feat: pass username to AXES_COOLOFF_TIME callback

If the AXES_COOLOFF_TIME is a callable or path to a callable taking
an argument, pass the username to it.

This should enable users to customize the cool off to be user dependant,
and possibly implement a growing cool-off time:

- First lockout cools off after 5 mins
- Second one after 10 mins
- etc...

axes/handlers/cache.py

@@ -113,7 +113,7 @@ def user_login_failed(self, sender, credentials: dict, request=None, **kwargs):
             return
 
         cache_keys = get_client_cache_keys(request, credentials)
-        cache_timeout = get_cache_timeout()
+        cache_timeout = get_cache_timeout(username)
         failures = []
         for cache_key in cache_keys:
             added = self.cache.add(key=cache_key, value=1, timeout=cache_timeout)

axes/helpers.py

@@ -1,3 +1,5 @@
+import functools
+import inspect
 from datetime import timedelta
 from hashlib import sha256
 from logging import getLogger
@@ -32,7 +34,7 @@ def get_cache() -> BaseCache:
     return caches[getattr(settings, "AXES_CACHE", "default")]
 
 
-def get_cache_timeout() -> Optional[int]:
+def get_cache_timeout(username: Optional[str]=None) -> Optional[int]:
     """
     Return the cache timeout interpreted from settings.AXES_COOLOFF_TIME.
 
@@ -43,21 +45,22 @@ def get_cache_timeout() -> Optional[int]:
     for use with the Django cache backends.
     """
 
-    cool_off = get_cool_off()
+    cool_off = get_cool_off(username)
     if cool_off is None:
         return None
     return int(cool_off.total_seconds())
 
 
-def get_cool_off() -> Optional[timedelta]:
+def get_cool_off(username: Optional[str]=None) -> Optional[timedelta]:
     """
     Return the login cool off time interpreted from settings.AXES_COOLOFF_TIME.
 
     The return value is either None or timedelta.
 
-    Notice that the settings.AXES_COOLOFF_TIME is either None, timedelta, or integer/float of hours,
-    and this function offers a unified _timedelta or None_ representation of that configuration
-    for use with the Axes internal implementations.
+    Notice that the settings.AXES_COOLOFF_TIME is either None, timedelta, integer/float of hours,
+    a path to a callable or a callable taking zero or 1 argument (the username). This function
+    offers a unified _timedelta or None_ representation of that configuration for use with the
+    Axes internal implementations.
 
     :exception TypeError: if settings.AXES_COOLOFF_TIME is of wrong type.
     """
@@ -69,13 +72,22 @@ def get_cool_off() -> Optional[timedelta]:
     if isinstance(cool_off, float):
         return timedelta(minutes=cool_off * 60)
     if isinstance(cool_off, str):
-        return import_string(cool_off)()
+        cool_off_func = import_string(cool_off)
+        return _maybe_partial(cool_off_func, username)()
     if callable(cool_off):
-        return cool_off()  # pylint: disable=not-callable
+        return _maybe_partial(cool_off, username)()  # pylint: disable=not-callable
 
     return cool_off
 
 
+def _maybe_partial(func: Callable, username: Optional[str] = None):
+    """Bind the given username to the function if it accepts a single argument."""
+    sig = inspect.signature(func)
+    if len(sig.parameters) == 1:
+        return functools.partial(func, username)
+    return func
+
+
 def get_cool_off_iso8601(delta: timedelta) -> str:
     """
     Return datetime.timedelta translated to ISO 8601 formatted duration for use in e.g. cool offs.
@@ -114,7 +126,7 @@ def get_credentials(username: Optional[str] = None, **kwargs) -> dict:
 
 def get_client_username(
     request: HttpRequest, credentials: Optional[dict] = None
-) -> str:
+) -> Optional[str]:
     """
     Resolve client username from the given request or credentials if supplied.
 

docs/4_configuration.rst

@@ -23,7 +23,7 @@ The following ``settings.py`` options are available for customizing Axes behavio
 +------------------------------------------------------+----------------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
 | AXES_LOCK_OUT_AT_FAILURE                             | True                                         | After the number of allowed login attempts are exceeded, should we lock out this IP (and optional user agent)?                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
 +------------------------------------------------------+----------------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
-| AXES_COOLOFF_TIME                                    | None                                         | If set, defines a period of inactivity after which  old failed login attempts will be cleared.  Can be set to a Python timedelta object, an integer, a float, a callable, or a string path to a callable which takes no arguments.  If an integer or float, will be interpreted as a number of hours:  ``AXES_COOLOFF_TIME = 2`` 2 hours,   ``AXES_COOLOFF_TIME = 2.0`` 2 hours, 120 minutes,  ``AXES_COOLOFF_TIME = 1.7`` 1.7 hours, 102 minutes, 6120 seconds                                                                                                                                                                                                                                                                           |
+| AXES_COOLOFF_TIME                                    | None                                         | If set, defines a period of inactivity after which  old failed login attempts will be cleared.  Can be set to a Python timedelta object, an integer, a float, a callable, or a string path to a callable which takes the username as argument.  If an integer or float, will be interpreted as a number of hours:  ``AXES_COOLOFF_TIME = 2`` 2 hours,   ``AXES_COOLOFF_TIME = 2.0`` 2 hours, 120 minutes,  ``AXES_COOLOFF_TIME = 1.7`` 1.7 hours, 102 minutes, 6120 seconds                                                                                                                                                                                                                                                                           |
 +------------------------------------------------------+----------------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
 | AXES_ONLY_ADMIN_SITE                                 | False                                        | If ``True``, lock is only enabled for admin site. Admin site is determined by checking request path against the path of ``"admin:index"`` view. If admin urls are not registered in current urlconf, all requests will not be locked.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
 +------------------------------------------------------+----------------------------------------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

tests/test_helpers.py

@@ -59,6 +59,32 @@ def test_get_cache_timeout_timedelta(self):
     def test_get_cache_timeout_none(self):
         self.assertEqual(get_cache_timeout(), None)
 
+    def test_get_increasing_cache_timeout(self):
+        user_durations = {
+            "ben": timedelta(minutes=5),
+            "jen": timedelta(minutes=10),
+        }
+
+        def _callback(username):
+            previous_duration = user_durations.get(username, timedelta())
+            user_durations[username] = previous_duration + timedelta(minutes=5)
+            return user_durations[username]
+
+        with override_settings(AXES_COOLOFF_TIME=_callback):
+            with self.subTest("no username"):
+                self.assertEqual(get_cache_timeout(), 300)
+
+            with self.subTest("ben"):
+                self.assertEqual(get_cache_timeout("ben"), 600)
+                self.assertEqual(get_cache_timeout("ben"), 900)
+                self.assertEqual(get_cache_timeout("ben"), 1200)
+
+            with self.subTest("jen"):
+                self.assertEqual(get_cache_timeout("jen"), 900)
+
+            with self.subTest("james"):
+                self.assertEqual(get_cache_timeout("james"), 300)
+
 
 class TimestampTestCase(AxesTestCase):
     def test_iso8601(self):