Generate an avro file with a single row containing all null values

avro_null_generator.py

import fastavro

schema = {
    "type": "record",
    "name": "topLevelRecord",
    "fields": [
        {"name": "string_col", "type": ["null", "string"], "default": None},
        {"name": "int_col", "type": ["null", "int"], "default": None},
        {"name": "bool_col", "type": ["null", "boolean"], "default": None},
        {"name": "bigint_col", "type": ["null", "long"], "default": None},
        {"name": "float_col", "type": ["null", "float"], "default": None},
        {"name": "double_col", "type": ["null", "double"], "default": None},
        {"name": "bytes_col", "type": ["null", "bytes"], "default": None}
    ]
}

data = {"string_col": None, "int_col": None, "bool_col": None, "bigint_col": None, "float_col": None, "double_col": None, "bytes_col": None}

with open("alltypes_nulls_plain.avro", "wb") as avro_file:
    fastavro.writer(avro_file, schema, [data])