Files
spothole/providers/callsigndata/file_download_callsign_data_provider.py
T

85 lines
3.8 KiB
Python

import logging
from datetime import datetime
from threading import Thread, Event
import pytz
from requests import ReadTimeout
from requests.exceptions import ConnectionError, ConnectTimeout
from core.constants import HTTP_HEADERS
from core.url_data_cache import URLDataCache
from providers.callsigndata.callsign_data_provider import CallsignDataProvider
class FileDownloadCallsignDataProvider(CallsignDataProvider):
"""Generic callsign data provider class for providers that fetch their data from the web by downloading a file."""
def __init__(self, name, provider_config, url, cache_file_path, poll_interval):
""" Set up the provider, note poll_interval is in *days*."""
super().__init__(name, provider_config)
self._url = url
self._cache_file_path = cache_file_path
self._poll_interval = poll_interval
self._thread = None
self._stop_event = Event()
self._url_data_cache = URLDataCache("callsigndata_" + 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.
logging.info(
"Set up query of " + self.name + " callsign reference data every " + str(self._poll_interval) + " days.")
self._thread = Thread(target=self._run, daemon=True)
self._thread.start()
def stop(self):
self._stop_event.set()
def _run(self):
while True:
self._poll()
if self._stop_event.wait(timeout=self._poll_interval * 60 * 60 * 24):
break
def _poll(self):
try:
# Request the file. Use the data cache (with a TTL of 1 day) here, not as the main mechanism for
# caching, but just so continual restarts of the software during testing don't hammer the servers.
logging.debug("Downloading " + self.name + " callsign reference data...")
http_response = self._url_data_cache.get(self._url, headers=HTTP_HEADERS)
# Check response code was good
if http_response.ok:
# Save the data to a local file
with open(self._cache_file_path, "wb") as f:
f.write(http_response.content)
f.flush()
# Pass off to the subclass for processing
ok = self._handle_file(self._cache_file_path)
if ok:
self.status = "OK"
self.last_update_time = datetime.now(pytz.UTC)
logging.info("Updated callsign reference data from " + self.name)
else:
self.status = "Error"
logging.warning(f"Error updating callsign reference data from {self.name}.")
else:
self.status = "Error"
logging.warning(f"HTTP {http_response.status_code} when downloading callsign reference data from {self.name}.")
except ConnectionError:
self.status = "Error"
logging.warning(f"Connection error when downloading callsign reference data from {self.name}.")
except (ConnectTimeout, ReadTimeout):
self.status = "Error"
logging.warning(f"Timeout when downloading callsign reference data from {self.name}.")
except Exception:
self.status = "Error"
logging.exception("Exception in callsign reference data provider (" + self.name + ")")
self._stop_event.wait(timeout=1)
def _handle_file(self, path):
"""Handle an updated file downloaded from the server. Return true if successful, false otherwise."""
raise NotImplementedError("Subclasses must implement this method")