Retry PowerShell script (.ps1) if failing with specific error message - powershell

Question

We have a PowerShell build script (Cake bootstrapper) that occasionally fails to download/restore nuget packages. How would I create a generic .ps1 script that can be used to make calls to another .ps1 script, and retry if failed and the output contained a specific string (I don't want to retry if it's a build error)?
Possible example usage:
.\ExecuteWithRetry.ps1 -Script "Build.ps1 -target Restore" -OutputTrigger "RemoteException"

Answer 1

Created a script that does the trick.
Example usage:
./Execute-With-Retry.ps1 -RetryDelay 1 -MaxRetries 2 { & ./Build.ps1 -target Restore } -RetryFilter RemoteException
Based on this gist from Alex Bevilacqua.
<#
This script can be used to pass a ScriptBlock (closure) to be executed and returned.
The operation retried a few times on failure, and if the maximum threshold is surpassed, the operation fails completely.
Params:
Command - The ScriptBlock to be executed
RetryDelay - Number (in seconds) to wait between retries
(default: 5)
MaxRetries - Number of times to retry before accepting failure
(default: 5)
VerboseOutput - More info about internal processing
(default: false)
RetyFilter - Only retry if retry filter value is contained in the command output
Examples:
./Execute-With-Retry.ps1 -RetryDelay 1 -MaxRetries 2 { & ./Build.ps1 -target Restore } -RetryFilter RemoteException
#>
param(
[Parameter(ValueFromPipeline, Mandatory)]
$Command,
$RetryDelay = 5,
$MaxRetries = 5,
$VerboseOutput = $false,
$RetryFilter
)
$currentRetry = 0
$success = $false
$cmd = $Command.ToString()
do {
try {
$result = & $Command
$success = $true
if ($VerboseOutput -eq $true) {
$Host.UI.WriteDebugLine("Successfully executed [$cmd]")
}
return $result
}
catch [System.Exception] {
$currentRetry = $currentRetry + 1
$exMessage = $_.Exception.Message;
if ($RetryFilter -AND !$exMessage.Contains($RetryFilter)) {
throw $exMessage
}
if ($VerboseOutput -eq $true) {
$Host.UI.WriteErrorLine("Failed to execute [$cmd]: " + $_.Exception.Message)
}
if ($currentRetry -gt $MaxRetries) {
throw "Could not execute [$cmd]. The error: " + $_.Exception.ToString()
}
else {
if ($VerboseOutput -eq $true) {
$Host.UI.WriteDebugLine("Waiting $RetryDelay second(s) before attempt #$currentRetry of [$cmd]")
}
Start-Sleep -s $RetryDelay
}
}
} while (!$success);