Public/Retry.ps1
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<#
.SYNOPSIS Calls a script block with retries .DESCRIPTION The Invoke-ScriptBlockWithRetries function calls a script block, retrying when an exception is thrown .PARAMETER ScriptBlock The script block to call. .PARAMETER RetryCount The maximum number of times to retry the script block .PARAMETER TimeoutInSecs The time in seconds benteen retries .PARAMETER SuccessMessage The message to print when the script block was successfully execited .PARAMETER FailureMessage The message to print when the script block was unsuccessfully execited .OUTPUTS The output of the last successful script block execution. #> function Invoke-ScriptBlockWithRetries { [CmdletBinding()] param ( [parameter(Mandatory, ValueFromPipeline)] [ValidateNotNullOrEmpty()] [scriptblock] $ScriptBlock, [int] $RetryCount = 3, [int] $TimeoutInSecs = 30, [string] $SuccessMessage = "", [string] $FailureMessage = "" ) process { $Attempt = 1 do { try { $PreviousPreference = $ErrorActionPreference $ErrorActionPreference = 'Stop' Invoke-Command -ScriptBlock $ScriptBlock -OutVariable Result | Out-Null $ErrorActionPreference = $PreviousPreference # flow control will execute the next line only if the command in the scriptblock executed without any errors # if an error is thrown, flow control will go to the 'catch' block if (-not [string]::IsNullOrEmpty($SuccessMessage)) { Write-Host "$SuccessMessage `n" } return $result } catch { if ($Attempt -gt $RetryCount) { if (-not [string]::IsNullOrEmpty($FailureMessage)) { Write-Host "$FailureMessage! Error was $($_.exception.Message). Total retry attempts: $RetryCount" } throw $_.exception } else { if (-not [string]::IsNullOrEmpty($FailureMessage)) { Write-Host "[$Attempt/$RetryCount] $FailureMessage. Error was $($_.exception.Message). Retrying in $TimeoutInSecs seconds..." } Start-Sleep -Seconds $TimeoutInSecs $Attempt = $Attempt + 1 } } } While ($true) } } <# .SYNOPSIS Calls a shell (cmd) command with retries .DESCRIPTION The Invoke-CommandWithRetries function calls shell (cmd) commands using the provided parameters, with optional retries in configurable intervals upon failures. .PARAMETER Command The command to call. .PARAMETER Arguments Arguments to pass when invoking the comand. .PARAMETER TrustExitCode Trust the command's exit code for the purpose of determining whether it was successful or not. If this parameter is $False, a non-empty stderr will also be considered a failure. .PARAMETER RetrySleepSeconds Time in seconds to sleep between retry attempts in case of command failure. .PARAMETER MaxAttempts Maximum number of retry attempts in case of command failure. .PARAMETER PrintCommand Determines whether or not to print the full command to the host before execution. .PARAMETER AllowedReturnValues An array of acceptable return codes (in addition to 0). If omitted only a return code of 0 is used to indicate success. .PARAMETER ErrorMessage A message to add include when the command has failed to be run. .INPUTS None. You cannot pipe objects to Call-CommandWithRetries. .OUTPUTS The output of the last command execution. .EXAMPLE Use cURL for Windows to download the latest NuGet command-line client C:\PS> Call-CommandWithRetries "curl.exe" @("--fail", "-O", "https://dist.nuget.org/win-x86-commandline/latest/nuget.exe") #> function Invoke-CommandWithRetries { [CmdletBinding()] param ( [Parameter(Mandatory = $True)] [string]$Command, [Array]$Arguments, [bool]$TrustExitCode = $True, [int]$RetrySleepSeconds = 10, [int]$MaxAttempts = 10, [bool]$PrintCommand = $True, [bool]$PrintOutput = $False, [int[]]$AllowedReturnValues = @(), [string]$ErrorMessage ) Process { $attempt = 0 while ($true) { Write-Host $(if ($PrintCommand) { "Executing: $Command $Arguments" } else { "Executing command..." }) try { $output = & $Command $Arguments 2>&1 if ($PrintOutput) { Write-Host $output } $stderr = $output | where { $_ -is [System.Management.Automation.ErrorRecord] } if (($LASTEXITCODE -eq 0 -or $AllowedReturnValues -contains $LASTEXITCODE) -and ($TrustExitCode -or !($stderr))) { Write-Host "Command executed successfully" return $output } Write-Host "Command failed with exit code ($LASTEXITCODE) and stderr: $stderr" -ForegroundColor Yellow } catch { Write-Host "Command failed with exit code ($LASTEXITCODE), exception ($_) and stderr: $stderr" -ForegroundColor Yellow } if ($attempt -eq $MaxAttempts) { $ex = new-object System.Management.Automation.CmdletInvocationException "All retry attempts exhausted $ErrorMessage" $category = [System.Management.Automation.ErrorCategory]::LimitsExceeded $errRecord = new-object System.Management.Automation.ErrorRecord $ex, "CommandFailed", $category, $Command $psCmdlet.WriteError($errRecord) return $output } $attempt++; Write-Host "Retrying test execution [#$attempt/$MaxAttempts] in $RetrySleepSeconds seconds..." Start-Sleep -s $RetrySleepSeconds } } } |