add etag models (#542)

Author: ybz1013

dao-api/src/main/pegasus/com/linkedin/metadata/internal/IngestionParams.pdl

@@ -2,6 +2,7 @@ namespace com.linkedin.metadata.internal
 
 import com.linkedin.metadata.events.IngestionMode
 import com.linkedin.metadata.events.IngestionTrackingContext
+import pegasus.com.linkedin.metadata.events.IngestionAspectETag
 
 /**
  * Record defining ingestion-related parameters that can be passed into DAO API calls.
@@ -22,4 +23,9 @@ record IngestionParams {
    * For validation purposes. And no MAE will be emitted during the persistance
    */
   testMode: boolean = false
-}
+
+  /**
+   * eTag for aspect ingestion optimistic locking
+   */
+  ingestionETags: optional array[IngestionAspectETag] = [ ]
+}

dao-api/src/main/pegasus/pegasus/com/linkedin/metadata/events/IngestionAspectETag.pdl

@@ -0,0 +1,17 @@
+namespace pegasus.com.linkedin.metadata.events
+
+/**
+ * eTag used for atomic aspect updating
+ */
+record IngestionAspectETag {
+
+  /**
+   * aspect FQCN
+   */
+  aspect_name: optional string = ""
+
+  /**
+   * e.g. timestamp used for optimistic locking when writing new aspect value
+   */
+  eTag: optional long = 0
+}