[ARROW-15908] [Python] FlightClient.DoAction raises RPC exception (C# Client <-> Python Flight Server)

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Bug
• Affects Version/s: 7.0.0
• Component/s: C#, Python
• Labels: C# Python3
• Environment: Rider 2021.3 ; Windows ; ; Server Packages/Versions: ; Python 3.10.2 ; pyarrow 7.0.0 ; ; Client Details: ; C# 9 ; Grpc.Net.Client 2.42.0 ; Apache.Arrow.Flight 7.0.0
• External issue URL: https://github.com/apache/arrow/issues/20148
• Assignee: Unassigned
• Reporter: Chris Dunderdale
• Created: 10/Mar/22 16:13
• Updated: 11/Jan/23 11:40
• Resolved: 10/Mar/22 16:45

Description

Hi all

I'm busy testing arrow flight and I'm noticing that requesting actions from C# to Python is raising the following exception.

Unhandled exception. System.AggregateException: One or more errors occurred. (Status(StatusCode="Unknown", Detail="a bytes-like object is required, not 'str'. Detail: Python exception: TypeError"))
 ---> Grpc.Core.RpcException: Status(StatusCode="Unknown", Detail="a bytes-like object is required, not 'str'. Detail: Python exception: TypeError")
   at Grpc.Net.Client.Internal.HttpContentClientStreamReader`2.MoveNextCore(CancellationToken cancellationToken)
   at Apache.Arrow.Flight.Internal.StreamReader`2.MoveNext(CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at System.Threading.Tasks.Task.Wait()
   at Test.Program.Main(String[] args) in C:\Users\Chris\Test\Program.cs:line 33
 

I've built a C# client and Python server which I've obtained from the Arrow Github repo.

I've trimmed down the C# client to just the following code:

using System;
using Grpc.Net.Client;
using Apache.Arrow.Flight.Client;
using Apache.Arrow.Flight;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            var address = "http://localhost:5005";
            Console.WriteLine($"Connecting to: {address}");
            var channel = GrpcChannel.ForAddress(address);
            var client = new FlightClient(channel);
            var shutdownAction = client.DoAction(new FlightAction("shutdown"));                 shutdownAction.ResponseStream.MoveNext(default).Wait();
            
        }
    }
} 

 

I've noted that the original code on the github repo example uses await (which no longer seems to work) and if I leave the final line out, the do_action() method is never called server-side.