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changedetection.io/changedetectionio/update_worker.py

156 lines
8.6 KiB

import threading
import queue
import time
from changedetectionio import content_fetcher
# A single update worker
#
# Requests for checking on a single site(watch) from a queue of watches
# (another process inserts watches into the queue that are time-ready for checking)
class update_worker(threading.Thread):
current_uuid = None
def __init__(self, q, notification_q, app, datastore, *args, **kwargs):
self.q = q
self.app = app
self.notification_q = notification_q
self.datastore = datastore
super().__init__(*args, **kwargs)
def run(self):
from changedetectionio import fetch_site_status
update_handler = fetch_site_status.perform_site_check(datastore=self.datastore)
while not self.app.config.exit.is_set():
try:
uuid = self.q.get(block=False)
except queue.Empty:
pass
else:
self.current_uuid = uuid
if uuid in list(self.datastore.data['watching'].keys()):
changed_detected = False
contents = ""
screenshot = False
update_obj= {}
xpath_data = False
now = time.time()
try:
changed_detected, update_obj, contents, screenshot, xpath_data = update_handler.run(uuid)
# Re #342
# In Python 3, all strings are sequences of Unicode characters. There is a bytes type that holds raw bytes.
# We then convert/.decode('utf-8') for the notification etc
if not isinstance(contents, (bytes, bytearray)):
raise Exception("Error - returned data from the fetch handler SHOULD be bytes")
except PermissionError as e:
self.app.logger.error("File permission error updating", uuid, str(e))
except content_fetcher.ReplyWithContentButNoText as e:
# Totally fine, it's by choice - just continue on, nothing more to care about
# Page had elements/content but no renderable text
self.datastore.update_watch(uuid=uuid, update_obj={'last_error': "Got HTML content but no text found."})
pass
except content_fetcher.EmptyReply as e:
# Some kind of custom to-str handler in the exception handler that does this?
err_text = "EmptyReply: Status Code {}".format(e.status_code)
self.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
'last_check_status': e.status_code})
except Exception as e:
self.app.logger.error("Exception reached processing watch UUID: %s - %s", uuid, str(e))
self.datastore.update_watch(uuid=uuid, update_obj={'last_error': str(e)})
else:
try:
watch = self.datastore.data['watching'][uuid]
fname = "" # Saved history text filename
# For the FIRST time we check a site, or a change detected, save the snapshot.
if changed_detected or not watch['last_checked']:
# A change was detected
fname = watch.save_history_text(contents=contents, timestamp=str(round(time.time())))
# Generally update anything interesting returned
self.datastore.update_watch(uuid=uuid, update_obj=update_obj)
# A change was detected
if changed_detected:
n_object = {}
print (">> Change detected in UUID {} - {}".format(uuid, watch['url']))
# Notifications should only trigger on the second time (first time, we gather the initial snapshot)
if watch.history_n >= 2:
dates = list(watch.history.keys())
prev_fname = watch.history[dates[-2]]
# Did it have any notification alerts to hit?
if len(watch['notification_urls']):
print(">>> Notifications queued for UUID from watch {}".format(uuid))
n_object['notification_urls'] = watch['notification_urls']
n_object['notification_title'] = watch['notification_title']
n_object['notification_body'] = watch['notification_body']
n_object['notification_format'] = watch['notification_format']
# No? maybe theres a global setting, queue them all
elif len(self.datastore.data['settings']['application']['notification_urls']):
print(">>> Watch notification URLs were empty, using GLOBAL notifications for UUID: {}".format(uuid))
n_object['notification_urls'] = self.datastore.data['settings']['application']['notification_urls']
n_object['notification_title'] = self.datastore.data['settings']['application']['notification_title']
n_object['notification_body'] = self.datastore.data['settings']['application']['notification_body']
n_object['notification_format'] = self.datastore.data['settings']['application']['notification_format']
else:
print(">>> NO notifications queued, watch and global notification URLs were empty.")
# Only prepare to notify if the rules above matched
if 'notification_urls' in n_object:
# HTML needs linebreak, but MarkDown and Text can use a linefeed
if n_object['notification_format'] == 'HTML':
line_feed_sep = "</br>"
else:
line_feed_sep = "\n"
from changedetectionio import diff
n_object.update({
'watch_url': watch['url'],
'uuid': uuid,
'current_snapshot': contents.decode('utf-8'),
'diff': diff.render_diff(prev_fname, fname, line_feed_sep=line_feed_sep),
'diff_full': diff.render_diff(prev_fname, fname, True, line_feed_sep=line_feed_sep)
})
self.notification_q.put(n_object)
except Exception as e:
# Catch everything possible here, so that if a worker crashes, we don't lose it until restart!
print("!!!! Exception in update_worker !!!\n", e)
self.app.logger.error("Exception reached processing watch UUID: %s - %s", uuid, str(e))
self.datastore.update_watch(uuid=uuid, update_obj={'last_error': str(e)})
finally:
# Always record that we atleast tried
self.datastore.update_watch(uuid=uuid, update_obj={'fetch_time': round(time.time() - now, 3),
'last_checked': round(time.time())})
# Always save the screenshot if it's available
if screenshot:
self.datastore.save_screenshot(watch_uuid=uuid, screenshot=screenshot)
if xpath_data:
self.datastore.save_xpath_data(watch_uuid=uuid, data=xpath_data)
self.current_uuid = None # Done
self.q.task_done()
# Give the CPU time to interrupt
time.sleep(0.1)
self.app.config.exit.wait(1)