Add API runtime selection

Author: anthonychu

articles/static-web-apps/apis.md

@@ -5,7 +5,7 @@ services: static-web-apps
 author: craigshoemaker
 ms.service: static-web-apps
 ms.topic:  conceptual
-ms.date: 11/08/2021
+ms.date: 02/22/2022
 ms.author: cshoe
 ---
 
@@ -28,7 +28,7 @@ The following table contrasts the differences between using managed and existing
 | Feature | Managed Functions | Bring your own Functions |
 | --- | --- | --- |
 | Access to Azure Functions [triggers](../azure-functions/functions-triggers-bindings.md#supported-bindings) | Http only | All |
-| Supported Azure Functions [runtimes](../azure-functions/supported-languages.md#languages-by-runtime-version) | Node.js 12<br>.NET Core 3.1<br>.NET 6.0<br>Python 3.8 | All |
+| Supported Azure Functions [runtimes](../azure-functions/supported-languages.md#languages-by-runtime-version)<sup>1</sup> | Node.js 12<br>Node.js 14<br>Node.js 16 (preview)<br>.NET Core 3.1<br>.NET 6.0<br>Python 3.8<br>Python 3.9 | All |
 | Supported Azure Functions [hosting plans](../azure-functions/functions-scale.md) | Consumption | Consumption<br>Premium<br>Dedicated |
 | [Integrated security](user-information.md) with direct access to user authentication and role-based authorization data | ✔ | ✔ |
 | [Routing integration](./configuration.md?#routes) that makes the _api_ route available to the web app securely without requiring custom CORS rules. | ✔ | ✔ |
@@ -38,6 +38,8 @@ The following table contrasts the differences between using managed and existing
 | API functions available outside Azure Static Web Apps | ✕ | ✔ |
 | [Key Vault references](../app-service/app-service-key-vault-references.md) | ✕ | ✔ |
 
+<sup>1</sup> To specify the runtime version in managed functions, add a configuration file to your frontend app and set the [`apiRuntime` property](configuration.md).
+
 ## Configuration
 
 API endpoints are available to the web app through the _api_ route.
@@ -61,7 +63,7 @@ Logs are only available if you add [Application Insights](monitor.md).
 
 | Managed functions | Bring your own functions |
 | --- | --- |
-| <ul><li>Triggers are limited to [HTTP](../azure-functions/functions-bindings-http-webhook.md).</li><li>The Azure Functions app must either be in Node.js 12, .NET Core 3.1, .NET 6.0, or Python 3.8.</li><li>Some application settings are managed by the service, therefore the following prefixes are reserved by the runtime:<ul><li>*APPSETTING\_, AZUREBLOBSTORAGE\_, AZUREFILESSTORAGE\_, AZURE_FUNCTION\_, CONTAINER\_, DIAGNOSTICS\_, DOCKER\_, FUNCTIONS\_, IDENTITY\_, MACHINEKEY\_, MAINSITE\_, MSDEPLOY\_, SCMSITE\_, SCM\_, WEBSITES\_, WEBSITE\_, WEBSOCKET\_, AzureWeb*</li></ul></li></ul> | <ul><li>You are responsible to manage the Functions app deployment.</li></ul> |
+| <ul><li>Triggers are limited to [HTTP](../azure-functions/functions-bindings-http-webhook.md).</li><li>The Azure Functions app must either be in Node.js 12, Node.js 14, Node.js 16 (preview), .NET Core 3.1, .NET 6.0, Python 3.8, or Python 3.9.</li><li>Some application settings are managed by the service, therefore the following prefixes are reserved by the runtime:<ul><li>*APPSETTING\_, AZUREBLOBSTORAGE\_, AZUREFILESSTORAGE\_, AZURE_FUNCTION\_, CONTAINER\_, DIAGNOSTICS\_, DOCKER\_, FUNCTIONS\_, IDENTITY\_, MACHINEKEY\_, MAINSITE\_, MSDEPLOY\_, SCMSITE\_, SCM\_, WEBSITES\_, WEBSITE\_, WEBSOCKET\_, AzureWeb*</li></ul></li></ul> | <ul><li>You are responsible to manage the Functions app deployment.</li></ul> |
 
 ## Next steps
 

articles/static-web-apps/configuration.md

@@ -310,6 +310,35 @@ The following example configuration demonstrates how to override an error code.
 }
 ```
 
+## Platform
+
+The `platform` section controls platform specific settings, such as the API language runtime version.
+
+### Selecting the API language runtime version
+
+To configure the API language runtime version, set the `apiRuntime` property in the `platform` section to the desired version from the following values.
+
+| Language runtime version | Operating system | Azure Functions version | `apiRuntime` value |
+|--|--|--|--|
+| .NET Core 3.1 | Windows | 3.x | `dotnet:3.1` |
+| .NET 6.0 in-process | Windows | 4.x | `dotnet:6.0` |
+| .NET 6.0 isolated | Windows | 4.x | `dotnet-isolated:6.0` |
+| Node.js 12.x | Linux | 3.x | `node:12` |
+| Node.js 14.x | Linux | 4.x | `node:14` |
+| Node.js 16.x (preview) | Linux | 4.x | `node:16` |
+| Python 3.8 | Linux | 3.x | `python:3.8` |
+| Python 3.9 | Linux | 4.x | `python:3.9` |
+
+The following example configuration demonstrates how to use the `apiRuntime` property to select Node.js 16 as the API language runtime version.
+
+```json
+{
+  "platform": {
+    "apiRuntime": "node:16"
+  }
+}
+```
+
 ## Networking
 
 The `networking` section controls the network configuration of your static web app. To restrict access to your app, specify a list of allowed IP address blocks in `allowedIpRanges`.
@@ -348,7 +377,7 @@ In addition to IP address blocks, you can also specify [service tags](../virtual
 
 For details on how to restrict routes to authenticated users, see [Securing routes with roles](#securing-routes-with-roles).
 
-### Disable cache for authenticated paths
+### Disabling cache for authenticated paths
 
 If you set up [manual integration with Azure Front Door](front-door-manual.md), you may want to disable caching for your secured routes. If you have enabled [enterprise-grade edge](enterprise-edge.md) this is already configured for you.