[Backport to 0.4.latest] Add support for conversion metrics (#224)

### Description
Backporting conversion metric support PRs to `0.4.latest`
- #221
- #209
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### Checklist

- [x] I have read [the contributing
guide](https://github.com/dbt-labs/dbt-semantic-interfaces/blob/main/CONTRIBUTING.md)
and understand what's expected of me
- [x] I have signed the
[CLA](https://docs.getdbt.com/docs/contributor-license-agreements)
- [x] This PR includes tests, or tests are not required/relevant for
this PR
- [x] I have run `changie new` to [create a changelog
entry](https://github.com/dbt-labs/dbt-semantic-interfaces/blob/main/CONTRIBUTING.md#adding-a-changelog-entry)

.changes/unreleased/Features-20231127-124601.yaml

@@ -0,0 +1,6 @@
+kind: Features
+body: Added spec changes for conversion metrics.
+time: 2023-11-27T12:46:01.036548-05:00
+custom:
+  Author: WilliamDee
+  Issue: "210"

.changes/unreleased/Features-20231127-150021.yaml

@@ -0,0 +1,6 @@
+kind: Features
+body: Added validation for conversion metric configurations.
+time: 2023-11-27T15:00:21.734245-05:00
+custom:
+  Author: WilliamDee
+  Issue: "211"

dbt_semantic_interfaces/implementations/metric.py

@@ -17,7 +17,11 @@
 )
 from dbt_semantic_interfaces.implementations.metadata import PydanticMetadata
 from dbt_semantic_interfaces.references import MeasureReference, MetricReference
-from dbt_semantic_interfaces.type_enums import MetricType, TimeGranularity
+from dbt_semantic_interfaces.type_enums import (
+    ConversionCalculationType,
+    MetricType,
+    TimeGranularity,
+)
 
 
 class PydanticMetricInputMeasure(PydanticCustomInputParser, HashableBaseModel):
@@ -114,6 +118,13 @@ def parse(window: str) -> PydanticMetricTimeWindow:
         )
 
 
+class PydanticConstantPropertyInput(HashableBaseModel):
+    """Input of a constant property used in conversion metrics."""
+
+    base_property: str
+    conversion_property: str
+
+
 class PydanticMetricInput(HashableBaseModel):
     """Provides a pointer to a metric along with the additional properties used on that metric."""
 
@@ -134,6 +145,17 @@ def post_aggregation_reference(self) -> MetricReference:
         return MetricReference(element_name=self.alias or self.name)
 
 
+class PydanticConversionTypeParams(HashableBaseModel):
+    """Type params to provide context for conversion metrics properties."""
+
+    base_measure: PydanticMetricInputMeasure
+    conversion_measure: PydanticMetricInputMeasure
+    entity: str
+    calculation: ConversionCalculationType = ConversionCalculationType.CONVERSION_RATE
+    window: Optional[PydanticMetricTimeWindow]
+    constant_properties: Optional[List[PydanticConstantPropertyInput]]
+
+
 class PydanticMetricTypeParams(HashableBaseModel):
     """Type params add additional context to certain metric types (the context depends on the metric type)."""
 
@@ -144,6 +166,7 @@ class PydanticMetricTypeParams(HashableBaseModel):
     window: Optional[PydanticMetricTimeWindow]
     grain_to_date: Optional[TimeGranularity]
     metrics: Optional[List[PydanticMetricInput]]
+    conversion_type_params: Optional[PydanticConversionTypeParams]
 
     input_measures: List[PydanticMetricInputMeasure] = Field(default_factory=list)
 
@@ -172,7 +195,7 @@ def measure_references(self) -> List[MeasureReference]:
     @property
     def input_metrics(self) -> Sequence[PydanticMetricInput]:
         """Return the associated input metrics for this metric."""
-        if self.type is MetricType.SIMPLE or self.type is MetricType.CUMULATIVE:
+        if self.type is MetricType.SIMPLE or self.type is MetricType.CUMULATIVE or self.type is MetricType.CONVERSION:
             return ()
         elif self.type is MetricType.DERIVED:
             assert self.type_params.metrics is not None, f"{MetricType.DERIVED} should have type_params.metrics set"

dbt_semantic_interfaces/parsing/generated_json_schemas/default_explicit_schema.json

@@ -17,6 +17,61 @@
             },
             "type": "object"
         },
+        "constant_property_input_schema": {
+            "$id": "constant_property_input_schema",
+            "additionalProperties": false,
+            "properties": {
+                "base_property": {
+                    "type": "string"
+                },
+                "conversion_property": {
+                    "type": "string"
+                }
+            },
+            "required": [
+                "base_property",
+                "conversion_property"
+            ],
+            "type": "object"
+        },
+        "conversion_type_params_schema": {
+            "$id": "conversion_type_params_schema",
+            "additionalProperties": false,
+            "properties": {
+                "base_measure": {
+                    "$ref": "#/definitions/metric_input_measure_schema"
+                },
+                "calculation": {
+                    "enum": [
+                        "CONVERSIONS",
+                        "CONVERSION_RATE",
+                        "conversions",
+                        "conversion_rate"
+                    ]
+                },
+                "constant_properties": {
+                    "items": {
+                        "$ref": "#/definitions/constant_property_input_schema"
+                    },
+                    "type": "array"
+                },
+                "conversion_measure": {
+                    "$ref": "#/definitions/metric_input_measure_schema"
+                },
+                "entity": {
+                    "type": "string"
+                },
+                "window": {
+                    "type": "string"
+                }
+            },
+            "required": [
+                "base_measure",
+                "conversion_measure",
+                "entity"
+            ],
+            "type": "object"
+        },
         "dimension_schema": {
             "$id": "dimension_schema",
             "additionalProperties": false,
@@ -347,10 +402,12 @@
                         "RATIO",
                         "CUMULATIVE",
                         "DERIVED",
+                        "CONVERSION",
                         "simple",
                         "ratio",
                         "cumulative",
-                        "derived"
+                        "derived",
+                        "conversion"
                     ]
                 },
                 "type_params": {
@@ -368,6 +425,9 @@
             "$id": "metric_type_params",
             "additionalProperties": false,
             "properties": {
+                "conversion_type_params": {
+                    "$ref": "#/definitions/conversion_type_params_schema"
+                },
                 "denominator": {
                     "$ref": "#/definitions/metric_input_measure_schema"
                 },

dbt_semantic_interfaces/parsing/schemas.py

@@ -9,9 +9,12 @@
 
 
 # Enums
-metric_types_enum_values = ["SIMPLE", "RATIO", "CUMULATIVE", "DERIVED"]
+metric_types_enum_values = ["SIMPLE", "RATIO", "CUMULATIVE", "DERIVED", "CONVERSION"]
 metric_types_enum_values += [x.lower() for x in metric_types_enum_values]
 
+calculation_types_enum_values = ["CONVERSIONS", "CONVERSION_RATE"]
+calculation_types_enum_values += [x.lower() for x in calculation_types_enum_values]
+
 entity_type_enum_values = ["PRIMARY", "UNIQUE", "FOREIGN", "NATURAL"]
 entity_type_enum_values += [x.lower() for x in entity_type_enum_values]
 
@@ -85,6 +88,32 @@
     "additionalProperties": False,
 }
 
+conversion_type_params_schema = {
+    "$id": "conversion_type_params_schema",
+    "type": "object",
+    "properties": {
+        "base_measure": {"$ref": "metric_input_measure_schema"},
+        "conversion_measure": {"$ref": "metric_input_measure_schema"},
+        "calculation": {"enum": calculation_types_enum_values},
+        "entity": {"type": "string"},
+        "window": {"type": "string"},
+        "constant_properties": {"type": "array", "items": {"$ref": "constant_property_input_schema"}},
+    },
+    "additionalProperties": False,
+    "required": ["base_measure", "conversion_measure", "entity"],
+}
+
+constant_property_input_schema = {
+    "$id": "constant_property_input_schema",
+    "type": "object",
+    "properties": {
+        "base_property": {"type": "string"},
+        "conversion_property": {"type": "string"},
+    },
+    "additionalProperties": False,
+    "required": ["base_property", "conversion_property"],
+}
+
 metric_type_params_schema = {
     "$id": "metric_type_params",
     "type": "object",
@@ -99,6 +128,7 @@
             "type": "array",
             "items": {"$ref": "metric_input_schema"},
         },
+        "conversion_type_params": {"$ref": "conversion_type_params_schema"},
     },
     "additionalProperties": False,
 }
@@ -382,6 +412,8 @@
     filter_schema["$id"]: filter_schema,
     metric_input_measure_schema["$id"]: metric_input_measure_schema,
     metric_type_params_schema["$id"]: metric_type_params_schema,
+    conversion_type_params_schema["$id"]: conversion_type_params_schema,
+    constant_property_input_schema["$id"]: constant_property_input_schema,
     entity_schema["$id"]: entity_schema,
     measure_schema["$id"]: measure_schema,
     dimension_schema["$id"]: dimension_schema,

dbt_semantic_interfaces/protocols/__init__.py

@@ -11,6 +11,8 @@
 )
 from dbt_semantic_interfaces.protocols.metadata import FileSlice, Metadata  # noqa:F401
 from dbt_semantic_interfaces.protocols.metric import (  # noqa:F401
+    ConstantPropertyInput,
+    ConversionTypeParams,
     Metric,
     MetricInput,
     MetricInputMeasure,

dbt_semantic_interfaces/protocols/metric.py

@@ -6,7 +6,11 @@
 from dbt_semantic_interfaces.protocols.metadata import Metadata
 from dbt_semantic_interfaces.protocols.where_filter import WhereFilterIntersection
 from dbt_semantic_interfaces.references import MeasureReference, MetricReference
-from dbt_semantic_interfaces.type_enums import MetricType, TimeGranularity
+from dbt_semantic_interfaces.type_enums import (
+    ConversionCalculationType,
+    MetricType,
+    TimeGranularity,
+)
 
 
 class MetricInputMeasure(Protocol):
@@ -113,6 +117,67 @@ def post_aggregation_reference(self) -> MetricReference:
         pass
 
 
+class ConstantPropertyInput(Protocol):
+    """Provides the constant property set for conversion metrics.
+
+    Constant properties are additional elements linking a base event to a conversion event.
+    The specified properties will typically be a reference to a dimension or entity, and will be used
+    to join the base event to the final conversion event. Typical constant properties are things like
+    session keys (for services where conversions are measured within a user session), or secondary entities
+    (like a user/application pair for an app platform or a user/shop pair for a retail/online storefront platform).
+    """
+
+    @property
+    @abstractmethod
+    def base_property(self) -> str:  # noqa: D
+        pass
+
+    @property
+    @abstractmethod
+    def conversion_property(self) -> str:  # noqa: D
+        pass
+
+
+class ConversionTypeParams(Protocol):
+    """Type params to provide context for conversion metrics properties."""
+
+    @property
+    @abstractmethod
+    def base_measure(self) -> MetricInputMeasure:
+        """Measure used to calculate the base event."""
+        pass
+
+    @property
+    @abstractmethod
+    def conversion_measure(self) -> MetricInputMeasure:
+        """Measure used to calculate the conversion event."""
+        pass
+
+    @property
+    @abstractmethod
+    def entity(self) -> str:
+        """Specified join entity."""
+        pass
+
+    @property
+    @abstractmethod
+    def calculation(self) -> ConversionCalculationType:
+        """Type of conversion metric calculation."""
+        pass
+
+    @property
+    @abstractmethod
+    def window(self) -> Optional[MetricTimeWindow]:
+        """Maximum time range for finding successive conversion events."""
+        pass
+
+    @property
+    @abstractmethod
+    def constant_properties(self) -> Optional[Sequence[ConstantPropertyInput]]:
+        """Return the list of defined constant properties."""
+        pass
+
+
 class MetricTypeParams(Protocol):
     """Type params add additional context to certain metric types (the context depends on the metric type)."""
 
@@ -157,6 +222,11 @@ def grain_to_date(self) -> Optional[TimeGranularity]:  # noqa: D
     def metrics(self) -> Optional[Sequence[MetricInput]]:  # noqa: D
         pass
 
+    @property
+    @abstractmethod
+    def conversion_type_params(self) -> Optional[ConversionTypeParams]:  # noqa: D
+        pass
+
 
 class Metric(Protocol):
     """Describes a metric."""

dbt_semantic_interfaces/transformations/add_input_metric_measures.py

@@ -42,6 +42,11 @@ def _get_measures_for_metric(
                     measures.update(
                         AddInputMetricMeasuresRule._get_measures_for_metric(semantic_manifest, input_metric.name)
                     )
+            elif matched_metric.type is MetricType.CONVERSION:
+                conversion_type_params = matched_metric.type_params.conversion_type_params
+                assert conversion_type_params, "Conversion metric should have conversion_type_params."
+                measures.add(conversion_type_params.base_measure)
+                measures.add(conversion_type_params.conversion_measure)
             else:
                 assert_values_exhausted(matched_metric.type)
         else:

dbt_semantic_interfaces/type_enums/__init__.py

@@ -1,6 +1,9 @@
 from dbt_semantic_interfaces.type_enums.aggregation_type import (  # noqa:F401
     AggregationType,
 )
+from dbt_semantic_interfaces.type_enums.conversion_calculation_type import (  # noqa:F401
+    ConversionCalculationType,
+)
 from dbt_semantic_interfaces.type_enums.dimension_type import DimensionType  # noqa:F401
 from dbt_semantic_interfaces.type_enums.entity_type import EntityType  # noqa:F401
 from dbt_semantic_interfaces.type_enums.metric_type import MetricType  # noqa:F401

dbt_semantic_interfaces/type_enums/conversion_calculation_type.py

@@ -0,0 +1,8 @@
+from dbt_semantic_interfaces.enum_extension import ExtendedEnum
+
+
+class ConversionCalculationType(ExtendedEnum):
+    """Types of calculations for a conversion metric."""
+
+    CONVERSIONS = "conversions"
+    CONVERSION_RATE = "conversion_rate"

dbt_semantic_interfaces/type_enums/metric_type.py

@@ -8,3 +8,4 @@ class MetricType(ExtendedEnum):
     RATIO = "ratio"
     CUMULATIVE = "cumulative"
     DERIVED = "derived"
+    CONVERSION = "conversion"