Find outdated Azure ARM QuickStart Templates on GitHub

In my previous post Determine latest API version for a resource provider I showed you how to retrieve the latest API version for a specific resource provider using the Get-AzureRmResourceProviderLatestApiVersion cmdlet. In this post I will use the cmdlet to find any outdated resource provider within an ARM template. Also, we will analyze the Azure quickstart templates on GitHub!

To analyze an ARM template we have to convert the JavaScript Object Notation (JSON) to a custom PowerShell object that has a property for each field in the JSON.
We will use the following lean template for testing purpose (download):

{
    "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
    "contentVersion": "1.0.0.0",
    "resources": [
        {
            "type": "Microsoft.Storage/storageAccounts",
            "name": "myuniquestorageaccountname",
            "apiVersion": "2016-01-01",
            "location": "West Europe",
            "sku": {
                "name": "Standard_LRS"
            },
            "kind": "Storage"
        }
    ]
}

The first thing we have to do is to load the file using the Get-Content cmdlet and pipe the result to the ConvertFrom-Json cmdlet. To retrieve the resources we further pipe the result to the Select-Object cmdlet:


Get-Content leanArmTemplate.json |
        ConvertFrom-Json |
        Select-Object -ExpandProperty resources

This will give us all necessary information like the resource provider and the used API version:

type       : Microsoft.Storage/storageAccounts
name       : myuniquestorageaccountname
apiVersion : 2016-01-01
location   : West Europe
sku        : @{name=Standard_LRS}
kind       : Storage

Now finally to analyze the template, we have to iterate over each resource and retrieve the latest API version using the previous mentioned Get-AzureRmResourceProviderLatestApiVersion cmdlet. To get a handy output we create a new PsCustomObject containing the resource type, the used and latest API Version and a flag that specifies whether the used API version is the latest:

Get-Content leanArmTemplate.json |
        ConvertFrom-Json |
        Select-Object -ExpandProperty resources |
         ForEach-Object {
            $latestApiVersion = Get-AzureRmResourceProviderLatestApiVersion -Type $_.type
            [PsCustomObject]@{
                Type = $_.type
                UsedApiVersion = $_.apiVersion
                LatestVersion = $latestApiVersion
                Latest = $_.apiVersion -eq $latestApiVersion
            }
        }

This is the output:

Type                              UsedApiVersion LatestVersion Latest
----                              -------------- ------------- ------
Microsoft.Storage/storageAccounts 2016-01-01     2018-02-01     False

In this example, the used API for the resource provider Microsoft.Storage/storageAccounts is not up to date.

For the sake of convenience I wrapped the code into a Get-OutdatedResourceProvider cmdlet and added some special treatment to handle nested resources:

function Get-OutdatedResourceProvider
{
    [CmdletBinding()]
    [Alias()]
    [OutputType([string])]
    Param
    (
        [Parameter(Mandatory = $true, Position = 0)]
        [string]$Path,

        [switch]$IncludePreview
    )
    Get-Content $Path |
        ConvertFrom-Json |
        Select-Object -ExpandProperty resources |
        ForEach-Object {
        $latestApiVersion = Get-AzureRmResourceProviderLatestApiVersion -Type $_.type
        [PsCustomObject]@{
            Type = $_.type
            UsedApiVersion = $_.apiVersion
            LatestVersion = $latestApiVersion
            Latest = $_.apiVersion -eq $latestApiVersion
        }

        # a resource may include sub resources
        foreach ($subResource in $_.resources)
        {
            $latestApiVersion = Get-AzureRmResourceProviderLatestApiVersion -Type ('{0}/{1}' -f $_.type, $subResource.type)
            [PsCustomObject]@{
                Type = '{0}/{1}' -f $_.type, $subResource.type
                UsedApiVersion = $_.apiVersion
                LatestVersion = $_.apiVersion -eq $latestApiVersion
            }
        }
    }
}

🕵️‍♂️🕵️‍♂️🕵️‍♂️ Now it’s time to analyze some templates  🕵️‍♂️🕵️‍♂️🕵️‍♂️.

Lets clone the whole azure-quickstart-templates Git repository:

git clone https://github.com/Azure/azure-quickstart-templates.git

Then we can filter all ARM templates using the Get-ChildItem cmdlet:

$armTemplates = Get-ChildItem 'azure-quickstart-templates' -Filter 'azuredeploy.json' -Recurse

To analyze them we iterate over each template and pass it to the above created Get-OutdatedResourceProvider cmdlet. Because there might be some invalid templates, we try to parse the JSON first and filter all valid templates:

$invalidTemplates = @()
$analyzedTemplates = $armTemplates |
    ForEach-Object {
    $template = $_
    try
    {
        $null = $template | Get-Content | ConvertFrom-Json
        Get-OutdatedResourceProvider -Path $template.FullName
    }
    catch
    {
        $invalidTemplates += $template
    }
}

Finally we gather and output some metrics:

$validAnalyzes = $analyzedTemplates | Where-Object LatestVersion
$uptodateproviderCount = $validAnalyzes | Where-Object LatestVersion -eq TRUE | Measure-Object | Select-Object -ExpandProperty Count
$outdatedproviderCount = $validAnalyzes | Where-Object LatestVersion -ne TRUE | Measure-Object | Select-Object -ExpandProperty Count

Write-Host "Found $($armTemplates.Count) ARM templates in the Azure quickstart repository ($($invalidTemplates.Count) of them are invalid).
They are using $($analyzedTemplates.Count) resource providers. I was able to determine the latest version for $($validAnalyzes.count) resource provider. $uptodateproviderCount of them are using the latest API version whereas $outdatedproviderCount are using an outdated API." -ForegroundColor Cyan

Here is the output:

Found 675 ARM templates in the Azure quickstart repository (3 of them are invalid).
They are using 3873 resource providers. I was able to determine the latest version for 3288 resource provider. 18 of them are using the latest API version whereas 3270 are using an outdated API.

Note: There is no need to always use the latest API version. You should consider upgrading only if you encounter issues with the resource provider or if you want to use new features that are not part of the currently used API.

You can download the complete script and run it for yourself here.

Determine latest API version for a resource provider

Azure Resource Manager templates are great to deploy one or more resources to a resource group.

A mandatory part of an ARM template is the resources section which defines the resource types that are deployed or updated. Here is an example:

"type": "Microsoft.Storage/storageAccounts",
"name": "[variables('storageAccountName')]",
"apiVersion": "2016-01-01",
"location": "[parameters('location')]",
"sku": {
	"name": "Standard_LRS"
},
"kind": "Storage",
"properties": {}

The name of a resource type has the following format: {resource-provider}/{resource-type}. In this example Microsoft.Storage/storageAccounts. The apiVersion specifies the version of the API that is used to deploy / manage the resource.

A resource provider offers a set of operations to deploy and manage resources using a REST API. If a resource provider adds new features, it releases a new version of the API. Therefore, if you have to utilize new features you may have to use the latest API Version. To determine the latest version of a resource type you can use the following Get-AzureRmResourceProviderLatestApiVersion cmdlet:

function Get-AzureRmResourceProviderLatestApiVersion
{
    [CmdletBinding()]
    [Alias()]
    [OutputType([string])]
    Param
    (
        [Parameter(ParameterSetName = 'Full', Mandatory = $true, Position = 0)]
        [string]$Type,

        [Parameter(ParameterSetName = 'ProviderAndType', Mandatory = $true, Position = 0)]
        [string]$ResourceProvider,

        [Parameter(ParameterSetName = 'ProviderAndType', Mandatory = $true, Position = 1)]
        [string]$ResourceType,

        [switch]$IncludePreview
    )

    # retrieving the resource providers is time consuming therefore we store
    # them in a script variable to accelerate subsequent requests.
    if (-not $script:resourceProvider)
    {
        $script:resourceProvider = Get-AzureRmResourceProvider   
    }

    if ($PSCmdlet.ParameterSetName -eq 'Full')
    {
        $ResourceProvider = ($Type -replace "\/.*")
        $ResourceType = ($Type -replace ".*?\/(.+)", '$1')
    }
    
    $provider = $script:resourceProvider | 
        Where-Object {
        $_.ProviderNamespace -eq $ResourceProvider -and 
        $_.ResourceTypes.ResourceTypeName -eq $ResourceType
    }

    if ($IncludePreview)
    {
        $provider.ResourceTypes.ApiVersions[0]
    }
    else
    {
        $provider.ResourceTypes.ApiVersions | Where-Object {
            $_ -notmatch '-preview'
        } | Select-Object -First 1
    }
}

You can now determine the latest API Version using either the full type:

Get-AzureRmResourceProviderLatestApiVersion -Type Microsoft.Storage/storageAccounts

Or by passing the Resource Provider and Resource Type:

Get-AzureRmResourceProviderLatestApiVersion -ResourceProvider Microsoft.Storage -ResourceType storageAccounts

Finally, to include preview versions you can append the -IncludePreview switch:

Get-AzureRmResourceProviderLatestApiVersion -Type Microsoft.Storage/storageAccounts -IncludePreview

You can download the script from my GitHub repository.

Additional information: Resource providers and types