Error when calling Azure Powershell New-AzResource: request content invalid - azure

Question

I am stuck on this Azure PowerShell error when calling New-AzResource:
new-azresource : InvalidRequestContent : The request content was invalid and could not be deserialized: 'Could not find member 'dependsOn' on object of type 'ResourceProxyDefinition'. Path 'dependsOn'.'.
The object I pass into the -property argument of New-AzResource is indeed an object with a dependsOn property. So the message is a decoy. And, of course, it works just fine in the CLI.
Interestingly, you cannot even find that message, or the substring ResourceProxyDefinition in any of the code for the Az PS module (https://github.com/Azure/azure-powershell). I have researched this to the extent I can think of, like looking at the underlyzing Azure API and source code. Try a Google search for ResourceProxyDefinition (no spaces) and you will mostly land on a GitHub issue I hijacked.
For the property object, I start from a json template (given below, partially). That JSON works directly in the CLI. However, for the azure powershell module, I use ConvertFrom-Json on the file contents and pass the resulting object as the argument.
{
"type": "Microsoft.VirtualMachineImages/imageTemplates",
"apiVersion": "2019-05-01-preview",
"location": "eastus2",
"dependsOn": [],
"tags": {
"imagebuilderTemplate": "My.WindowsServer.2019-Datacenter-1910020354.tpl"
},
"properties": {
"buildTimeoutInMinutes": 100,
"source": {
"type": "PlatformImage",
"publisher": "MicrosoftWindowsServer",
"offer": "WindowsServer",
"sku": "2019-Datacenter",
"version": "2019.0.20190603"
},

Answer 1

With some changes to your template to be like this:
{
"$schema": "http://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"resources": [
{
"name": "My.WindowsServer.2019-Datacenter-1910030425.tpl",
"type": "Microsoft.VirtualMachineImages/imageTemplates",
"apiVersion": "2019-05-01-preview",
"location": "eastus2",
"dependsOn": [],
"tags": {
"imagebuilderTemplate": "My.WindowsServer.2019-Datacenter-1910030425.tpl"
},
"properties": {
"buildTimeoutInMinutes": 100,
"source": {
"type": "PlatformImage",
"publisher": "MicrosoftWindowsServer",
"offer": "WindowsServer",
"sku": "2019-Datacenter",
"version": "2019.0.20190603"
which includes adding an extra level (nesting the previous template under "resources" and adding a "$schema" and "contentVersion" you are set for deployment.
Now, use:
New-AzResourceGroupDeployment -ResourceGroupName $imageResourceGroup `
-TemplateFile $imageTemplateFile
which will read in the JSON file and it works! Don't use New-AzResource.