Issue 623854: Support unit annotations in ts_mon metrics

infra_libs/ts_mon/common/metrics.py

Index: infra_libs/ts_mon/common/metrics.py
diff --git a/infra_libs/ts_mon/common/metrics.py b/infra_libs/ts_mon/common/metrics.py
index 33a543761940d2f758dd5294ec722b361daeadbb..a9ee417384f1b4142449ab25ecf93beb040cf339 100644
--- a/infra_libs/ts_mon/common/metrics.py
+++ b/infra_libs/ts_mon/common/metrics.py
@@ -32,6 +32,12 @@ class Metric(object):
   set() or increment() methods to modify a particular value, or passed to the
   constructor in which case they will be used as the defaults for this Metric.
 
+  The unit of measurement for Metric data can be specified with MetricsDataUnits
+  when a Metric object is created:
+  e.g., MetricsDataUnits.SECONDS, MetricsDataUnits.BYTES, and etc..,
+  A full list of supported units can be found in the following protobuf file
+  : infra_libs/ts_mon/protos/metrics.proto
+
   Do not directly instantiate an object of this class.
   Use the concrete child classes instead:
   * StringMetric for metrics with string value
@@ -44,7 +50,7 @@ class Metric(object):
   See http://go/inframon-doc for help designing and using your metrics.
   """
 
-  def __init__(self, name, fields=None, description=None):
+  def __init__(self, name, fields=None, description=None, units=None):
     """Create an instance of a Metric.
 
     Args:
@@ -52,6 +58,9 @@ class Metric(object):
       fields (dict): a set of key-value pairs to be set as default metric fields
       description (string): help string for the metric. Should be enough to
                             know what the metric is about.
+      units (int): the unit used to measure data for given
+                   metric. Please use the attributes of MetricDataUnit to find
+                   valid integer values for this argument.
     """
     self._name = name.lstrip('/')
     self._start_time = None
@@ -61,6 +70,7 @@ class Metric(object):
     self._fields = fields
     self._normalized_fields = self._normalize_fields(self._fields)
     self._description = description
+    self._units = units
 
     interface.register(self)
 
@@ -98,6 +108,8 @@ class Metric(object):
     metric_pb.name = self._name
     if self._description is not None:
       metric_pb.description = self._description
+    if self._units is not None:
+      metric_pb.units = self._units
 
     self._populate_value(metric_pb, value, start_time)
     self._populate_fields(metric_pb, fields)
@@ -250,9 +262,10 @@ class NumericMetric(Metric):  # pylint: disable=abstract-method
 class CounterMetric(NumericMetric):
   """A metric whose value type is a monotonically increasing integer."""
 
-  def __init__(self, name, fields=None, start_time=None, description=None):
+  def __init__(self, name, fields=None, start_time=None, description=None,
+               units=None):
     super(CounterMetric, self).__init__(
-        name, fields=fields, description=description)
+        name, fields=fields, description=description, units=units)
     self._start_time = start_time
 
   def _populate_value(self, metric, value, start_time):
@@ -291,9 +304,10 @@ class GaugeMetric(NumericMetric):
 class CumulativeMetric(NumericMetric):
   """A metric whose value type is a monotonically increasing float."""
 
-  def __init__(self, name, fields=None, start_time=None, description=None):
+  def __init__(self, name, fields=None, start_time=None, description=None,
+               units=None):
     super(CumulativeMetric, self).__init__(
-        name, fields=fields, description=description)
+        name, fields=fields, description=description, units=units)
     self._start_time = start_time
 
   def _populate_value(self, metric, value, start_time):
@@ -339,9 +353,9 @@ class DistributionMetric(Metric):
   }
 
   def __init__(self, name, is_cumulative=True, bucketer=None, fields=None,
-               start_time=None, description=None):
+               start_time=None, description=None, units=None):
     super(DistributionMetric, self).__init__(
-        name, fields=fields, description=description)
+        name, fields=fields, description=description, units=units)
     self._start_time = start_time
 
     if bucketer is None:
@@ -435,13 +449,14 @@ class CumulativeDistributionMetric(DistributionMetric):
   """A DistributionMetric with is_cumulative set to True."""
 
   def __init__(self, name, bucketer=None, fields=None,
-               description=None):
+               description=None, units=None):
     super(CumulativeDistributionMetric, self).__init__(
         name,
         is_cumulative=True,
         bucketer=bucketer,
         fields=fields,
-        description=description)
+        description=description,
+        units=units)
 
   def is_cumulative(self):
     return True
@@ -451,13 +466,28 @@ class NonCumulativeDistributionMetric(DistributionMetric):
   """A DistributionMetric with is_cumulative set to False."""
 
   def __init__(self, name, bucketer=None, fields=None,
-               description=None):
+               description=None, units=None):
     super(NonCumulativeDistributionMetric, self).__init__(
         name,
         is_cumulative=False,
         bucketer=bucketer,
         fields=fields,
-        description=description)
+        description=description,
+        units=units)
 
   def is_cumulative(self):
     return False
+
+
+class MetaMetricsDataUnits(type):
+  """Metaclass to populate the enum values of metrics_pb2.MetricsData.Units."""
+  def __new__(mcs, name, bases, attrs):
+    attrs.update(metrics_pb2.MetricsData.Units.items())
+    return super(MetaMetricsDataUnits, mcs).__new__(mcs, name, bases, attrs)
+
+
+class MetricsDataUnits(object):
+  """An enumeration class for units of measurement for Metrics data.
+  See infra_libs/ts_mon/protos/metrics.proto for a full list of supported units.
+  """
+  __metaclass__ = MetaMetricsDataUnits