Create a load test for Azure Functions

Learn how to create a load test for an app in Azure Functions with Azure Load Testing. In this article, you'll learn how to create a URL-based load test for your function app in the Azure portal, and then use the load testing dashboard to analyze performance issues and identify bottlenecks.

With the integrated load testing experience in Azure Functions, you can:

• Create a URL-based load test for functions with an HTTP trigger
• View the load test runs associated with a function app
• Create a load testing resource

Prerequisites

• An Azure account with an active subscription. If you don't have an Azure subscription, create a free account before you begin.
• A function app with at least one function with an HTTP trigger. If you need to create a function app, see Getting started with Azure Functions.

Create a load test for a function app

You can create a URL-based load test directly from your Azure Function App in the Azure portal.

To create a load test for a function app:

1. In the Azure portal, go to your function app.

2. On the left pane, select Load Testing (Preview) under the Performance section.

   On this page, you can see the list of tests and the load test runs for this function app.

   

3. Optionally, select Create load testing resource if you don't have a load testing resource yet.

4. Select Create test to start creating a URL-based load test for the function app.

5. On the Create test page, first enter the test details:

   Field	Description
   Load Testing Resource	Select your load testing resource.
   Test name	Enter a unique test name.
   Test description	(Optional) Enter a load test description.
   Run test after creation	When selected, the load test starts automatically after creating the test.

6. Select Add request to add HTTP requests to the load test:

   On the Add request page, enter the details for the request:

   Field	Description
   Request name	Unique name within the load test to identify the request. You can use this request name when defining test criteria.
   Function name	Select the function that you want to test
   Key	Select the key required for accessing the function
   HTTP method	Select an HTTP method from the list. Azure Load Testing supports GET, POST, PUT, DELETE, PATCH, HEAD, and OPTIONS.
   Query parameters	(Optional) Enter query string parameters to append to the URL.
   Headers	(Optional) Enter HTTP headers to include in the HTTP request.
   Body	(Optional) Depending on the HTTP method, you can specify the HTTP body content. Azure Load Testing supports the following formats: raw data, JSON view, JavaScript, HTML, and XML.

   

   Learn more about adding HTTP requests to a load test.

7. Select the Load configuration tab to configure the load parameters for the load test.

   Field	Description
   Engine instances	Enter the number of load test engine instances. The load test runs in parallel across all the engine instances.
   Load pattern	Select the load pattern (linear, step, spike) for ramping up to the target number of virtual users.
   Concurrent users per engine	Enter the number of virtual users to simulate on each of the test engines. The total number of virtual users for the load test is: #test engines * #users per engine.
   Test duration (minutes)	Enter the duration of the load test in minutes.
   Ramp-up time (minutes)	Enter the ramp-up time of the load test in minutes. The ramp-up time is the time it takes to reach the target number of virtual users.

8. Optionally, configure the network settings if the function app isn't publicly accessible.

   Learn more about load testing privately hosted endpoints.

   

9. Select Review + create to review the test configuration, and then select Create to create the load test.

   Azure Load Testing now creates the load test. If you selected Run test after creation previously, the load test starts automatically.

Note

If the test was converted from a URL test to a JMX test directly from the Load Testing resource, the test cannot be modified from the function app.

View test runs

You can view the list of test runs and a summary overview of the test results directly from within the function app configuration in the Azure portal.

1. In the Azure portal, go to your Azure Function App.

2. On the left pane, select Load testing.

3. In the Test runs tab, you can view the list of test runs for your function app.

   For each test run, you can view the test details and a summary of the test outcome, such as average response time, throughput, and error state.

4. Select a test run to go to the Azure Load Testing dashboard and analyze the test run details.

   

Next steps

• Learn more about load testing Azure App Service applications.