Files
spothole/sigrefdataproviders/file_download_sig_ref_data_provider.py
T

76 lines
3.2 KiB
Python

import logging
from datetime import datetime
from threading import Thread, Event
import pytz
import requests
from requests import ReadTimeout
from requests.exceptions import ConnectionError, ConnectTimeout
from core.constants import HTTP_HEADERS
from sigrefdataproviders.sig_ref_data_provider import SIGRefDataProvider
class FileDownloadSIGRefDataProvider(SIGRefDataProvider):
"""Generic SIG ref data provider class for providers that fetch their data from the web by downloading a file."""
def __init__(self, sig_name, provider_config, url, poll_interval):
super().__init__(sig_name, provider_config)
self._url = url
self._poll_interval = poll_interval
self._thread = None
self._stop_event = Event()
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.sig_name + " SIG ref data every " + str(self._poll_interval) + " seconds.")
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):
break
def _poll(self):
try:
# Request data from API
logging.debug("Downloading " + self.sig_name + " SIG ref data...")
http_response = requests.get(self._url, headers=HTTP_HEADERS, timeout=(5, 30))
# Check response code was good
if http_response.ok:
# Pass off to the subclass for processing
new_data = self._http_response_to_data(http_response)
# Submit the new spots for processing. There might not be any spots for the less popular programs.
if new_data:
self._replace_data(new_data)
self.status = "OK"
self.last_update_time = datetime.now(pytz.UTC)
logging.debug("Received SIG ref data for " + self.sig_name)
else:
self.status = "Error"
logging.warning(f"HTTP {http_response.status_code} when downloading SIG ref data for {self.sig_name}.")
except ConnectionError:
logging.warning(f"Connection error when downloading SIG ref data for {self.sig_name}.")
except (ConnectTimeout, ReadTimeout):
logging.warning(f"Timeout when downloading SIG ref data for {self.sig_name}.")
except Exception:
self.status = "Error"
logging.exception("Exception in HTTP SIG Ref Data Provider (" + self.sig_name + ")")
self._stop_event.wait(timeout=1)
def _http_response_to_data(self, http_response):
"""Convert an HTTP response returned by the server into SIG Ref data. The whole response is provided here so the
subclass implementations can check for HTTP status codes if necessary, and handle the response as JSON, CSV,
whatever the remote file actually is."""
raise NotImplementedError("Subclasses must implement this method")