Allow custom granularity names in string name to struct conversion

metricflow-semantics/metricflow_semantics/naming/linkable_spec_name.py

@@ -7,6 +7,8 @@
 from dbt_semantic_interfaces.type_enums.date_part import DatePart
 from dbt_semantic_interfaces.type_enums.time_granularity import TimeGranularity
 
+from metricflow_semantics.time.granularity import ExpandedTimeGranularity
+
 DUNDER = "__"
 
 logger = logging.getLogger(__name__)
@@ -24,9 +26,36 @@ class StructuredLinkableSpecName:
 
     entity_link_names: Tuple[str, ...]
     element_name: str
-    time_granularity: Optional[TimeGranularity] = None
+    time_granularity_name: Optional[str] = None
     date_part: Optional[DatePart] = None
 
+    def __post_init__(self) -> None:
+        """Post init method to ensure all name values are lower-case.
+
+        This implies that all values in the TimeGranularity enumeration must be lower-case.
+        """
+        assert self.element_name.lower() == self.element_name, (
+            f"Element name {self.element_name} is not all lower-case. This should have been addressed at model "
+            "parse time!"
+        )
+        assert all([link_name.lower() == link_name for link_name in self.entity_link_names]), (
+            f"Found entity link name that includes upper-case letters. Entity link names: {self.entity_link_names}. "
+            "This should have been addressed at model parse time!"
+        )
+
+        if self.time_granularity_name:
+            is_standard_name = ExpandedTimeGranularity.is_standard_granularity_name(self.time_granularity_name)
+            if is_standard_name:
+                follow_up = (
+                    "This indicates a bug where someone added a non-lowercase value to the TimeGranularity "
+                    "enum in dbt-semantic-interfaces!"
+                )
+            else:
+                follow_up = "This should have been addressed at model parse time!"
+            assert (
+                self.time_granularity_name.lower() == self.time_granularity_name
+            ), f"The time_granularity_name {self.time_granularity_name} includes upper-case letters. {follow_up}"
+
     @staticmethod
     def from_name(qualified_name: str) -> StructuredLinkableSpecName:
         """Construct from a name e.g. listing__ds__month."""
@@ -43,6 +72,7 @@ def from_name(qualified_name: str) -> StructuredLinkableSpecName:
                 )
 
         associated_granularity = None
+        # TODO: [custom granularity] Update parsing to account for custom granularities
         for granularity in TimeGranularity:
             if name_parts[-1] == granularity.value:
                 associated_granularity = granularity
@@ -52,13 +82,13 @@ def from_name(qualified_name: str) -> StructuredLinkableSpecName:
             #  e.g. "ds__month"
             if len(name_parts) == 2:
                 return StructuredLinkableSpecName(
-                    entity_link_names=(), element_name=name_parts[0], time_granularity=associated_granularity
+                    entity_link_names=(), element_name=name_parts[0], time_granularity_name=associated_granularity.value
                 )
             # e.g. "messages__ds__month"
             return StructuredLinkableSpecName(
                 entity_link_names=tuple(name_parts[:-2]),
                 element_name=name_parts[-2],
-                time_granularity=associated_granularity,
+                time_granularity_name=associated_granularity.value,
             )
 
         # e.g. "messages__ds"
@@ -74,8 +104,8 @@ def qualified_name(self) -> str:
         items = list(self.entity_link_names) + [self.element_name]
         if self.date_part:
             items.append(self.date_part_suffix(date_part=self.date_part))
-        elif self.time_granularity:
-            items.append(self.time_granularity.value)
+        elif self.time_granularity_name:
+            items.append(self.time_granularity_name)
         return DUNDER.join(items)
 
     @property

metricflow-semantics/metricflow_semantics/specs/time_dimension_spec.py

@@ -122,7 +122,7 @@ def qualified_name(self) -> str:  # noqa: D102
         return StructuredLinkableSpecName(
             entity_link_names=tuple(x.element_name for x in self.entity_links),
             element_name=self.element_name,
-            time_granularity=self.time_granularity,
+            time_granularity_name=self.time_granularity.value,
             date_part=self.date_part,
         ).qualified_name
 

metricflow-semantics/metricflow_semantics/time/granularity.py

@@ -30,3 +30,12 @@ def is_custom_granularity(self) -> bool:  # noqa: D102
     def from_time_granularity(cls, granularity: TimeGranularity) -> ExpandedTimeGranularity:
         """Factory method for creating an ExpandedTimeGranularity from a standard TimeGranularity enumeration value."""
         return ExpandedTimeGranularity(name=granularity.value, base_granularity=granularity)
+
+    @staticmethod
+    def is_standard_granularity_name(time_granularity_name: str) -> bool:
+        """Helper for checking if a given time granularity name is part of the standard TimeGranularity enumeration."""
+        for granularity in TimeGranularity:
+            if time_granularity_name == granularity.value:
+                return True
+
+        return False

metricflow/engine/metricflow_engine.py

@@ -595,9 +595,8 @@ def simple_dimensions_for_metrics(  # noqa: D102
                                     entity_reference.element_name
                                     for entity_reference in linkable_dimension.entity_links
                                 ),
-                                # TODO: Update StructuredLinkableSpecName to use ExpandedTimeGranularity
-                                time_granularity=(
-                                    linkable_dimension.time_granularity.base_granularity
+                                time_granularity_name=(
+                                    linkable_dimension.time_granularity.name
                                     if linkable_dimension.time_granularity is not None
                                     else None
                                 ),