Rewrite BucketCollector
This was a bit unweildy for what I wanted: in particular, I wanted to assign each measurement straight into a bucket, rather than storing an intermediate Counter which didn't do any bucketing at all. I've replaced it with something that is hopefully a bit easier to use. (I'm not entirely sure what the difference between a HistogramMetricFamily and a GaugeHistogramMetricFamily is, but given our counters can go down as well as up the latter *sounds* more accurate?)
This commit is contained in:
Richard van der Hoff
parent
1c8ca2c543
commit
6d2d42f8fb
|
|
@ -15,6 +15,7 @@
|
|||
|
||||
import functools
|
||||
import gc
|
||||
import itertools
|
||||
import logging
|
||||
import os
|
||||
import platform
|
||||
|
|
@ -27,8 +28,8 @@ from prometheus_client import Counter, Gauge, Histogram
|
|||
from prometheus_client.core import (
|
||||
REGISTRY,
|
||||
CounterMetricFamily,
|
||||
GaugeHistogramMetricFamily,
|
||||
GaugeMetricFamily,
|
||||
HistogramMetricFamily,
|
||||
)
|
||||
|
||||
from twisted.internet import reactor
|
||||
|
|
@ -46,7 +47,7 @@ logger = logging.getLogger(__name__)
|
|||
METRICS_PREFIX = "/_synapse/metrics"
|
||||
|
||||
running_on_pypy = platform.python_implementation() == "PyPy"
|
||||
all_gauges = {} # type: Dict[str, Union[LaterGauge, InFlightGauge, BucketCollector]]
|
||||
all_gauges = {} # type: Dict[str, Union[LaterGauge, InFlightGauge]]
|
||||
|
||||
HAVE_PROC_SELF_STAT = os.path.exists("/proc/self/stat")
|
||||
|
||||
|
|
@ -205,63 +206,83 @@ class InFlightGauge:
|
|||
all_gauges[self.name] = self
|
||||
|
||||
|
||||
@attr.s(slots=True, hash=True)
|
||||
class BucketCollector:
|
||||
"""
|
||||
Like a Histogram, but allows buckets to be point-in-time instead of
|
||||
incrementally added to.
|
||||
class GaugeBucketCollector:
|
||||
"""Like a Histogram, but the buckets are Gauges which are updated atomically.
|
||||
|
||||
The data is updated by calling `update_data` with an iterable of measurements.
|
||||
|
||||
We assume that the data is updated less frequently than it is reported to
|
||||
Prometheus, and optimise for that case.
|
||||
"""
|
||||
|
||||
__slots__ = ("_name", "_documentation", "_bucket_bounds", "_metric")
|
||||
|
||||
def __init__(
|
||||
self,
|
||||
name: str,
|
||||
documentation: str,
|
||||
buckets: Iterable[float],
|
||||
registry=REGISTRY,
|
||||
):
|
||||
"""
|
||||
Args:
|
||||
name (str): Base name of metric to be exported to Prometheus.
|
||||
data_collector (callable -> dict): A synchronous callable that
|
||||
returns a dict mapping bucket to number of items in the
|
||||
bucket. If these buckets are not the same as the buckets
|
||||
given to this class, they will be remapped into them.
|
||||
buckets (list[float]): List of floats/ints of the buckets to
|
||||
give to Prometheus. +Inf is ignored, if given.
|
||||
|
||||
name: base name of metric to be exported to Prometheus. (a _bucket suffix
|
||||
will be added.)
|
||||
documentation: help text for the metric
|
||||
buckets: The top bounds of the buckets to report
|
||||
registry: metric registry to register with
|
||||
"""
|
||||
self._name = name
|
||||
self._documentation = documentation
|
||||
|
||||
name = attr.ib()
|
||||
data_collector = attr.ib()
|
||||
buckets = attr.ib()
|
||||
# the tops of the buckets
|
||||
self._bucket_bounds = [float(b) for b in buckets]
|
||||
if self._bucket_bounds != sorted(self._bucket_bounds):
|
||||
raise ValueError("Buckets not in sorted order")
|
||||
|
||||
if self._bucket_bounds[-1] != float("inf"):
|
||||
self._bucket_bounds.append(float("inf"))
|
||||
|
||||
self._metric = self._values_to_metric([])
|
||||
registry.register(self)
|
||||
|
||||
def collect(self):
|
||||
yield self._metric
|
||||
|
||||
# Fetch the data -- this must be synchronous!
|
||||
data = self.data_collector()
|
||||
def update_data(self, values: Iterable[float]):
|
||||
"""Update the data to be reported by the metric
|
||||
|
||||
buckets = {} # type: Dict[float, int]
|
||||
The existing data is cleared, and each measurement in the input is assigned
|
||||
to the relevant bucket.
|
||||
"""
|
||||
self._metric = self._values_to_metric(values)
|
||||
|
||||
res = []
|
||||
for x in data.keys():
|
||||
for i, bound in enumerate(self.buckets):
|
||||
if x <= bound:
|
||||
buckets[bound] = buckets.get(bound, 0) + data[x]
|
||||
def _values_to_metric(self, values: Iterable[float]) -> GaugeHistogramMetricFamily:
|
||||
total = 0.0
|
||||
bucket_values = [0 for _ in self._bucket_bounds]
|
||||
|
||||
for i in self.buckets:
|
||||
res.append([str(i), buckets.get(i, 0)])
|
||||
for v in values:
|
||||
# assign each value to a bucket
|
||||
for i, bound in enumerate(self._bucket_bounds):
|
||||
if v <= bound:
|
||||
bucket_values[i] += 1
|
||||
break
|
||||
|
||||
res.append(["+Inf", sum(data.values())])
|
||||
# ... and increment the sum
|
||||
total += v
|
||||
|
||||
metric = HistogramMetricFamily(
|
||||
self.name, "", buckets=res, sum_value=sum(x * y for x, y in data.items())
|
||||
# now, aggregate the bucket values so that they count the number of entries in
|
||||
# that bucket or below.
|
||||
accumulated_values = itertools.accumulate(bucket_values)
|
||||
|
||||
return GaugeHistogramMetricFamily(
|
||||
self._name,
|
||||
self._documentation,
|
||||
buckets=list(
|
||||
zip((str(b) for b in self._bucket_bounds), accumulated_values)
|
||||
),
|
||||
gsum_value=total,
|
||||
)
|
||||
yield metric
|
||||
|
||||
def __attrs_post_init__(self):
|
||||
self.buckets = [float(x) for x in self.buckets if x != "+Inf"]
|
||||
if self.buckets != sorted(self.buckets):
|
||||
raise ValueError("Buckets not sorted")
|
||||
|
||||
self.buckets = tuple(self.buckets)
|
||||
|
||||
if self.name in all_gauges.keys():
|
||||
logger.warning("%s already registered, reregistering" % (self.name,))
|
||||
REGISTRY.unregister(all_gauges.pop(self.name))
|
||||
|
||||
REGISTRY.register(self)
|
||||
all_gauges[self.name] = self
|
||||
|
||||
|
||||
#
|
||||
|
|
|
|||
|
|
@ -12,10 +12,8 @@
|
|||
# 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 typing
|
||||
from collections import Counter
|
||||
|
||||
from synapse.metrics import BucketCollector
|
||||
from synapse.metrics import GaugeBucketCollector
|
||||
from synapse.metrics.background_process_metrics import run_as_background_process
|
||||
from synapse.storage._base import SQLBaseStore
|
||||
from synapse.storage.database import DatabasePool
|
||||
|
|
@ -23,6 +21,14 @@ from synapse.storage.databases.main.event_push_actions import (
|
|||
EventPushActionsWorkerStore,
|
||||
)
|
||||
|
||||
# Collect metrics on the number of forward extremities that exist.
|
||||
_extremities_collecter = GaugeBucketCollector(
|
||||
"synapse_forward_extremities",
|
||||
"Number of rooms on the server with the given number of forward extremities"
|
||||
" or fewer",
|
||||
buckets=[1, 2, 3, 5, 7, 10, 15, 20, 50, 100, 200, 500],
|
||||
)
|
||||
|
||||
|
||||
class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
|
||||
"""Functions to pull various metrics from the DB, for e.g. phone home
|
||||
|
|
@ -32,18 +38,6 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
|
|||
def __init__(self, database: DatabasePool, db_conn, hs):
|
||||
super().__init__(database, db_conn, hs)
|
||||
|
||||
# Collect metrics on the number of forward extremities that exist.
|
||||
# Counter of number of extremities to count
|
||||
self._current_forward_extremities_amount = (
|
||||
Counter()
|
||||
) # type: typing.Counter[int]
|
||||
|
||||
BucketCollector(
|
||||
"synapse_forward_extremities",
|
||||
lambda: self._current_forward_extremities_amount,
|
||||
buckets=[1, 2, 3, 5, 7, 10, 15, 20, 50, 100, 200, 500, "+Inf"],
|
||||
)
|
||||
|
||||
# Read the extrems every 60 minutes
|
||||
def read_forward_extremities():
|
||||
# run as a background process to make sure that the database transactions
|
||||
|
|
@ -65,7 +59,7 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
|
|||
return txn.fetchall()
|
||||
|
||||
res = await self.db_pool.runInteraction("read_forward_extremities", fetch)
|
||||
self._current_forward_extremities_amount = Counter([x[0] for x in res])
|
||||
_extremities_collecter.update_data(x[0] for x in res)
|
||||
|
||||
async def count_daily_messages(self):
|
||||
"""
|
||||
|
|
|
|||
|
|
@ -52,14 +52,14 @@ class ExtremStatisticsTestCase(HomeserverTestCase):
|
|||
self.reactor.advance(60 * 60 * 1000)
|
||||
self.pump(1)
|
||||
|
||||
items = set(
|
||||
items = list(
|
||||
filter(
|
||||
lambda x: b"synapse_forward_extremities_" in x,
|
||||
generate_latest(REGISTRY).split(b"\n"),
|
||||
generate_latest(REGISTRY, emit_help=False).split(b"\n"),
|
||||
)
|
||||
)
|
||||
|
||||
expected = {
|
||||
expected = [
|
||||
b'synapse_forward_extremities_bucket{le="1.0"} 0.0',
|
||||
b'synapse_forward_extremities_bucket{le="2.0"} 2.0',
|
||||
b'synapse_forward_extremities_bucket{le="3.0"} 2.0',
|
||||
|
|
@ -72,9 +72,12 @@ class ExtremStatisticsTestCase(HomeserverTestCase):
|
|||
b'synapse_forward_extremities_bucket{le="100.0"} 3.0',
|
||||
b'synapse_forward_extremities_bucket{le="200.0"} 3.0',
|
||||
b'synapse_forward_extremities_bucket{le="500.0"} 3.0',
|
||||
b'synapse_forward_extremities_bucket{le="+Inf"} 3.0',
|
||||
b"synapse_forward_extremities_count 3.0",
|
||||
b"synapse_forward_extremities_sum 10.0",
|
||||
}
|
||||
|
||||
# per https://docs.google.com/document/d/1KwV0mAXwwbvvifBvDKH_LU1YjyXE_wxCkHNoCGq1GX0/edit#heading=h.wghdjzzh72j9,
|
||||
# "inf" is valid: "this includes variants such as inf"
|
||||
b'synapse_forward_extremities_bucket{le="inf"} 3.0',
|
||||
b"# TYPE synapse_forward_extremities_gcount gauge",
|
||||
b"synapse_forward_extremities_gcount 3.0",
|
||||
b"# TYPE synapse_forward_extremities_gsum gauge",
|
||||
b"synapse_forward_extremities_gsum 10.0",
|
||||
]
|
||||
self.assertEqual(items, expected)
|
||||
|
|
|
|||
Loading…
Reference in New Issue