invoke-expressionwithretry.yml

########################################################################
# Template:    invoke-expressionwithretry.yml
# Description: Invoke a PowerShell expression, retrying the specified
#              number of time on failure.
########################################################################

parameters:
  # Number of time to retry calling the provided PowerShell expression.
  # Set to -1 to retry indefinately.
  - name: numberOfRetries
    type: number
    default: 10

  # The PowerShell expression to execute. Expression is executed using
  # 'Invoke-Expression -Command "& <expression>"'.
  - name: expression
    type: string

  # Failures outside this time frame will restart the retry process.
  - name: recentFailureThresholdInMinutes
    type: number
    default: 3

  # Maximum time to wait between attempts. The retry wait time will be
  # increased incrementally up until this number.
  - name: maxRetryWaitTimeInMinutes
    type: number
    default: 6

  # The task display name.
  - name: displayName
    type: string

  # Number of times to retry task on failure.
  - name: retryCountOnTaskFailure
    type: number
    default: 10

  # Environment variables passed to the task.
  - name: env
    type: object
    default: []

steps:
  - pwsh: |
      # Setup parameters
      $succeedWithIssues = $false
      $failureCount = 0
      $numberOfRetries = [int]::Parse("${{ parameters.numberOfRetries }}")
      if ($numberOfRetries -eq -1) {
          $numberOfRetries = [int]::MaxValue
      }
      $retryCounter = $numberOfRetries
      $lastFailure = [DateTime]::MinValue

      # Call provided expression and retry on failure
      while ($true) {
          try {
              $expression = "${{ parameters.expression }}"
              Write-Host "##[command]Invoke-Expression -Command `"& $expression`""
              Invoke-Expression -Command "& $expression"
              break # normal exit
          }
          catch {
              # if multiple failures within the given time
              $currentFailure = [DateTime]::Now
              if ($currentFailure -lt $lastFailure.AddMinutes([int]::Parse("${{ parameters.recentFailureThresholdInMinutes }}"))) {
                  # update failure count and retry counter
                  $failureCount++
                  $retryCounter--
              } else {
                  # reset failure count and retry counter
                  $failureCount = 0
                  $retryCounter = $numberOfRetries
              }

              if ($retryCounter -gt 0) {
                  # wait before trying again
                  $retryWaitTime = [Math]::Min([Math]::Pow($failureCount, 2), [int]::Parse("${{ parameters.maxRetryWaitTimeInMinutes }}") * 60)
                  Write-Host "##vso[task.logissue type=warning]$($currentFailure.ToString('HH:mm:ssK')) | Keep calm and carry on... [Last failure = $($lastFailure.ToString('HH:mm:ssK')) | Recent failures = $failureCount | Wait time = $retryWaitTime | Attempt = $($numberOfRetries - $retryCounter + 1)] :: $_"
                  Start-Sleep -Seconds $retryWaitTime
              }
              else {
                  throw $_
              }

              $succeedWithIssues = $true
              $lastFailure = $currentFailure
          }
      }

      # Exit with warning if any failures
      if ($succeedWithIssues) {
          Write-Host "##vso[task.complete result=SucceededWithIssues;]DONE"
          exit 0
      }
    displayName: ${{ parameters.displayName }}
    workingDirectory: $(Build.SourcesDirectory)
    retryCountOnTaskFailure: ${{ parameters.retryCountOnTaskFailure }}
    env: ${{ parameters.env }}