deb-gnocchi/gnocchi/storage/incoming/ceph.py

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# -*- encoding: utf-8 -*-
#
# 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.
from collections import defaultdict
import contextlib
import datetime
import functools
import json
import uuid
import six
from gnocchi.storage.common import ceph
from gnocchi.storage.incoming import _carbonara
rados = ceph.rados
class CephStorage(_carbonara.CarbonaraBasedStorage):
Q_LIMIT = 1000
def __init__(self, conf):
super(CephStorage, self).__init__(conf)
self.rados, self.ioctx = ceph.create_rados_connection(conf)
# NOTE(sileht): constants can't be class attributes because
# they rely on presence of rados module
# NOTE(sileht): We allow to read the measure object on
# outdated replicats, that safe for us, we will
# get the new stuffs on next metricd pass.
self.OMAP_READ_FLAGS = (rados.LIBRADOS_OPERATION_BALANCE_READS |
rados.LIBRADOS_OPERATION_SKIPRWLOCKS)
# NOTE(sileht): That should be safe to manipulate the omap keys
# with any OSDs at the same times, each osd should replicate the
# new key to others and same thing for deletion.
# I wonder how ceph handle rm_omap and set_omap run at same time
# on the same key. I assume the operation are timestamped so that will
# be same. If not, they are still one acceptable race here, a rm_omap
# can finish before all replicats of set_omap are done, but we don't
# care, if that occurs next metricd run, will just remove it again, no
# object with the measure have already been delected by previous, so
# we are safe and good.
self.OMAP_WRITE_FLAGS = rados.LIBRADOS_OPERATION_SKIPRWLOCKS
def stop(self):
ceph.close_rados_connection(self.rados, self.ioctx)
super(CephStorage, self).stop()
def get_storage_sacks(self):
try:
return json.loads(
self.ioctx.read(self.CFG_PREFIX).decode())[self.CFG_SACKS]
except rados.ObjectNotFound:
return
def set_storage_settings(self, num_sacks):
self.ioctx.write_full(self.CFG_PREFIX,
json.dumps({self.CFG_SACKS: num_sacks}).encode())
def remove_sack_group(self, num_sacks):
prefix = self.get_sack_prefix(num_sacks)
for i in six.moves.xrange(num_sacks):
try:
self.ioctx.remove_object(prefix % i)
except rados.ObjectNotFound:
pass
def add_measures_batch(self, metrics_and_measures):
names_by_sack = defaultdict(list)
for metric, measures in six.iteritems(metrics_and_measures):
name = "_".join((
self.MEASURE_PREFIX,
str(metric.id),
str(uuid.uuid4()),
datetime.datetime.utcnow().strftime("%Y%m%d_%H:%M:%S")))
sack = self.get_sack_name(self.sack_for_metric(metric.id))
names_by_sack[sack].append(name)
data = self._encode_measures(measures)
self.ioctx.write_full(name, data)
for sack, names in names_by_sack.items():
with rados.WriteOpCtx() as op:
# NOTE(sileht): list all objects in a pool is too slow with
# many objects (2min for 20000 objects in 50osds cluster),
# and enforce us to iterrate over all objects
# So we create an object MEASURE_PREFIX, that have as
# omap the list of objects to process (not xattr because
# it doesn't # allow to configure the locking behavior)
self.ioctx.set_omap(op, tuple(names), (b"",) * len(names))
self.ioctx.operate_write_op(op, sack,
flags=self.OMAP_WRITE_FLAGS)
def _build_report(self, details):
metrics = set()
count = 0
metric_details = defaultdict(int)
for i in six.moves.range(self.NUM_SACKS):
marker = ""
while True:
names = list(self._list_object_names_to_process(
i, marker=marker, limit=self.Q_LIMIT))
if names and names[0] < marker:
raise _carbonara.ReportGenerationError("Unable to cleanly "
"compute backlog.")
for name in names:
count += 1
metric = name.split("_")[1]
metrics.add(metric)
if details:
metric_details[metric] += 1
if len(names) < self.Q_LIMIT:
break
else:
marker = name
return len(metrics), count, metric_details if details else None
def _list_object_names_to_process(self, sack, prefix="", marker="",
limit=-1):
with rados.ReadOpCtx() as op:
omaps, ret = self.ioctx.get_omap_vals(op, marker, prefix, limit)
try:
self.ioctx.operate_read_op(
op, self.get_sack_name(sack), flag=self.OMAP_READ_FLAGS)
except rados.ObjectNotFound:
# API have still written nothing
return ()
# NOTE(sileht): after reading the libradospy, I'm
# not sure that ret will have the correct value
# get_omap_vals transforms the C int to python int
# before operate_read_op is called, I dunno if the int
# content is copied during this transformation or if
# this is a pointer to the C int, I think it's copied...
try:
ceph.errno_to_exception(ret)
except rados.ObjectNotFound:
return ()
return (k for k, v in omaps)
def list_metric_with_measures_to_process(self, sack):
names = set()
marker = ""
while True:
obj_names = list(self._list_object_names_to_process(
sack, marker=marker, limit=self.Q_LIMIT))
names.update(name.split("_")[1] for name in obj_names)
if len(obj_names) < self.Q_LIMIT:
break
else:
marker = obj_names[-1]
return names
def delete_unprocessed_measures_for_metric_id(self, metric_id):
sack = self.sack_for_metric(metric_id)
object_prefix = self.MEASURE_PREFIX + "_" + str(metric_id)
object_names = tuple(self._list_object_names_to_process(
sack, object_prefix))
if not object_names:
return
for op in list(map(self.ioctx.aio_remove, object_names)):
op.wait_for_complete_and_cb()
# Now clean objects and omap
with rados.WriteOpCtx() as op:
# NOTE(sileht): come on Ceph, no return code
# for this operation ?!!
self.ioctx.remove_omap_keys(op, object_names)
self.ioctx.operate_write_op(op, self.get_sack_name(sack),
flags=self.OMAP_WRITE_FLAGS)
def has_unprocessed(self, metric):
sack = self.sack_for_metric(metric.id)
object_prefix = self.MEASURE_PREFIX + "_" + str(metric.id)
return bool(self._list_object_names_to_process(sack, object_prefix))
@contextlib.contextmanager
def process_measure_for_metric(self, metric):
sack = self.sack_for_metric(metric.id)
object_prefix = self.MEASURE_PREFIX + "_" + str(metric.id)
object_names = tuple(self._list_object_names_to_process(
sack, object_prefix))
measures = []
ops = []
bufsize = 8192 # Same sa rados_read one
tmp_measures = {}
def add_to_measures(name, comp, data):
# Check that the measure file has not been deleted while still
# listed in the OMAP this can happen after a crash
ret = comp.get_return_value()
try:
ceph.errno_to_exception(ret)
except rados.ObjectNotFound:
# Object has been deleted, so this is just a stalled entry
# in the OMAP listing, ignore
return
if name in tmp_measures:
tmp_measures[name] += data
else:
tmp_measures[name] = data
if len(data) < bufsize:
measures.extend(self._unserialize_measures(name,
tmp_measures[name]))
del tmp_measures[name]
else:
ops.append(self.ioctx.aio_read(
name, bufsize, len(tmp_measures[name]),
functools.partial(add_to_measures, name)
))
for name in object_names:
ops.append(self.ioctx.aio_read(
name, bufsize, 0,
functools.partial(add_to_measures, name)
))
while ops:
op = ops.pop()
op.wait_for_complete_and_cb()
yield measures
# First delete all objects
for op in list(map(self.ioctx.aio_remove, object_names)):
op.wait_for_complete_and_cb()
# Now clean omap
with rados.WriteOpCtx() as op:
# NOTE(sileht): come on Ceph, no return code
# for this operation ?!!
self.ioctx.remove_omap_keys(op, object_names)
self.ioctx.operate_write_op(op, self.get_sack_name(sack),
flags=self.OMAP_WRITE_FLAGS)