2019-04-24 11:42:20 +02:00

241 lines
9.2 KiB
Python

from threading import Lock
import typing
import weakref
import collections
import time
import math
from .metric_base import MetricValue, MetricBase, MetricGroupDefinition, MetricGroupBase, EMPTY_GROUP_DEFINITION
from .path import Path, Labels
class _MetricGroup:
metrics: typing.Mapping[Labels, typing.Union[MetricBase, MetricGroupBase]]
weak_metric: typing.Any
def __init__(self, metrics: typing.Mapping[Labels, typing.Union[MetricBase, MetricGroupBase]], weak_metric):
self.metrics = metrics
self.weak_metric = weak_metric
def get(self) -> typing.Sequence[typing.Tuple[Path, MetricValue]]:
return [(k, m.get()) for (k, m) in self.metrics.items()]
class _MetricCollection:
metric_type: str
help_text: typing.Optional[str]
metrics: typing.MutableMapping[Labels, typing.Union[MetricBase, _MetricGroup]]
group_definition: typing.Optional[MetricGroupDefinition]
_groups: typing.MutableSet[_MetricGroup]
def __init__(self, metric_type: str, group_definition: typing.Optional[MetricGroupDefinition] = None):
self.metric_type = metric_type
self.help_text = None
self.metrics = weakref.WeakValueDictionary()
if group_definition is None:
group_definition = EMPTY_GROUP_DEFINITION
self.group_definition = group_definition
self._groups = set()
def check(self, path: Path, metric_type: str, group_definition: typing.Optional[MetricGroupDefinition] = None):
if self.metric_type != metric_type:
raise RuntimeError("metric type doesn't match for {}: {} != {}".format(
path.name, self.metric_type, metric_type))
if group_definition is None:
group_definition = EMPTY_GROUP_DEFINITION
if self.group_definition.reserved_suffixes != group_definition.reserved_suffixes:
raise RuntimeError("reserved suffixes don't match for {}: {} != {}".format(
path.name, self.group_definition.reserved_suffixes, group_definition.reserved_suffixes))
if self.group_definition.reserved_labels != group_definition.reserved_labels:
raise RuntimeError("reserved labels don't match for {}: {} != {}".format(
path.name, self.group_definition.reserved_labels, group_definition.reserved_labels))
for l in self.group_definition.reserved_labels:
if l in path.labels.map:
raise RuntimeError("'{} {}' uses reserved label {}".format(
path.name, path.labels.key, l))
if path.labels.key in self.metrics:
raise RuntimeError("'{} {}' already registered".format(
path.name, path.labels.key))
def insert(self, path: Path, metric: typing.Union[MetricBase, MetricGroupBase]):
if isinstance(metric, MetricBase):
self.metrics[path.labels.key] = metric
else:
key = path.labels.key
metrics = dict()
for (add_path, m) in metric.metrics():
assert (
add_path.name == '' or add_path.name in self.group_definition.reserved_suffixes)
for l in add_path.labels.map:
assert l in self.group_definition.reserved_labels
p = Path(path.name + add_path.name, {**path.labels.map, **add_path.labels.map})
metrics[p] = m
g = None # set below, but need for cleanup
def cleanup(_weak_metric):
self._groups.remove(g)
del self.metrics[key]
weak_metric = weakref.ref(metric, cleanup)
g = _MetricGroup(metrics, weak_metric)
self.metrics[key] = g
if self.help_text is None:
self.help_text = metric.help_text
_INF = float("inf")
_MINUS_INF = float("-inf")
def _floatToGoString(d: float):
if d == _INF:
return '+Inf'
elif d == _MINUS_INF:
return '-Inf'
elif math.isnan(d):
return 'NaN'
else:
s = repr(d)
dot = s.find('.')
# Go switches to exponents sooner than Python.
# We only need to care about positive values for le/quantile.
if d > 0 and dot > 6:
mantissa = '{0}.{1}{2}'.format(
s[0], s[1:dot], s[dot + 1:]).rstrip('0.')
return '{0}e+0{1}'.format(mantissa, dot - 1)
return s
class Registry:
_metrics: typing.MutableMapping[str, typing.Union[_MetricCollection, str]]
_paths: typing.MutableMapping[typing.Union[MetricBase, MetricGroupBase], Path]
_strong_metrics: typing.MutableSet[typing.Union[MetricBase, MetricGroupBase]]
def __init__(self):
self._lock = Lock()
self._metrics = dict()
self._paths = weakref.WeakKeyDictionary()
self._strong_metrics = set()
# requires lock
def _unregister(self, metric: MetricBase):
# don't keep alive anymore
try:
self._strong_metrics.remove(metric)
except KeyError:
pass
try:
path = self._paths[metric]
c = self._metrics[path.name]
del c[path.labels]
except KeyError:
pass
def unregister(self, metric: typing.Union[MetricBase, MetricGroupBase]):
with self._lock:
if isinstance(metric, MetricGroupBase):
metrics = metric.metrics(Path(""))
for (_, m) in metrics:
self._unregister(m)
else:
self._unregister(metric)
# requires lock
def _remove_collection(self, metric_name: str):
try:
c = self._metrics[metric_name]
except KeyError:
return
assert isinstance(
c, _MetricCollection), "cannot remove reserved metric names directly"
for suffix in c.reserved_suffixes:
assert isinstance(
self._metrics[metric_name + suffix], str), "reserved suffix missing"
del self._metrics[metric_name + suffix]
del self._metrics[metric_name]
# requires lock
def _get_collection(self, path: Path, metric_type: str, group_definition: typing.Optional[MetricGroupDefinition] = None):
c = None
try:
c = self._metrics[path.name]
except KeyError:
pass
if not c is None:
if not isinstance(c, _MetricCollection):
c_parent = self._metrics[c]
assert isinstance(
c_parent, _MetricCollection), "nested metric groups not allowed"
if 0 == len(c_parent.metrics):
self._remove_collection(c)
else:
raise RuntimeError(
"Metric name {} reserved for group {}".format(path.name, c))
else:
if 0 == len(c.metrics):
self._remove_collection(path.name)
else:
c.check(path, metric_type, group_definition)
return c
c = _MetricCollection(metric_type, group_definition)
self._metrics[path.name] = c
return c
def register(self, path: Path, metric: typing.Union[MetricBase, MetricGroupBase], strong: bool = False):
with self._lock:
if metric in self._paths:
raise RuntimeError("metric already registered")
if isinstance(metric, MetricGroupBase):
group_definition = metric.group_definition
else:
group_definition = None
c = self._get_collection(
path, metric.metric_type, group_definition)
c.insert(path, metric)
self._paths[metric] = path
if strong:
# keep metric alive
self._strong_metrics.add(metric)
def collect(self):
metrics = []
with self._lock:
for (metric_name, c) in self._metrics.items():
l = [(k, m.get()) for (k, m) in c.metrics.items()]
metrics.append((metric_name, c.metric_type, c.help_text, l))
from io import StringIO
result = StringIO()
for (metric_name, metric_type, help_text, data) in metrics:
if 0 == len(data):
continue
if not help_text is None:
result.write("# HELP {} {}\n".format(
metric_name, help_text.replace('\\', r'\\').replace('\n', r'\n')))
result.write('# TYPE {} {}\n'.format(metric_name, metric_type))
for (key, entry) in data:
if isinstance(entry, MetricValue):
if entry.timestamp is None:
timestamp = ''
else:
timestamp = ' {0:d}'.format(entry.timestamp)
result.write("{} {} {}{}\n".format(
metric_name, key, _floatToGoString(entry.value), timestamp))
else:
for (subpath, subentry) in entry:
if subentry.timestamp is None:
timestamp = ''
else:
timestamp = ' {0:d}'.format(subentry.timestamp)
result.write("{} {} {}{}\n".format(
subpath.name, subpath.labels.key, _floatToGoString(subentry.value), timestamp))
return result.getvalue()
GLOBAL_REGISTRY = Registry()