Source code for apache_beam.metrics.metricbase

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"""
The classes in this file are interfaces for metrics. They are not intended
to be subclassed or created directly by users. To work with and access metrics,
users should use the classes and methods exposed in metric.py.

Available classes:

- Metric - Base interface of a metrics object.
- Counter - Counter metric interface. Allows a count to be incremented or
    decremented during pipeline execution.
- Distribution - Distribution Metric interface. Allows statistics about the
    distribution of a variable to be collected during pipeline execution.
- Gauge - Gauge Metric interface. Allows to track the latest value of a
    variable during pipeline execution.
- MetricName - Namespace and name used to refer to a Metric.
"""

# pytype: skip-file

from typing import Dict
from typing import Optional

__all__ = [
    'Metric',
    'Counter',
    'Distribution',
    'Gauge',
    'StringSet',
    'Histogram',
    'MetricName'
]


[docs] class MetricName(object): """The name of a metric. The name of a metric consists of a namespace and a name. The namespace allows grouping related metrics together and also prevents collisions between multiple metrics of the same name. """ def __init__( self, namespace: Optional[str], name: Optional[str], urn: Optional[str] = None, labels: Optional[Dict[str, str]] = None) -> None: """Initializes ``MetricName``. Note: namespace and name should be set for user metrics, urn and labels should be set for an arbitrary metric to package into a MonitoringInfo. Args: namespace: A string with the namespace of a metric. name: A string with the name of a metric. urn: URN to populate on a MonitoringInfo, when sending to RunnerHarness. labels: Labels to populate on a MonitoringInfo """ if not urn: if not namespace: raise ValueError('Metric namespace must be non-empty') if not name: raise ValueError('Metric name must be non-empty') self.namespace = namespace self.name = name self.urn = urn self.labels = labels if labels else {} def __eq__(self, other): return ( self.namespace == other.namespace and self.name == other.name and self.urn == other.urn and self.labels == other.labels) def __str__(self): if self.urn: return 'MetricName(namespace={}, name={}, urn={}, labels={})'.format( self.namespace, self.name, self.urn, self.labels) else: # User counter case. return 'MetricName(namespace={}, name={})'.format( self.namespace, self.name) def __hash__(self): return hash((self.namespace, self.name, self.urn) + tuple(self.labels.items()))
[docs] def fast_name(self): name = self.name or '' namespace = self.namespace or '' urn = self.urn or '' labels = '' if self.labels: labels = '_'.join(['%s=%s' % (k, v) for (k, v) in self.labels.items()]) return '%d_%s%s%s%s' % (len(name), name, namespace, urn, labels)
[docs] class Metric(object): """Base interface of a metric object.""" def __init__(self, metric_name: MetricName) -> None: self.metric_name = metric_name
[docs] class Counter(Metric): """Counter metric interface. Allows a count to be incremented/decremented during pipeline execution."""
[docs] def inc(self, n=1): raise NotImplementedError
[docs] def dec(self, n=1): self.inc(-n)
[docs] class Distribution(Metric): """Distribution Metric interface. Allows statistics about the distribution of a variable to be collected during pipeline execution."""
[docs] def update(self, value): raise NotImplementedError
[docs] class Gauge(Metric): """Gauge Metric interface. Allows tracking of the latest value of a variable during pipeline execution."""
[docs] def set(self, value): raise NotImplementedError
[docs] class StringSet(Metric): """StringSet Metric interface. Reports set of unique string values during pipeline execution.."""
[docs] def add(self, value): raise NotImplementedError
[docs] class Histogram(Metric): """Histogram Metric interface. Allows statistics about the percentile of a variable to be collected during pipeline execution."""
[docs] def update(self, value): raise NotImplementedError