Hi all, I have created an Azure Function App on an App Service Plan in order to increase the function running time for my Time Trigger python script function (my code takes around 30 mins to run on my computer, and was timing out when it used to be a http trigger). It is set to run once a day. It's currently on pricing plan B1. I'm wondering if I can switch to F1 though and not lose the unlimited timeout length? I don't really understand the costs so am worried about them blowing out on B1, since it seems to be using memory and CPU even when my time trigger function isn't running.

Hello @Boop444, welcome to this moderated Azure community forum. Azure functions run for a maximum of 5 minutes by default or for 10 minutes if you manipulate the settings , depending on the kind of app plan. This is to protect users from the costs because the price of functions is based on the duration (amongst others) for a consumption plan. The F1 app plan offloads the function from memory after not being called for 20 minutes. The same goes for other plans without the ' always on ' setting. If you call it once per day, you will have to wait until the function app is started again, before execution. I recommend pumping up the 'functionTimeout' setting to 45 minutes, just to be sure and just testing your application on the F1 and watching the logging to see what happens. This answer is written by myself, not by some AI. If the response helped, do "Accept Answer". If it doesn't work, please let us know the progress. All community members with similar issues will benefit by doing so. Your contribution is highly appreciated.

App service plan requirements for time trigger function

Accepted answer

Sander van de Velde | MVP 31,211 Reputation points MVP

2023-11-09T21:33:01.48+00:00

Hello @Boop444,

welcome to this moderated Azure community forum.

Azure functions run for a maximum of 5 minutes by default or for 10 minutes if you manipulate the settings, depending on the kind of app plan.

This is to protect users from the costs because the price of functions is based on the duration (amongst others) for a consumption plan.

The F1 app plan offloads the function from memory after not being called for 20 minutes. The same goes for other plans without the 'always on' setting. If you call it once per day, you will have to wait until the function app is started again, before execution.

I recommend pumping up the 'functionTimeout' setting to 45 minutes, just to be sure and just testing your application on the F1 and watching the logging to see what happens.

This answer is written by myself, not by some AI. If the response helped, do "Accept Answer". If it doesn't work, please let us know the progress. All community members with similar issues will benefit by doing so. Your contribution is highly appreciated.
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Boop444 25 Reputation points

2023-11-09T21:54:40.4766667+00:00

Hi Sander, thanks very much for your response! I have the max timeout set for 90 mins at the moment but could definitely drop it down. If I switch to F1, you mention about waiting for the app to start before the function can run... So if I just had the time trigger function sitting there, not connected to any data factory or anything, will it start the app when it reaches the trigger time and run on its own? Or would I need to go onto Azure and start the app since it's not "always on"? When I was creating the function, the estimated price for the B1 service app was 17$p/m, which would be fine, but I guess there's the additional consumption costs on top of that which may be a worry? I looked at premium instead but the estimated cost was much higher.

Sander van de Velde | MVP 31,211 Reputation points MVP

2023-11-09T22:44:38.0033333+00:00

Always on means the application is kept in memory, like it is 'always running'.

The free version and heavier versions without 'always on' need to start up once a function is triggered. This could be a HTTP trigger, EventHub trigger, Timer trigger, etc.

So there is a delay in that case. After starting up, the function will execute within the limits of the tier. Once it's ready executing the trigger function and no new trigger is executed (within the 20 minutes or so), the function app will be offloaded until the next trigger..

The 17$ p/m is basically what you pay for the compute, keeping a processor running, for a whole month. There are some additional costs like the storage account for the costs and the optional Application Insights. As with everything in cloud, keep an eye on the consumption and costs and compare it with the amount of money you want to spend. Check also the costs alerts.

If the response helped, do "Accept Answer". If it doesn't work, please let us know the progress. All community members with similar issues will benefit by doing so. Your contribution is highly appreciated.

Boop444 25 Reputation points

2023-11-09T23:19:27.76+00:00

Ah that is way better than I thought then! Thank you for the explanation. Unfortunately getting an error trying to switch to F1 due to 64 bit work processes. Tried switch "always on" to "off" first, and can't see the 32/64 bit option in platform settings, maybe because it's Linux? Sounds like B1 might be worth the cost though!
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App service plan requirements for time trigger function

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