Merge pull request #1460 from lzybkr/jasonsh/CronTab-Demo

Add crontab demo

demos/crontab.ps1

@@ -1,9 +0,0 @@
-# Use the crontab module available at ./modules/CronTab
-
-# Get the existing cron jobs
-
-# Sort them by data
-
-# Create a new one using a DateTime object
-
-# Show in bash that the new cron job exists

demos/crontab/CronTab/CronTab.psd1

@@ -0,0 +1,61 @@
+@{
+
+# Script module or binary module file associated with this manifest.
+RootModule = 'CronTab.psm1'
+
+# Version number of this module.
+ModuleVersion = '0.1.0.0'
+
+# Supported PSEditions
+CompatiblePSEditions = @('Linux')
+
+# ID used to uniquely identify this module
+GUID = '508bb97f-de2e-482e-aae2-01caec0be8c7'
+
+# Author of this module
+Author = 'Microsoft'
+
+# Company or vendor of this module
+CompanyName = 'Unknown'
+
+# Copyright statement for this module
+Copyright = '(c) 2016 Microsoft. All rights reserved.'
+
+# Description of the functionality provided by this module
+Description = 'Sample module for managing CronTab'
+
+# Format files (.ps1xml) to be loaded when importing this module
+FormatsToProcess = 'CronTab.ps1xml'
+
+# Functions to export from this module, for best performance, do not use wildcards and do not delete the entry, use an empty array if there are no functions to export.
+FunctionsToExport = 'New-CronJob','Remove-CronJob','Get-CronJob','Get-CronTabUser'
+
+# Private data to pass to the module specified in RootModule/ModuleToProcess. This may also contain a PSData hashtable with additional module metadata used by PowerShell.
+PrivateData = @{
+
+    PSData = @{
+
+        # Tags applied to this module. These help with module discovery in online galleries.
+        # Tags = @()
+
+        # A URL to the license for this module.
+        # LicenseUri = ''
+
+        # A URL to the main website for this project.
+        # ProjectUri = ''
+
+        # A URL to an icon representing this module.
+        # IconUri = ''
+
+        # ReleaseNotes of this module
+        # ReleaseNotes = ''
+
+    } # End of PSData hashtable
+
+} # End of PrivateData hashtable
+
+# HelpInfo URI of this module
+# HelpInfoURI = ''
+
+}
+

demos/crontab/CronTab/CronTab.psm1

@@ -1,22 +1,31 @@
+
+using namespace System.Collections.Generic
+using namespace System.Management.Automation
+
 $crontabcmd = "/usr/bin/crontab"
 
-#TODO fix after https://github.com/PowerShell/PowerShell/issues/932 is fixed
-#class CronJob {
-#    [string] $Minute
-#    [string] $Hour
-#    [string] $DayOfMonth
-#    [string] $Month
-#    [string] $DayOfWeek
-#    [string] $Command
-#}
+class CronJob {
+    [string] $Minute
+    [string] $Hour
+    [string] $DayOfMonth
+    [string] $Month
+    [string] $DayOfWeek
+    [string] $Command
+
+    [string] ToString()
+    {
+        return "{0} {1} {2} {3} {4} {5}" -f
+            $this.Minute, $this.Hour, $this.DayOfMonth, $this.Month, $this.DayOfWeek, $this.Command
+    }
+}
 
 # Internal helper functions
 
 function Get-CronTab ([String] $user) {
     $crontab = Invoke-CronTab -user $user -arguments "-l" -noThrow
-    if ($crontab -is [System.Management.Automation.ErrorRecord]) {
+    if ($crontab -is [ErrorRecord]) {
         if ($crontab.Exception.Message.StartsWith("no crontab for ")) {
-            $crontab = $null
+            $crontab = @()
         }
         else {
             throw $crontab.Exception
@@ -27,8 +36,7 @@ function Get-CronTab ([String] $user) {
 
 function ConvertTo-CronJob ([String] $crontab) {
     $split = $crontab.split(" ", 6)
-    $cronjob = New-Object -TypeName PSObject -Property @{  #TODO: change to CronJob type
-        PSTypeName="CronJob";
+    $cronjob = [CronJob]@{
         Minute = $split[0];
         Hour = $split[1];
         DayOfMonth= $split[2];
@@ -39,14 +47,13 @@ function ConvertTo-CronJob ([String] $crontab) {
     $cronjob
 }
 
-function Invoke-CronTab ([String] $user, [String] $arguments, [Switch] $noThrow) {
+function Invoke-CronTab ([String] $user, [String[]] $arguments, [Switch] $noThrow) {
     If ($user -ne [String]::Empty) {
-        $arguments = "-u $UserName $arguments"
+        $arguments = Write-Output "-u" $UserName $arguments
     }
     
-    $cmd  = "$crontabcmd $arguments 2>&1"
-    Write-Verbose $cmd
-    $output = Invoke-Expression $cmd
+    Write-Verbose "Running: $crontabcmd $arguments"
+    $output = & $crontabcmd @arguments 2>&1
     if ($LastExitCode -ne 0 -and -not $noThrow) {
         $e = New-Object System.InvalidOperationException -ArgumentList $output.Exception.Message
         throw $e
@@ -78,24 +85,37 @@ function Remove-CronJob {
   Optional parameter to specify a specific user's cron table
 .PARAMETER Job
   Cron job object returned from Get-CronJob
+.PARAMETER Force
+  Don't prompt when removing the cron job
 #>   
     [CmdletBinding(SupportsShouldProcess=$true,ConfirmImpact="High")]
     param (
-        [Alias("u")][Parameter(Mandatory=$false)][String] $UserName,
-        [Alias("j")][Parameter(Mandatory=$true,ValueFromPipeline=$true)][PSTypeName("CronJob")] $Job  #TODO use CronJob type  
+        [ArgumentCompleter( { $wordToComplete = $args[2]; Get-CronTabUser | Where-Object { $_ -like "$wordToComplete*" } | Sort-Object } )]
+        [Alias("u")]
+        [Parameter(Mandatory=$false)]
+        [String]
+        $UserName,
+
+        [Alias("j")]
+        [Parameter(Mandatory=$true,ValueFromPipeline=$true)]
+        [CronJob]
+        $Job,
+
+        [Switch]
+        $Force
     )
     process {
 
         [string[]] $crontab = Get-CronTab -user $UserName
-        [string[]] $newcrontab = $null
+        $newcrontab = [List[string]]::new()
         $found = $false
         
+        $JobAsString = $Job.ToString()
         foreach ($line in $crontab) {
-            $cronjob = ConvertTo-CronJob -crontab $line
-            if ((Compare-object $cronjob.psobject.properties $Job.psobject.properties) -eq $null) {
+            if ($JobAsString -ceq $line) {
                 $found = $true
             } else {
-                $newcrontab += $line
+                $newcrontab.Add($line)
             }
         }
         
@@ -103,7 +123,7 @@ function Remove-CronJob {
             $e = New-Object System.Exception -ArgumentList "Job not found"
             throw $e
         }
-        if ($pscmdlet.ShouldProcess($Job.Command,"Remove")) {
+        if ($Force -or $pscmdlet.ShouldProcess($Job.Command,"Remove")) {
             Import-CronTab -user $UserName -crontab $newcrontab
         }
     }        
@@ -140,7 +160,12 @@ function New-CronJob {
 #>   
     [CmdletBinding()]
     param (
-        [Alias("u")][Parameter(Mandatory=$false)][String] $UserName,
+        [ArgumentCompleter( { $wordToComplete = $args[2]; Get-CronTabUser | Where-Object { $_ -like "$wordToComplete*" } | Sort-Object } )]
+        [Alias("u")]
+        [Parameter(Mandatory=$false)]
+        [String]
+        $UserName,
+
         [Alias("mi")][Parameter(Position=1)][String[]] $Minute = "*",
         [Alias("h")][Parameter(Position=2)][String[]] $Hour = "*",
         [Alias("dm")][Parameter(Position=3)][String[]] $DayOfMonth = "*",
@@ -173,7 +198,7 @@ function Get-CronJob {
   Optional parameter to specify a specific user's cron table
 #>   
     [CmdletBinding()]
-    [OutputType([PSObject])]
+    [OutputType([CronJob])]
     param (
         [Alias("u")][Parameter(Mandatory=$false)][String] $UserName
     )
@@ -187,3 +212,33 @@ function Get-CronJob {
         }
     }
 }
+
+function Get-CronTabUser {
+<#
+.SYNOPSIS
+  Returns the users allowed to use crontab
+#>
+    [CmdletBinding()]
+    [OutputType([String])]
+    param()
+
+    $allow = '/etc/cron.allow'
+    if (Test-Path $allow)
+    {
+        Get-Content $allow
+    }
+    else
+    {
+        $users = Get-Content /etc/passwd | ForEach-Object { ($_ -split ':')[0] }
+        $deny = '/etc/cron.deny'
+        if (Test-Path $deny)
+        {
+            $denyUsers = Get-Content $deny
+            $users | Where-Object { $denyUsers -notcontains $_ }
+        }
+        else
+        {
+            $users
+        }
+    }
+}

demos/crontab/README.md

@@ -0,0 +1,15 @@
+## CronTab demo
+
+This demo shows examining, creating, and removing cron jobs via crontab.
+
+Output of Get-CronJob is a strongly typed object with properties like DayOfWeek or Command.
+Remove-CronJob prompts before removing the job unless you specifiy -Force.
+
+Tab completion of -UserName is supported, e.g.
+
+Get-CronJob -u <TAB>
+
+NYI: no way to run crontab with sudo if necessary
+NYI: ignoring shell variables or comments
+NYI: New-CronJob -Description "..." (save in comments"
+NYI: @reboot,@daily,@hourly,etc

demos/crontab/crontab.ps1

@@ -0,0 +1,27 @@
+
+Import-Module $PSScriptRoot/CronTab/CronTab.psd1
+
+Write-Host -Foreground Yellow "Remove all jobs to start, no prompting"
+Get-CronJob | Remove-CronJob -Force
+
+Write-Host -Foreground Yellow "Get the existing cron jobs"
+Get-CronJob | Out-Host
+
+Write-Host -Foreground Yellow "New cron job to clean out tmp every day at 1am"
+New-CronJob -Command 'rm -rf /tmp/*' -Hour 1 | Out-Host
+
+Write-Host -Foreground Yellow "Add some more jobs"
+New-CronJob -Command 'python -c ~/scripts/backup_users' -Hour 2 -DayOfWeek 1-5 | Out-Host
+New-CronJob -Command 'powershell -c "cd ~/src/PowerShell; ipmo ./build.psm1; Start-PSBuild"' -Hour 2 -DayOfWeek * | Out-Host
+
+Write-Host -Foreground Yellow "Show in bash that the new cron job exists"
+crontab -l
+
+Write-Host -Foreground Yellow "Get jobs that run every day"
+Get-CronJob | Where-Object { $_.DayOfWeek -eq '*' -or $_.DayOfWeek -eq '1-7' } | Out-Host
+
+Write-Host -Foreground Yellow "Remove one cron job, with prompting to confirm"
+Get-CronJob | Where-Object { $_.Command -match '^powershell.*' } | Remove-CronJob | Out-Host
+
+Write-Host -Foreground Yellow "And the other job remains"
+Get-CronJob | Out-Host