| title | description | ms.topic | ms.date | ms.custom |
|---|---|---|---|---|
How to disable functions in Azure Functions |
Learn how to disable and enable functions in Azure Functions. |
conceptual |
12/01/2022 |
devx-track-csharp |
This article explains how to disable a function in Azure Functions. To disable a function means to make the runtime ignore the automatic trigger that's defined for the function. This lets you prevent a specific function from running without stopping the entire function app.
The recommended way to disable a function is with an app setting in the format AzureWebJobs.<FUNCTION_NAME>.Disabled set to true. You can create and modify this application setting in several ways, including by using the Azure CLI and from your function's Overview tab in the Azure portal.
Use the Enable and Disable buttons on the function's Overview page. These buttons work by changing the value of the AzureWebJobs.<FUNCTION_NAME>.Disabled app setting. This function-specific setting is created the first time it's disabled.
Even when you publish to your function app from a local project, you can still use the portal to disable functions in the function app.
Note
Disabled functions can still be run by calling the REST endpoint using a master key. To learn more, see Run a disabled function. This means that a disabled function still runs when started from the Test/Run window in the portal using the master (Host key).
In the Azure CLI, you use the az functionapp config appsettings set command to create and modify the app setting. The following command disables a function named QueueTrigger by creating an app setting named AzureWebJobs.QueueTrigger.Disabled and setting it to true.
az functionapp config appsettings set --name <FUNCTION_APP_NAME> \
--resource-group <RESOURCE_GROUP_NAME> \
--settings AzureWebJobs.QueueTrigger.Disabled=true
To re-enable the function, rerun the same command with a value of false.
az functionapp config appsettings set --name <myFunctionApp> \
--resource-group <myResourceGroup> \
--settings AzureWebJobs.QueueTrigger.Disabled=false
The Update-AzFunctionAppSetting command adds or updates an application setting. The following command disables a function named QueueTrigger by creating an app setting named AzureWebJobs.QueueTrigger.Disabled and setting it to true.
Update-AzFunctionAppSetting -Name <FUNCTION_APP_NAME> -ResourceGroupName <RESOURCE_GROUP_NAME> -AppSetting @{"AzureWebJobs.QueueTrigger.Disabled" = "true"}
To re-enable the function, rerun the same command with a value of false.
Update-AzFunctionAppSetting -Name <FUNCTION_APP_NAME> -ResourceGroupName <RESOURCE_GROUP_NAME> -AppSetting @{"AzureWebJobs.QueueTrigger.Disabled" = "false"}
By default, app settings also apply to apps running in deployment slots. You can, however, override the app setting used by the slot by setting a slot-specific app setting. For example, you might want a function to be active in production but not during deployment testing, such as a timer triggered function.
To disable a function only in the staging slot:
Navigate to the slot instance of your function app by selecting Deployment slots under Deployment, choosing your slot, and selecting Functions in the slot instance. Choose your function, then use the Enable and Disable buttons on the function's Overview page. These buttons work by changing the value of the AzureWebJobs.<FUNCTION_NAME>.Disabled app setting. This function-specific setting is created the first time it's disabled.
You can also directly add the app setting named AzureWebJobs.<FUNCTION_NAME>.Disabled with value of true in the Configuration for the slot instance. When you add a slot-specific app setting, make sure to check the Deployment slot setting box. This maintains the setting value with the slot during swaps.
az functionapp config appsettings set --name <FUNCTION_APP_NAME> \
--resource-group <RESOURCE_GROUP_NAME> --slot <SLOT_NAME> \
--slot-settings AzureWebJobs.QueueTrigger.Disabled=true
To re-enable the function, rerun the same command with a value of false.
az functionapp config appsettings set --name <myFunctionApp> \
--resource-group <myResourceGroup> --slot <SLOT_NAME> \
--slot-settings AzureWebJobs.QueueTrigger.Disabled=false
Azure PowerShell currently doesn't support this functionality.
To learn more, see Azure Functions Deployment slots.
You can still cause a disabled function to run by supplying the master key in a REST request to the endpoint URL of the disabled function. In this way, you can develop and validate functions in Azure in a disabled state while preventing them from being accessed by others. Using any other type of key in the request returns an HTTP 404 response.
[!INCLUDE functions-master-key-caution]
To learn more about the master key, see Obtaining keys. To learn more about calling non-HTTP triggered functions, see Manually run a non HTTP-triggered function.
Functions can be disabled in the same way when running locally. To disable a function named HttpExample, add an entry to the Values collection in the local.settings.json file, as follows:
{
"IsEncrypted": false,
"Values": {
"FUNCTIONS_WORKER_RUNTIME": "python",
"AzureWebJobsStorage": "UseDevelopmentStorage=true",
"AzureWebJobs.HttpExample.Disabled": true
}
}While the application setting method is recommended for all languages and all runtime versions, there are several other ways to disable functions. These methods, which vary by language and runtime version, are maintained for backward compatibility.
In a class library function, you can also use the Disable attribute to prevent the function from being triggered. This attribute lets you customize the name of the setting used to disable the function. Use the version of the attribute that lets you define a constructor parameter that refers to a Boolean app setting, as shown in the following example:
public static class QueueFunctions
{
[Disable("MY_TIMER_DISABLED")]
[FunctionName("QueueTrigger")]
public static void QueueTrigger(
[QueueTrigger("myqueue-items")] string myQueueItem,
TraceWriter log)
{
log.Info($"C# function processed: {myQueueItem}");
}
}This method lets you enable and disable the function by changing the app setting, without recompiling or redeploying. Changing an app setting causes the function app to restart, so the disabled state change is recognized immediately.
There's also a constructor for the parameter that doesn't accept a string for the setting name. This version of the attribute isn't recommended. If you use this version, you must recompile and redeploy the project to change the function's disabled state.
In version 1.x, you can also use the disabled property of the function.json file to tell the runtime not to trigger a function. This method only works for scripting languages such as C# script and JavaScript. The disabled property can be set to true or to the name of an app setting:
{
"bindings": [
{
"type": "queueTrigger",
"direction": "in",
"name": "myQueueItem",
"queueName": "myqueue-items",
"connection":"MyStorageConnectionAppSetting"
}
],
"disabled": true
}or
"bindings": [
...
],
"disabled": "IS_DISABLED"In the second example, the function is disabled when there's an app setting that is named IS_DISABLED and is set to true or 1.
Important
The portal uses application settings to disable v1.x functions. When an application setting conflicts with the function.json file, an error can occur. You should remove the disabled property from the function.json file to prevent errors.
Keep the following considerations in mind when you disable functions:
-
When you disable an HTTP triggered function by using the methods described in this article, the endpoint may still by accessible when running on your local computer and in the portal.
-
At this time, function names that contain a hyphen (
-) can't be disabled when running on Linux plan. If you need to disable your functions when running on Linux plan, don't use hyphens in your function names.
This article is about disabling automatic triggers. For more information about triggers, see Triggers and bindings.