Properly extract kafka schema

metadata-ingestion/src/gometa/ingestion/extractor/schema_util.py

@@ -1,38 +1,65 @@
 import logging
+from typing import List, Dict, Any
 import avro.schema
-"""A helper file for Avro schema -> MCE schema transformations"""
 
+from gometa.metadata.com.linkedin.pegasus2avro.schema import (
+    SchemaMetadata, KafkaSchema, SchemaField, SchemaFieldDataType,
+    BooleanTypeClass, FixedTypeClass, StringTypeClass, BytesTypeClass, NumberTypeClass, EnumTypeClass, NullTypeClass, MapTypeClass, ArrayTypeClass, UnionTypeClass, RecordTypeClass,
+)
+
+"""A helper file for Avro schema -> MCE schema transformations"""
 
 logger = logging.getLogger(__name__)
 
-#TODO: Broken (UnionSchemas)
 _field_type_mapping = {
-    "int" : "int",
-    "string" : "string",
-    "record" : "struct",
+    "null": NullTypeClass,
+    "bool": BooleanTypeClass,
+    "int" : NumberTypeClass,
+    "long" : NumberTypeClass,
+    "float" : NumberTypeClass,
+    "double" : NumberTypeClass,
+    "bytes" : BytesTypeClass,
+    "string" : StringTypeClass,
+    "record" : RecordTypeClass,
+    "enum" : EnumTypeClass,
+    "array" : ArrayTypeClass,
+    "union" : UnionTypeClass,
+    "fixed" : FixedTypeClass,
 }
 
-#TODO: Broken  
-def _get_column_type(field_type):
-    return _field_type_mapping.get(str(field_type), str(field_type))
-
-#TODO: Broken
-def avro_schema_to_mce_fields(avro_schema_string):
+def _get_column_type(field_type) -> SchemaFieldDataType:
+    tp = field_type
+    if hasattr(tp, 'type'):
+        tp = tp.type
+    tp = str(tp)
+    TypeClass: Any = _field_type_mapping.get(tp)
+    # TODO: we could populate the nestedTypes field for unions and similar fields
+    # for the other types as well. However, since we already populate the nativeDataType
+    # field below, it is mostly ok to leave this as not fully initialized.
+    dt = SchemaFieldDataType(type=TypeClass())
+    return dt
+   
+def avro_schema_to_mce_fields(avro_schema_string: str) -> List[SchemaField]:
     """Converts an avro schema into a schema compatible with MCE"""
-    schema: avro.schema.RecordSchema = avro.schema.Parse(avro_schema_string)
-    canonical_fields = []
-    fields_skipped = 0
-    for field in schema.fields:
-        # only transform the fields we can, ignore the rest
-        if _field_type_mapping.get(str(field.type),None):
-            canonical_field = {
-                'fieldPath': field.name,
-                'nativeDataType': str(field.type),
-                'type': { "type": _get_column_type(field.type)},
-                'description': field.doc,
-            }
-            canonical_fields.append(canonical_field)
-        else:
-            fields_skipped = fields_skipped + 1
-    logger.warn(f'Schema {schema.name}: Skipped {fields_skipped} fields during Avro schema to canonical schema conversion')
-    return canonical_fields
+
+    # Handle some library compatability issues.
+    if hasattr(avro.schema, 'parse'):
+        schema_parse_fn = avro.schema.parse
+    else:
+        schema_parse_fn = avro.schema.Parse
+
+    parsed_schema: avro.schema.RecordSchema = schema_parse_fn(avro_schema_string)
+
+    fields: List[SchemaField] = []
+    for parsed_field in parsed_schema.fields:
+        field = SchemaField(
+            fieldPath=parsed_field.name,
+            nativeDataType=str(parsed_field.type),
+            type=_get_column_type(parsed_field.type),
+            description=parsed_field.props.get('doc', None),
+        )
+
+        fields.append(field)
+    
+    breakpoint()
+    return fields

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

@@ -16,7 +16,7 @@ import gometa.ingestion.extractor.schema_util as schema_util
 
 from gometa.metadata.com.linkedin.pegasus2avro.mxe import MetadataChangeEvent
 from gometa.metadata.com.linkedin.pegasus2avro.metadata.snapshot import DatasetSnapshot
-from gometa.metadata.com.linkedin.pegasus2avro.schema import SchemaMetadata, KafkaSchema
+from gometa.metadata.com.linkedin.pegasus2avro.schema import SchemaMetadata, KafkaSchema, SchemaField
 from gometa.metadata.com.linkedin.pegasus2avro.common import AuditStamp
 
 logger = logging.getLogger(__name__)
@@ -99,11 +99,18 @@ class KafkaSource(Source):
         except Exception as e:
             logger.debug(f"failed to get schema for {topic} with {e}")
 
+        fields: Optional[List[SchemaField]] = None
+        if schema and schema.schema_type == 'AVRO':
+            fields = schema_util.avro_schema_to_mce_fields(schema.schema_str)
+        elif schema:
+            logger.debug(f"unable to parse kafka schema type {schema.schema_type}")
+
+        is_incomplete = True
         if schema:
-            # TODO: add schema parsing capabilities
-            # canonical_schema = []
-            # if schema.schema_type == "AVRO":
-            #     canonical_schema = schema_util.avro_schema_to_mce_fields(schema.schema_str)
+            if not fields:
+                fields = []
+            else:
+                is_incomplete = False
 
             schema_metadata = SchemaMetadata(
                 schemaName=topic,
@@ -111,16 +118,16 @@ class KafkaSource(Source):
                 hash=str(schema._hash),
                 platform=f"urn:li:dataPlatform:{platform}",
                 platformSchema = KafkaSchema(
-                    # TODO: keySchema
                     documentSchema=schema.schema_str
                 ),
-                fields=[],
+                fields=(fields if fields is not None else []),
                 created=AuditStamp(time=sys_time, actor=actor),
                 lastModified=AuditStamp(time=sys_time, actor=actor),
             )
 
             dataset_snapshot.aspects.append(schema_metadata)
-        else:
+
+        if is_incomplete:
             self.report.report_schema_incomplete(topic)
 
         metadata_record.proposedSnapshot = dataset_snapshot