Passing the output from one arm deployment resource linked template to another - json

Question

I am using a series of json ARM templates to deploy Azure VMs, and am having issues passing information from one resource deployment to another.
I deploy two resources using linked templates from blob storage, one which in and of itself deploys nothing, but returns an object populated with configuration settings, and a second which then passes that output of configuration settings to another template as a parameter:
"resources": [
{
"name": "[concat(deployment().name, '-config')]",
"type": "Microsoft.Resources/deployments",
"apiVersion": "2016-09-01",
"properties": {
"mode": "Incremental",
"templateLink": {
"uri": "[variables('configurationTemplate')]",
"contentVersion": "1.0.0.0"
},
"parameters": {
"subscriptionParameters": { "value": "[variables('subscriptionParameters')]" }
}
}
},
{
"name": "[concat(deployment().name, '-vm')]",
"type": "Microsoft.Resources/deployments",
"apiVersion": "2016-09-01",
"properties": {
"mode": "Incremental",
"templateLink": {
"uri": "[variables('vmTemplate')]",
"contentVersion": "1.0.0.0"
},
"parameters": {
"configuration": { "value": "[reference(concat(deployment().name, '-config').outputs.configuration.value)]" },
"vmName": { "value": "[parameters('vmName')]" },
"vmSize": { "value": "[parameters('vmSize')]" },
"os": { "value": "[parameters('os')]" },
"managedDiskTier": { "value": "[parameters('managedDiskTier')]" },
"dataDisksToProvision": { "value": "[parameters('dataDisksToProvision')]" },
"dataDiskSizeGB": { "value": "[parameters('dataDiskSizeGB')]" },
"domainJoined": { "value": "[parameters('domainJoined')]" },
"localAdminUsername": { "value": "[parameters('localAdminUsername')]" },
"localAdminPassword": { "value": "[parameters('localAdminPassword')]" },
"numberOfNics": { "value": "[parameters('numberOfNics')]" },
"subnetName": { "value": "[parameters('subnetName')]" },
"highlyAvailable": { "value": "[parameters('highlyAvailable')]" },
"availabilitySetName": { "value": "[parameters('availabilitySetName')]" },
"availabilitySetUpdateDomains": { "value": "[parameters('availabilitySetUpdateDomains')]" },
"availabilitySetFaultDomains": { "value": "[parameters('availabilitySetFaultDomains')]" }
}
}
}
],
"outputs": {
"configuration": {
"type": "object",
"value": "[reference(concat(deployment().name, '-config')).outputs.configuration.value]"
}
}
Deploying the first resource on it's own succeeds, and the output [reference(concat(deployment().name, '-config')).outputs.configuration.value] is correctly returned, and contains all the correct information and is well formed.
If I then add the second resource into the mix, then the deployment fails with
the following error:
08:57:41 - [ERROR] New-AzureRmResourceGroupDeployment : 08:57:41 - Error: Code=InvalidTemplate;
08:57:41 - [ERROR] Message=Deployment template validation failed: 'The template resource
08:57:41 - [ERROR] 'rcss.test.vm-0502-0757-rcss-vm' at line '317' and column '6' is not valid:
08:57:41 - [ERROR] The language expression property 'Microsoft.WindowsAzure.ResourceStack.Frontdoo
08:57:41 - [ERROR] r.Expression.Expressions.JTokenExpression' can't be evaluated.. Please see
08:57:41 - [ERROR] https://aka.ms/arm-template-expressions for usage details.'.
If I remove the "configuration" parameter from both this parameter set and from the referenced template (the referenced template has all contents commented out to ensure we are testing only the pass-through of the parameters), then the deployment succeeds, indicating that the issue is related to the parsing of the parameter string "[reference(concat(deployment().name, '-config').outputs.configuration.value)]".
Can anyone offer any insight as to whether I need to refer to output objects from deployment resources in a specific way in the context of a linked template parameter set?

Answer 1

So after examining this more closely, I found that the syntax I was using was incorrect, but not reported by the parser:
"[reference(concat(deployment().name, '-config').outputs.configuration.value)]"
Should have been:
"[reference(concat(deployment().name, '-config')).outputs.configuration.value]"
Schoolboy error.