Powershell：系统诊断-processstartinfo 挂起，原因未知

Question

深受 Stackoverflow 上其他问题的影响，我最终采用了这种从 Powershell 脚本启动进程的方法

function global:system-diagnostics-processstartinfo {
[CmdletBinding(SupportsShouldProcess=$True,ConfirmImpact='Low')]
param
(
    [Parameter(Mandatory=$True,HelpMessage='Full path to exectuable')]
    [Alias('exectuable')]
    [string]$exe,
    [Parameter(Mandatory=$True,HelpMessage='All arguments to be sent to exectuable')]
    [Alias('args')]
    [string]$arguments
)

if (!(Test-Path $exe)) {
    $log.errorFormat("Did not find exectuable={0}, aborting script", $exe)
    exit 1  
}

$log.infoFormat("Start exectuable={0} with arguments='{1}'", $exe, $arguments)
$processStartInfo = New-Object System.Diagnostics.ProcessStartInfo($exe)
$processStartInfo.FileName = $exe
$processStartInfo.RedirectStandardError = $true
$processStartInfo.RedirectStandardOutput = $true
$processStartInfo.UseShellExecute = $false
$processStartInfo.Arguments = $arguments
$p = New-Object System.Diagnostics.Process
$p.StartInfo = $processStartInfo
$log.info("Start exectuable and wait for exit")
$p.Start() | Out-Null

#$p.WaitForExit()
$stdout = $p.StandardOutput.ReadToEnd()
$stderr = $p.StandardError.ReadToEnd()
$log.infoFormat("exectuable={0}  stdout: {1}", $exe, $stdout)
$log.debugFormat("exectuable={0} stderr: {1}",  $exe,$stderr)
$global:ExitCode = $p.ExitCode
$log.debugFormat("exectuable={0} Exitcode: {1}", $exe, $p.ExitCode)

return $stdout
}

非常简单，添加了一些日志记录等。它适用于我当前的所有用例，除了一个。我创建了一个脚本，将 Confluence 生产实例的数据库转储复制到测试服务器。然后它使用上面的方法删除现有数据库，一切正常。但实际的恢复只是永远挂起。所以现在我必须退出脚本，然后手动运行以下命令

d:\postgresql\bin\pg_restore.exe -U postgres -d confluencedb -v -1 d:\temp\latest-backup.pgdump

需要一些时间，产出也相当多。这让我相信一定有以下任一原因导致了问题

• 输出量导致缓冲区溢出并导致脚本停止
• 需要很多时间

有类似经历的人可以帮我解决这个问题。它将能够安排导入，而不必像今天一样手动执行。

Answer 1

处理后我必须立即执行以下操作。开始：

# Capture output during process execution so we don't hang
# if there is too much output.
do
{
    if (!$process.StandardOutput.EndOfStream)
    {
        [void]$StdOut.AppendLine($process.StandardOutput.ReadLine())
    }
    if (!$process.StandardError.EndOfStream)
    {
        [void]$StdErr.AppendLine($process.StandardError.ReadLine())
    }

    Start-Sleep -Milliseconds 10
}
while (!$process.HasExited)
        
# Capture any standard output generated between our last poll and process end.
while (!$process.StandardOutput.EndOfStream)
{
    [void]$StdOut.AppendLine($process.StandardOutput.ReadLine())
}
    
# Capture any error output generated between our last poll and process end.
while (!$process.StandardError.EndOfStream)
{
    [void]$StdErr.AppendLine($process.StandardError.ReadLine())
}

# Wait for the process to exit.
$process.WaitForExit()
LogWriteFunc ("END process: " + $ProcessName)

if ($process.ExitCode -ne 0)
{
    LogWriteFunc ("Error: Script execution failed: " + $process.ExitCode )
    $FuncResult = 1
}

# Log and display any standard output.
if ($StdOut.Length -gt 0)
{
    LogWriteFunc ($StdOut.ToString())
}
    
# Log and display any error output.
if ($StdErr.Length -gt 0)
{
    LogWriteFunc ($StdErr.ToString())
}

Answer 2

Greg Prosch提供的答案可能会陷入僵局。如此处所述：

如果没有缓冲任何字符，StreamReader.EndOfStream 属性将调用 StandardOutput.Read()。如果进程没有向其输出管道发送任何内容并且没有关闭它，则 Read() 调用将阻塞。

此代码采用了

Microsoft 文档 关于防止死锁的建议，以及 这篇文章 关于确保捕获所有输出的建议：

$global:stdErr = [System.Text.StringBuilder]::new()
$global:myprocessrunning = $true

Function Invoke-CustomCommand
{
    Param (
        $commandPath,
        $commandArguments,
        $workingDir = (Get-Location),
        $path = @()
    )

    $global:stdErr.Clear()
    $global:myprocessrunning = $true

    $path += $env:PATH
    $newPath = $path -join [IO.Path]::PathSeparator

    $pinfo = New-Object System.Diagnostics.ProcessStartInfo
    $pinfo.FileName = $commandPath
    $pinfo.WorkingDirectory = $workingDir
    $pinfo.RedirectStandardError = $true
    $pinfo.RedirectStandardOutput = $true
    $pinfo.StandardOutputEncoding = [System.Text.Encoding]::UTF8
    $pinfo.StandardErrorEncoding = [System.Text.Encoding]::UTF8
    $pinfo.UseShellExecute = $false
    $pinfo.Arguments = $commandArguments
    $pinfo.EnvironmentVariables["PATH"] = $newPath
    $p = New-Object System.Diagnostics.Process

    # https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.process.standardoutput
    # Reading from one stream must be async
    # We read the error stream, because events can be handled out of order,
    # and it is better to have this happen with debug output
    Register-ObjectEvent -InputObject $p -EventName "ErrorDataReceived" -Action {
        $global:stdErr.AppendLine($EventArgs.Data)
    } | Out-Null

    # We must wait for the Exited event rather than WaitForExit()
    # because WaitForExit() can result in events being missed
    # https://stackoverflow.com/questions/13113624/captured-output-of-command-run-by-powershell-is-sometimes-incomplete
    Register-ObjectEvent -InputObject $p -EventName "Exited" -action {
        $global:myprocessrunning = $false
    } | Out-Null

    $p.StartInfo = $pinfo
    $p.Start() | Out-Null

    $p.BeginErrorReadLine()

    # Wait 10 minutes before forcibly killing the process
    $processTimeout = 1000 * 60 * 10
    while (($global:myprocessrunning -eq $true) -and ($processTimeout -gt 0))
    {
        # We must use lots of shorts sleeps rather than a single long one otherwise events are not processed
        $processTimeout -= 50
        Start-Sleep -m 50
    }

    $output = $p.StandardOutput.ReadToEnd()

    if ($processTimeout -le 0)
    {
        $p.Kill()
    }

    $executionResults = [pscustomobject]@{
        StdOut = $output
        StdErr = $global:stdErr.ToString()
        ExitCode = $p.ExitCode
    }

    return $executionResults
}