Concat object and string in ARM template

Question

I have a parameters.json file that is an object that contains application settings for different environments. So, it looks something like this:

"parameters": {
    "applicationSettings": {
        "value": {
            "CI": {
                "setting1": "asdf"
            },
            "DEV": {
                "setting1": "1234"
            }
        }
    }
}

In the template file, I have a parameter called "applicationSettings" that is the object from the parameter file. In the template file, I also have a parameter called "deploymentEnvironment" that defines which environment the template is being deployed to. So, when I deploy a function app with applicationSettings, I need to only get those settings for the CI environment, for example.

I tried this:

[concat('parameters(''applicationSettings'').', parameters('deploymentEnvironment'))]

But a deployment error occurred:

{
  "ErrorEntity": {
    "ExtendedCode": "51008",
    "MessageTemplate": "The parameter {0} has an invalid value.",
    "Parameters": [
      "properties"
    ],
    "Code": "BadRequest",
    "Message": "The parameter properties has an invalid value."
  }
}

How can I reference a property of an object in a parameters.json file so I can pull specific application settings based on my deploymentEnvironment parameter?

Answer 1

you need to use the [] notation:

"[parameters('applicationSettings')[parameters('deploymentEnvironment')]]"

ps. you can combine those as well:

"[parameters('applicationSettings')[parameters('deploymentEnvironment')].property[xxx]]"
"[parameters('applicationSettings').property[xxx][parameters('deploymentEnvironment')]]"