Private/Invoke-CommandRetry.ps1
|
<# Inspired by https://blogs.endjin.com/2014/07/how-to-retry-commands-in-powershell/ #> Function Invoke-CommandRetry { <# .SYNOPSIS Retrying a specific command multiple times until it fails. This can be used e.g. to try to write in a file if multiple write commands can occur at the same time. .DESCRIPTION This function is a helper for the logging script function. It retries a specific command, e.g. you have concurrent calls to write to the logfile. In this case this function can try the write command multiple times until it fails. .PARAMETER Command The command to be executed like Write-Output or Set-Content .PARAMETER Args The arguments for the command defined in a hashtable because it uses splatting .PARAMETER Retries Optional parameter (default 10) for retries of this command .PARAMETER MillisecondsDelay Optional parameter (default random between 0 and 3000) to define the milliseconds to wait before the next try .EXAMPLE Invoke-CommandRetry -command "Write-Output" -args @{"InputObject"="Hello World"} .EXAMPLE $randomDelay = Get-Random -Maximum 3000 $outArgs = @{ FilePath = $logfile InputObject = $logstring Encoding = "utf8" Append = $true NoClobber = $true } Invoke-CommandRetry -Command 'Out-File' -Args $outArgs -retries 10 -MillisecondsDelay $randomDelay .INPUTS String, HashTable .OUTPUTS Boolean .NOTES Author: florian.von.bracht@apteco.de #> param ( [Parameter(Mandatory=$true)][string]$Command, [Parameter(Mandatory=$true)][hashtable]$Args, [Parameter(Mandatory=$false)][int]$Retries = 10, [Parameter(Mandatory=$false)][int]$MillisecondsDelay = ( Get-Random -Maximum 3000 ) ) # Setting ErrorAction to Stop is important. This ensures any errors that occur in the command are # treated as terminating errors, and will be caught by the catch block. $Args.ErrorAction = "Stop" $retrycount = 0 $completed = $false while ($completed -ne $true) { try { & $Command @Args Write-Verbose -Message "Command [$( $Command )] succeeded." $completed = $true } catch { if ($retrycount -ge $Retries) { Write-Verbose -Message "Command [$( $Command )] failed the maximum number of $( $retrycount ) times." -Verbose throw } else { Write-Verbose -Message "Command [$( $Command )] failed. Retrying in $( $secondsDelay ) seconds." -Verbose Start-Sleep -Milliseconds $MillisecondsDelay $retrycount++ } } } # Return $completed } |