feat: Add sql-datatype to the SDK discovery and catalog

singer_sdk/_singerlib/catalog.py

@@ -96,6 +96,11 @@ class StreamMetadata(Metadata):
     schema_name: str | None = None
 
 
+@dataclass
+class SqlMetadata(Metadata):
+    sql_datatype: str | None = None
+
+
 AnyMetadata: TypeAlias = t.Union[Metadata, StreamMetadata]
 
 
@@ -167,6 +172,7 @@ def get_standard_metadata(
         valid_replication_keys: list[str] | None = None,
         replication_method: str | None = None,
         selected_by_default: bool | None = None,
+        sql_datatypes: dict | None = None,
     ) -> MetadataMapping:
         """Get default metadata for a stream.
 
@@ -177,6 +183,7 @@ def get_standard_metadata(
             valid_replication_keys: Stream valid replication keys.
             replication_method: Stream replication method.
             selected_by_default: Whether the stream is selected by default.
+            sql_datatypes: SQL datatypes present in the stream.
 
         Returns:
             Metadata mapping.
@@ -196,14 +203,19 @@ def get_standard_metadata(
                 root.schema_name = schema_name
 
             for field_name in schema.get("properties", {}):
+                if sql_datatypes is None:
+                    entry = Metadata()
+                else:
+                    entry = SqlMetadata(sql_datatype=sql_datatypes.get(field_name))
+
                 if (
                     key_properties
                     and field_name in key_properties
                     or (valid_replication_keys and field_name in valid_replication_keys)
                 ):
-                    entry = Metadata(inclusion=Metadata.InclusionType.AUTOMATIC)
+                    entry.inclusion = Metadata.InclusionType.AUTOMATIC
                 else:
-                    entry = Metadata(inclusion=Metadata.InclusionType.AVAILABLE)
+                    entry.inclusion = Metadata.InclusionType.AVAILABLE
 
                 mapping[("properties", field_name)] = entry
 

singer_sdk/connectors/sql.py

@@ -396,6 +396,33 @@ def get_object_names(
             view_names = []
         return [(t, False) for t in table_names] + [(v, True) for v in view_names]
 
+    def discover_catalog_entry_sql_datatype(
+        self,
+        data_type: sqlalchemy.types.TypeEngine,
+    ) -> str:
+        """Retrun SQL Datatype as a string to utilize in the catalog.
+
+        Args:
+            data_type: given data type as sqlalchemy.types.TypeEngine
+
+        Returns:
+            A string description the given data type example "VARCHAR(length=15)".
+        """
+        datatype_attributes = ("length", "scale", "precision")
+
+        catalog_format = f"{type(data_type).__name__}("
+
+        for attribute in datatype_attributes:
+            if hasattr(data_type, attribute) and getattr(data_type, attribute):
+                catalog_format += f"{attribute}={(getattr(data_type, attribute))}, "
+
+        if catalog_format.endswith(", "):
+            catalog_format = catalog_format[:-2]
+
+        catalog_format += ")"
+
+        return catalog_format
+
     # TODO maybe should be splitted into smaller parts?
     def discover_catalog_entry(
         self,
@@ -441,21 +468,34 @@ def discover_catalog_entry(
 
         # Initialize columns list
         table_schema = th.PropertiesList()
-        for column_def in inspected.get_columns(table_name, schema=schema_name):
-            column_name = column_def["name"]
-            is_nullable = column_def.get("nullable", False)
-            jsonschema_type: dict = self.to_jsonschema_type(
-                t.cast(sqlalchemy.types.TypeEngine, column_def["type"]),
-            )
-            table_schema.append(
-                th.Property(
-                    name=column_name,
-                    wrapped=th.CustomType(jsonschema_type),
-                    required=not is_nullable,
-                ),
-            )
+        with warnings.catch_warnings(record=True) as inspection_warnings:
+            for column_def in inspected.get_columns(table_name, schema=schema_name):
+                column_name = column_def["name"]
+                is_nullable = column_def.get("nullable", False)
+                jsonschema_type: dict = self.to_jsonschema_type(
+                    t.cast(sqlalchemy.types.TypeEngine, column_def["type"]),
+                )
+                table_schema.append(
+                    th.Property(
+                        name=column_name,
+                        wrapped=th.CustomType(jsonschema_type),
+                        required=not is_nullable,
+                    ),
+                )
+        if len(inspection_warnings) > 0:
+            for line in inspection_warnings:
+                expanded_msg: str = (
+                    f"Discovery warning: {line.message} in '{unique_stream_id}'"
+                )
+                self.logger.info(expanded_msg)
         schema = table_schema.to_dict()
 
+        sql_datatypes = {}
+        for column_def in inspected.get_columns(table_name, schema=schema_name):
+            sql_datatypes[
+                str(column_def["name"])
+            ] = self.discover_catalog_entry_sql_datatype(column_def["type"])
+
         # Initialize available replication methods
         addl_replication_methods: list[str] = [""]  # By default an empty list.
         # Notes regarding replication methods:
@@ -480,6 +520,7 @@ def discover_catalog_entry(
                 replication_method=replication_method,
                 key_properties=key_properties,
                 valid_replication_keys=None,  # Must be defined by user
+                sql_datatypes=sql_datatypes,
             ),
             database=None,  # Expects single-database context
             row_count=None,