Describe which rate limiter was hit in logs

synapse/config/ratelimiting.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import Any, Dict, Optional
+from typing import Any, Dict, Optional, cast
 
 import attr
 
@@ -21,16 +21,46 @@
 from ._base import Config
 
 
+@attr.s(slots=True, frozen=True, auto_attribs=True)
 class RatelimitSettings:
-    def __init__(
-        self,
-        config: Dict[str, float],
-        defaults: Optional[Dict[str, float]] = None,
-    ):
-        defaults = defaults or {"per_second": 0.17, "burst_count": 3.0}
+    key: str
+    per_second: float
+    burst_count: int
 
-        self.per_second = config.get("per_second", defaults["per_second"])
-        self.burst_count = int(config.get("burst_count", defaults["burst_count"]))
+
+def parse_rate_limit(
+    config: Dict[str, Any],
+    key: str,
+    defaults: Optional[Dict[str, float]] = None,
+) -> RatelimitSettings:
+    """Parse config[key] as a new-style rate limiter config.
+
+    The key may refer to a nested dictionary using a full stop (.) to separate
+    each nested key. For example, use the key "a.b.c" to parse the following:
+
+    a:
+      b:
+        c:
+          per_second: 10
+          burst_count: 200
+
+    If this lookup fails, we'll fallback to the defaults.
+    """
+    defaults = defaults or {"per_second": 0.17, "burst_count": 3.0}
+
+    rl_config = config
+    for part in key.split("."):
+        rl_config = rl_config.get(part, {})
+
+    # By this point we should have hit the rate limiter parameters.
+    # We don't actually check this though!
+    rl_config = cast(Dict[str, float], rl_config)
+
+    return RatelimitSettings(
+        key=key,
+        per_second=rl_config.get("per_second", defaults["per_second"]),
+        burst_count=int(rl_config.get("burst_count", defaults["burst_count"])),
+    )
 
 
 @attr.s(auto_attribs=True)
@@ -49,15 +79,14 @@ def read_config(self, config: JsonDict, **kwargs: Any) -> None:
         # Load the new-style messages config if it exists. Otherwise fall back
         # to the old method.
         if "rc_message" in config:
-            self.rc_message = RatelimitSettings(
-                config["rc_message"], defaults={"per_second": 0.2, "burst_count": 10.0}
+            self.rc_message = parse_rate_limit(
+                config, "rc_message", defaults={"per_second": 0.2, "burst_count": 10.0}
             )
         else:
             self.rc_message = RatelimitSettings(
-                {
-                    "per_second": config.get("rc_messages_per_second", 0.2),
-                    "burst_count": config.get("rc_message_burst_count", 10.0),
-                }
+                key="rc_messages",
+                per_second=config.get("rc_messages_per_second", 0.2),
+                burst_count=config.get("rc_message_burst_count", 10.0),
             )
 
         # Load the new-style federation config, if it exists. Otherwise, fall
@@ -79,51 +108,57 @@ def read_config(self, config: JsonDict, **kwargs: Any) -> None:
                 }
             )
 
-        self.rc_registration = RatelimitSettings(config.get("rc_registration", {}))
+        self.rc_registration = parse_rate_limit(config, "rc_registration", {})
 
-        self.rc_registration_token_validity = RatelimitSettings(
-            config.get("rc_registration_token_validity", {}),
+        self.rc_registration_token_validity = parse_rate_limit(
+            config,
+            "rc_registration_token_validity",
             defaults={"per_second": 0.1, "burst_count": 5},
         )
 
         # It is reasonable to login with a bunch of devices at once (i.e. when
         # setting up an account), but it is *not* valid to continually be
         # logging into new devices.
-        rc_login_config = config.get("rc_login", {})
-        self.rc_login_address = RatelimitSettings(
-            rc_login_config.get("address", {}),
+        self.rc_login_address = parse_rate_limit(
+            config,
+            "rc_login.address",
             defaults={"per_second": 0.003, "burst_count": 5},
         )
-        self.rc_login_account = RatelimitSettings(
-            rc_login_config.get("account", {}),
+        self.rc_login_account = parse_rate_limit(
+            config,
+            "rc_login.account",
             defaults={"per_second": 0.003, "burst_count": 5},
         )
-        self.rc_login_failed_attempts = RatelimitSettings(
-            rc_login_config.get("failed_attempts", {})
+        self.rc_login_failed_attempts = parse_rate_limit(
+            config,
+            "rc_login.failed_attempts",
+            {},
         )
 
         self.federation_rr_transactions_per_room_per_second = config.get(
             "federation_rr_transactions_per_room_per_second", 50
         )
 
-        rc_admin_redaction = config.get("rc_admin_redaction")
         self.rc_admin_redaction = None
-        if rc_admin_redaction:
-            self.rc_admin_redaction = RatelimitSettings(rc_admin_redaction)
+        if "rc_admin_redaction" in config:
+            self.rc_admin_redaction = parse_rate_limit(config, "rc_admin_redaction", {})
 
-        self.rc_joins_local = RatelimitSettings(
-            config.get("rc_joins", {}).get("local", {}),
+        self.rc_joins_local = parse_rate_limit(
+            config,
+            "rc_joins.local",
             defaults={"per_second": 0.1, "burst_count": 10},
         )
-        self.rc_joins_remote = RatelimitSettings(
-            config.get("rc_joins", {}).get("remote", {}),
+        self.rc_joins_remote = parse_rate_limit(
+            config,
+            "rc_joins.remote",
             defaults={"per_second": 0.01, "burst_count": 10},
         )
 
         # Track the rate of joins to a given room. If there are too many, temporarily
         # prevent local joins and remote joins via this server.
-        self.rc_joins_per_room = RatelimitSettings(
-            config.get("rc_joins_per_room", {}),
+        self.rc_joins_per_room = parse_rate_limit(
+            config,
+            "rc_joins_per_room",
             defaults={"per_second": 1, "burst_count": 10},
         )
 
@@ -132,31 +167,37 @@ def read_config(self, config: JsonDict, **kwargs: Any) -> None:
         # * For requests received over federation this is keyed by the origin.
         #
         # Note that this isn't exposed in the configuration as it is obscure.
-        self.rc_key_requests = RatelimitSettings(
-            config.get("rc_key_requests", {}),
+        self.rc_key_requests = parse_rate_limit(
+            config,
+            "rc_key_requests",
             defaults={"per_second": 20, "burst_count": 100},
         )
 
-        self.rc_3pid_validation = RatelimitSettings(
-            config.get("rc_3pid_validation") or {},
+        self.rc_3pid_validation = parse_rate_limit(
+            config,
+            "rc_3pid_validation",
             defaults={"per_second": 0.003, "burst_count": 5},
         )
 
-        self.rc_invites_per_room = RatelimitSettings(
-            config.get("rc_invites", {}).get("per_room", {}),
+        self.rc_invites_per_room = parse_rate_limit(
+            config,
+            "rc_invites.per_room",
             defaults={"per_second": 0.3, "burst_count": 10},
         )
-        self.rc_invites_per_user = RatelimitSettings(
-            config.get("rc_invites", {}).get("per_user", {}),
+        self.rc_invites_per_user = parse_rate_limit(
+            config,
+            "rc_invites.per_user",
             defaults={"per_second": 0.003, "burst_count": 5},
         )
 
-        self.rc_invites_per_issuer = RatelimitSettings(
-            config.get("rc_invites", {}).get("per_issuer", {}),
+        self.rc_invites_per_issuer = parse_rate_limit(
+            config,
+            "rc_invites.per_issuer",
             defaults={"per_second": 0.3, "burst_count": 10},
         )
 
-        self.rc_third_party_invite = RatelimitSettings(
-            config.get("rc_third_party_invite", {}),
+        self.rc_third_party_invite = parse_rate_limit(
+            config,
+            "rc_third_party_invite",
             defaults={"per_second": 0.0025, "burst_count": 5},
         )

tests/config/test_ratelimiting.py

@@ -12,11 +12,42 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 from synapse.config.homeserver import HomeServerConfig
+from synapse.config.ratelimiting import RatelimitSettings, parse_rate_limit
 
 from tests.unittest import TestCase
 from tests.utils import default_config
 
 
+class ParseRatelimitSettingsTestcase(TestCase):
+    def test_depth_1(self) -> None:
+        cfg = {
+            "a": {
+                "per_second": 5,
+                "burst_count": 10,
+            }
+        }
+        parsed = parse_rate_limit(cfg, "a")
+        self.assertEqual(parsed, RatelimitSettings("a", 5, 10))
+
+    def test_depth_2(self) -> None:
+        cfg = {
+            "a": {
+                "b": {
+                    "per_second": 5,
+                    "burst_count": 10,
+                },
+            }
+        }
+        parsed = parse_rate_limit(cfg, "a.b")
+        self.assertEqual(parsed, RatelimitSettings("a.b", 5, 10))
+
+    def test_missing(self) -> None:
+        parsed = parse_rate_limit(
+            {}, "a", defaults={"per_second": 5, "burst_count": 10}
+        )
+        self.assertEqual(parsed, RatelimitSettings("a", 5, 10))
+
+
 class RatelimitConfigTestCase(TestCase):
     def test_parse_rc_federation(self) -> None:
         config_dict = default_config("test")