Enable custom granularity inputs for filters

We are enabling support for custom granularity, which means
users will need to be able to reference them in where filters and
other contexts where their input representations of their manifest
elements will need to be parsed.

Historically, we have restricted time granularities to an enumerated
set of standard supported grains. With the addition of custom
granularities we must now admit the possibility of arbitrary string
names representing valid time granularities.

This change updates the interfaces for parsing time dimensions out
of filter expressions to allow for arbitrary string inputs representing
custom granularity names.

For various reasons - mainly having to do with the filter parser
not having access to the semantic manifest - we will NOT be able
to support custom granularity references via dundered string names. So
something like `metric_time__martian_year` will not work, but
the explicit syntax of `Dimension('metric_time').grain('martian_year')`
will be accepted and processed.

.changes/unreleased/Features-20240908-221757.yaml

@@ -0,0 +1,6 @@
+kind: Features
+body: Allow filter parameters to accept custom granularities
+time: 2024-09-08T22:17:57.865557-07:00
+custom:
+    Author: tlento
+    Issue: "345"

dbt_semantic_interfaces/call_parameter_sets.py

@@ -10,7 +10,6 @@
     MetricReference,
     TimeDimensionReference,
 )
-from dbt_semantic_interfaces.type_enums import TimeGranularity
 from dbt_semantic_interfaces.type_enums.date_part import DatePart
 
 
@@ -29,7 +28,7 @@ class TimeDimensionCallParameterSet:
 
     entity_path: Tuple[EntityReference, ...]
     time_dimension_reference: TimeDimensionReference
-    time_granularity: Optional[TimeGranularity] = None
+    time_granularity_name: Optional[str] = None
     date_part: Optional[DatePart] = None
 
 

dbt_semantic_interfaces/naming/dundered.py

@@ -20,7 +20,11 @@ class StructuredDunderedName:
     element_name: "ds"
     granularity: TimeGranularity.WEEK
 
-    The time granularity is part of legacy query syntax and there are plans to migrate away from this format.
+    The time granularity is part of legacy query syntax and there are plans to migrate away from this format. As such,
+    this will not be updated to allow for custom granularity values. This implies that any query paths that push named
+    parameters through this class will not support a custom grain reference of the form `metric_time__martian_year`,
+    and users wishing to use their martian year grain will have to explicitly reference it via a separate parameter
+    instead of gluing it onto the end of the name.
     """
 
     entity_links: Tuple[EntityReference, ...]

dbt_semantic_interfaces/parsing/text_input/ti_description.py

@@ -7,7 +7,6 @@
 from dbt_semantic_interfaces.enum_extension import assert_values_exhausted
 from dbt_semantic_interfaces.errors import InvalidQuerySyntax
 from dbt_semantic_interfaces.naming.dundered import StructuredDunderedName
-from dbt_semantic_interfaces.type_enums import TimeGranularity
 from dbt_semantic_interfaces.type_enums.date_part import DatePart
 
 
@@ -65,21 +64,13 @@ def __post_init__(self) -> None:  # noqa: D105
                 raise InvalidQuerySyntax("The entity path should not be specified for a metric.")
             if len(structured_item_name.entity_links) > 0:
                 raise InvalidQuerySyntax("The name of the metric should not have entity links.")
-        # Check that dimensions / time dimensions have a valid time granularity / date part.
+        # Check that dimensions / time dimensions have a valid date part.
         elif item_type is QueryItemType.DIMENSION or item_type is QueryItemType.TIME_DIMENSION:
-            if self.time_granularity_name is not None:
-                valid_time_granularity_names = set(time_granularity.value for time_granularity in TimeGranularity)
-                if self.time_granularity_name.lower() not in valid_time_granularity_names:
-                    raise InvalidQuerySyntax(
-                        f"{self.time_granularity_name!r} is not a valid time granularity. Valid values are"
-                        f" {valid_time_granularity_names}"
-                    )
-
             if self.date_part_name is not None:
                 valid_date_part_names = set(date_part.value for date_part in DatePart)
                 if self.date_part_name.lower() not in set(date_part.value for date_part in DatePart):
                     raise InvalidQuerySyntax(
-                        f"{self.time_granularity_name!r} is not a valid time granularity. Valid values are"
+                        f"{self.date_part_name!r} is not a valid date part. Valid values are"
                         f" {valid_date_part_names}"
                     )
 

dbt_semantic_interfaces/parsing/where_filter/parameter_set_factory.py

@@ -16,12 +16,19 @@
     MetricReference,
     TimeDimensionReference,
 )
-from dbt_semantic_interfaces.type_enums import TimeGranularity
 from dbt_semantic_interfaces.type_enums.date_part import DatePart
 
 
 class ParameterSetFactory:
-    """Creates parameter sets for use in the Jinja sandbox."""
+    """Creates parameter sets for use in the Jinja sandbox.
+
+    This is ONLY to be used for parsing where filters, and then only for the purposes of extracting
+    some basic information about which elements are being accessed in the filter expression in the
+    small number of contexts where a more complete semantic layer implementation is not available.
+
+    In practice, today, this is used by the dbt core parser, which cannot take on a MetricFlow
+    dependency, in order to provide some DAG annotations around elements referenced in where filters.
+    """
 
     @staticmethod
     def _exception_message_for_incorrect_format(element_name: str) -> str:
@@ -37,26 +44,46 @@ def create_time_dimension(
         entity_path: Sequence[str] = (),
         date_part_name: Optional[str] = None,
     ) -> TimeDimensionCallParameterSet:
-        """Gets called by Jinja when rendering {{ TimeDimension(...) }}."""
+        """Gets called by Jinja when rendering {{ TimeDimension(...) }}.
+
+        There is a lot of strangeness around the time granularity specification here. Historically,
+        we accepted time dimension names of the form `metric_time__week` or `customer__registration_date__month`
+        in this interface. We have not yet fully deprecated this, and it's unclear if we ever will.
+
+        Key points to note:
+          1. The time dimension name parsing only accepts standard time granularities. This will not change.
+          2. The time granularity parameter is what we want everybody to use because it's more explicit.
+          3. The time granularity parameter will support custom granularities, so that's nice
+
+        While this all may seem pretty bad it's not as terrible as all that - this class is only used
+        for parsing where filters. When we solve the problems with our current where filter spec this will
+        persist as a backwards compatibility model, but nothing more.
+        """
         group_by_item_name = DunderedNameFormatter.parse_name(time_dimension_name)
         if len(group_by_item_name.entity_links) != 1 and not is_metric_time_name(group_by_item_name.element_name):
             raise ParseWhereFilterException(
                 ParameterSetFactory._exception_message_for_incorrect_format(time_dimension_name)
             )
-        grain_parsed_from_name = group_by_item_name.time_granularity
-        grain_from_param = TimeGranularity(time_granularity_name) if time_granularity_name else None
+        grain_parsed_from_name = (
+            group_by_item_name.time_granularity.value if group_by_item_name.time_granularity else None
+        )
+        grain_from_param = time_granularity_name
         if grain_parsed_from_name and grain_from_param and grain_from_param != grain_parsed_from_name:
             raise ParseWhereFilterException(
                 f"Received different grains in `time_dimension_name` parameter ('{time_dimension_name}') "
-                f"and `time_granularity_name` parameter ('{time_granularity_name}')."
+                f"and `time_granularity_name` parameter ('{time_granularity_name}'). Remove the grain suffix "
+                f"(`{grain_parsed_from_name}`) from the time dimension name and use the `time_granularity_name` "
+                "parameter to specify the intendend grain."
             )
 
+        time_granularity_name = grain_parsed_from_name or grain_from_param
+
         return TimeDimensionCallParameterSet(
             time_dimension_reference=TimeDimensionReference(element_name=group_by_item_name.element_name),
             entity_path=(
                 tuple(EntityReference(element_name=arg) for arg in entity_path) + group_by_item_name.entity_links
             ),
-            time_granularity=grain_parsed_from_name or grain_from_param,
+            time_granularity_name=time_granularity_name.lower() if time_granularity_name else None,
             date_part=DatePart(date_part_name.lower()) if date_part_name else None,
         )
 

tests/implementations/where_filter/test_parse_calls.py

@@ -69,7 +69,7 @@ def test_extract_dimension_with_grain_call_parameter_sets() -> None:  # noqa: D
             TimeDimensionCallParameterSet(
                 entity_path=(),
                 time_dimension_reference=TimeDimensionReference(element_name="metric_time"),
-                time_granularity=TimeGranularity.WEEK,
+                time_granularity_name=TimeGranularity.WEEK.value,
             ),
         ),
         entity_call_parameter_sets=(),
@@ -91,7 +91,7 @@ def test_extract_time_dimension_call_parameter_sets() -> None:  # noqa: D
                     EntityReference("listing"),
                     EntityReference("user"),
                 ),
-                time_granularity=TimeGranularity.MONTH,
+                time_granularity_name=TimeGranularity.MONTH.value,
             ),
         )
     )
@@ -110,7 +110,7 @@ def test_extract_time_dimension_call_parameter_sets() -> None:  # noqa: D
                     EntityReference("listing"),
                     EntityReference("user"),
                 ),
-                time_granularity=TimeGranularity.MONTH,
+                time_granularity_name=TimeGranularity.MONTH.value,
             ),
         )
     )
@@ -126,7 +126,7 @@ def test_extract_metric_time_dimension_call_parameter_sets() -> None:  # noqa: D
             TimeDimensionCallParameterSet(
                 time_dimension_reference=TimeDimensionReference(element_name="metric_time"),
                 entity_path=(),
-                time_granularity=TimeGranularity.MONTH,
+                time_granularity_name=TimeGranularity.MONTH.value,
             ),
         )
     )
@@ -216,7 +216,7 @@ def test_where_filter_interesection_extract_call_parameter_sets() -> None:
             TimeDimensionCallParameterSet(
                 time_dimension_reference=TimeDimensionReference(element_name="metric_time"),
                 entity_path=(),
-                time_granularity=TimeGranularity.MONTH,
+                time_granularity_name=TimeGranularity.MONTH.value,
             ),
         )
     )
@@ -269,7 +269,7 @@ def test_time_dimension_without_granularity() -> None:  # noqa: D
             TimeDimensionCallParameterSet(
                 entity_path=(EntityReference("booking"),),
                 time_dimension_reference=TimeDimensionReference(element_name="created_at"),
-                time_granularity=None,
+                time_granularity_name=None,
             ),
         ),
         entity_call_parameter_sets=(),

tests/parsing/test_object_builder_item_description.py

@@ -19,9 +19,11 @@ def test_valid_object_builder_items() -> None:  # noqa: D
     valid_items = (
         "Dimension('listing__created_at', entity_path=['host'])",
         "Dimension('listing__created_at', entity_path=['host']).grain('day').date_part('day')",
+        "Dimension('metric_time').grain('martian_year')",
         "TimeDimension('listing__created_at', time_granularity_name='day', entity_path=['host'], date_part_name='day')",
         "Entity('listing__created_at', entity_path=['host'])",
         "Metric('bookings', group_by=['listing__created_at'])",
+        "TimeDimension('metric_time', time_granularity_name='martian_year')",
     )
     for valid_item in valid_items:
         logger.info(f"Checking {valid_item=}")
@@ -32,9 +34,7 @@ def test_invalid_object_builder_items() -> None:  # noqa: D
     text_processor = ObjectBuilderTextProcessor()
 
     invalid_items = (
-        "Dimension('listing__created_at').grain('invalid')",
         "Dimension('listing__created_at').date_part('invalid')",
-        "TimeDimension('listing__created_at', 'invalid', 'day')",
         "TimeDimension('listing__created_at', 'day', date_part_name='invalid')",
         "TimeDimension('listing__created_at', 'day', date_part_name='month').grain('month')",
         "TimeDimension('listing__created_at', 'day', date_part_name='month').date_part('month')",

tests/parsing/test_where_filter_parsing.py

@@ -185,15 +185,15 @@ def test_dimension_date_part() -> None:  # noqa
             TimeDimensionCallParameterSet(
                 time_dimension_reference=TimeDimensionReference("metric_time"),
                 entity_path=(),
-                time_granularity=TimeGranularity.WEEK,
+                time_granularity_name=TimeGranularity.WEEK.value,
             ),
         ),
         (
             "{{ TimeDimension('metric_time', time_granularity_name='week') }} > '2023-01-01'",
             TimeDimensionCallParameterSet(
                 time_dimension_reference=TimeDimensionReference("metric_time"),
                 entity_path=(),
-                time_granularity=TimeGranularity.WEEK,
+                time_granularity_name=TimeGranularity.WEEK.value,
             ),
         ),
     ],