Deploy function app at subscription level

azuredeploy.json

{
  "$schema": "https://schema.management.azure.com/schemas/2018-05-01/subscriptionDeploymentTemplate.json#",
  "contentVersion": "1.0.0.1",
  "parameters": {
    "resourceGroupName": {
      "type": "string",
      "metadata": {
        "description": "Specify the name of the resource group"
      }
    },
    "functionAppName": {
      "type": "string",
      "defaultValue": "[uniqueString(resourceGroup().id)]",
      "metadata": {
        "description": "Specify the name of the function application. Default value is to create a unique name"
      }
    },
    "location": {
      "type": "string",
      "defaultValue": "[deployment().location]",
      "metadata": {
        "description": "Specify the location for the function application resources"
      }
    },
    "ApplicationInsightsLocation": {
      "type": "string",
      "defaultValue": "West Europe",
      "allowedValues": [
        "North Europe",
        "West Europe",
        "Norway East"
      ],
      "metadata": {
        "description": "Specify the region for Application Insights data"
      }
    },
    "runtimeStack": {
      "type": "string",
      "defaultValue": "powershell",
      "allowedValues": [
        "powershell",
        "dotnet",
        "node",
        "java"
      ],
      "metadata": {
        "description": "Pick the language runtime that you want enabled"
      }
    },
    "timezone": {
      "type": "string",
      "defaultValue": "UTC",
      "metadata": {
        "description": "Pick the timezone to use for the function"
      }
    }
  },
  "variables": {
    "hostingPlanName": "[concat('plan', parameters('functionAppName'))]",
    "storageAccountName": "[concat('str', parameters('functionappName'))]"
  },
  "resources": [
    {
      "type": "Microsoft.Resources/resourceGroups",
      "apiVersion": "2018-05-01",
      "location": "[parameters('location')]",
      "name": "[parameters('resourceGroupName')]",
      "properties": {
      }
    },
    {
      "type": "Microsoft.Resources/deployments",
      "apiVersion": "2018-05-01",
      "name": "function-db",
      "resourceGroup": "[parameters('resourceGroupName')]",
      "dependsOn": [
        "[resourceId('Microsoft.Resources/resourceGroups/', parameters('resourceGroupName'))]"
      ],
      "properties": {
        "mode": "Incremental",
        "template": {
          "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
          "contentVersion": "1.0.0.0",
          "parameters": {},
          "variables": {},
          "resources": [
            {
              "apiVersion": "2019-06-01",
              "type": "Microsoft.Storage/storageAccounts",
              "name": "[variables('storageAccountName')]",
              "location": "[parameters('location')]",
              "sku": {
                "name": "Standard_LRS"
              }
            },
            {
              "name": "[parameters('functionAppName')]",
              "type": "Microsoft.Web/sites",
              "apiVersion": "2018-11-01",
              "location": "[parameters('location')]",
              "kind": "functionapp",
              "dependsOn": [
                "[resourceId('Microsoft.Web/serverfarms/', variables('hostingPlanName'))]",
                "[resourceId('Microsoft.Storage/storageAccounts', variables('storageAccountName'))]",
                "[resourceId('microsoft.insights/components/', parameters('functionAppName'))]"
              ],
              "identity": {
                "type": "SystemAssigned"
              },
              "properties": {
                "siteConfig": {
                  "appSettings": [
                    {
                      "name": "COSMOSDB_CONNECTION_STRING",
                      "value": "[parameters('runtimeStack')]"
                    },
                    {
                      "name": "FUNCTIONS_WORKER_RUNTIME",
                      "value": "[parameters('runtimeStack')]"
                    },
                    {
                      "name": "AzureWebJobsStorage",
                      "value": "[concat('DefaultEndpointsProtocol=https;AccountName=',variables('storageAccountName'),';AccountKey=',listKeys(resourceId(subscription().subscriptionId, 'Microsoft.Storage/storageAccounts', variables('storageAccountName')), '2017-06-01').keys[0].value)]"
                    },
                    {
                      "name": "FUNCTIONS_EXTENSION_VERSION",
                      "value": "~2"
                    },
                    {
                      "name": "APPINSIGHTS_INSTRUMENTATIONKEY",
                      "value": "[resourceId(subscription().subscriptionId, parameters('functionAppName'), 'Microsoft.Insights/components', '2018-05-01-preview').InstrumentationKey]"
                    },
                    {
                      "name": "WEBSITE_CONTENTAZUREFILECONNECTIONSTRING",
                      "value": "[concat('DefaultEndpointsProtocol=https;AccountName=', variables('storageAccountName'), ';AccountKey=', listKeys(resourceId(subscription().subscriptionId, 'Microsoft.Storage/storageAccounts', variables('storageAccountName')),'2017-06-01').keys[0].value)]"
                    },
                    {
                      "name": "WEBSITE_CONTENTSHARE",
                      "value": "[toLower(parameters('functionAppName'))]"
                    },
                    {
                      "name": "WEBSITE_TIME_ZONE",
                      "value": "[parameters('timezone')]"
                    }
                  ]
                },
                "name": "[parameters('functionAppName')]",
                "clientAffinityEnabled": false,
                "serverFarmId": "[variables('hostingPlanName')]"
              }
            },
            {
              "type": "Microsoft.Web/serverfarms",
              "apiVersion": "2018-11-01",
              "name": "[variables('hostingPlanName')]",
              "location": "[parameters('location')]",
              "properties": {
                "name": "[variables('hostingPlanName')]"
              },
              "sku": {
                "name": "Y1",
                "tier": "Dynamic",
                "size": "Y1",
                "family": "Y",
                "capacity": 0
              }
            },
            {
              "apiVersion": "2018-05-01-preview",
              "name": "[parameters('functionAppName')]",
              "type": "Microsoft.Insights/components",
              "location": "[parameters('ApplicationInsightsLocation')]",
              "tags": {
                "[concat('hidden-link:', resourceId('Microsoft.Web/sites/', parameters('functionAppName')))]": "Resource"
              },
              "properties": {
                "ApplicationId": "[parameters('functionAppName')]"
              }
            }
          ],
          "outputs": {
            "principalId": {
              "type": "string",
              "value": "[variables('hostingPlanName')]" //"[reference(resourceId('Microsoft.Web/sites', parameters('functionAppName')), '2018-11-01', 'Full').identity.principalId]"
            }
          }
        }
      }
    }
  ]

}