From ab825aa328e089b28cf858332bb95f47e1490377 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Wed, 11 Apr 2018 11:07:33 +0100 Subject: [PATCH] Add GaugeMetric --- synapse/metrics/__init__.py | 9 ++++++++- synapse/metrics/metric.py | 30 ++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+), 1 deletion(-) diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py index 2ed82b04a..2666f982a 100644 --- a/synapse/metrics/__init__.py +++ b/synapse/metrics/__init__.py @@ -23,7 +23,7 @@ from twisted.internet import reactor from .metric import ( CounterMetric, CallbackMetric, DistributionMetric, CacheMetric, - MemoryUsageMetric, + MemoryUsageMetric, GaugeMetric, ) from .process_collector import register_process_collector @@ -65,6 +65,13 @@ class Metrics(object): """ return self._register(CounterMetric, *args, **kwargs) + def register_gauge(self, *args, **kwargs): + """ + Returns: + GaugeMetric + """ + return self._register(GaugeMetric, *args, **kwargs) + def register_callback(self, *args, **kwargs): """ Returns: diff --git a/synapse/metrics/metric.py b/synapse/metrics/metric.py index ff5aa8c0e..9ebf2d6fd 100644 --- a/synapse/metrics/metric.py +++ b/synapse/metrics/metric.py @@ -145,6 +145,36 @@ class CounterMetric(BaseMetric): ) +class GaugeMetric(BaseMetric): + """A metric that can go up or down + """ + + def __init__(self, *args, **kwargs): + super(GaugeMetric, self).__init__(*args, **kwargs) + + # dict[list[str]]: value for each set of label values. the keys are the + # label values, in the same order as the labels in self.labels. + # + # (if the metric is a scalar, the (single) key is the empty list). + self.guages = {} + + def set(self, v, *values): + if len(values) != self.dimension(): + raise ValueError( + "Expected as many values to inc() as labels (%d)" % (self.dimension()) + ) + + # TODO: should assert that the tag values are all strings + + self.guages[values] = v + + def render(self): + return flatten( + self._render_for_labels(k, self.guages[k]) + for k in sorted(self.guages.keys()) + ) + + class CallbackMetric(BaseMetric): """A metric that returns the numeric value returned by a callback whenever it is rendered. Typically this is used to implement gauges that yield the