diff --git a/synapse/http/request_metrics.py b/synapse/http/request_metrics.py
index 34a730d5bc..0984870e7e 100644
--- a/synapse/http/request_metrics.py
+++ b/synapse/http/request_metrics.py
@@ -17,6 +17,7 @@
import logging
from prometheus_client.core import Counter, Histogram
+from synapse.metrics import LaterGauge
from synapse.util.logcontext import LoggingContext
@@ -50,14 +51,75 @@ response_db_sched_duration = Counter("synapse_http_request_response_db_sched_dur
response_size = Counter("synapse_http_request_response_size", "", ["method", "servlet", "tag"]
)
+# In flight metrics are incremented while the requests are in flight, rather
+# than when the response was written.
+
+in_flight_requests_ru_utime = Counter("synapse_http_request_in_flight_requests_ru_utime_seconds", "", ["method", "servlet"])
+
+in_flight_requests_ru_stime = Counter("synapse_http_request_in_flight_requests_ru_stime_seconds", "", ["method", "servlet"])
+
+in_flight_requests_db_txn_count = Counter("synapse_http_request_in_flight_requests_db_txn_count", "", ["method", "servlet"])
+
+# seconds spent waiting for db txns, excluding scheduling time, when processing
+# this request
+in_flight_requests_db_txn_duration = Counter("synapse_http_request_in_flight_requests_db_txn_duration_seconds", "", ["method", "servlet"])
+
+# seconds spent waiting for a db connection, when processing this request
+in_flight_requests_db_sched_duration = Counter("synapse_http_request_in_flight_requests_db_sched_duration_seconds", "", ["method", "servlet"])
+
+# The set of all in flight requests, set[RequestMetrics]
+_in_flight_requests = set()
+
+
+def _collect_in_flight():
+ """Called just before metrics are collected, so we use it to update all
+ the in flight request metrics
+ """
+
+ for rm in _in_flight_requests:
+ rm.update_metrics()
+
+
+metrics.register_collector(_collect_in_flight)
+
+
+def _get_in_flight_counts():
+ """Returns a count of all in flight requests by (method, server_name)
+
+ Returns:
+ dict[tuple[str, str], int]
+ """
+
+ # Map from (method, name) -> int, the number of in flight requests of that
+ # type
+ counts = {}
+ for rm in _in_flight_requests:
+ key = (rm.method, rm.name,)
+ counts[key] = counts.get(key, 0) + 1
+
+ return counts
+
+LaterGauge(
+ "synapse_http_request_metrics_in_flight_requests_count", "",
+ ["method", "servlet"],
+ _get_in_flight_counts
+)
+
class RequestMetrics(object):
- def start(self, time_msec, name):
+ def start(self, time_msec, name, method):
self.start = time_msec
self.start_context = LoggingContext.current_context()
self.name = name
+ self.method = method
+
+ self._request_stats = _RequestStats.from_context(self.start_context)
+
+ _in_flight_requests.add(self)
def stop(self, time_msec, request):
+ _in_flight_requests.discard(self)
+
context = LoggingContext.current_context()
tag = ""
@@ -87,3 +149,76 @@ class RequestMetrics(object):
context.db_sched_duration_ms / 1000.)
response_size.labels(request.method, self.name, tag).inc(request.sentLength)
+
+ # We always call this at the end to ensure that we update the metrics
+ # regardless of whether a call to /metrics while the request was in
+ # flight.
+ self.update_metrics()
+
+ def update_metrics(self):
+ """Updates the in flight metrics with values from this request.
+ """
+ diff = self._request_stats.update(self.start_context)
+
+ in_flight_requests_ru_utime.labels(self.method, self.name).inc(diff.ru_utime)
+ in_flight_requests_ru_stime.labels(self.method, self.name).inc(diff.ru_stime)
+
+ in_flight_requests_db_txn_count.labels(self.method, self.name).inc(diff.db_txn_count)
+
+ in_flight_requests_db_txn_duration.labels(self.method, self.name).inc(diff.db_txn_duration_ms / 1000.)
+
+ in_flight_requests_db_sched_duration.labels(self.method, self.name).inc(diff.db_sched_duration_ms / 1000.)
+
+
+class _RequestStats(object):
+ """Keeps tracks of various metrics for an in flight request.
+ """
+
+ __slots__ = [
+ "ru_utime", "ru_stime",
+ "db_txn_count", "db_txn_duration_ms", "db_sched_duration_ms",
+ ]
+
+ def __init__(self, ru_utime, ru_stime, db_txn_count,
+ db_txn_duration_ms, db_sched_duration_ms):
+ self.ru_utime = ru_utime
+ self.ru_stime = ru_stime
+ self.db_txn_count = db_txn_count
+ self.db_txn_duration_ms = db_txn_duration_ms
+ self.db_sched_duration_ms = db_sched_duration_ms
+
+ @staticmethod
+ def from_context(context):
+ ru_utime, ru_stime = context.get_resource_usage()
+
+ return _RequestStats(
+ ru_utime, ru_stime,
+ context.db_txn_count,
+ context.db_txn_duration_ms,
+ context.db_sched_duration_ms,
+ )
+
+ def update(self, context):
+ """Updates the current values and returns the difference between the
+ old and new values.
+
+ Returns:
+ _RequestStats: The difference between the old and new values
+ """
+ new = _RequestStats.from_context(context)
+
+ diff = _RequestStats(
+ new.ru_utime - self.ru_utime,
+ new.ru_stime - self.ru_stime,
+ new.db_txn_count - self.db_txn_count,
+ new.db_txn_duration_ms - self.db_txn_duration_ms,
+ new.db_sched_duration_ms - self.db_sched_duration_ms,
+ )
+
+ self.ru_utime = new.ru_utime
+ self.ru_stime = new.ru_stime
+ self.db_txn_count = new.db_txn_count
+ self.db_txn_duration_ms = new.db_txn_duration_ms
+ self.db_sched_duration_ms = new.db_sched_duration_ms
+
+ return diff
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