[enh] checker: background check

See settings.yml for the options
SIGUSR1 signal starts the checker.
The result is available at /stats/checker

searx/search/checker/background.py

@@ -0,0 +1,106 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+import json
+import random
+import time
+import threading
+import os
+import signal
+
+from searx import logger, settings, searx_debug
+from searx.exceptions import SearxSettingsException
+from searx.search.processors import processors
+from searx.search.checker import Checker
+from searx.shared import schedule, storage
+
+
+CHECKER_RESULT = 'CHECKER_RESULT'
+running = threading.Lock()
+
+
+def _get_interval(every, error_msg):
+    if isinstance(every, int):
+        every = (every, every)
+    if not isinstance(every, (tuple, list))\
+       or len(every) != 2\
+       or not isinstance(every[0], int)\
+       or not isinstance(every[1], int):
+        raise SearxSettingsException(error_msg, None)
+    return every
+
+
+def _get_every():
+    every = settings.get('checker', {}).get('scheduling', {}).get('every', (300, 1800))
+    return _get_interval(every, 'checker.scheduling.every is not a int or list')
+
+
+def get_result():
+    serialized_result = storage.get_str('CHECKER_RESULT')
+    if serialized_result is not None:
+        return json.loads(serialized_result)
+
+
+def run():
+    if not running.acquire(blocking=False):
+        return
+    try:
+        logger.info('Starting checker')
+        result = {}
+        for name, processor in processors.items():
+            logger.debug('Checking %s engine', name)
+            checker = Checker(processor)
+            checker.run()
+            if checker.test_results.succesfull:
+                result[name] = {'status': True}
+            else:
+                result[name] = {'status': False, 'errors': checker.test_results.errors}
+
+        storage.set_str('CHECKER_RESULT', json.dumps(result))
+        logger.info('Check done')
+    finally:
+        running.release()
+
+
+def _run_with_delay():
+    every = _get_every()
+    delay = random.randint(0, every[1] - every[0])
+    logger.debug('Start checker in %i seconds', delay)
+    time.sleep(delay)
+    run()
+
+
+def _start_scheduling():
+    every = _get_every()
+    schedule(every[0], _run_with_delay)
+    run()
+
+
+def _signal_handler(signum, frame):
+    t = threading.Thread(target=run)
+    t.daemon = True
+    t.start()
+
+
+def initialize():
+    logger.info('Send SIGUSR1 signal to pid %i to start the checker', os.getpid())
+    signal.signal(signal.SIGUSR1, _signal_handler)
+
+    # special case when debug is activate
+    if searx_debug and settings.get('checker', {}).get('off_when_debug', True):
+        logger.info('debug mode: checker is disabled')
+        return
+
+    # check value of checker.scheduling.every now
+    scheduling = settings.get('checker', {}).get('scheduling', None)
+    if scheduling is None or not scheduling:
+        logger.info('Checker scheduler is disabled')
+        return
+
+    #
+    start_after = scheduling.get('start_after', (300, 1800))
+    start_after = _get_interval(start_after, 'checker.scheduling.start_after is not a int or list')
+    delay = random.randint(start_after[0], start_after[1])
+    logger.info('Start checker in %i seconds', delay)
+    t = threading.Timer(delay, _start_scheduling)
+    t.daemon = True
+    t.start()