You can profile a C# function app on your own machine, while it runs under Azure Functions Core Tools. This is the same way Visual Studio runs it when you press F5.

You can't profile functions that are deployed to Azure.

Before you start

You need:

• Azure Functions Core Tools v4. It's installed with the Azure development workload in Visual Studio. You can also install it with npm or the Microsoft installer.
• The .NET SDK that your function project targets.
• The function project folder. This is the folder that contains host.json.

Setting up the session

1. On the startup page, click New profiling session.
2. Under Cloud & serverless, select Azure Functions (Core Tools).
3. In Working Directory (Azure App), select your function project folder.
4. Check Path to Azure Functions Core Tools (func.exe).
   ANTS Performance Profiler normally fills this in automatically. It first looks for a cached Core Tools build that matches your project type,
   isolated or in-process. If no matching cached build is available, it searches PATH, standard npm installation locations, and the standalone Core Tools installation directories.
   To use a different Core Tools installation, click ... and browse to func.exe.
5. Optionally, click Show startup options and change Command line arguments. The default is start.
   For example, use start --port 7072 if port 7071 is already in use.
6. Choose a profiling mode and any other options, then click Start profiling.

What happens when you start profiling

1. Your function project is built (dotnet build). The build isn't profiled.
2. func.exe starts your function app and the profiler attaches to it.
3. When the host is ready, call your functions as normal. For example, for an HTTP trigger, open http://localhost:7071/api/<FunctionName> in a browser.
4. When you've finished, click Stop profiling. func.exe and the worker process are stopped.

Finding your code in the results

Your functions appear in the call tree with the rest of your code. For isolated function apps they run in a separate worker process (dotnet.exe), which is included in the results.

To jump to a function, type its name in Find method in call tree.

If profiling doesn't start