Add metrics for tracking 3PID /requestToken requests. (#8712)

The main use case is to see how many requests are being made, and how
many are second/third/etc attempts. If there are large number of retries
then that likely indicates a delivery problem.

changelog.d/8712.misc

@@ -0,0 +1 @@
+Add metrics the allow the local sysadmin to track 3PID `/requestToken` requests.

synapse/metrics/__init__.py

@@ -502,6 +502,16 @@ def collect(self):
 
 last_ticked = time.time()
 
+# 3PID send info
+threepid_send_requests = Histogram(
+    "synapse_threepid_send_requests_with_tries",
+    documentation="Number of requests for a 3pid token by try count. Note if"
+    " there is a request with try count of 4, then there would have been one"
+    " each for 1, 2 and 3",
+    buckets=(1, 2, 3, 4, 5, 10),
+    labelnames=("type", "reason"),
+)
+
 
 class ReactorLastSeenMetric:
     def collect(self):

synapse/rest/client/v2_alpha/account.py

@@ -38,6 +38,7 @@
     parse_json_object_from_request,
     parse_string,
 )
+from synapse.metrics import threepid_send_requests
 from synapse.push.mailer import Mailer
 from synapse.util.msisdn import phone_number_to_msisdn
 from synapse.util.stringutils import assert_valid_client_secret, random_string
@@ -143,6 +144,10 @@ async def on_POST(self, request):
             # Wrap the session id in a JSON object
             ret = {"sid": sid}
 
+        threepid_send_requests.labels(type="email", reason="password_reset").observe(
+            send_attempt
+        )
+
         return 200, ret
 
 
@@ -411,6 +416,10 @@ async def on_POST(self, request):
             # Wrap the session id in a JSON object
             ret = {"sid": sid}
 
+        threepid_send_requests.labels(type="email", reason="add_threepid").observe(
+            send_attempt
+        )
+
         return 200, ret
 
 
@@ -481,6 +490,10 @@ async def on_POST(self, request):
             next_link,
         )
 
+        threepid_send_requests.labels(type="msisdn", reason="add_threepid").observe(
+            send_attempt
+        )
+
         return 200, ret
 
 

synapse/rest/client/v2_alpha/register.py

@@ -45,6 +45,7 @@
     parse_json_object_from_request,
     parse_string,
 )
+from synapse.metrics import threepid_send_requests
 from synapse.push.mailer import Mailer
 from synapse.util.msisdn import phone_number_to_msisdn
 from synapse.util.ratelimitutils import FederationRateLimiter
@@ -163,6 +164,10 @@ async def on_POST(self, request):
             # Wrap the session id in a JSON object
             ret = {"sid": sid}
 
+        threepid_send_requests.labels(type="email", reason="register").observe(
+            send_attempt
+        )
+
         return 200, ret
 
 
@@ -234,6 +239,10 @@ async def on_POST(self, request):
             next_link,
         )
 
+        threepid_send_requests.labels(type="msisdn", reason="register").observe(
+            send_attempt
+        )
+
         return 200, ret