问题

我正在使用Powershell编写部署脚本。使用Copy-Item命令不会在两次运行之间提供相同的结果，即使使用相同的数据也是如此。（似乎不是幂等的）

有关我的意思的示例，请参见下面的结果。我意识到我可以C:\products在复制“新”版本之前删除其中的文件，但是我对这在Powershell中是否是预期的行为感到好奇。（我假设是这样）

我宁愿学习“正确”的使用方式，也Copy-Item不要因为缺乏知识而乱砍。

我尝试使用target\*path代替，target但是这将我的lib文件夹分解到的根中showcase，即使带该-Recurse标志我也没想到。

C:\products
  - showcase
    - showcase.jar
    - logback.jar
    - foo.jar
    - junit.jar
    - etc, etc

我也对这里的文档（特别是示例7,10和11）感到困惑，因为7使用了该-Recurse标志，而11使用了该标志。同时，示例10表示：

如果scripts文件夹在子文件夹中包含文件，则这些子文件夹将在其文件树完好无损的情况下被复制。

但也不会指定任何递归标志。

结果

部署前

C:\products
  - backup

初始部署

C:\products
  - showcase
    - showcase.jar
    - lib
      - <dependencies for showcase.jar>
  - backup
    <empty>
# Expected, as there wasn't a prior deployment yet.

第二次部署

C:\products
  - showcase
    - showcase.jar
    - lib
      - <dependencies for showcase.jar>
    - target
      - showcase.jar
      - lib
        - <dependencies for inner showcase.jar>
  - backup
    - showcase
      - showcase.jar
      - lib
        - <dependencies for "old" showcase.jar>
  # Expected, the old version was backed up

部署脚本及其调用方式

./deploy.ps1 -hostname foobar (it's a remote server)

deploy.ps1

param( [String]$hostname, [switch]$debug )

$folder_to_copy = "target"
$init_file = "./init.ps1"

function Backup-Binary ( [String]$source, [String]$name, [String]$dest ) {

    $FullyQualifiedSourcePath = "$source\$name"

    if (Test-Path $FullyQualifiedSourcePath) {
        Write-Host "Backing up $FullyQualifiedSourcePath to the destination $dest"
        Copy-Item -Recurse -Force -Path $FullyQualifiedSourcePath -Destination $dest -ErrorAction Stop
    } else {
        Write-Output "Directory $FullyQualifiedSourcePath didn't exist. May be an initial deployment. Continuing with deployment."
    }

}

function Verify-Env ([String]$env_var) {
     $check = [Environment]::GetEnvironmentVariable($env_var)
     if ($check -eq $null) {
         Write-Error "$env_var environment variable doesn't exist. Exiting program."
         exit 1
     }
}

function Deploy-Local {

    # Checks that the given string exists as an Environment variable
    Verify-Env "DEPLOY_DRIVE"
    Verify-Env "CI_PROJECT_NAME"

    # C:\products or D:\products *most* of the time.
    $root = "$env:DEPLOY_DRIVE\products"
    $destination = "$root\$env:CI_PROJECT_NAME"
    $backup_loc = "$root\backup"

    # Removes prior binaries
    Backup-Binary -source $root -name $env:CI_PROJECT_NAME -dest $backup_loc

    # Copy binary locally since we're deploying to local machine.
    Copy-Item -Recurse -Force -Path $folder_to_copy -Destination $destination -ErrorAction Stop

    # Run the init script the developer has written
    Invoke-Expression "$init_file" -ErrorAction Stop

}

function Deploy-Remote {

    $session = New-PSSession -ComputerName $hostname

    $DEPLOY_DRIVE = Invoke-Command -Session $session -ScriptBlock { 
        [Environment]::GetEnvironmentVariable("DEPLOY_DRIVE")
    } -ErrorAction Stop

    $root = "$DEPLOY_DRIVE\products"
    $destination = "$root\$env:CI_PROJECT_NAME"
    $backup_loc = "$root\backup"

    Write-Host "$root = root $destination = destination $backup_loc = backup_location"

    Invoke-Command -Session $session -ScriptBlock ${function:Backup-Binary} -ArgumentList $root,$env:CI_PROJECT_NAME,$backup_loc -ErrorAction Stop

    Copy-Item -Recurse -Force -ToSession $session -Path $folder_to_copy -Destination $destination -ErrorAction Stop

    Invoke-Command -Session $session -FilePath $init_file -ErrorAction Stop

    Remove-PSSession $session -ErrorAction Stop

}

if ( $hostname.ToLower() -eq $env:COMPUTERNAME.ToLower() ) {

    Deploy-Local

} else {

    Deploy-Remote

}