main.py

import polars as pl
import fastavro
from pathlib import Path

# Define an Avro schema with both record (struct) and map
schema = {
    "type": "record",
    "name": "Inventory",
    "fields": [
        {"name": "id", "type": "int"},
        {"name": "info", "type": {
            "type": "record",
            "name": "UserInfo",
            "fields": [
                {"name": "name", "type": "string"},
                {"name": "age", "type": "int"}
            ]
        }},
        {"name": "items", "type": {"type": "map", "values": "int"}}
    ]
}

# Example records
records = [
    {"id": 1, "info": {"name": "Alice", "age": 30}, "items": {"apples": 10, "bananas": 25}},
    {"id": 2, "info": {"name": "Bob", "age": 40}, "items": {"oranges": 5}},
]

# Write them to Avro using fastavro
out_path = Path("map_record_demo.avro")
with out_path.open("wb") as out:
    fastavro.writer(out, schema, records)

# Read back with Polars
df = pl.read_avro(out_path)
print("Polars schema:", df.schema)
print(df)