Azure Durable Function timeout exception

Question

I have an Azure Durable Function whose host.json file sets all functions to never timeout: { "version": "2.0", "functionTimeout": "-1", ... } }

When the durable function is run though the activity function called by the orchestrator function gets a timeout after the default 30 minutes:

Timeout value of 00:30:00 was exceeded by function: LongRunningActivity

Microsoft.Azure.WebJobs.Host.FunctionTimeoutException: at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+d__29.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.23.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.23.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.23.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 624) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)

The documentation states that the timeout defined in host.json should apply to all functions in the function app.

Have I missed something? Or is this a bug in Azure Durable Functions?

Answer 1

Yes, you've missed. The default timeout for App Service Plan is 30 minutes. You can extend using host.json setting, but according to what you described in here, you haven't changed.

More info:

https://docs.microsoft.com/en-us/azure/azure-functions/functions-scale?WT.mc_id=AZ-MVP-4021705#timeout

host.json

{
    "functionTimeout": "-1"
}

https://docs.microsoft.com/en-us/azure/azure-functions/functions-host-json#functiontimeout