Neater introspection methods on BaseMetric so that subclasses don't need to touch self.keys directly

This commit is contained in:
Paul "LeoNerd" Evans 2015-03-04 17:53:51 +00:00
parent 8664599af7
commit 849300bc73

View File

@ -20,6 +20,12 @@ class BaseMetric(object):
self.name = name
self.keys = keys # OK not to clone as we never write it
def dimension(self):
return len(self.keys)
def is_scalar(self):
return not len(self.keys)
def _render_key(self, values):
# TODO: some kind of value escape
return ",".join(["%s=%s" % kv for kv in zip(self.keys, values)])
@ -35,13 +41,13 @@ class CounterMetric(BaseMetric):
self.counts = {}
# Scalar metrics are never empty
if not len(self.keys):
if self.is_scalar():
self.counts[()] = 0
def inc(self, *values):
if len(values) != len(self.keys):
if len(values) != self.dimension():
raise ValueError("Expected as many values to inc() as keys (%d)" %
(len(self.keys))
(self.dimension())
)
# TODO: should assert that the tag values are all strings
@ -55,7 +61,7 @@ class CounterMetric(BaseMetric):
return dict(self.counts)
def render(self):
if not len(self.keys):
if self.is_scalar():
return ["%s %d" % (self.name, self.counts[()])]
return ["%s{%s} %d" % (self.name, self._render_key(k), self.counts[k])
@ -76,6 +82,7 @@ class CallbackMetric(BaseMetric):
# TODO(paul): work out something we can do with keys and vectors
return ["%s %d" % (self.name, self.callback())]
class CacheMetric(object):
"""A combination of two CounterMetrics, one to count cache hits and one to
count misses, and a callback metric to yield the current size.