Handling empty Pandas DataFrames

Author: igorborgest

awswrangler/exceptions.py

@@ -52,3 +52,7 @@ class InvalidRedshiftSortstyle(Exception):
 
 class InvalidRedshiftSortkey(Exception):
     pass
+
+
+class EmptyDataframe(Exception):
+    pass

awswrangler/pandas.py

@@ -9,7 +9,8 @@
 import pyarrow
 from pyarrow import parquet
 
-from awswrangler.exceptions import UnsupportedWriteMode, UnsupportedFileFormat, AthenaQueryError, EmptyS3Object, LineTerminatorNotFound
+from awswrangler.exceptions import UnsupportedWriteMode, UnsupportedFileFormat,\
+    AthenaQueryError, EmptyS3Object, LineTerminatorNotFound, EmptyDataframe
 from awswrangler.utils import calculate_bounders
 from awswrangler import s3
 
@@ -535,6 +536,8 @@ def to_s3(self,
         :param cast_columns: Dictionary of columns indexes and Arrow types to be casted. (E.g. {2: "int64", 5: "int32"}) (Only for "parquet" file_format)
         :return: List of objects written on S3
         """
+        if dataframe.empty:
+            raise EmptyDataframe()
         if not partition_cols:
             partition_cols = []
         if mode == "overwrite" or (mode == "overwrite_partitions"

testing/test_awswrangler/test_pandas.py

@@ -9,7 +9,7 @@
 import numpy
 
 from awswrangler import Session, Pandas
-from awswrangler.exceptions import LineTerminatorNotFound
+from awswrangler.exceptions import LineTerminatorNotFound, EmptyDataframe
 
 logging.basicConfig(
     level=logging.INFO,
@@ -391,3 +391,14 @@ def test_to_parquet_with_kms(
             break
         sleep(1)
     assert len(dataframe.index) == len(dataframe2.index)
+
+
+def test_to_parquet_with_empty_dataframe(session, bucket, database):
+    dataframe = pandas.DataFrame()
+    with pytest.raises(EmptyDataframe):
+        assert session.pandas.to_parquet(dataframe=dataframe,
+                                         database=database,
+                                         path=f"s3://{bucket}/test/",
+                                         preserve_index=False,
+                                         mode="overwrite",
+                                         procs_cpu_bound=1)