Azure ARM Template for Web App with Composer Extension installed

azuredeploy.json

{
    "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
        "siteName": {
            "type": "string",
            "defaultValue": "[resourceGroup().name]"
        },
        "appServicePlan":{
            "type": "string",
            "allowedValues": [
                "Free",
                "Shared",
                "Basic",
                "Standard",
                "Premium"
            ],
            "defaultValue": "Free"
        }
    },
    "variables": {
        "appServiceName": "[parameters('siteName')]",
        "appName": "[parameters('siteName')]",
        "configAppName":"[concat(parameters('siteName'), '/web')]"
    },
    "resources": [
        {
            "comments": "The App Service to host the Web App",
            "type": "Microsoft.Web/serverfarms",
            "sku": {
                "name": "[parameters('appServicePlan')]"
            },
            "kind": "app",
            "name": "[variables('appServiceName')]",
            "apiVersion": "2015-08-01",
            "location": "[resourceGroup().location]",
            "scale": null,
            "properties": {
                "name": "[variables('appServiceName')]",
                "numberOfWorkers": 0
            },
            "dependsOn": []
        },
        {
            "comments": "The Web App",
            "type": "Microsoft.Web/sites",
            "kind": "app",
            "name": "[variables('appName')]",
            "apiVersion": "2015-08-01",
            "location": "[resourceGroup().location]",
            "properties": {
                "name": "[variables('appName')]",
                "serverFarmId": "[resourceId('Microsoft.Web/serverfarms', variables('appServiceName'))]"
            },
            "dependsOn": [
                "[resourceId('Microsoft.Web/serverfarms', variables('appServiceName'))]"
            ],
            "resources": [   
                {
                    "apiVersion": "2015-08-01",
                    "name": "ComposerExtension",
                    "type": "siteextensions",
                    "dependsOn": [
                        "[variables('appName')]"
                    ]
                }
            ]
        },
        {
            "comments": "The config for the Web App",
            "type": "Microsoft.Web/sites/config",
            "name": "[variables('configAppName')]",
            "apiVersion": "2015-08-01",
            "location": "[resourceGroup().location]",
            "scale": null,
            "properties": {              
                "localMySqlEnabled": true,
                "numberOfWorkers": 1,
                "netFrameworkVersion": "v4.0",
                "phpVersion": "7.1",
                "virtualApplications": [
                    {
                        "virtualPath": "/",
                        "physicalPath": "site\\wwwroot",
                        "preloadEnabled": false,
                        "virtualDirectories": null
                    }
                ],
                "defaultDocuments": [
                    "index.php"
                ]
            },
            "dependsOn": [
                "[resourceId('Microsoft.Web/sites', variables('appName'))]"
            ]
        }
    ]
}