grpc-dotnet服务器本地进程输出流

Question

我在grpc-dotnet 3.1中为一个项目工作。在服务器端，grpc调用将执行本地系统进程(例如二进制文件或脚本)。我遇到的问题是通过grpc客户端将来自进程的重定向输出进行流式处理。我现在得到的只是第一行输出。这是我的测试代码。

public override async Task ExecuteProcess(ProcessRequest request, IServerStreamWriter<ProcessReply> responseStream, ServerCallContext context)
    {
        _logger.LogInformation($"Received Execution request for {request.Name}");
        _logger.LogInformation($"Received Args {request.Args}");
        using (var process = new Process())
        {
            process.StartInfo.FileName = @"cmd.exe";
            process.StartInfo.Arguments = @"/c dir";      // print the current working directory information
            process.StartInfo.CreateNoWindow = true;
            process.StartInfo.UseShellExecute = false;
            process.StartInfo.RedirectStandardOutput = true;
            process.StartInfo.RedirectStandardError = true;
            //process.OutputDataReceived += async(sender, e) => await responseStream.WriteAsync(new ProcessReply { Message = e.Data });
            process.OutputDataReceived += (sender, e) => ShowOutput(e.Data, responseStream)
            process.Start();
            process.BeginOutputReadLine();
            //process.BeginErrorReadLine();
            var exited = process.WaitForExit(1000 * 10);     // (optional) wait up to 10 second
        }
        //return Task.FromResult(new ProcessReply { Message = "Executed " + request.Name });
        await responseStream.WriteAsync(new ProcessReply
        {
            Message = "Process Complete"
        });
    }

    private async Task ShowOutput(string data, IServerStreamWriter<ProcessReply> responseStream)
    {
        if (data != null)
        {
            _logger.LogInformation($"Process Output {data}");
            await responseStream.WriteAsync(new ProcessReply { Message = data });

        }
    }

在客户端，我只是使用流服务器示例代码来读取流中的行。

await foreach (var message in call.ResponseStream.ReadAllAsync())
{
     Console.WriteLine("Server Out: " + message.Message);
}

你知道为什么我只能从重定向的进程输出中得到一行进程输出吗？我也只看到了记录器输出中的一行。

Answer 1

这可能是因为您正在从事件处理程序写入ResponseStream，该事件处理程序不一定会在流的正确异步上下文中被调用。

看看CliWrap，它将整个流程执行过程包装在一个非常好的应用程序接口中，其中包括一个ListenAsync方法，它返回一个IAsyncEnumerable，您可以对其进行await foreach覆盖，并将输出写入流。

借用README，它看起来像这样：

var cmd = Cli.Wrap("cmd.exe").WithArguments("/c dir");

await foreach (var cmdEvent in cmd.ListenAsync())
{
    switch (cmdEvent)
    {
        case StandardOutputCommandEvent stdOut:
            await responseStream.WriteAsync(new ProcessReply { Message = stdOut.Text });
            break;
    }
}

await responseStream.WriteAsync(new ProcessReply { Message = "Process Complete" });