InvalidResourceNamespace error when attempting to deploy Event Grid Subscription for Azure Function - azure

Question

I have an existing Event Grid Topic and want to add an Event Subscription to it, with an existing Azure Function endpoint.
To achieve this I am using Linked Templates. ARM Template validation passes, but deployment fails, with quite a peculiar error:
"InvalidResourceNamespace: "The resource namespace 'subscriptions' is invalid. (Code: InvalidResourceNamespace)"
Here's the raw error:
{
"code": "DeploymentFailed",
"message": "At least one resource deployment operation failed. Please list deployment operations for details. Please see https://aka.ms/DeployOperations for usage details.",
"details": [
{
"code": "InvalidContentLink",
"message": "Unable to download deployment content from 'https://storagearmtpl.blob.core.windows.net/arm-tpl-service-cd-11111-artifacts/nestedtemplates/eventGridSubscriptionTemplate.json?sv=sasartifactsstring'. The tracking Id is '11111111'. Please see https://aka.ms/arm-deploy for usage details."
},
{
"code": "InvalidResourceNamespace",
"message": "The resource namespace 'subscriptions' is invalid."
}
]
}
Where sasartifactsstring is a valid artifacts locations sas token. (I'm assuming, it looks correct)
I understand that this error stems from the "type" of the resource in the template being invalid, but as you can see below, it's simply Microsoft.EventGrid/topics/providers/eventSubscriptions.
/nestedtemplates/eventGridSubscriptionTemplate.json
{
"$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"subscriptionName": {
"type": "string",
"metadata": {
"description": "Name of the event grid subscription"
}
},
"topicName": {
"type": "string",
"metadata": {
"description": "Event grid Topic Name to Subscribe."
}
},
"functionResourceGroupName": {
"type": "string",
"metadata": {
"description": "Resource group name for functionapp"
}
},
"functionAppName": {
"type": "string",
"metadata": {
"description": "function app name"
}
},
"subscriptionId": {
"type": "string",
"metadata": {
"description": "The id string of the Azure subscription"
}
},
"topicResourceGroupName": {
"type": "string",
"metadata": {
"description": "The name of the topic resource group"
}
}
},
"variables": {},
"resources": [
{
"name": "[concat(parameters('topicName'), '/Microsoft.EventGrid/', parameters('subscriptionName'))]",
"type": "Microsoft.EventGrid/topics/providers/eventSubscriptions",
"location": "[resourceGroup().location]",
"apiVersion": "2020-06-01",
"properties": {
"topic": "[concat('/subscriptions/', parameters('subscriptionId'), '/resourceGroups/', parameters('topicResourceGroupName'), 'providers/Microsoft.EventGrid/topics/', parameters('topicName'))]",
"destination": {
"endpointType": "AzureFunction",
"properties": {
"resourceId": "[concat('/subscriptions/', parameters('subscriptionId'), '/resourceGroups/', parameters('functionResourceGroupName'), '/providers/Microsoft.Web/sites/', parameters('functionAppName'), '/functions/HelloWorld')]",
"maxEventsPerBatch": 1,
"preferredBatchSizeInKilobytes": 64
}
},
}
},
"dependsOn": [
]
}
],
"outputs": {}
}
/azuredeploy.json
{
"$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"_artifactsLocation": {
"type": "string"
},
"_artifactsLocationSasToken": {
"type": "securestring"
},
"functionResourceGroupName": {
"type": "string"
},
"functionAppName": {
"type": "string"
},
"topicName": {
"type": "string"
},
"topicResourceGroupName": {
"type": "string"
},
"subscriptionId": {
"type": "string"
}
},
"variables": {
"templateFolder": "nestedtemplates",
"subscriptionTemplateFileName": "eventGridSubscriptionTemplate.json"
},
"resources": [
{
"name": "functionsubscription"
"type": "Microsoft.Resources/deployments",
"apiVersion": "2017-05-10"
"resourceGroup": "[parameters('topicResourceGroupName')]",
"dependsOn": [ ],
"properties": {
"mode": "Incremental",
"templateLink": {
"uri": "[concat(parameters('_artifactsLocation'), '/', variables('templateFolder'), '/', variables('subscriptionTemplateFileName'), parameters('_artifactsLocationSasToken'))]",
"contentVersion": "1.0.0.0"
},
"parameters": {
"subscriptionName": {
"value": "FunctionSubscription"
},
"topicName": {
"value": "[parameters('topicName')]"
},
"functionResourceGroupName": {
"value": "[parameters('functionResourceGroupName')]"
},
"functionAppName": {
"value": "[parameters('functionAppName')]"
},
"topicResourceGroupName": {
"value": "[parameters('topicResourceGroupName')]"
},
"subscriptionId": {
"value": "[parameters('subscriptionId')]"
}
}
}
}
]
}
azure deploy parameters file
{
"$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentParameters.json#",
"contentVersion": "1.0.0.0",
"parameters": {
,
"functionResourceGroupName": {
"value": "functionResourceGroup"
},
"functionAppName": {
"value": "functionAppName"
},
"subscriptionId": {
"value": "1111111111"
},
"topicName": {
"value": "topicName"
},
"topicResourceGroupName": {
"value": "topicResourceGroup"
}
}
Really not sure what I'm doing wrong here. Worth noting that the first error is annoying as well and I'm not sure why it can't download the deployment content...
update/edit:
It's worth noting that the release is using Classic Azure Release Pipelines. And the error comes up during the release.
Looking into the deployment logs for the resource group, I was able to see that the deployment was trying to deploy an invalid resource, with the type starting "subscriptions/.....", so at least I know where the error is coming from. Still investigating what is causing this misread...

Answer 1

The cause of the odd 'subscriptions' error was due to the fact that I inserted a new resource into my resources list in my deployment (parent) ARM template, but not at the end of the list.
Once I put the deployment resource that references the new event grid subscription at the end of the resources list, the error did not show up.
azuredeploy.json
resources: [
{all other existing deployment resources ....},
{
"name": "functionsubscription"
"type": "Microsoft.Resources/deployments",
"apiVersion": "2017-05-10"
"resourceGroup": "[parameters('topicResourceGroupName')]",
"dependsOn": [ ],
"properties": {
"mode": "Incremental",
"templateLink": {
"uri": "[concat(parameters('_artifactsLocation'), '/', variables('templateFolder'), '/', variables('subscriptionTemplateFileName'), parameters('_artifactsLocationSasToken'))]",
"contentVersion": "1.0.0.0"
},
"parameters": {
"subscriptionName": {
"value": "FunctionSubscription"
},
"topicName": {
"value": "[parameters('topicName')]"
},
"functionResourceGroupName": {
"value": "[parameters('functionResourceGroupName')]"
},
"functionAppName": {
"value": "[parameters('functionAppName')]"
},
"topicResourceGroupName": {
"value": "[parameters('topicResourceGroupName')]"
},
"subscriptionId": {
"value": "[parameters('subscriptionId')]"
}
}
}
}
]
However, I am still dealing with the InvalidContentLink error, the main problem of the question has been resolved.