[FIXED] Is there a way to wrap asyncio Writer as FileWriter to pass the async writer to an existing API?

Issue

In my app I'd like to have an an async output channel to write data which is actually written by an existing API (https://github.com/ynqa/pandavro). Unfortunately the interface of the asyncio writer doesn't conform to the interface of the classic file-like writer.

Is there a way, like in Java, to somehow wrap the asyncio channel within a classic FileWriter interface? (w/o writing the wrapper by my own ...)

This is the code which I'd like to get running:

import numpy as np
import pandas as pd
import pandavro as pdx
import asyncio


async def main():
    df = pd.DataFrame({
        "Boolean": [True, False, True, False],
        "Float64": np.random.randn(4),
        "Int64": np.random.randint(0, 10, 4),
        "String": ['foo', 'bar', 'foo', 'bar'],
        "DateTime64": [pd.Timestamp('20190101'), pd.Timestamp('20190102'),
                       pd.Timestamp('20190103'), pd.Timestamp('20190104')]})

    reader, writer = await asyncio.open_connection('127.0.0.1', 9090)

    pdx.to_avro(writer, df)

    writer.close()
    await writer.wait_closed()

if __name__ == '__main__':
    asyncio.run(main())

Solution

The only solution I have found by myself is to write a simple wrapper class:

class ChannelWriter:

    __delegate = None

    def __init__(self, delegate: asyncio.streams.StreamWriter):
        self.__delegate = delegate

    async def close(self):
        await self.__delegate.drain()
        return self.__delegate.close()

    @staticmethod
    def seekable():
        return False

    def write(self, value):
        self.__delegate.write(value)

    def flush(self):
        pass

Answered By - cokeSchlumpf