feat(ingestion/kafka)-Add support for ingesting schemas from schema r…

…egistry (datahub-project#10612)

metadata-ingestion/src/datahub/ingestion/source/confluent_schema_registry.py

@@ -231,16 +231,25 @@ def get_schemas_from_confluent_ref_json(
         return all_schemas
 
     def _get_schema_and_fields(
-        self, topic: str, is_key_schema: bool
+        self, topic: str, is_key_schema: bool, is_subject: bool
     ) -> Tuple[Optional[Schema], List[SchemaField]]:
         schema: Optional[Schema] = None
-        schema_type_str: str = "key" if is_key_schema else "value"
-        topic_subject: Optional[str] = self._get_subject_for_topic(
-            topic=topic, is_key_schema=is_key_schema
-        )
+        kafka_entity = "subject" if is_subject else "topic"
+
+        # if provided schema as topic, assuming it as value subject
+        schema_type_str: Optional[str] = "value"
+        topic_subject: Optional[str] = None
+        if not is_subject:
+            schema_type_str = "key" if is_key_schema else "value"
+            topic_subject = self._get_subject_for_topic(
+                topic=topic, is_key_schema=is_key_schema
+            )
+        else:
+            topic_subject = topic
+
         if topic_subject is not None:
             logger.debug(
-                f"The {schema_type_str} schema subject:'{topic_subject}' is found for topic:'{topic}'."
+                f"The {schema_type_str} schema subject:'{topic_subject}' is found for {kafka_entity}:'{topic}'."
             )
             try:
                 registered_schema = self.schema_registry_client.get_latest_version(
@@ -249,29 +258,31 @@ def _get_schema_and_fields(
                 schema = registered_schema.schema
             except Exception as e:
                 logger.warning(
-                    f"For topic: {topic}, failed to get {schema_type_str} schema from schema registry using subject:'{topic_subject}': {e}."
+                    f"For {kafka_entity}: {topic}, failed to get {schema_type_str} schema from schema registry using subject:'{topic_subject}': {e}."
                 )
                 self.report.report_warning(
                     topic,
                     f"failed to get {schema_type_str} schema from schema registry using subject:'{topic_subject}': {e}.",
                 )
         else:
             logger.debug(
-                f"For topic: {topic}, the schema registry subject for the {schema_type_str} schema is not found."
+                f"For {kafka_entity}: {topic}, the schema registry subject for the {schema_type_str} schema is not found."
             )
             if not is_key_schema:
                 # Value schema is always expected. Report a warning.
                 self.report.report_warning(
                     topic,
                     f"The schema registry subject for the {schema_type_str} schema is not found."
-                    f" The topic is either schema-less, or no messages have been written to the topic yet.",
+                    f" The {kafka_entity} is either schema-less, or no messages have been written to the {kafka_entity} yet.",
                 )
 
         # Obtain the schema fields from schema for the topic.
         fields: List[SchemaField] = []
         if schema is not None:
             fields = self._get_schema_fields(
-                topic=topic, schema=schema, is_key_schema=is_key_schema
+                topic=topic,
+                schema=schema,
+                is_key_schema=is_key_schema,
             )
         return (schema, fields)
 
@@ -352,16 +363,21 @@ def _get_schema_fields(
         return fields
 
     def _get_schema_metadata(
-        self, topic: str, platform_urn: str
+        self, topic: str, platform_urn: str, is_subject: bool
     ) -> Optional[SchemaMetadata]:
+
         # Process the value schema
         schema, fields = self._get_schema_and_fields(
-            topic=topic, is_key_schema=False
+            topic=topic,
+            is_key_schema=False,
+            is_subject=is_subject,
         )  # type: Tuple[Optional[Schema], List[SchemaField]]
 
         # Process the key schema
         key_schema, key_fields = self._get_schema_and_fields(
-            topic=topic, is_key_schema=True
+            topic=topic,
+            is_key_schema=True,
+            is_subject=is_subject,
         )  # type:Tuple[Optional[Schema], List[SchemaField]]
 
         # Create the schemaMetadata aspect.
@@ -388,17 +404,22 @@ def _get_schema_metadata(
         return None
 
     def get_schema_metadata(
-        self, topic: str, platform_urn: str
+        self, topic: str, platform_urn: str, is_subject: bool
     ) -> Optional[SchemaMetadata]:
-        logger.debug(f"Inside _get_schema_metadata {topic} {platform_urn}")
+        logger.debug(f"Inside get_schema_metadata {topic} {platform_urn}")
+
         # Process the value schema
         schema, fields = self._get_schema_and_fields(
-            topic=topic, is_key_schema=False
+            topic=topic,
+            is_key_schema=False,
+            is_subject=is_subject,
         )  # type: Tuple[Optional[Schema], List[SchemaField]]
 
         # Process the key schema
         key_schema, key_fields = self._get_schema_and_fields(
-            topic=topic, is_key_schema=True
+            topic=topic,
+            is_key_schema=True,
+            is_subject=is_subject,
         )  # type:Tuple[Optional[Schema], List[SchemaField]]
 
         # Create the schemaMetadata aspect.
@@ -423,3 +444,6 @@ def get_schema_metadata(
                 fields=key_fields + fields,
             )
         return None
+
+    def get_subjects(self) -> List[str]:
+        return self.known_schema_registry_subjects

metadata-ingestion/src/datahub/ingestion/source/kafka.py

@@ -303,34 +303,63 @@ def get_workunits_internal(self) -> Iterable[MetadataWorkUnit]:
         ).topics
         extra_topic_details = self.fetch_extra_topic_details(topics.keys())
 
-        for t, t_detail in topics.items():
-            self.report.report_topic_scanned(t)
-            if self.source_config.topic_patterns.allowed(t):
+        for topic, topic_detail in topics.items():
+            self.report.report_topic_scanned(topic)
+            if self.source_config.topic_patterns.allowed(topic):
                 try:
                     yield from self._extract_record(
-                        t, t_detail, extra_topic_details.get(t)
+                        topic, False, topic_detail, extra_topic_details.get(topic)
                     )
                 except Exception as e:
-                    logger.warning(f"Failed to extract topic {t}", exc_info=True)
+                    logger.warning(f"Failed to extract topic {topic}", exc_info=True)
                     self.report.report_warning(
-                        "topic", f"Exception while extracting topic {t}: {e}"
+                        "topic", f"Exception while extracting topic {topic}: {e}"
                     )
             else:
-                self.report.report_dropped(t)
+                self.report.report_dropped(topic)
+
+        # Get all subjects from schema registry and ingest them as SCHEMA DatasetSubTypes
+        for subject in self.schema_registry_client.get_subjects():
+            try:
+                yield from self._extract_record(
+                    subject, True, topic_detail=None, extra_topic_config=None
+                )
+            except Exception as e:
+                logger.warning(f"Failed to extract subject {subject}", exc_info=True)
+                self.report.report_warning(
+                    "subject", f"Exception while extracting topic {subject}: {e}"
+                )
 
     def _extract_record(
         self,
         topic: str,
+        is_subject: bool,
         topic_detail: Optional[TopicMetadata],
         extra_topic_config: Optional[Dict[str, ConfigEntry]],
     ) -> Iterable[MetadataWorkUnit]:
-        logger.debug(f"topic = {topic}")
-
         AVRO = "AVRO"
 
-        # 1. Create the default dataset snapshot for the topic.
-        dataset_name = topic
+        kafka_entity = "subject" if is_subject else "topic"
+
+        logger.debug(f"extracting schema metadata from kafka entity = {kafka_entity}")
+
         platform_urn = make_data_platform_urn(self.platform)
+
+        # 1. Create schemaMetadata aspect (pass control to SchemaRegistry)
+        schema_metadata = self.schema_registry_client.get_schema_metadata(
+            topic, platform_urn, is_subject
+        )
+
+        # topic can have no associated subject, but still it can be ingested without schema
+        # for schema ingestion, ingest only if it has valid schema
+        if is_subject:
+            if schema_metadata is None:
+                return
+            dataset_name = schema_metadata.schemaName
+        else:
+            dataset_name = topic
+
+        # 2. Create the default dataset snapshot for the topic.
         dataset_urn = make_dataset_urn_with_platform_instance(
             platform=self.platform,
             name=dataset_name,
@@ -342,10 +371,6 @@ def _extract_record(
             aspects=[Status(removed=False)],  # we append to this list later on
         )
 
-        # 2. Attach schemaMetadata aspect (pass control to SchemaRegistry)
-        schema_metadata = self.schema_registry_client.get_schema_metadata(
-            topic, platform_urn
-        )
         if schema_metadata is not None:
             dataset_snapshot.aspects.append(schema_metadata)
 
@@ -356,9 +381,19 @@ def _extract_record(
         browse_path = BrowsePathsClass([browse_path_str])
         dataset_snapshot.aspects.append(browse_path)
 
-        custom_props = self.build_custom_properties(
-            topic, topic_detail, extra_topic_config
-        )
+        # build custom properties for topic, schema properties may be added as needed
+        custom_props: Dict[str, str] = {}
+        if not is_subject:
+            custom_props = self.build_custom_properties(
+                topic, topic_detail, extra_topic_config
+            )
+            schema_name: Optional[
+                str
+            ] = self.schema_registry_client._get_subject_for_topic(
+                topic, is_key_schema=False
+            )
+            if schema_name is not None:
+                custom_props["Schema Name"] = schema_name
 
         # 4. Set dataset's description, tags, ownership, etc, if topic schema type is avro
         description: Optional[str] = None
@@ -414,7 +449,7 @@ def _extract_record(
                 )
 
         dataset_properties = DatasetPropertiesClass(
-            name=topic, customProperties=custom_props, description=description
+            name=dataset_name, customProperties=custom_props, description=description
         )
         dataset_snapshot.aspects.append(dataset_properties)
 
@@ -431,12 +466,13 @@ def _extract_record(
 
         # 6. Emit the datasetSnapshot MCE
         mce = MetadataChangeEvent(proposedSnapshot=dataset_snapshot)
-        yield MetadataWorkUnit(id=f"kafka-{topic}", mce=mce)
+        yield MetadataWorkUnit(id=f"kafka-{kafka_entity}", mce=mce)
 
-        # 7. Add the subtype aspect marking this as a "topic"
+        # 7. Add the subtype aspect marking this as a "topic" or "schema"
+        typeName = DatasetSubTypes.SCHEMA if is_subject else DatasetSubTypes.TOPIC
         yield MetadataChangeProposalWrapper(
             entityUrn=dataset_urn,
-            aspect=SubTypesClass(typeNames=[DatasetSubTypes.TOPIC]),
+            aspect=SubTypesClass(typeNames=[typeName]),
         ).as_workunit()
 
         domain_urn: Optional[str] = None

metadata-ingestion/src/datahub/ingestion/source/kafka_schema_registry_base.py

@@ -1,12 +1,22 @@
 from abc import ABC, abstractmethod
-from typing import Optional
+from typing import List, Optional
 
 from datahub.metadata.com.linkedin.pegasus2avro.schema import SchemaMetadata
 
 
 class KafkaSchemaRegistryBase(ABC):
     @abstractmethod
     def get_schema_metadata(
-        self, topic: str, platform_urn: str
+        self, topic: str, platform_urn: str, is_subject: bool
     ) -> Optional[SchemaMetadata]:
         pass
+
+    @abstractmethod
+    def get_subjects(self) -> List[str]:
+        pass
+
+    @abstractmethod
+    def _get_subject_for_topic(
+        self, dataset_subtype: str, is_key_schema: bool
+    ) -> Optional[str]:
+        pass

metadata-ingestion/src/datahub/ingestion/source/snowflake/snowflake_assertion.py

@@ -59,7 +59,6 @@ def __init__(
     def get_assertion_workunits(
         self, discovered_datasets: List[str]
     ) -> Iterable[MetadataWorkUnit]:
-
         self.connection = self.create_connection()
         if self.connection is None:
             return
@@ -80,7 +79,6 @@ def get_assertion_workunits(
                     yield self._gen_platform_instance_wu(mcp.entityUrn)
 
     def _gen_platform_instance_wu(self, urn: str) -> MetadataWorkUnit:
-
         # Construct a MetadataChangeProposalWrapper object for assertion platform
         return MetadataChangeProposalWrapper(
             entityUrn=urn,

metadata-ingestion/src/datahub/ingestion/source/snowflake/snowflake_query.py

@@ -1019,7 +1019,6 @@ def table_upstreams_only(
 
     @staticmethod
     def dmf_assertion_results(start_time_millis: int, end_time_millis: int) -> str:
-
         pattern = r"datahub\\_\\_%"
         escape_pattern = r"\\"
         return f"""