fix rate limiting per engine

searx/engines/__init__.py

@@ -45,7 +45,7 @@ ENGINE_DEFAULT_ARGS = {
     "using_tor_proxy": False,
     "display_error_messages": True,
     "send_accept_language_header": False,
-    "rate_limit": [{"max_requests": float('inf'), "interval": 1}],
+    "rate_limit": [{"max_requests": None, "interval": 1}],
     "tokens": [],
     "about": {},
 }

searx/search/__init__.py

@@ -98,10 +98,6 @@ class Search:
             if request_params is None:
                 continue
 
-            # stop request if it exceeds engine's rate limit
-            if processor.exceeds_rate_limit():
-                continue
-
             counter_inc('engine', engineref.name, 'search', 'count', 'sent')
 
             # append request to list

searx/search/processors/abstract.py

@@ -136,34 +136,27 @@ class EngineProcessor(ABC):
                 self.engine_name, self.suspended_status.suspend_reason, suspended=True
             )
             return True
+        if self.exceeds_rate_limit():
+            result_container.add_unresponsive_engine(self.engine_name, "Exceed rate limit", suspended=True)
+            return True
         return False
 
     def exceeds_rate_limit(self):
-        def check_rate_limiter(engine_name, max_requests, interval):
-            key = f'rate_limiter_{engine_name}_{max_requests}r/{interval}s'
-            # check requests count
-            count = storage.get_int(key)
-            if count is None:
-                # initialize counter with expiration time
-                storage.set_int(key, 1, interval)
-            elif count >= max_requests:
-                logger.debug(f"{engine_name} exceeded rate limit of {max_requests} requests per {interval} seconds")
-                return True
-            else:
-                # update counter
-                storage.set_int(key, count + 1)
-            return False
-
         result = False
+
         # add counter to all of the engine's rate limiters
         for rate_limit in self.engine.rate_limit:
             max_requests = rate_limit['max_requests']
             interval = rate_limit.get('interval', 1)
 
-            if max_requests == float('inf'):
+            if not max_requests:
                 continue
 
-            if run_locked(check_rate_limiter, self.engine_name, max_requests, interval):
+            name = f'{self.engine_name}_{max_requests}r/{interval}s'
+            if run_locked(storage.incr_counter, name, max_requests, interval) >= max_requests:
+                logger.debug(
+                    f"{self.engine_name} exceeded rate limit of {max_requests} requests per {interval} seconds"
+                )
                 result = True
 
         return result

searx/shared/shared_abstract.py

@@ -1,8 +1,11 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # pyright: strict
+import hmac
 from abc import ABC, abstractmethod
 from typing import Optional
 
+from searx import get_setting
+
 
 class SharedDict(ABC):
     @abstractmethod
@@ -20,3 +23,23 @@ class SharedDict(ABC):
     @abstractmethod
     def set_str(self, key: str, value: str, expire: Optional[int] = None):
         pass
+
+    def incr_counter(self, name: str, limit: int = 0, expire: int = 0) -> int:
+        # generate dict key from name
+        m = hmac.new(bytes(name, encoding='utf-8'), digestmod='sha256')
+        m.update(bytes(get_setting('server.secret_key'), encoding='utf-8'))
+        key = 'SearXNG_counter_' + m.hexdigest()
+
+        # check requests count
+        count = self.get_int(key)
+        if count is None:
+            # initialize counter with expiration time
+            self.set_int(key, 1, expire)
+            return 1
+        elif limit >= count or not limit:
+            # update counter
+            new_count = count + 1
+            self.set_int(key, new_count, expire)
+            return new_count
+        else:
+            return count

searx/shared/shared_simple.py

@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
+import time
 import threading
 from typing import Optional
 
@@ -12,27 +13,32 @@ class SimpleSharedDict(shared_abstract.SharedDict):
 
     def __init__(self):
         self.d = {}
+        self.expire_times = {}
+        schedule(1, self._expire)
 
     def get_int(self, key: str) -> Optional[int]:
         return self.d.get(key, None)
 
     def set_int(self, key: str, value: int, expire: Optional[int] = None):
         self.d[key] = value
-        if expire:
-            self._expire(key, expire)
+        if expire and not self.expire_times.get(key):
+            self.expire_times[key] = (time.time(), expire)
 
     def get_str(self, key: str) -> Optional[str]:
         return self.d.get(key, None)
 
     def set_str(self, key: str, value: str, expire: Optional[int] = None):
         self.d[key] = value
-        if expire:
-            self._expire(key, expire)
+        if expire and not self.expire_times.get(key):
+            self.expire_times[key] = (time.time(), expire)
 
-    def _expire(self, key: str, expire: int):
-        t = threading.Timer(expire, lambda k, d: d.pop(k), args=[key, self.d])
-        t.daemon = True
-        t.start()
+    def _expire(self):
+        now = time.time()
+        for key, val in self.expire_times.items():
+            created_at, expire = val
+            if now - created_at >= expire:
+                self.d.pop(key)
+                self.expire_times.pop(key)
 
 
 def run_locked(func, *args):

searx/shared/shared_uwsgi.py

@@ -1,8 +1,8 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
+import json
 import time
-from typing import Optional
-import threading
+from typing import Optional, Tuple, Union
 import uwsgi  # pyright: ignore # pylint: disable=E0401
 from . import shared_abstract
 
@@ -12,35 +12,50 @@ _last_signal = 10
 
 class UwsgiCacheSharedDict(shared_abstract.SharedDict):
     def get_int(self, key: str) -> Optional[int]:
-        value = uwsgi.cache_get(key)
+        value, _, _ = self._get_value(key)
         if value is None:
             return value
         else:
-            return int.from_bytes(value, 'big')
+            return int(value)
 
     def set_int(self, key: str, value: int, expire: Optional[int] = None):
-        b = value.to_bytes(4, 'big')
-        uwsgi.cache_update(key, b)
-        if expire:
-            self._expire(key, expire)
+        self._set_value(key, value, expire)
 
     def get_str(self, key: str) -> Optional[str]:
-        value = uwsgi.cache_get(key)
+        value, _, _ = self._get_value(key)
         if value is None:
             return value
         else:
-            return value.decode('utf-8')
+            return str(value)
 
     def set_str(self, key: str, value: str, expire: Optional[int] = None):
-        b = value.encode('utf-8')
-        uwsgi.cache_update(key, b)
-        if expire:
-            self._expire(key, expire)
+        self._set_value(key, value, expire)
 
-    def _expire(self, key: str, expire: int):
-        t = threading.Timer(expire, uwsgi.cache_del, args=[key])
-        t.daemon = True
-        t.start()
+    def _get_value(self, key: str) -> Tuple[Optional[Union[str, int]], Optional[float], Optional[int]]:
+        serialized_data = uwsgi.cache_get(key)
+        if not serialized_data:
+            return None, None, None
+        else:
+            data = json.loads(serialized_data.decode())
+            if 'expire' in data:
+                now = time.time()
+                if now - data['created_at'] >= data['expire']:
+                    uwsgi.cache_del(key)
+                    return None, None, None
+            return data.get('value'), data.get('created_at'), data.get('expire')
+
+    def _set_value(self, key: str, value: Union[str, int], expire: Optional[int] = None):
+        _, created_at, original_expire = self._get_value(key)
+
+        data = {'value': value}
+        if expire is None and created_at is None:
+            serialized_data = json.dumps(data).encode()
+            uwsgi.cache_update(key, serialized_data)
+        else:
+            data['created_at'] = created_at or time.time()
+            data['expire'] = original_expire or expire
+            serialized_data = json.dumps(data).encode()
+            uwsgi.cache_update(key, serialized_data, expire)
 
 
 def run_locked(func, *args):