Add unit to view instrument selection criteria (#3341)

Co-authored-by: Srikanth Chekuri <srikanth.chekuri92@gmail.com>

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Add max_scale option to Exponential Bucket Histogram Aggregation [#3323](https://github.com/open-telemetry/opentelemetry-python/pull/3323))
 - Use BoundedAttributes instead of raw dict to extract attributes from LogRecord and Support dropped_attributes_count in LogRecord ([#3310](https://github.com/open-telemetry/opentelemetry-python/pull/3310))
+- Add unit to view instrument selection criteria
+  ([#3341](https://github.com/open-telemetry/opentelemetry-python/pull/3341))
 - Upgrade opentelemetry-proto to 0.20 and regen
   [#3355](https://github.com/open-telemetry/opentelemetry-python/pull/3355))
 

opentelemetry-sdk/src/opentelemetry/sdk/metrics/_internal/view.py

@@ -76,6 +76,9 @@ class View:
             corresponding metrics stream. If `None` an instance of
             `DefaultAggregation` will be used.
 
+        instrument_unit: This is an instrument matching attribute: the unit the
+            instrument must have to match the view.
+
     This class is not intended to be subclassed by the user.
     """
 
@@ -92,10 +95,12 @@ def __init__(
         description: Optional[str] = None,
         attribute_keys: Optional[Set[str]] = None,
         aggregation: Optional[Aggregation] = None,
+        instrument_unit: Optional[str] = None,
     ):
         if (
             instrument_type
             is instrument_name
+            is instrument_unit
             is meter_name
             is meter_version
             is meter_schema_url
@@ -122,6 +127,7 @@ def __init__(
         self._name = name
         self._instrument_type = instrument_type
         self._instrument_name = instrument_name
+        self._instrument_unit = instrument_unit
         self._meter_name = meter_name
         self._meter_version = meter_version
         self._meter_schema_url = meter_schema_url
@@ -143,6 +149,10 @@ def _match(self, instrument: Instrument) -> bool:
             if not fnmatch(instrument.name, self._instrument_name):
                 return False
 
+        if self._instrument_unit is not None:
+            if not fnmatch(instrument.unit, self._instrument_unit):
+                return False
+
         if self._meter_name is not None:
             if instrument.instrumentation_scope.name != self._meter_name:
                 return False

opentelemetry-sdk/tests/metrics/test_view.py

@@ -37,6 +37,15 @@ def test_instrument_name(self):
             View(instrument_name="instrument_name")._match(mock_instrument)
         )
 
+    def test_instrument_unit(self):
+
+        mock_instrument = Mock()
+        mock_instrument.configure_mock(**{"unit": "instrument_unit"})
+
+        self.assertTrue(
+            View(instrument_unit="instrument_unit")._match(mock_instrument)
+        )
+
     def test_meter_name(self):
 
         self.assertTrue(