self._running:
+            while not connected and not self._stop_event.is_set():
                 try:
                     self.status = "Connecting"
                     logger.info(f"DX Cluster {self._hostname} connecting...")
@@ -69,14 +71,14 @@ class DXCluster(SpotProvider):
                 except ConnectionRefusedError:
                     self.status = "Error"
                     logger.warning(f"Connection refused to DX cluster {self._hostname}")
-                    sleep(300)
+                    self._stop_event.wait(timeout=300)
                 except Exception:
                     self.status = "Error"
                     logger.exception(f"Exception while connecting to DX Cluster Provider ({self._hostname}).")
-                    sleep(5)
+                    self._stop_event.wait(timeout=5)
 
             self.status = "Waiting for Data"
-            while connected and self._running:
+            while connected and not self._stop_event.is_set():
                 try:
                     # Check new telnet info against regular expression
                     telnet_output = self._telnet.read_until("\n".encode("latin-1"))
@@ -106,19 +108,19 @@ class DXCluster(SpotProvider):
 
                 except EOFError:
                     connected = False
-                    if self._running:
+                    if not self._stop_event.is_set():
                         self.status = "Restarting"
                         logger.warning(f"Disconnected from DX Cluster {self._hostname}. Reconnecting...")
-                        sleep(5)
+                        self._stop_event.wait(timeout=5)
                     else:
                         logger.info(f"DX Cluster {self._hostname} shutting down...")
                         self.status = "Shutting down"
                 except Exception:
                     connected = False
-                    if self._running:
+                    if not self._stop_event.is_set():
                         self.status = "Error"
                         logger.exception(f"Exception in DX Cluster Provider ({self._hostname})")
-                        sleep(5)
+                        self._stop_event.wait(timeout=5)
                     else:
                         logger.info(f"DX Cluster {self._hostname} shutting down...")
                         self.status = "Shutting down"

providers/spot/http_spot_provider.py

@@ -28,12 +28,16 @@ class HTTPSpotProvider(SpotProvider):
         # Fire off the polling thread. It will poll immediately on startup, then sleep for poll_interval between
         # subsequent polls, so start() returns immediately and the application can continue starting.
         logger.info(f"Set up query of {self.name} spot API every {self._poll_interval!s} seconds.")
-        self._thread = Thread(target=self._run, name=f"HTTPSpotProvider-{self.name}")
+        self._thread = Thread(target=self._run, name=f"HTTPSpotProvider-{self.name}", daemon=True)
         self._thread.start()
 
     def stop(self):
         self._stop_event.set()
         self._wakeup_event.set()
+        if self._thread:
+            self._thread.join(timeout=35)
+            if self._thread.is_alive():
+                logger.warning(f"{self.name} spot worker thread did not exit on time and will be killed.")
 
     def force_poll(self):
         """Trigger an immediate poll without waiting for the normal interval."""

providers/spot/rbn.py

@@ -1,8 +1,7 @@
 import logging
 import re
 from datetime import datetime
-from threading import Thread
+from threading import Event, Thread
-from time import sleep
 
 import pytz
 import telnetlib3
@@ -30,23 +29,26 @@ class RBN(SpotProvider):
         super().__init__(name, provider_config)
         self._port = provider_config["port"]
         self._telnet = None
-        self._thread = Thread(target=self._handle, name=f"RBNSpotProvider-{self.name}")
+        self._thread = None
-        self._thread.daemon = True
+        self._stop_event = Event()
-        self._running = True
 
     def start(self):
+        self._thread = Thread(target=self._handle, name=f"RBNSpotProvider-{self.name}", daemon=True)
         self._thread.start()
 
     def stop(self):
-        self._running = False
+        self._stop_event.set()
         if self._telnet:
             self._telnet.close()
-        self._thread.join()
+        if self._thread:
+            self._thread.join(timeout=15)
+            if self._thread.is_alive():
+                logger.warning(f"RBN (port {self._port!s}) worker thread did not exit on time and will be killed.")
 
     def _handle(self):
-        while self._running:
+        while not self._stop_event.is_set():
             connected = False
-            while not connected and self._running:
+            while not connected and not self._stop_event.is_set():
                 try:
                     self.status = "Connecting"
                     logger.info(f"RBN port {self._port!s} connecting...")
@@ -58,10 +60,10 @@ class RBN(SpotProvider):
                 except Exception:
                     self.status = "Error"
                     logger.exception(f"Exception while connecting to RBN (port {self._port!s}).")
-                    sleep(5)
+                    self._stop_event.wait(timeout=5)
 
             self.status = "Waiting for Data"
-            while connected and self._running:
+            while connected and not self._stop_event.is_set():
                 try:
                     # Check new telnet info against regular expression
                     telnet_output = self._telnet.read_until("\n".encode("latin-1"))
@@ -91,19 +93,19 @@ class RBN(SpotProvider):
 
                 except EOFError:
                     connected = False
-                    if self._running:
+                    if not self._stop_event.is_set():
                         self.status = "Restarting"
                         logger.warning(f"Disconnected from RBN provider (port {self._port!s}). Reconnecting...")
-                        sleep(5)
+                        self._stop_event.wait(timeout=5)
                     else:
                         logger.info(f"RBN provider (port {self._port!s}) shutting down...")
                         self.status = "Shutting down"
                 except Exception:
                     connected = False
-                    if self._running:
+                    if not self._stop_event.is_set():
                         self.status = "Error"
                         logger.exception(f"Exception in RBN provider (port {self._port!s})")
-                        sleep(5)
+                        self._stop_event.wait(timeout=5)
                     else:
                         logger.info(f"RBN provider (port {self._port!s}) shutting down...")
                         self.status = "Shutting down"

providers/spot/ukpacketnet.py

@@ -42,7 +42,7 @@ class UKPacketNet(HTTPSpotProvider):
                                 )
                                 comment = (
                                     f"{comment} {listed_port['baud']!s} baud"
-                                    if "baud" in listed_port and listed_port["baud"] > 0
+                                    if listed_port.get("baud") and listed_port["baud"] > 0
                                     else comment
                                 )
 
@@ -50,7 +50,7 @@ class UKPacketNet(HTTPSpotProvider):
                                 # very hacky but a lot of node comments contain their frequency as the first or second
                                 # word of their comment, but not in the proper data structure field.
                                 freq = (
-                                    listed_port["freq"] if "freq" in listed_port and listed_port["freq"] > 0 else None
+                                    listed_port["freq"] if listed_port.get("freq") and listed_port["freq"] > 0 else None
                                 )
                                 if not freq and comment:
                                     possible_freq = comment.split(" ")[0].upper().replace("MHZ", "")

providers/spot/websocket_spot_provider.py

@@ -1,7 +1,6 @@
 import logging
 from datetime import datetime
-from threading import Thread
+from threading import Event, Thread
-from time import sleep
 
 import pytz
 from websocket import create_connection
@@ -20,22 +19,24 @@ class WebsocketSpotProvider(SpotProvider):
         self._url = url
         self._ws = None
         self._thread = None
-        self._stopped = False
+        self._stop_event = Event()
         self._last_event_id = None
 
     def start(self):
         logger.info(f"Set up websocket connection to {self.name} spot API.")
-        self._stopped = False
+        self._stop_event.clear()
         self._thread = Thread(target=self._run, name=f"WebsocketSpotProvider-{self.name}")
         self._thread.daemon = True
         self._thread.start()
 
     def stop(self):
-        self._stopped = True
+        self._stop_event.set()
         if self._ws:
             self._ws.close()
         if self._thread:
-            self._thread.join()
+            self._thread.join(timeout=15)
+            if self._thread.is_alive():
+                logger.warning(f"{self.name} websocket worker thread did not exit on time and will be killed.")
 
     def _on_open(self):
         self.status = "Waiting for Data"
@@ -44,14 +45,19 @@ class WebsocketSpotProvider(SpotProvider):
         self.status = "Connecting"
 
     def _run(self):
-        while not self._stopped:
+        while not self._stop_event.is_set():
             try:
                 logger.debug(f"Connecting to {self.name} spot API...")
                 self.status = "Connecting"
                 self._ws = create_connection(self._url, header=HTTP_HEADERS)
                 self.status = "Connected"
+
+                # Keep reading from this same connection until it drops or we're asked to stop, rather than
+                # reconnecting for every message.
+                while not self._stop_event.is_set():
                     data = self._ws.recv()
-                if data:
+                    if not data:
+                        break
                     try:
                         new_spot = self._ws_message_to_spot(data)
                         if new_spot:
@@ -69,7 +75,16 @@ class WebsocketSpotProvider(SpotProvider):
                 logger.exception(f"Exception in Websocket Spot Provider ({self.name})")
             else:
                 self.status = "Disconnected"
-            sleep(5)  # Wait before trying to reconnect
+            finally:
+                if self._ws:
+                    try:
+                        self._ws.close()
+                    except Exception:
+                        # No problem, we were getting rid of this object anyway.
+                        pass
+                    self._ws = None
+            if not self._stop_event.is_set():
+                self._stop_event.wait(timeout=5)  # Wait before trying to reconnect
 
     def _ws_message_to_spot(self, b):
         """Convert a WS message received from the API into a spot. The exact message data (in bytes) is provided here so the

providers/spot/wwbota.py

@@ -36,7 +36,7 @@ class WWBOTA(SSESpotProvider):
             dx_call=source_spot["call"].upper(),
             de_call=source_spot["spotter"].upper(),
             freq=float(source_spot["freq"]) * 1000000,
-            mode=Mode.from_name(source_spot["mode"].upper()) if "mode" in source_spot else None,
+            mode=Mode.from_name(source_spot["mode"].upper()) if source_spot.get("mode") else None,
             comment=source_spot["comment"],
             sig="WWBOTA",
             sig_refs=refs,

providers/staticdata/file_download_static_data_provider.py

@@ -29,11 +29,15 @@ class FileDownloadStaticDataProvider(StaticDataProvider):
         # Fire off the polling thread. It will poll immediately on startup, then sleep for poll_interval between
         # subsequent polls, so start() returns immediately and the application can continue starting.
         logger.info(f"Set up query of {self.name} static reference data every {self._poll_interval!s} days.")
-        self._thread = Thread(target=self._run, name=f"FileDownloadStaticDataProvider-{self.name}")
+        self._thread = Thread(target=self._run, name=f"FileDownloadStaticDataProvider-{self.name}", daemon=True)
         self._thread.start()
 
     def stop(self):
         self._stop_event.set()
+        if self._thread:
+            self._thread.join(timeout=35)
+            if self._thread.is_alive():
+                logger.warning(f"{self.name} static data worker thread did not exit on time and will be killed.")
 
     def _run(self):
         while True:

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "spothole"
-version = "2.1-pre"
+version = "2.1.1"
 authors = [
     { name = "Ian Renton", email = "ian@ianrenton.com" },
 ]

spothole.py

@@ -15,17 +15,25 @@ from webserver.webserver import WEB_SERVER
 
 logger = logging.getLogger(__name__)
 
+_shutdown_in_progress = False
+
 
 def shutdown(_signum=None, _frame=None):
     """Shutdown function"""
 
+    # Check if this is the second time a shutdown was asked for, if so immediately kill the program.
+    global _shutdown_in_progress
+    if _shutdown_in_progress:
+        os._exit(1)
+    _shutdown_in_progress = True
+
     logger.info("Stopping program...")
     WEB_SERVER.stop()
     TELNET_SERVER.stop()
     DATA_PROVIDERS.stop()
     CLEANUP_TIMER.stop()
     DATA_STORE.close()
-    os._exit(0)
+    logger.info("Stopped.")
 
 
 # Main function
@@ -43,8 +51,9 @@ if __name__ == "__main__":
     logger.info("Starting...")
     logger.info(f"This is Spothole version {SOFTWARE_VERSION}. This instance is run by {SERVER_OWNER_CALLSIGN}.")
 
-    # Shut down gracefully on SIGINT
+    # Shut down gracefully on SIGINT or SIGTERM
     signal.signal(signal.SIGINT, shutdown)
+    signal.signal(signal.SIGTERM, shutdown)
 
     # Set up data store
     DATA_STORE.setup()
@@ -59,14 +68,16 @@ if __name__ == "__main__":
     status_reporter = StatusReporter(run_interval=5)
     status_reporter.start()
 
-    # Set up the web server
-    WEB_SERVER.setup()
-
     # Run the telnet server
     if TELNET_SERVER_ENABLED:
         TELNET_SERVER.start(port=TELNET_SERVER_PORT)
 
-    # Run the web server. This is the blocking call that keeps the application running in the main thread, so this must
+    # Set up the web server
-    # be the last thing we do. web_server.stop() triggers an await condition in the web server which finishes the main
+    WEB_SERVER.setup()
-    # thread.
+
+    # Run the web server
     WEB_SERVER.start()
+
+    # Block the main thread until a termination signal arrives and shutdown() is running.
+    while not _shutdown_in_progress:
+        signal.pause()

static/apidocs/openapi.yml

@@ -901,7 +901,12 @@ components:
         - WAB
         - WAI
         - DME
+        - DMF
         - FEA
+        - DMUE
+        - DMVE
+        - DCE
+        - DEFE
         - DTMBA
         - BIWOTA
         - COTA

telnetserver/telnetserver.py

@@ -49,6 +49,7 @@ class TelnetServer:
         self._running = False
         self._clients = set()
         self._loop = None
+        self._thread = None
         self._shutdown_event = asyncio.Event()
 
     def start(self, port=7373):
@@ -58,8 +59,10 @@ class TelnetServer:
 
         # Start the telnet server. asyncio.run() needs a coroutine, and threading.Thread needs a plain callable, so
         # hand Thread the bridge between the two directly rather than writing a one-line wrapper method for it.
-        t = threading.Thread(target=asyncio.run, args=(self._start_internal(),), name="TelnetServer", daemon=True)
+        self._thread = threading.Thread(
-        t.start()
+            target=asyncio.run, args=(self._start_internal(),), name="TelnetServer", daemon=True
+        )
+        self._thread.start()
         logger.debug("Telnet server background thread spawned")
 
         # Listen for new spots and alerts being added to the cache, so we can notify SSE clients immediately
@@ -135,6 +138,10 @@ class TelnetServer:
         if self._loop and self._loop.is_running():
             logger.debug("Stopping telnet server...")
             self._loop.call_soon_threadsafe(self._shutdown_event.set)
+        if self._thread:
+            self._thread.join(timeout=15)
+            if self._thread.is_alive():
+                logger.warning("Telnet server background thread did not exit on time and will be killed.")
 
     @property
     def client_count(self) -> int:
@@ -163,9 +170,10 @@ class TelnetServer:
         # Ensure ASCII formatting for telnet clients
         encoded_line = self._format_dxspider_spot(spot).encode("ascii", errors="ignore")
 
-        # Try to write to all clients, and in the process find the ones that are disconnected
+        # Try to write to all clients, and in the process find the ones that are disconnected. Iterate over a copy
+        # since a new client can connect (mutating self._clients) while we're awaiting a write below.
         disconnected_clients = set()
-        for writer in self._clients:
+        for writer in list(self._clients):
             try:
                 writer.write(encoded_line)
                 await writer.drain()

templates/about.html

@@ -114,7 +114,7 @@
         Faros de España (FEA), Diploma Muesos de España (DMUE), Diploma Castillos de España (DCE), Diploma Monumentos y
         Vestigios de España (DMVE), Diploma Estaciones de Ferrocarril de España (DEFE), Diploma Teatri Musei e Belle
         Arti (DTMBA), British Inland Waterways on the Air (BIWOTA), Castles on the Air (COTA), Polish Gmina Award (PGA),
-        EME/Moonbounce, Amateur Satellite (AMSAT), and Toilets on the Air.</p>
+        Diplôme des Moulins de France (DMF), EME/Moonbounce, Amateur Satellite (AMSAT), and Toilets on the Air.</p>
     <p>As of the time of writing in August 2026, I think Spothole captures most outdoor radio programmes that have a
         defined, downloadable reference list, and almost certainly those that have a spotting/alerting API. If you know
         of one I've missed, please let me know!</p>

templates/add_spot.html

@@ -77,7 +77,7 @@
 
 </div>
 
-<script src="/static/js/add-spot.js?v=1789198850"></script>
+<script src="/static/js/add-spot.js?v=1789763826"></script>
 <script>$(document).ready(function () {
     $("#nav-link-add-spot").addClass("active");
 }); <!-- highlight active page in nav --></script>

templates/alerts.html

@@ -83,7 +83,7 @@
 
 </div>
 
-<script src="/static/js/alerts.js?v=1789198850"></script>
+<script src="/static/js/alerts.js?v=1789763826"></script>
 <script>$(document).ready(function () {
     $("#nav-link-alerts").addClass("active");
 }); <!-- highlight active page in nav --></script>

templates/bands.html

@@ -76,8 +76,8 @@
 
 </div>
 
-<script src="/static/js/spotsbandsandmap.js?v=1789198850"></script>
+<script src="/static/js/spotsbandsandmap.js?v=1789763826"></script>
-<script src="/static/js/bands.js?v=1789198850"></script>
+<script src="/static/js/bands.js?v=1789763826"></script>
 <script>$(document).ready(function () {
     $("#nav-link-bands").addClass("active");
 }); <!-- highlight active page in nav --></script>

templates/base.html

@@ -1,6 +1,6 @@
 {% extends "skeleton.html" %}
 {% block head_extra %}
-<link rel="stylesheet" href="/static/css/style.css?v=1789198850" type="text/css">
+<link rel="stylesheet" href="/static/css/style.css?v=1789763825" type="text/css">
 <link href="/static/vendor/css/bootstrap-5.3.8.min.css" rel="stylesheet">
 <link href="/static/vendor/css/fontawesome-6.7.2.min.css" rel="stylesheet">
 <link href="/static/vendor/css/solid-6.7.2.min.css" rel="stylesheet">
@@ -16,10 +16,10 @@
     window.fetchEventSource = fetchEventSource;
 </script>
 
-<script src="/static/js/utils.js?v=1789198850"></script>
+<script src="/static/js/utils.js?v=1789763825"></script>
-<script src="/static/js/ui-ham.js?v=1789198850"></script>
+<script src="/static/js/ui-ham.js?v=1789763825"></script>
-<script src="/static/js/geo.js?v=1789198850"></script>
+<script src="/static/js/geo.js?v=1789763825"></script>
-<script src="/static/js/common.js?v=1789198850"></script>
+<script src="/static/js/common.js?v=1789763825"></script>
 {% end %}
 {% block body %}
 <div class="container">

templates/conditions.html

@@ -284,7 +284,7 @@
 </div>
 
 <script src="/static/vendor/js/chart-4.4.9.umd.min.js"></script>
-<script src="/static/js/conditions.js?v=1789198850"></script>
+<script src="/static/js/conditions.js?v=1789763825"></script>
 <script>$(document).ready(function () {
     $("#nav-link-conditions").addClass("active");
 }); <!-- highlight active page in nav --></script>

templates/map.html

@@ -113,8 +113,8 @@
     const CARTODB_API_KEY = "{{ web_ui_options.get('cartodb_api_key', '') }}";
 </script>
 
-<script src="/static/js/spotsbandsandmap.js?v=1789198850"></script>
+<script src="/static/js/spotsbandsandmap.js?v=1789763825"></script>
-<script src="/static/js/map.js?v=1789198850"></script>
+<script src="/static/js/map.js?v=1789763825"></script>
 <script>$(document).ready(function () {
     $("#nav-link-map").addClass("active");
 }); <!-- highlight active page in nav --></script>

templates/spots.html

@@ -125,8 +125,8 @@
 
 </div>
 
-<script src="/static/js/spotsbandsandmap.js?v=1789198850"></script>
+<script src="/static/js/spotsbandsandmap.js?v=1789763825"></script>
-<script src="/static/js/spots.js?v=1789198850"></script>
+<script src="/static/js/spots.js?v=1789763825"></script>
 <script>$(document).ready(function () {
     $("#nav-link-spots").addClass("active");
 }); <!-- highlight active page in nav --></script>

templates/status.html

@@ -96,7 +96,7 @@
     </div>
 </div>
 
-<script src="/static/js/status.js?v=1789198850"></script>
+<script src="/static/js/status.js?v=1789763826"></script>
 <script>
     $(document).ready(function () {
         $("#nav-link-status").addClass("active");

webserver/handlers/api/v1_compatability.py

@@ -34,7 +34,7 @@ class V1RedirectHandler(tornado.web.RequestHandler):
             response = await client.fetch(
                 new_url,
                 method=self.request.method,
-                headers=self.request.headers,
+                headers=headers,
                 body=None if self.request.method == "GET" else (self.request.body or b""),
                 raise_error=False,
                 follow_redirects=False,

webserver/webserver.py

@@ -1,6 +1,7 @@
 import asyncio
 import logging
 import os
+import threading
 
 import tornado
 from tornado.web import StaticFileHandler
@@ -53,6 +54,8 @@ class WebServer:
         self._port = WEB_SERVER_PORT
         self._api_only_mode = API_ONLY_MODE
         self._shutdown_event = asyncio.Event()
+        self._loop = None
+        self._thread = None
         self.web_server_metrics = WebServerMetrics()
 
     def setup(self):
@@ -69,16 +72,34 @@ class WebServer:
     def start(self):
         """Start the web server"""
 
-        asyncio.run(self._start_inner())
+        self._thread = threading.Thread(target=asyncio.run, args=(self._start_inner(),), name="WebServer", daemon=True)
+        self._thread.start()
 
     def stop(self):
         """Stop the web server"""
 
-        self._shutdown_event.set()
+        if self._loop and self._loop.is_running():
+            self._loop.call_soon_threadsafe(self._shutdown_event.set)
+        if self._thread:
+            self._thread.join(timeout=15)
+            if self._thread.is_alive():
+                logger.warning("Web server background thread did not exit on time and will be killed.")
+
+    def _handle_loop_exception(self, loop, context):
+        """Ignore "cancelled" exceptions from the asyncio loop to avoid printing exceptions to the log on shutdown when
+        we cancel the SSE handler threads"""
+
+        exception = context.get("exception")
+        if isinstance(exception, asyncio.CancelledError):
+            return
+        loop.default_exception_handler(context)
 
     async def _start_inner(self):
         """Start method (async). Sets up the Tornado application."""
 
+        self._loop = asyncio.get_running_loop()
+        self._loop.set_exception_handler(self._handle_loop_exception)
+
         # Bind the SSE broadcasters to the web server's loop, so they fire correctly
         self._spot_broadcaster.bind_to_web_server_loop()
         self._alert_broadcaster.bind_to_web_server_loop()