Prometheus metrics for logins and registrations (#9511)

Add prom metrics for number of users successfully registering and logging in, by SSO provider.

changelog.d/9511.feature

@@ -0,0 +1 @@
+Add prometheus metrics for number of users successfully registering and logging in.

synapse/handlers/register.py

@@ -18,6 +18,8 @@
 import logging
 from typing import TYPE_CHECKING, Iterable, List, Optional, Tuple
 
+from prometheus_client import Counter
+
 from synapse import types
 from synapse.api.constants import MAX_USERID_LENGTH, EventTypes, JoinRules, LoginType
 from synapse.api.errors import AuthError, Codes, ConsentNotGivenError, SynapseError
@@ -41,6 +43,19 @@
 logger = logging.getLogger(__name__)
 
 
+registration_counter = Counter(
+    "synapse_user_registrations_total",
+    "Number of new users registered (since restart)",
+    ["guest", "shadow_banned", "auth_provider"],
+)
+
+login_counter = Counter(
+    "synapse_user_logins_total",
+    "Number of user logins (since restart)",
+    ["guest", "auth_provider"],
+)
+
+
 class RegistrationHandler(BaseHandler):
     def __init__(self, hs: "HomeServer"):
         super().__init__(hs)
@@ -156,6 +171,7 @@ async def register_user(
         bind_emails: Iterable[str] = [],
         by_admin: bool = False,
         user_agent_ips: Optional[List[Tuple[str, str]]] = None,
+        auth_provider_id: Optional[str] = None,
     ) -> str:
         """Registers a new client on the server.
 
@@ -181,8 +197,10 @@ async def register_user(
               admin api, otherwise False.
             user_agent_ips: Tuples of IP addresses and user-agents used
                 during the registration process.
+            auth_provider_id: The SSO IdP the user used, if any (just used for the
+                prometheus metrics).
         Returns:
-            The registere user_id.
+            The registered user_id.
         Raises:
             SynapseError if there was a problem registering.
         """
@@ -280,6 +298,12 @@ async def register_user(
                     # if user id is taken, just generate another
                     fail_count += 1
 
+        registration_counter.labels(
+            guest=make_guest,
+            shadow_banned=shadow_banned,
+            auth_provider=(auth_provider_id or ""),
+        ).inc()
+
         if not self.hs.config.user_consent_at_registration:
             if not self.hs.config.auto_join_rooms_for_guests and make_guest:
                 logger.info(
@@ -638,6 +662,7 @@ async def register_device(
         initial_display_name: Optional[str],
         is_guest: bool = False,
         is_appservice_ghost: bool = False,
+        auth_provider_id: Optional[str] = None,
     ) -> Tuple[str, str]:
         """Register a device for a user and generate an access token.
 
@@ -648,7 +673,8 @@ async def register_device(
             device_id: The device ID to check, or None to generate a new one.
             initial_display_name: An optional display name for the device.
             is_guest: Whether this is a guest account
-
+            auth_provider_id: The SSO IdP the user used, if any (just used for the
+                prometheus metrics).
         Returns:
             Tuple of device ID and access token
         """
@@ -687,6 +713,11 @@ async def register_device(
                 is_appservice_ghost=is_appservice_ghost,
             )
 
+        login_counter.labels(
+            guest=is_guest,
+            auth_provider=(auth_provider_id or ""),
+        ).inc()
+
         return (registered_device_id, access_token)
 
     async def post_registration_actions(

synapse/handlers/sso.py

@@ -606,6 +606,7 @@ async def _register_mapped_user(
             default_display_name=attributes.display_name,
             bind_emails=attributes.emails,
             user_agent_ips=[(user_agent, ip_address)],
+            auth_provider_id=auth_provider_id,
         )
 
         await self._store.record_user_external_id(

synapse/rest/client/v1/login.py

@@ -219,6 +219,7 @@ async def _complete_login(
         callback: Optional[Callable[[Dict[str, str]], Awaitable[None]]] = None,
         create_non_existent_users: bool = False,
         ratelimit: bool = True,
+        auth_provider_id: Optional[str] = None,
     ) -> Dict[str, str]:
         """Called when we've successfully authed the user and now need to
         actually login them in (e.g. create devices). This gets called on
@@ -234,6 +235,8 @@ async def _complete_login(
             create_non_existent_users: Whether to create the user if they don't
                 exist. Defaults to False.
             ratelimit: Whether to ratelimit the login request.
+            auth_provider_id: The SSO IdP the user used, if any (just used for the
+                prometheus metrics).
 
         Returns:
             result: Dictionary of account information after successful login.
@@ -256,7 +259,7 @@ async def _complete_login(
         device_id = login_submission.get("device_id")
         initial_display_name = login_submission.get("initial_device_display_name")
         device_id, access_token = await self.registration_handler.register_device(
-            user_id, device_id, initial_display_name
+            user_id, device_id, initial_display_name, auth_provider_id=auth_provider_id
         )
 
         result = {
@@ -286,7 +289,10 @@ async def _do_token_login(self, login_submission: JsonDict) -> Dict[str, str]:
         res = await auth_handler.validate_short_term_login_token(token)
 
         return await self._complete_login(
-            res.user_id, login_submission, self.auth_handler._sso_login_callback
+            res.user_id,
+            login_submission,
+            self.auth_handler._sso_login_callback,
+            auth_provider_id=res.auth_provider_id,
         )
 
     async def _do_jwt_login(self, login_submission: JsonDict) -> Dict[str, str]: