forked-synapse/synapse/http/request_metrics.py
Richard van der Hoff 55370331da
Refactor logcontext resource usage tracking (#3501)
Factor out the resource usage tracking out to a separate object, which can be
passed around and copied independently of the logcontext itself.
2018-07-10 13:56:07 +01:00

229 lines
6.9 KiB
Python

# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
# Copyright 2018 New Vector Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
from prometheus_client.core import Counter, Histogram
from synapse.metrics import LaterGauge
from synapse.util.logcontext import LoggingContext
logger = logging.getLogger(__name__)
# total number of responses served, split by method/servlet/tag
response_count = Counter(
"synapse_http_server_response_count", "", ["method", "servlet", "tag"]
)
requests_counter = Counter(
"synapse_http_server_requests_received", "", ["method", "servlet"]
)
outgoing_responses_counter = Counter(
"synapse_http_server_responses", "", ["method", "code"]
)
response_timer = Histogram(
"synapse_http_server_response_time_seconds", "sec", ["method", "servlet", "tag"]
)
response_ru_utime = Counter(
"synapse_http_server_response_ru_utime_seconds", "sec", ["method", "servlet", "tag"]
)
response_ru_stime = Counter(
"synapse_http_server_response_ru_stime_seconds", "sec", ["method", "servlet", "tag"]
)
response_db_txn_count = Counter(
"synapse_http_server_response_db_txn_count", "", ["method", "servlet", "tag"]
)
# seconds spent waiting for db txns, excluding scheduling time, when processing
# this request
response_db_txn_duration = Counter(
"synapse_http_server_response_db_txn_duration_seconds",
"",
["method", "servlet", "tag"],
)
# seconds spent waiting for a db connection, when processing this request
response_db_sched_duration = Counter(
"synapse_http_server_response_db_sched_duration_seconds",
"",
["method", "servlet", "tag"],
)
# size in bytes of the response written
response_size = Counter(
"synapse_http_server_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_server_in_flight_requests_ru_utime_seconds",
"",
["method", "servlet"],
)
in_flight_requests_ru_stime = Counter(
"synapse_http_server_in_flight_requests_ru_stime_seconds",
"",
["method", "servlet"],
)
in_flight_requests_db_txn_count = Counter(
"synapse_http_server_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_server_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_server_in_flight_requests_db_sched_duration_seconds",
"",
["method", "servlet"],
)
# The set of all in flight requests, set[RequestMetrics]
_in_flight_requests = set()
def _get_in_flight_counts():
"""Returns a count of all in flight requests by (method, server_name)
Returns:
dict[tuple[str, str], int]
"""
# Cast to a list to prevent it changing while the Prometheus
# thread is collecting metrics
reqs = list(_in_flight_requests)
for rm in reqs:
rm.update_metrics()
# Map from (method, name) -> int, the number of in flight requests of that
# type
counts = {}
for rm in reqs:
key = (rm.method, rm.name,)
counts[key] = counts.get(key, 0) + 1
return counts
LaterGauge(
"synapse_http_server_in_flight_requests_count",
"",
["method", "servlet"],
_get_in_flight_counts,
)
class RequestMetrics(object):
def start(self, time_sec, name, method):
self.start = time_sec
self.start_context = LoggingContext.current_context()
self.name = name
self.method = method
# _request_stats records resource usage that we have already added
# to the "in flight" metrics.
self._request_stats = self.start_context.get_resource_usage()
_in_flight_requests.add(self)
def stop(self, time_sec, request):
_in_flight_requests.discard(self)
context = LoggingContext.current_context()
tag = ""
if context:
tag = context.tag
if context != self.start_context:
logger.warn(
"Context have unexpectedly changed %r, %r",
context, self.start_context
)
return
outgoing_responses_counter.labels(request.method, str(request.code)).inc()
response_count.labels(request.method, self.name, tag).inc()
response_timer.labels(request.method, self.name, tag).observe(
time_sec - self.start
)
resource_usage = context.get_resource_usage()
response_ru_utime.labels(request.method, self.name, tag).inc(
resource_usage.ru_utime,
)
response_ru_stime.labels(request.method, self.name, tag).inc(
resource_usage.ru_stime,
)
response_db_txn_count.labels(request.method, self.name, tag).inc(
resource_usage.db_txn_count
)
response_db_txn_duration.labels(request.method, self.name, tag).inc(
resource_usage.db_txn_duration_sec
)
response_db_sched_duration.labels(request.method, self.name, tag).inc(
resource_usage.db_sched_duration_sec
)
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.
"""
new_stats = self.start_context.get_resource_usage()
diff = new_stats - self._request_stats
self._request_stats = new_stats
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_sec
)
in_flight_requests_db_sched_duration.labels(self.method, self.name).inc(
diff.db_sched_duration_sec
)