Error when passing variable with special parameters to the ARM template - azure

Question

I have a master template and a couple of linked templates. I want to pass parameter with special characters and have an error. Anyone know how to fix it?
The problem is caused by 'servicebus_1_connectionString' parameter in last linked template definition. I provided the error and modified few letters in the secret so you have an overview but still not revealing my secrets.
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"containerUri": {
"type": "string"
},
"containerSasToken": {
"type": "string"
}
},
"variables": {},
"resources": [
{
"type": "Microsoft.Resources/deployments",
"apiVersion": "2017-05-10",
"name": "AzureServiceBusLinkedTemplate",
"properties": {
"mode": "Incremental",
"templateLink": {
"uri": "[concat(parameters('containerUri'), 'Infrastructure/AzureServiceBus.json', parameters('containerSasToken'))]"
}
}
},
{
"type": "Microsoft.Resources/deployments",
"apiVersion": "2017-05-10",
"name": "AppFunctionsLinkedTemplate",
"properties": {
"mode": "Incremental",
"templateLink": {
"uri": "[concat(parameters('containerUri'), 'Infrastructure/AppFunctions.json', parameters('containerSasToken'))]"
}
}
},
{
"type": "Microsoft.Resources/deployments",
"apiVersion": "2017-05-10",
"name": "LogicAppLinkedTemplate",
"properties": {
"mode": "Incremental",
"templateLink": {
"uri": "[concat(parameters('containerUri'), 'LogicApp.json', parameters('containerSasToken'))]"
},
"parameters": {
"servicebus_1_connectionString": "[reference('AzureServiceBusLinkedTemplate').outputs.SBNamespaceDefaultConnectionString.value]"
}
},
"dependsOn": [
"AzureServiceBusLinkedTemplate"
]
}
],
"outputs": {
}
}
2020-02-26T09:47:34.3751880Z ##[error]At least one resource deployment operation failed. Please list deployment operations for details. Please see https://aka.ms/DeployOperations for usage details.
2020-02-26T09:47:34.3754763Z ##[error]Details:
2020-02-26T09:47:34.3758785Z ##[error]BadRequest: {
"error": {
"code": "InvalidRequestContent",
"message": "The request content was invalid and could not be deserialized: 'Error converting value \"Endpoint=sb://myservicebusname.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=I/COoOJCWH/PFMab0dzpseIbfA3+0sQMUj33d71/Rg4=\" to type 'Microsoft.WindowsAzure.ResourceStack.Frontdoor.Data.Definitions.DeploymentParameterDefinition'. Path 'properties.parameters.servicebus_1_connectionString', line 1, position 462.'."
}
}
2020-02-26T09:47:34.3786900Z ##[error]Task failed while creating or updating the template deployment.
Edit:
I solved it by changing the way I pass parameter to the following:
{
"type": "Microsoft.Resources/deployments",
"apiVersion": "2017-05-10",
"name": "LogicAppLinkedTemplate",
"properties": {
"mode": "Incremental",
"templateLink": {
"uri": "[concat(parameters('containerUri'), 'LogicApp.json', parameters('containerSasToken'))]"
},
"parameters": {
"servicebus_1_connectionString": {
"value": "[reference('AzureServiceBusLinkedTemplate').outputs.SBNamespaceDefaultConnectionString.value]"
},
"logicAppName": {
"value": "DeployedFromVS"
}
}
},
"dependsOn": [
"AzureServiceBusLinkedTemplate"
]
}

Answer 1

several options:
which makes more sense, don't pass it, just use the value in the nested template
bonus: instead of retrieving the value of the deployment output - retrieve the value of the connection string in the nested template. makes a lot more sense and is more secure
base64 encode it and decode it in the nested template. there is a base64encode\decode function for that

Answer 2

I solved it by changing the way I pass parameter to the following:
{
"type": "Microsoft.Resources/deployments",
"apiVersion": "2017-05-10",
"name": "LogicAppLinkedTemplate",
"properties": {
"mode": "Incremental",
"templateLink": {
"uri": "[concat(parameters('containerUri'), 'LogicApp.json', parameters('containerSasToken'))]"
},
"parameters": {
"servicebus_1_connectionString": {
"value": "[reference('AzureServiceBusLinkedTemplate').outputs.SBNamespaceDefaultConnectionString.value]"
},
"logicAppName": {
"value": "DeployedFromVS"
}
}
},
"dependsOn": [
"AzureServiceBusLinkedTemplate"
]
}