ProcessStartInfo 挂在“WaitForExit”上？为什么？

发布于 2024-07-06 18:01:52 字数 711 浏览 5 评论 0原文

我有以下代码：

info = new System.Diagnostics.ProcessStartInfo("TheProgram.exe", String.Join(" ", args));
info.CreateNoWindow = true;
info.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
info.RedirectStandardOutput = true;
info.UseShellExecute = false;
System.Diagnostics.Process p = System.Diagnostics.Process.Start(info);
p.WaitForExit();
Console.WriteLine(p.StandardOutput.ReadToEnd()); //need the StandardOutput contents

我知道我正在启动的进程的输出大约 7MB 长。在 Windows 控制台中运行它效果很好。不幸的是，以编程方式，这会无限期地挂在 WaitForExit 处。另请注意，对于较小的输出（例如 3KB），此代码不会挂起。

是否有可能ProcessStartInfo中的内部StandardOutput无法缓冲7MB？如果是这样，我该怎么办？如果不是，我做错了什么？

原文

I have the following code:

info = new System.Diagnostics.ProcessStartInfo("TheProgram.exe", String.Join(" ", args));
info.CreateNoWindow = true;
info.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
info.RedirectStandardOutput = true;
info.UseShellExecute = false;
System.Diagnostics.Process p = System.Diagnostics.Process.Start(info);
p.WaitForExit();
Console.WriteLine(p.StandardOutput.ReadToEnd()); //need the StandardOutput contents

I know that the output from the process I am starting is around 7MB long. Running it in the Windows console works fine. Unfortunately programmatically this hangs indefinitely at WaitForExit. Note also this code does NOT hang for smaller outputs (like 3KB).

Is it possible that the internal StandardOutput in ProcessStartInfo can't buffer 7MB? If so, what should I do instead? If not, what am I doing wrong?

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灼疼热情 2024-07-13 18:01:52

问题是，如果您重定向 StandardOutput 和/或 StandardError，内部缓冲区可能会变满。无论您使用什么顺序，都可能会出现问题：

如果您等待进程退出后再读取 StandardOutput，则进程可能会阻止尝试写入它，因此进程永远不会结束。
如果您使用 ReadToEnd 从 StandardOutput 读取数据，那么如果进程永远不会关闭 StandardOutput（例如，如果它从未终止，或者如果它写入 StandardError 时被阻止）。

解决方案是使用异步读取来确保缓冲区不会变满。为了避免任何死锁并收集 StandardOutput 和 StandardError 的所有输出，您可以执行以下操作：

编辑：请参阅下面的答案，了解如何避免 ObjectDisposeException如果发生超时。

using (Process process = new Process())
{
    process.StartInfo.FileName = filename;
    process.StartInfo.Arguments = arguments;
    process.StartInfo.UseShellExecute = false;
    process.StartInfo.RedirectStandardOutput = true;
    process.StartInfo.RedirectStandardError = true;

    StringBuilder output = new StringBuilder();
    StringBuilder error = new StringBuilder();

    using (AutoResetEvent outputWaitHandle = new AutoResetEvent(false))
    using (AutoResetEvent errorWaitHandle = new AutoResetEvent(false))
    {
        process.OutputDataReceived += (sender, e) => {
            if (e.Data == null)
            {
                outputWaitHandle.Set();
            }
            else
            {
                output.AppendLine(e.Data);
            }
        };
        process.ErrorDataReceived += (sender, e) =>
        {
            if (e.Data == null)
            {
                errorWaitHandle.Set();
            }
            else
            {
                error.AppendLine(e.Data);
            }
        };

        process.Start();

        process.BeginOutputReadLine();
        process.BeginErrorReadLine();

        if (process.WaitForExit(timeout) &&
            outputWaitHandle.WaitOne(timeout) &&
            errorWaitHandle.WaitOne(timeout))
        {
            // Process completed. Check process.ExitCode here.
        }
        else
        {
            // Timed out.
        }
    }
}

The problem is that if you redirect StandardOutput and/or StandardError the internal buffer can become full. Whatever order you use, there can be a problem:

If you wait for the process to exit before reading StandardOutput the process can block trying to write to it, so the process never ends.
If you read from StandardOutput using ReadToEnd then your process can block if the process never closes StandardOutput (for example if it never terminates, or if it is blocked writing to StandardError).

The solution is to use asynchronous reads to ensure that the buffer doesn't get full. To avoid any deadlocks and collect up all output from both StandardOutput and StandardError you can do this:

EDIT: See answers below for how avoid an ObjectDisposedException if the timeout occurs.

using (Process process = new Process())
{
    process.StartInfo.FileName = filename;
    process.StartInfo.Arguments = arguments;
    process.StartInfo.UseShellExecute = false;
    process.StartInfo.RedirectStandardOutput = true;
    process.StartInfo.RedirectStandardError = true;

    StringBuilder output = new StringBuilder();
    StringBuilder error = new StringBuilder();

    using (AutoResetEvent outputWaitHandle = new AutoResetEvent(false))
    using (AutoResetEvent errorWaitHandle = new AutoResetEvent(false))
    {
        process.OutputDataReceived += (sender, e) => {
            if (e.Data == null)
            {
                outputWaitHandle.Set();
            }
            else
            {
                output.AppendLine(e.Data);
            }
        };
        process.ErrorDataReceived += (sender, e) =>
        {
            if (e.Data == null)
            {
                errorWaitHandle.Set();
            }
            else
            {
                error.AppendLine(e.Data);
            }
        };

        process.Start();

        process.BeginOutputReadLine();
        process.BeginErrorReadLine();

        if (process.WaitForExit(timeout) &&
            outputWaitHandle.WaitOne(timeout) &&
            errorWaitHandle.WaitOne(timeout))
        {
            // Process completed. Check process.ExitCode here.
        }
        else
        {
            // Timed out.
        }
    }
}

ProcessStartInfo 挂在“WaitForExit”上？ 为什么？

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ProcessStartInfo 挂在“WaitForExit”上？为什么？

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