LuaState.DoFileAsync not cancelling when token is set

[tottaka]

When CancellationToken is set, the script never actually stops running. Am I doing something wrong here?

C# code:

internal class Program
{
    static void Main(string[] args)
    {
        CancellationTokenSource cts = new CancellationTokenSource();
        RunTest("main.lua", cts.Token);
        Task.Delay(5000).Wait();
        cts.Cancel(true);

        Console.WriteLine("Still running...?");

        // The lua code still continutes here for some reason
        Task.Delay(5000).Wait();
    }
    
    static async void RunTest(string app, CancellationToken token)
    {
        LuaState state = LuaState.Create();
        state.Environment["sleep"] = new LuaFunction("sleep", Env_Sleep);
        state.Environment["print"] = new LuaFunction("print", Env_Print);

        LuaValue[] values = await state.DoFileAsync(app, token);
        Console.WriteLine("Application exited.");
        foreach (LuaValue value in values)
        {
            Console.WriteLine(value.ToString());
        }
    }

    private static ValueTask<int> Env_Sleep(LuaFunctionExecutionContext context, Memory<LuaValue> buffer, CancellationToken token)
    {
        double timeout = context.GetArgument<double>(0);
        Thread.Sleep(TimeSpan.FromSeconds(timeout));
        return new(0);
    }

    private static ValueTask<int> Env_Print(LuaFunctionExecutionContext context, Memory<LuaValue> buffer, CancellationToken token)
    {
        StringBuilder sb = new();
        for (int i = 0; i < context.ArgumentCount; i++)
        {
            if (i < context.ArgumentCount - 1)
                sb.Append(context.Arguments[i].ToString() + " ");
            else
                sb.Append(context.Arguments[i].ToString());
        }

        Console.WriteLine(sb.ToString());
        return new(0);
    }
}

Lua code (main.lua):

print(1)
sleep(1.0)
print(2)
sleep(1.0)
print(3)
sleep(1.0)
print(4)
sleep(1.0)
print(5)
sleep(1.0)
print(6)
sleep(1.0)
print(7)
sleep(1.0)
print(8)
sleep(1.0)
print(9)
sleep(1.0)
print(10)

Output:

1
2
3
4
5
Still running...?
6
7
8
9
10
Application exited.

[nuskey8]

If you are waiting in a user-defined function, you must handle the cancellation within that.

Don't use Thread.Sleep() to wait within an asynchronous function. Use Task.Delay() instead.

private static async ValueTask<int> Env_Sleep(LuaFunctionExecutionContext context, Memory<LuaValue> buffer, CancellationToken token)
{
    double timeout = context.GetArgument<double>(0);
    await Task.Delay(TimeSpan.FromSeconds(timeout), cancellationToken);
    return 0;
}

[tottaka]

If you are waiting in a user-defined function, you must handle the cancellation within that.

Don't use Thread.Sleep() to wait within an asynchronous function. Use Task.Delay() instead.

private static async ValueTask Env_Sleep(LuaFunctionExecutionContext context, Memory buffer, CancellationToken token)
{
double timeout = context.GetArgument(0);
await Task.Delay(TimeSpan.FromSeconds(timeout), cancellationToken);
return 0;
}

Thank you for the advice, I'm glad you could clarify the sleep method because I was unsure about that and totally just winged it.

What about if I'm in a loop? For example:

idx = 0
while true do
	idx = idx + 0.01
end

This code also does not cancel when the CancellationToken is set... It continues to run the while loop even though the CancellationToken supplied to the DoFileAsync method is set

[nuskey8]

Yes, unfortunately it is not possible to cancel in the current version. However, a PR to support this has already been merged by @Akeit0 (#147). This will be released in the next version.

[tottaka]

Yes, unfortunately it is not possible to cancel in the current version. However, a PR to support this has already been merged by @Akeit0 (#147). This will be released in the next version.

Thank you for this. I'll check it out.

Side note:
I was looking at the way DoFileAsync/DoStringAsync works, and was thinking of a way to somehow serialize & compress the Chunk class to a file, so the idea is to just decompress/deserialize it and avoid parsing/compilation and just supply the "deserialized" version of the Chunk class to the LuaState.RunAsync method directly. I'm interested to know what are your comments on this?

[Akeit0]

@tottaka

Side note:
I was looking at the way DoFileAsync/DoStringAsync works, and was thinking of a way to somehow serialize & compress the Chunk class to a file, so the idea is to just decompress/deserialize it and avoid parsing/compilation and just supply the "deserialized" version of the Chunk class to the LuaState.RunAsync method directly. I'm interested to know what are your comments on this?

Is this what you are looking for?
https://www.lua.org/manual/5.2/manual.html#lua_dump
https://github.com/nuskey8/Lua-CSharp/blob/v0.5-dev/src/Lua/CodeAnalysis/Compilation/Dump.cs

[tottaka]

@tottaka

Side note:
I was looking at the way DoFileAsync/DoStringAsync works, and was thinking of a way to somehow serialize & compress the Chunk class to a file, so the idea is to just decompress/deserialize it and avoid parsing/compilation and just supply the "deserialized" version of the Chunk class to the LuaState.RunAsync method directly. I'm interested to know what are your comments on this?

Is this what you are looking for? https://www.lua.org/manual/5.2/manual.html#lua_dump https://github.com/nuskey8/Lua-CSharp/blob/v0.5-dev/src/Lua/CodeAnalysis/Compilation/Dump.cs

This seems very promising for what I was trying to explain, thank you very much!