Added if statement to check if metadata already exists.

Added if statement to copy-absolutes to check if metadata already exists before upload. If it does, the upload will be skipped. I could make this a separate function but not sure if it is necessary.

I have tested this thoroughly for 2023 data in production and it always works as expected. However, this often does not work correctly in staging due to the nature of the staging database. The MetadataFactory query will always return empty readings if they exist in the staging database which is bizarre. Empty readings should not exist in production but perhaps the MetadataFactory queries should be tested more in a separate issue.

geomagio/processing/copy_absolutes.py

@@ -185,10 +185,21 @@ def upload_reading(
     metadata = create_reading_metadata(
         reading=reading, created_by_label=created_by_label
     )
-    # TODO: should this check if metadata was already uploaded?
-    # TODO: should that check occur before calling this method?
+
+    # check if metadata already exists before uploading
     if metadata is not None:
-        return factory.create_metadata(metadata=metadata)
+        prior_metadata = Metadata(
+            category=MetadataCategory.READING,
+            starttime=metadata.starttime,
+            endtime=metadata.endtime,
+            station=metadata.station,
+        )
+        prior_metadata = factory.get_metadata(query=prior_metadata)
+        if len(prior_metadata) != 0:
+            print(" Metadata already exists, skipping upload")
+            pass
+        else:
+            return factory.create_metadata(metadata=metadata)
     else:
         print(" Absolute set is empty, skipping upload to webservice")
         pass