Enhance cron handling for MaintenancePlan

src/MaintenancePlan/Public/Schedule-MaintenancePlan.ps1

@@ -24,18 +24,92 @@ function Schedule-MaintenancePlan {
     Assert-ParameterNotNull $PlanPath 'PlanPath'
     Assert-ParameterNotNull $Cron 'Cron'
 
+    function Parse-CronField {
+        param(
+            [string]$Value,
+            [int]$Min,
+            [int]$Max,
+            [string]$Name,
+            [switch]$AllowStar,
+            [switch]$AllowStep
+        )
+        if ($AllowStar -and $Value -eq '*') { return @{} }
+        if ($AllowStep -and $Value -match '^\*/(\d+)$') {
+            $step = [int]$Matches[1]
+            if ($step -lt 1 -or $step -gt $Max) { throw "Cron $Name step must be between 1 and $Max" }
+            return @{ Interval = $step }
+        }
+        if ($Value -notmatch '^\d+$') { throw "Cron $Name field must be an integer" }
+        $num = [int]$Value
+        if ($num -lt $Min -or $num -gt $Max) { throw "Cron $Name field must be between $Min and $Max" }
+        return @{ Value = $num }
+    }
+
+    function Convert-Cron {
+        param([string]$CronExpression)
+        $parts = $CronExpression -split '\s+'
+        if ($parts.Length -ne 5) {
+            throw 'Cron expression must have 5 fields: minute hour day-of-month month day-of-week'
+        }
+        $minute = Parse-CronField $parts[0] 0 59 'minute'
+        $hour   = Parse-CronField $parts[1] 0 23 'hour'
+        $dom    = Parse-CronField $parts[2] 1 31 'day-of-month' -AllowStar -AllowStep
+        $month  = Parse-CronField $parts[3] 1 12 'month' -AllowStar
+        $dow    = Parse-CronField $parts[4] 0 7 'day-of-week' -AllowStar -AllowStep
+
+        return [pscustomobject]@{
+            Minute = $minute.Value
+            Hour   = $hour.Value
+            DayOfMonth = $dom.Value
+            DayInterval = $dom.Interval
+            Month  = $month.Value
+            DayOfWeek = if ($dow.Value) { if ($dow.Value -eq 7) { 0 } else { $dow.Value } } else { $null }
+            WeekInterval = $dow.Interval
+        }
+    }
+
     $modulePath = Join-Path (Split-Path $PSScriptRoot -Parent) 'MaintenancePlan.psd1'
     $command = "Import-Module '$modulePath'; `$plan = Import-MaintenancePlan -Path '$PlanPath'; Invoke-MaintenancePlan -Plan `$plan"
 
+    $cronParts = Convert-Cron $Cron
+
     if ($IsWindows) {
         Write-STStatus "Registering scheduled task $Name" -Level INFO -Log
-        $parts = $Cron -split '\s+'
-        if ($parts.Length -lt 2) { throw 'Cron expression must include minute and hour' }
-        $time = '{0:D2}:{1:D2}' -f [int]$parts[1], [int]$parts[0]
-        $action  = New-ScheduledTaskAction -Execute 'pwsh' -Argument "-NoProfile -Command \"$command\""
-        $trigger = New-ScheduledTaskTrigger -Daily -At $time
+        $time = '{0:D2}:{1:D2}' -f $cronParts.Hour, $cronParts.Minute
+        $action = New-ScheduledTaskAction -Execute 'pwsh' -Argument "-NoProfile -Command \"$command\""
+
+        $triggerParams = @{ At = $time }
+        if ($cronParts.DayOfWeek -ne $null -or $cronParts.WeekInterval) {
+            $triggerParams.Weekly = $true
+            if ($cronParts.DayOfWeek -ne $null) {
+                $triggerParams.DaysOfWeek = [System.DayOfWeek]$cronParts.DayOfWeek
+            }
+            if ($cronParts.WeekInterval) {
+                $triggerParams.WeeksInterval = $cronParts.WeekInterval
+            }
+        } elseif ($cronParts.DayOfMonth -ne $null -or $cronParts.Month -ne $null) {
+            $triggerParams.Monthly = $true
+            if ($cronParts.DayOfMonth -ne $null) {
+                $triggerParams.DaysOfMonth = $cronParts.DayOfMonth
+            }
+            if ($cronParts.Month -ne $null) {
+                $triggerParams.MonthsOfYear = $cronParts.Month
+            }
+            if ($cronParts.DayInterval) {
+                $triggerParams.DaysInterval = $cronParts.DayInterval
+            }
+        } else {
+            $triggerParams.Daily = $true
+            if ($cronParts.DayInterval) {
+                $triggerParams.DaysInterval = $cronParts.DayInterval
+            }
+        }
+
+        $trigger = New-ScheduledTaskTrigger @triggerParams
         Register-ScheduledTask -TaskName $Name -Action $action -Trigger $trigger -Force | Out-Null
     } else {
+        # validate cron on non-windows too
+        $null = $cronParts
         $entry = "$Cron pwsh -NoProfile -Command \"$command\" # $Name"
         Write-STStatus "Cron entry generated" -Level INFO -Log
         return $entry

tests/MaintenancePlan.Tests.ps1

@@ -46,11 +46,33 @@ Describe 'MaintenancePlan Module' {
             Set-Variable -Name IsWindows -Value $true -Scope Script -Force
             function Register-ScheduledTask {}
             function New-ScheduledTaskAction { param($Execute,$Argument) $script:arg = $Argument; [pscustomobject]@{Execute=$Execute;Argument=$Argument} }
-            function New-ScheduledTaskTrigger { param([string]$Daily,[string]$At) [pscustomobject]@{At=$At} }
+            function New-ScheduledTaskTrigger {
+                param($At,$Daily,$Weekly,$DaysOfWeek)
+                $script:trigger = @{ At=$At;Daily=$Daily;Weekly=$Weekly;DaysOfWeek=$DaysOfWeek }
+                [pscustomobject]@{ At=$At }
+            }
             Schedule-MaintenancePlan -PlanPath '/tmp/p.json' -Cron '5 1 * * *' -Name 'MP'
             $expectedModule = Join-Path (Get-Module MaintenancePlan).ModuleBase 'MaintenancePlan.psd1'
             $script:arg | Should -Match [Regex]::Escape($expectedModule)
             $script:arg | Should -Match '/tmp/p.json'
+            $script:trigger.At | Should -Be '01:05'
+            $script:trigger.Daily | Should -Be $true
+        }
+    }
+
+    Safe-It 'uses day-of-week from cron' {
+        InModuleScope MaintenancePlan {
+            Set-Variable -Name IsWindows -Value $true -Scope Script -Force
+            function Register-ScheduledTask {}
+            function New-ScheduledTaskAction { param($Execute,$Argument) }
+            function New-ScheduledTaskTrigger {
+                param($At,$Weekly,$DaysOfWeek)
+                $script:trigger = @{ At=$At;Weekly=$Weekly;DaysOfWeek=$DaysOfWeek }
+                [pscustomobject]@{ At=$At }
+            }
+            Schedule-MaintenancePlan -PlanPath '/tmp/p.json' -Cron '5 1 * * 0' -Name 'MP'
+            $script:trigger.Weekly | Should -Be $true
+            $script:trigger.DaysOfWeek | Should -Be [System.DayOfWeek]::Sunday
         }
     }