Add function app source files

function-apps/host.json

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+{
+  "version": "2.0",
+  "managedDependency": {
+    "Enabled": true
+  },
+  "extensionBundle": {
+    "id": "Microsoft.Azure.Functions.ExtensionBundle",
+    "version": "[2.*, 3.0.0)"
+  }
+}

function-apps/mw-autoshutdown-app/function.json

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+{
+  "bindings": [
+    {
+      "name": "Timer",
+      "schedule": "0 */15 * * * *",
+      "direction": "in",
+      "type": "timerTrigger"
+    }
+  ]
+}

function-apps/mw-autoshutdown-app/run.ps1

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+# Copyright 2022 The MathWorks, Inc.
+
+# Input bindings are passed in via param block.
+param($Timer)
+
+$ErrorActionPreference = "Stop"
+
+# The required parameters are fed in from the ARM template as environment variables
+$ResourceGroup = ${env:RESOURCE_GROUP_NAME}
+$NumberOfHoursBeforeShutdown = ${env:HOURS_BEFORE_SHUTDOWN}
+
+# Retrieve the VM name
+$VM = Get-AzVM -Status | Where-Object {$_.ResourceGroupName -eq $ResourceGroup}
+$CurrentSub = (Get-AzContext).Subscription.Id
+$VMName = $VM.Name
+
+# Messages to be logged are defined here
+$LogMessages = @{
+    instanceStopped =  "Instance is stopped."
+    tagNever = "Autoshutdown is not enabled. Change the value of mw-autoshutdown tag of the VM instance to enable the autoshutdown feature."
+    tagInvalid = "The value of the mw-autoshutdown tag you have set is not valid. The format of the timestamp must be a valid RFC 1123 UTC timestamp, such as Thu, 16 Dec 2021 12:28:47 GMT."
+    instanceJustBooted = "Instance has just started. Setting mw-autoshutdown tag value."
+    readyForShutdown = "Shutdown time has been reached. Shutting instance down."
+    tooEarlyToShutdown = "Shutdown time has not been reached yet. Too early to shutdown instance."
+    inbuiltScheduleActive = "An Azure DevTest Labs auto-shutdown schedule is already active for this VM instance. Please disable it and set shut-down time in the mw-autoshutdown tag attached to the matlab-vm to enable auto-shutdown using this app."  
+    }
+
+# Helper function to print information
+function LogInformation {
+    param(
+        [Parameter (Mandatory = $True)] [String] $MessageToLog
+    )
+    Write-Host $LogMessages[$MessageToLog]
+}
+
+function GetStartTime {
+    # This function utilizes the app's permissions over the resource group to generate token in order to fetch the boot time of the VM
+    $TokenResponse = Get-AzAccessToken -ResourceUrl "https://management.azure.com" 
+    $AccessToken = $TokenResponse.Token
+    $AzureUrl = "https://management.azure.com/subscriptions/{0}/resourceGroups/{1}/providers/Microsoft.Compute/virtualMachines/{2}/instanceView?api-version=2017-03-30" -f $CurrentSub, $ResourceGroup, $VMName  
+    $Response =  Invoke-RestMethod -Method GET -Uri $AzureUrl -Headers @{ Authorization= "Bearer $AccessToken"}
+    $BootTime = $Null
+    if ($response) {
+        $BootTime = [String] $Response.statuses.time
+        $BootTime = [Datetime] $BootTime
+    }
+    return $BootTime
+}
+
+# Retrieve the shutdown tag's value
+function GetShutDownTag {
+    $InstanceTags = $VM.tags."mw-autoshutdown"
+    return $InstanceTags
+}
+
+# Set the calculated value for shutdown
+function SetShutDownTag {
+    param(
+        [Parameter (Mandatory = $True)] [String] $ShutDownTime
+    )
+    $Tag = @{"mw-autoshutdown" = $ShutDownTime}
+    Update-AzTag -Tag $Tag -ResourceId $VM.Id -Operation Merge | Out-Null
+}
+
+# Calculate the shut down time for the VM
+function SetShutDownTime {
+    # Regex that extracts the integer value provided from the "AutoShutdown" parameter
+    $TimeIntervalBeforeShutdown = $NumberOfHoursBeforeShutdown -replace "[^0-9]",''
+    $LaunchTime = GetStartTime
+    if ($LaunchTime){
+        # Add the number of hours post launch 
+        $ShutDownTime = $LaunchTime.AddHours($TimeIntervalBeforeShutdown)
+        #Convert the DateTime object to the recommended format
+        $ShutDownTime = $ShutDownTime.ToString('ddd, dd MMM yyyy HH:mm:ss') + " GMT"
+        SetShutDownTag($ShutDownTime)
+    }
+}
+
+# Set the value of last autoshutdown triggered by the function app
+function SetLastAutoshutdownEventTag {
+    param(
+        [Parameter (Mandatory = $True)] [String] $LastShutDownTime
+    )
+    $Tag = @{"mw-last-autoshutdown-event" = $LastShutDownTime}
+    Update-AzTag -Tag $Tag -ResourceId $VM.Id -Operation Merge | Out-Null
+}
+
+# Check if the instance is stopped, if yes, then return
+function IsInstanceStopped {
+    $status = $VM.PowerState
+    if ($status -eq "VM deallocated"){
+        return $True
+    }
+    return $False
+}
+
+# Helper function to retrieve information about active in-built auto-shutdown schedule
+function getDevTestLabsSchedule {
+    <# 
+    Check if user has enabled the in-built DevTest Labs Auto-shutdown feature for this VM
+    If yes, we extract the schedule time and set the mw-autoshutdown tag accordingly. 
+    #>    
+    try{
+        $AutoShutdownSchedule = Get-AzResource -ResourceId ("/subscriptions/{0}/resourceGroups/{1}/providers/microsoft.devtestlab/schedules/shutdown-computevm-{2}" -f $CurrentSub, $ResourceGroup, $VMName)
+    }
+    catch [Microsoft.Azure.Commands.ResourceManager.Cmdlets.SdkClient.ResourceManagerCloudException] {
+        # if the schedule does not exist return false
+        return $null
+    }
+    if ($AutoShutdownSchedule.Properties.status -eq "Enabled"){
+        #Schedule exists and is enabled
+
+        #Get the scheduled time in HH:mm format
+        $AutoShutDownTime =  ($AutoShutdownSchedule.Properties.dailyRecurrence.time).Insert(2,':')
+        #Get the time zone for the DevTest Labs auto-shutdown schedule
+        $TimeZoneId = $AutoShutdownSchedule.Properties.timeZoneId
+        #Get current date 
+        $CurrentTime = Get-Date
+        #Convert to the time zone set in the schedule
+        $CurrentTimeConverted = [System.TimeZoneInfo]::ConvertTimeBySystemTimeZoneId($CurrentTime, $TimeZoneId)
+
+        #Create date-time for the auto-shutdown schedule
+        $CurrentDate = ($CurrentTimeConverted).ToString("dd/MM/yyyy")
+        $DateTimeString = $CurrentDate + " " + $AutoShutDownTime
+        $AutoShutDownDateTime = [DateTime]::ParseExact($DateTimeString,'dd/MM/yyyy HH:mm',$null)
+
+        <# 
+        Compare with the current time and if the shut down time has already passed that implies the VM will shut down
+        at the same time the next day, else, the shut down time need not be altered 
+        #>
+        if ($CurrentTimeConverted -gt $AutoShutDownDateTime){
+            $AutoShutDownDateTime = $AutoShutDownDateTime.AddDays(1)
+        }
+
+        # Convert the auto-shutdown date-time to GMT and change it to RFC 1123 UTC timestamp format
+        $AutoShutDownDateTime = [System.TimeZoneInfo]::ConvertTimeBySystemTimeZoneId($AutoShutDownDateTime, $TimeZoneId, "UTC");
+        $AutoShutDownDateTime = $AutoShutDownDateTime.ToString('ddd, dd MMM yyyy HH:mm:ss') + " GMT"
+
+        return $AutoShutDownDateTime
+    }
+    #Schedule exists but disabled
+    return $null
+}
+
+function main {
+    # If instance is stopped, no action required
+    if (IsInstanceStopped){
+        LogInformation("instanceStopped")
+        return
+    }
+
+    # Else, retrieve information about in-built auto-shutdown schedule
+    $AutoShutDownDateTime = getDevTestLabsSchedule
+    $Tag = $VM.tags."user-managed-shutdown"
+
+    if ($AutoShutDownDateTime){
+        <# 
+        If an Azure DevTest Labs auto-shutdown schedule if active for the VM, we check and set the user-managed-shutdown tag to true
+        We do not interfere with this schedule, just log this information and return 
+        #>
+        if (!$Tag -or ($Tag -eq "False")){
+            <# 
+            If tag does not exists or is set to False, then add it to the VM with value as "True"
+            #>
+            $TagValue = @{"user-managed-shutdown" = "True"}
+            Update-AzTag -Tag $TagValue -ResourceId $VM.Id -Operation Merge | Out-Null
+        }
+        SetShutDownTag($AutoShutDownDateTime)
+        LogInformation("inbuiltScheduleActive")
+        return
+    }
+
+    # If in-built auto-shutdown is not active and the user-managed-shutdown tag is 'True' or non-existent, set it to true
+    if ($Tag -ne "False"){
+        $TagValue = @{"user-managed-shutdown" = "False"}
+        Update-AzTag -Tag $TagValue -ResourceId $VM.Id -Operation Merge | Out-Null
+    }
+
+    # Once in-built auto-shutdown is handled, retrieve mw-autoshutdown tag
+    $ShutDownTag = GetShutDownTag
+
+    # Initialize the mw-autoshutdown tag according to user's choice for shut down
+    if (!$ShutDownTag){
+        <# if tag doesn't exists, then it means this is the first function app execution or the tag has been explicitly deleted
+         in such cases, create the tag and attach it to the VM #>
+        if ($NumberOfHoursBeforeShutdown -eq "Never"){
+            SetShutDownTag("never")
+            LogInformation("tagNever")
+            return
+        }
+        else {
+            # Calculate the shut down time according user input
+            SetShutDownTime
+            LogInformation("instanceJustBooted")
+            return
+        }
+    }
+
+    # This is to check the status of the mw-autoshutdown tag in subsequent runs
+    if ($ShutDownTag -eq "change_me_on_boot"){
+        # This tag value reflects that the VM was shutdown by the app in a previous run
+        SetShutDownTime
+        LogInformation("instanceJustBooted")
+    }
+    elseif ($ShutDownTag -eq "Never"){
+        LogInformation("tagNever")
+    }
+    else {
+        # In this case, the tag must be containing a timestamp, we validated if this value is in the correct format
+        try{
+            $ShutdownTime = [DateTime]::ParseExact($ShutDownTag,'ddd, dd MMM yyyy HH:mm:ss GMT',$null)   
+        }
+        catch [System.FormatException]
+        {
+            LogInformation("tagInvalid")
+            return
+        }
+        $CurrentTime = (Get-Date).ToUniversalTime()
+        if ($CurrentTime -gt $ShutdownTime){
+            # If the shutdown time in the tag has reached/passed, force stop the VM
+            Stop-AzVM -Name $VM.Name -ResourceGroupName $VM.ResourceGroupName -Confirm:$False -Force
+            LogInformation("readyForShutdown")
+            $LastShutDownTime = $CurrentTime.ToString('ddd, dd MMM yyyy HH:mm:ss') + " GMT"
+            SetLastAutoshutdownEventTag($LastShutDownTime)
+
+            # Prepare tag for next runs
+            if ($NumberOfHoursBeforeShutdown -eq "Never"){
+                # If the default choice for auto-shutdown was 'Never', set tag accordingly
+                SetShutDownTag("never")
+            }
+            else{
+                # Else, set it to a phrase that relates to shutdown by app
+                SetShutDownTag("change_me_on_boot")
+            }
+            return
+        }
+        else{
+            # If shutdown time has not been reached, log the same information
+            LogInformation("tooEarlyToShutdown")
+            return
+        } 
+    }
+}
+
+main

function-apps/requirements.psd1

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+<#
+ This file contains the modules required by the run.ps1 script.
+ It enables modules to be automatically managed by the Functions service.
+ See https://aka.ms/functionsmanageddependency for additional information.
+#>
+@{
+ 'Az.Compute' = '4.*'
+ 'Az.Accounts' = '2.*'
+ 'Az.Resources' = '5.*'
+ }