oops

changedetectionio/__init__.py

@@ -18,6 +18,7 @@ import threading
 import time
 from copy import deepcopy
 from threading import Event
+from PriorityThreadPoolExecutor import PriorityThreadPoolExecutor
 
 import flask_login
 import logging
@@ -49,12 +50,12 @@ __version__ = '0.39.18'
 datastore = None
 
 # Local
-running_update_threads = []
+running_update_uuids = set()
 ticker_thread = None
 
 extra_stylesheets = []
 
-update_q = queue.PriorityQueue()
+pool = None
 
 notification_q = queue.Queue()
 
@@ -105,10 +106,9 @@ def init_app_secret(datastore_path):
 # running or something similar.
 @app.template_filter('format_last_checked_time')
 def _jinja2_filter_datetime(watch_obj, format="%Y-%m-%d %H:%M:%S"):
-    # Worker thread tells us which UUID it is currently processing.
-    for t in running_update_threads:
-        if t.current_uuid == watch_obj['uuid']:
-            return '<span class="loader"></span><span> Checking now</span>'
+
+    if watch_obj['uuid'] in running_update_uuids:
+        return '<span class="loader"></span><span> Checking now</span>'
 
     if watch_obj['last_checked'] == 0:
         return 'Not yet'
@@ -178,13 +178,15 @@ class User(flask_login.UserMixin):
 
 def changedetection_app(config=None, datastore_o=None):
     global datastore
+    global pool
     datastore = datastore_o
 
     # so far just for read-only via tests, but this will be moved eventually to be the main source
     # (instead of the global var)
     app.config['DATASTORE']=datastore_o
 
-    #app.config.update(config or {})
+    pool = PriorityThreadPoolExecutor(max_workers=int(os.getenv("FETCH_WORKERS", datastore.data['settings']['requests']['workers'])))
+
 
     login_manager = flask_login.LoginManager(app)
     login_manager.login_view = 'login'
@@ -193,20 +195,17 @@ def changedetection_app(config=None, datastore_o=None):
 
     watch_api.add_resource(api_v1.WatchSingleHistory,
                            '/api/v1/watch/<string:uuid>/history/<string:timestamp>',
-                           resource_class_kwargs={'datastore': datastore, 'update_q': update_q})
+                           resource_class_kwargs={'datastore': datastore, 'queue_single_watch': queue_single_watch})
 
     watch_api.add_resource(api_v1.WatchHistory,
                            '/api/v1/watch/<string:uuid>/history',
                            resource_class_kwargs={'datastore': datastore})
 
     watch_api.add_resource(api_v1.CreateWatch, '/api/v1/watch',
-                           resource_class_kwargs={'datastore': datastore, 'update_q': update_q})
+                           resource_class_kwargs={'datastore': datastore, 'queue_single_watch': queue_single_watch})
 
     watch_api.add_resource(api_v1.Watch, '/api/v1/watch/<string:uuid>',
-                           resource_class_kwargs={'datastore': datastore, 'update_q': update_q})
-
-
-
+                           resource_class_kwargs={'datastore': datastore, 'queue_single_watch': queue_single_watch})
 
 
     # Setup cors headers to allow all domains
@@ -417,8 +416,7 @@ def changedetection_app(config=None, datastore_o=None):
                                  # Don't link to hosting when we're on the hosting environment
                                  hosted_sticky=os.getenv("SALTED_PASS", False) == False,
                                  guid=datastore.data['app_guid'],
-                                 queued_uuids=[uuid for p,uuid in update_q.queue])
-
+                                 queued_uuids=get_uuids_in_queue())
 
         if session.get('share-link'):
             del(session['share-link'])
@@ -632,7 +630,7 @@ def changedetection_app(config=None, datastore_o=None):
             datastore.needs_write_urgent = True
 
             # Queue the watch for immediate recheck, with a higher priority
-            update_q.put((1, uuid))
+            queue_single_watch(uuid=uuid, priority=1)
 
             # Diff page [edit] link should go back to diff page
             if request.args.get("next") and request.args.get("next") == 'diff':
@@ -749,7 +747,7 @@ def changedetection_app(config=None, datastore_o=None):
                 importer = import_url_list()
                 importer.run(data=request.values.get('urls'), flash=flash, datastore=datastore)
                 for uuid in importer.new_uuids:
-                    update_q.put((1, uuid))
+                    queue_single_watch(uuid=uuid, priority=1)
 
                 if len(importer.remaining_data) == 0:
                     return redirect(url_for('index'))
@@ -762,7 +760,7 @@ def changedetection_app(config=None, datastore_o=None):
                 d_importer = import_distill_io_json()
                 d_importer.run(data=request.values.get('distill-io'), flash=flash, datastore=datastore)
                 for uuid in d_importer.new_uuids:
-                    update_q.put((1, uuid))
+                    queue_single_watch(uuid=uuid, priority=1)
 
 
 
@@ -1107,7 +1105,7 @@ def changedetection_app(config=None, datastore_o=None):
 
         if not add_paused and new_uuid:
             # Straight into the queue.
-            update_q.put((1, new_uuid))
+            queue_single_watch(uuid=new_uuid, priority=1)
             flash("Watch added.")
 
         if add_paused:
@@ -1144,7 +1142,7 @@ def changedetection_app(config=None, datastore_o=None):
             uuid = list(datastore.data['watching'].keys()).pop()
 
         new_uuid = datastore.clone(uuid)
-        update_q.put((5, new_uuid))
+        queue_single_watch(uuid=uuid, priority=5)
         flash('Cloned.')
 
         return redirect(url_for('index'))
@@ -1157,31 +1155,25 @@ def changedetection_app(config=None, datastore_o=None):
         uuid = request.args.get('uuid')
         i = 0
 
-        running_uuids = []
-        for t in running_update_threads:
-            running_uuids.append(t.current_uuid)
-
-        # @todo check thread is running and skip
-
         if uuid:
-            if uuid not in running_uuids:
-                update_q.put((1, uuid))
+            if uuid not in get_uuids_in_queue():
+                queue_single_watch(uuid=uuid, priority=1)
             i = 1
 
         elif tag != None:
             # Items that have this current tag
             for watch_uuid, watch in datastore.data['watching'].items():
                 if (tag != None and tag in watch['tag']):
-                    if watch_uuid not in running_uuids and not datastore.data['watching'][watch_uuid]['paused']:
-                        update_q.put((1, watch_uuid))
+                    if watch_uuid not in get_uuids_in_queue() and not datastore.data['watching'][watch_uuid]['paused']:
+                        queue_single_watch(uuid=watch_uuid, priority=1)
                         i += 1
 
         else:
             # No tag, no uuid, add everything.
             for watch_uuid, watch in datastore.data['watching'].items():
 
-                if watch_uuid not in running_uuids and not datastore.data['watching'][watch_uuid]['paused']:
-                    update_q.put((1, watch_uuid))
+                if watch_uuid not in get_uuids_in_queue() and not datastore.data['watching'][watch_uuid]['paused']:
+                    queue_single_watch(uuid=watch_uuid, priority=1)
                     i += 1
         flash("{} watches are queued for rechecking.".format(i))
         return redirect(url_for('index', tag=tag))
@@ -1346,33 +1338,31 @@ def notification_runner():
             # Trim the log length
             notification_debug_log = notification_debug_log[-100:]
 
-# Thread runner to check every minute, look for new watches to feed into the Queue.
+def queue_single_watch(uuid, priority=1):
+    pool.submit(process_single_watch, uuid, priority=int(time.time()) - priority)
+
+def process_single_watch(uuid):
+    running_update_uuids.add(uuid)
+    from changedetectionio import update_worker
+    worker = update_worker.update_worker(notification_q=notification_q, datastore=datastore)
+    worker.run(uuid)
+    running_update_uuids.remove(uuid)
+
+def get_uuids_in_queue():
+    return [workitem.args[0] for p, workitem in pool._work_queue.queue]
+
+# Thread runner to load watch jobs into the queue as they become ready/due for checking again
 def ticker_thread_check_time_launch_checks():
     import random
-    from changedetectionio import update_worker
 
     recheck_time_minimum_seconds = int(os.getenv('MINIMUM_SECONDS_RECHECK_TIME', 20))
     print("System env MINIMUM_SECONDS_RECHECK_TIME", recheck_time_minimum_seconds)
 
-    # Spin up Workers that do the fetching
-    # Can be overriden by ENV or use the default settings
-    n_workers = int(os.getenv("FETCH_WORKERS", datastore.data['settings']['requests']['workers']))
-    for _ in range(n_workers):
-        new_worker = update_worker.update_worker(update_q, notification_q, app, datastore)
-        running_update_threads.append(new_worker)
-        new_worker.start()
-
     while not app.config.exit.is_set():
 
-        # Get a list of watches by UUID that are currently fetching data
-        running_uuids = []
-        for t in running_update_threads:
-            if t.current_uuid:
-                running_uuids.append(t.current_uuid)
-
         # Re #232 - Deepcopy the data incase it changes while we're iterating through it all
         watch_uuid_list = []
-        while True:
+        while not app.config.exit.is_set():
             try:
                 watch_uuid_list = datastore.data['watching'].keys()
             except RuntimeError as e:
@@ -1382,8 +1372,9 @@ def ticker_thread_check_time_launch_checks():
                 break
 
         # Re #438 - Don't place more watches in the queue to be checked if the queue is already large
-        while update_q.qsize() >= 2000:
-            time.sleep(1)
+        while pool._work_queue.qsize() >= 2000:
+            if not app.config.exit.is_set():
+                time.sleep(1)
 
 
         recheck_time_system_seconds = int(datastore.threshold_seconds)
@@ -1414,7 +1405,8 @@ def ticker_thread_check_time_launch_checks():
 
             seconds_since_last_recheck = now - watch['last_checked']
             if seconds_since_last_recheck >= (threshold + watch.jitter_seconds) and seconds_since_last_recheck >= recheck_time_minimum_seconds:
-                if not uuid in running_uuids and uuid not in [q_uuid for p,q_uuid in update_q.queue]:
+                #@todo check 'not in running_uuids'
+                if not uuid and uuid not in get_uuids_in_queue():
                     # Use Epoch time as priority, so we get a "sorted" PriorityQueue, but we can still push a priority 1 into it.
                     priority = int(time.time())
                     print(
@@ -1425,8 +1417,8 @@ def ticker_thread_check_time_launch_checks():
                             priority,
                             watch.jitter_seconds,
                             now - watch['last_checked']))
-                    # Into the queue with you
-                    update_q.put((priority, uuid))
+
+                    queue_single_watch(uuid=uuid, priority=priority)
 
                     # Reset for next time
                     watch.jitter_seconds = 0

changedetectionio/api/api_v1.py

@@ -1,6 +1,8 @@
 from flask_restful import abort, Resource
 from flask import request, make_response
+
 import validators
+
 from . import auth
 
 
@@ -11,7 +13,7 @@ class Watch(Resource):
     def __init__(self, **kwargs):
         # datastore is a black box dependency
         self.datastore = kwargs['datastore']
-        self.update_q = kwargs['update_q']
+        self.queue_single_watch = kwargs['queue_single_watch']
 
     # Get information about a single watch, excluding the history list (can be large)
     # curl http://localhost:4000/api/v1/watch/<string:uuid>
@@ -24,7 +26,7 @@ class Watch(Resource):
             abort(404, message='No watch exists with the UUID of {}'.format(uuid))
 
         if request.args.get('recheck'):
-            self.update_q.put((1, uuid))
+            self.queue_single_watch(uuid, priority=1)
             return "OK", 200
 
         # Return without history, get that via another API call
@@ -86,7 +88,7 @@ class CreateWatch(Resource):
     def __init__(self, **kwargs):
         # datastore is a black box dependency
         self.datastore = kwargs['datastore']
-        self.update_q = kwargs['update_q']
+        self.queue_single_watch = kwargs['queue_single_watch']
 
     @auth.check_token
     def post(self):
@@ -100,7 +102,7 @@ class CreateWatch(Resource):
         extras = {'title': json_data['title'].strip()} if json_data.get('title') else {}
 
         new_uuid = self.datastore.add_watch(url=json_data['url'].strip(), tag=tag, extras=extras)
-        self.update_q.put((1, new_uuid))
+        self.queue_single_watch(new_uuid, priority=1)
         return {'uuid': new_uuid}, 201
 
     # Return concise list of available watches and some very basic info
@@ -118,7 +120,7 @@ class CreateWatch(Resource):
 
         if request.args.get('recheck_all'):
             for uuid in self.datastore.data['watching'].keys():
-                self.update_q.put((1, uuid))
+                self.queue_single_watch(uuid, priority=1)
             return {'status': "OK"}, 200
 
         return list, 200

changedetectionio/update_worker.py

@@ -1,8 +1,7 @@
+import logging
 import os
-import threading
-import queue
 import time
-
+logging.basicConfig(level=logging.DEBUG)
 from changedetectionio import content_fetcher
 from changedetectionio.html_tools import FilterNotFoundInResponse
 
@@ -12,15 +11,12 @@ from changedetectionio.html_tools import FilterNotFoundInResponse
 # (another process inserts watches into the queue that are time-ready for checking)
 
 
-class update_worker(threading.Thread):
+class update_worker():
     current_uuid = None
 
-    def __init__(self, q, notification_q, app, datastore, *args, **kwargs):
-        self.q = q
-        self.app = app
+    def __init__(self,  notification_q, datastore):
         self.notification_q = notification_q
         self.datastore = datastore
-        super().__init__(*args, **kwargs)
 
     def send_content_changed_notification(self, t, watch_uuid):
 
@@ -116,182 +112,168 @@ class update_worker(threading.Thread):
             if os.path.isfile(full_path):
                 os.unlink(full_path)
 
-    def run(self):
+    def run(self, uuid):
         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():
+        self.current_uuid = uuid
+
+        if uuid in list(self.datastore.data['watching'].keys()):
+            changed_detected = False
+            contents = b''
+            screenshot = False
+            update_obj= {}
+            xpath_data = False
+            process_changedetection_results = True
+            print("> Processing UUID {} Priority {} URL {}".format(uuid, 1, self.datastore.data['watching'][uuid]['url']))
+            now = time.time()
 
             try:
-                priority, uuid = self.q.get(block=False)
-            except queue.Empty:
-                pass
+                changed_detected, update_obj, contents = 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:
+                logging.error("File permission error updating", uuid, str(e))
+                process_changedetection_results = False
+            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
+                # Backend (not filters) gave zero output
+                self.datastore.update_watch(uuid=uuid, update_obj={'last_error': "Got HTML content but no text found (With {} reply code).".format(e.status_code)})
+                if e.screenshot:
+                    self.datastore.save_screenshot(watch_uuid=uuid, screenshot=e.screenshot)
+                process_changedetection_results = False
 
+            except content_fetcher.Non200ErrorCodeReceived as e:
+                if e.status_code == 403:
+                    err_text = "Error - 403 (Access denied) received"
+                elif e.status_code == 404:
+                    err_text = "Error - 404 (Page not found) received"
+                elif e.status_code == 500:
+                    err_text = "Error - 500 (Internal server Error) received"
+                else:
+                    err_text = "Error - Request returned a HTTP error code {}".format(str(e.status_code))
+
+                if e.screenshot:
+                    self.datastore.save_screenshot(watch_uuid=uuid, screenshot=e.screenshot, as_error=True)
+                if e.xpath_data:
+                    self.datastore.save_xpath_data(watch_uuid=uuid, data=e.xpath_data, as_error=True)
+                if e.page_text:
+                    self.datastore.save_error_text(watch_uuid=uuid, contents=e.page_text)
+
+                self.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
+                                                                   # So that we get a trigger when the content is added again
+                                                                   'previous_md5': ''})
+                process_changedetection_results = False
+
+            except FilterNotFoundInResponse as e:
+                err_text = "Warning, filter '{}' not found".format(str(e))
+                self.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
+                                                                   # So that we get a trigger when the content is added again
+                                                                   'previous_md5': ''})
+
+                # Only when enabled, send the notification
+                if self.datastore.data['watching'][uuid].get('filter_failure_notification_send', False):
+                    c = self.datastore.data['watching'][uuid].get('consecutive_filter_failures', 5)
+                    c += 1
+                    # Send notification if we reached the threshold?
+                    threshold = self.datastore.data['settings']['application'].get('filter_failure_notification_threshold_attempts',
+                                                                                   0)
+                    print("Filter for {} not found, consecutive_filter_failures: {}".format(uuid, c))
+                    if threshold > 0 and c >= threshold:
+                        if not self.datastore.data['watching'][uuid].get('notification_muted'):
+                            self.send_filter_failure_notification(uuid)
+                        c = 0
+
+                    self.datastore.update_watch(uuid=uuid, update_obj={'consecutive_filter_failures': c})
+
+                process_changedetection_results = True
+
+            except content_fetcher.EmptyReply as e:
+                # Some kind of custom to-str handler in the exception handler that does this?
+                err_text = "EmptyReply - try increasing 'Wait seconds before extracting text', 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 content_fetcher.ScreenshotUnavailable as e:
+                err_text = "Screenshot unavailable, page did not render fully in the expected time - try increasing 'Wait seconds before extracting text'"
+                self.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
+                                                                   'last_check_status': e.status_code})
+                process_changedetection_results = False
+            except content_fetcher.JSActionExceptions as e:
+                err_text = "Error running JS Actions - Page request - "+e.message
+                if e.screenshot:
+                    self.datastore.save_screenshot(watch_uuid=uuid, screenshot=e.screenshot, as_error=True)
+                self.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
+                                                                   'last_check_status': e.status_code})
+            except content_fetcher.PageUnloadable as e:
+                err_text = "Page request from server didnt respond correctly"
+                if e.message:
+                    err_text = "{} - {}".format(err_text, e.message)
+
+                if e.screenshot:
+                    self.datastore.save_screenshot(watch_uuid=uuid, screenshot=e.screenshot, as_error=True)
+
+                self.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
+                                                                   'last_check_status': e.status_code})
+            except Exception as e:
+                logging.error("Exception reached processing watch UUID: %s - %s", uuid, str(e))
+                self.datastore.update_watch(uuid=uuid, update_obj={'last_error': str(e)})
+                # Other serious error
+                process_changedetection_results = False
             else:
-                self.current_uuid = uuid
+                # Crash protection, the watch entry could have been removed by this point (during a slow chrome fetch etc)
+                if not self.datastore.data['watching'].get(uuid):
+                    return
 
-                if uuid in list(self.datastore.data['watching'].keys()):
-                    changed_detected = False
-                    contents = b''
-                    screenshot = False
-                    update_obj= {}
-                    xpath_data = False
-                    process_changedetection_results = True
-                    print("> Processing UUID {} Priority {} URL {}".format(uuid, priority, self.datastore.data['watching'][uuid]['url']))
-                    now = time.time()
+                # Mark that we never had any failures
+                if not self.datastore.data['watching'][uuid].get('ignore_status_codes'):
+                    update_obj['consecutive_filter_failures'] = 0
 
-                    try:
-                        changed_detected, update_obj, contents = 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))
-                        process_changedetection_results = False
-                    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
-                        # Backend (not filters) gave zero output
-                        self.datastore.update_watch(uuid=uuid, update_obj={'last_error': "Got HTML content but no text found (With {} reply code).".format(e.status_code)})
-                        if e.screenshot:
-                            self.datastore.save_screenshot(watch_uuid=uuid, screenshot=e.screenshot)
-                        process_changedetection_results = False
+                self.cleanup_error_artifacts(uuid)
 
-                    except content_fetcher.Non200ErrorCodeReceived as e:
-                        if e.status_code == 403:
-                            err_text = "Error - 403 (Access denied) received"
-                        elif e.status_code == 404:
-                            err_text = "Error - 404 (Page not found) received"
-                        elif e.status_code == 500:
-                            err_text = "Error - 500 (Internal server Error) received"
-                        else:
-                            err_text = "Error - Request returned a HTTP error code {}".format(str(e.status_code))
+            # Different exceptions mean that we may or may not want to bump the snapshot, trigger notifications etc
+            if process_changedetection_results:
+                try:
+                    watch = self.datastore.data['watching'][uuid]
+                    fname = "" # Saved history text filename
 
-                        if e.screenshot:
-                            self.datastore.save_screenshot(watch_uuid=uuid, screenshot=e.screenshot, as_error=True)
-                        if e.xpath_data:
-                            self.datastore.save_xpath_data(watch_uuid=uuid, data=e.xpath_data, as_error=True)
-                        if e.page_text:
-                            self.datastore.save_error_text(watch_uuid=uuid, contents=e.page_text)
+                    # 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
+                        watch.save_history_text(contents=contents, timestamp=str(round(time.time())))
 
-                        self.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
-                                                                           # So that we get a trigger when the content is added again
-                                                                           'previous_md5': ''})
-                        process_changedetection_results = False
+                    self.datastore.update_watch(uuid=uuid, update_obj=update_obj)
 
-                    except FilterNotFoundInResponse as e:
-                        err_text = "Warning, filter '{}' not found".format(str(e))
-                        self.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
-                                                                           # So that we get a trigger when the content is added again
-                                                                           'previous_md5': ''})
+                    # A change was detected
+                    if changed_detected:
+                        print (">> Change detected in UUID {} - {}".format(uuid, watch['url']))
 
-                        # Only when enabled, send the notification
-                        if self.datastore.data['watching'][uuid].get('filter_failure_notification_send', False):
-                            c = self.datastore.data['watching'][uuid].get('consecutive_filter_failures', 5)
-                            c += 1
-                            # Send notification if we reached the threshold?
-                            threshold = self.datastore.data['settings']['application'].get('filter_failure_notification_threshold_attempts',
-                                                                                           0)
-                            print("Filter for {} not found, consecutive_filter_failures: {}".format(uuid, c))
-                            if threshold > 0 and c >= threshold:
-                                if not self.datastore.data['watching'][uuid].get('notification_muted'):
-                                    self.send_filter_failure_notification(uuid)
-                                c = 0
-
-                            self.datastore.update_watch(uuid=uuid, update_obj={'consecutive_filter_failures': c})
-
-                        process_changedetection_results = True
-
-                    except content_fetcher.EmptyReply as e:
-                        # Some kind of custom to-str handler in the exception handler that does this?
-                        err_text = "EmptyReply - try increasing 'Wait seconds before extracting text', 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 content_fetcher.ScreenshotUnavailable as e:
-                        err_text = "Screenshot unavailable, page did not render fully in the expected time - try increasing 'Wait seconds before extracting text'"
-                        self.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
-                                                                           'last_check_status': e.status_code})
-                        process_changedetection_results = False
-                    except content_fetcher.JSActionExceptions as e:
-                        err_text = "Error running JS Actions - Page request - "+e.message
-                        if e.screenshot:
-                            self.datastore.save_screenshot(watch_uuid=uuid, screenshot=e.screenshot, as_error=True)
-                        self.datastore.update_watch(uuid=uuid, update_obj={'last_error': err_text,
-                                                                           'last_check_status': e.status_code})
-                    except content_fetcher.PageUnloadable as e:
-                        err_text = "Page request from server didnt respond correctly"
-                        if e.message:
-                            err_text = "{} - {}".format(err_text, e.message)
-
-                        if e.screenshot:
-                            self.datastore.save_screenshot(watch_uuid=uuid, screenshot=e.screenshot, as_error=True)
-
-                        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)})
-                        # Other serious error
-                        process_changedetection_results = False
-                    else:
-                        # Crash protection, the watch entry could have been removed by this point (during a slow chrome fetch etc)
-                        if not self.datastore.data['watching'].get(uuid):
-                            continue
-
-                        # Mark that we never had any failures
-                        if not self.datastore.data['watching'][uuid].get('ignore_status_codes'):
-                            update_obj['consecutive_filter_failures'] = 0
-
-                        self.cleanup_error_artifacts(uuid)
-
-                    # Different exceptions mean that we may or may not want to bump the snapshot, trigger notifications etc
-                    if process_changedetection_results:
-                        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
-                                watch.save_history_text(contents=contents, timestamp=str(round(time.time())))
-
-                            self.datastore.update_watch(uuid=uuid, update_obj=update_obj)
-
-                            # A change was detected
-                            if changed_detected:
-                                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:
-                                    if not self.datastore.data['watching'][uuid].get('notification_muted'):
-                                        self.send_content_changed_notification(self, watch_uuid=uuid)
+                        # Notifications should only trigger on the second time (first time, we gather the initial snapshot)
+                        if watch.history_n >= 2:
+                            if not self.datastore.data['watching'][uuid].get('notification_muted'):
+                                self.send_content_changed_notification(self, watch_uuid=uuid)
 
 
-                        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)})
+                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)
+                    logging.error("Exception reached processing watch UUID: %s - %s", uuid, str(e))
+                    self.datastore.update_watch(uuid=uuid, update_obj={'last_error': str(e)})
 
 
-                    # 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 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 update_handler.screenshot:
-                        self.datastore.save_screenshot(watch_uuid=uuid, screenshot=update_handler.screenshot)
-                    if update_handler.xpath_data:
-                        self.datastore.save_xpath_data(watch_uuid=uuid, data=update_handler.xpath_data)
+            # Always save the screenshot if it's available
+            if update_handler.screenshot:
+                self.datastore.save_screenshot(watch_uuid=uuid, screenshot=update_handler.screenshot)
+            if update_handler.xpath_data:
+                self.datastore.save_xpath_data(watch_uuid=uuid, data=update_handler.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)
+        self.current_uuid = None

requirements.txt

@@ -33,6 +33,8 @@ bs4
 # XPath filtering, lxml is required by bs4 anyway, but put it here to be safe.
 lxml
 
+PriorityThreadPoolExecutor
+
 # 3.141 was missing socksVersion, 3.150 was not in pypi, so we try 4.1.0
 selenium ~= 4.1.0