MatrixSynapse/synapse/util/metrics.py

179 lines
5.4 KiB
Python

# Copyright 2016 OpenMarket 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 functools import wraps
from typing import Any, Callable, Optional, TypeVar, cast
from prometheus_client import Counter
from synapse.logging.context import (
ContextResourceUsage,
LoggingContext,
current_context,
)
from synapse.metrics import InFlightGauge
logger = logging.getLogger(__name__)
block_counter = Counter("synapse_util_metrics_block_count", "", ["block_name"])
block_timer = Counter("synapse_util_metrics_block_time_seconds", "", ["block_name"])
block_ru_utime = Counter(
"synapse_util_metrics_block_ru_utime_seconds", "", ["block_name"]
)
block_ru_stime = Counter(
"synapse_util_metrics_block_ru_stime_seconds", "", ["block_name"]
)
block_db_txn_count = Counter(
"synapse_util_metrics_block_db_txn_count", "", ["block_name"]
)
# seconds spent waiting for db txns, excluding scheduling time, in this block
block_db_txn_duration = Counter(
"synapse_util_metrics_block_db_txn_duration_seconds", "", ["block_name"]
)
# seconds spent waiting for a db connection, in this block
block_db_sched_duration = Counter(
"synapse_util_metrics_block_db_sched_duration_seconds", "", ["block_name"]
)
# Tracks the number of blocks currently active
in_flight = InFlightGauge(
"synapse_util_metrics_block_in_flight",
"",
labels=["block_name"],
sub_metrics=["real_time_max", "real_time_sum"],
)
T = TypeVar("T", bound=Callable[..., Any])
def measure_func(name: Optional[str] = None) -> Callable[[T], T]:
"""
Used to decorate an async function with a `Measure` context manager.
Usage:
@measure_func()
async def foo(...):
...
Which is analogous to:
async def foo(...):
with Measure(...):
...
"""
def wrapper(func: T) -> T:
block_name = func.__name__ if name is None else name
@wraps(func)
async def measured_func(self, *args, **kwargs):
with Measure(self.clock, block_name):
r = await func(self, *args, **kwargs)
return r
return cast(T, measured_func)
return wrapper
class Measure:
__slots__ = [
"clock",
"name",
"_logging_context",
"start",
]
def __init__(self, clock, name: str):
"""
Args:
clock: A n object with a "time()" method, which returns the current
time in seconds.
name: The name of the metric to report.
"""
self.clock = clock
self.name = name
curr_context = current_context()
if not curr_context:
logger.warning(
"Starting metrics collection %r from sentinel context: metrics will be lost",
name,
)
parent_context = None
else:
assert isinstance(curr_context, LoggingContext)
parent_context = curr_context
self._logging_context = LoggingContext(str(curr_context), parent_context)
self.start = None # type: Optional[int]
def __enter__(self) -> "Measure":
if self.start is not None:
raise RuntimeError("Measure() objects cannot be re-used")
self.start = self.clock.time()
self._logging_context.__enter__()
in_flight.register((self.name,), self._update_in_flight)
logger.debug("Entering block %s", self.name)
return self
def __exit__(self, exc_type, exc_val, exc_tb):
if self.start is None:
raise RuntimeError("Measure() block exited without being entered")
logger.debug("Exiting block %s", self.name)
duration = self.clock.time() - self.start
usage = self.get_resource_usage()
in_flight.unregister((self.name,), self._update_in_flight)
self._logging_context.__exit__(exc_type, exc_val, exc_tb)
try:
block_counter.labels(self.name).inc()
block_timer.labels(self.name).inc(duration)
block_ru_utime.labels(self.name).inc(usage.ru_utime)
block_ru_stime.labels(self.name).inc(usage.ru_stime)
block_db_txn_count.labels(self.name).inc(usage.db_txn_count)
block_db_txn_duration.labels(self.name).inc(usage.db_txn_duration_sec)
block_db_sched_duration.labels(self.name).inc(usage.db_sched_duration_sec)
except ValueError:
logger.warning("Failed to save metrics! Usage: %s", usage)
def get_resource_usage(self) -> ContextResourceUsage:
"""Get the resources used within this Measure block
If the Measure block is still active, returns the resource usage so far.
"""
return self._logging_context.get_resource_usage()
def _update_in_flight(self, metrics):
"""Gets called when processing in flight metrics"""
duration = self.clock.time() - self.start
metrics.real_time_max = max(metrics.real_time_max, duration)
metrics.real_time_sum += duration
# TODO: Add other in flight metrics.