How do you queue multiple Azure Functions HttpTriggers to prevent memory errors?

Question

I have a Python Azure Function (Linux Consumption Plan) that is being set up to run multiple HttpTriggers at various times throughout the day. It's possible for more than one of these triggers to execute at or around the same time as the other triggers. To avoid exceeding the 1.5 GB memory limit, I'd like to make sure only one function invocation is allowed to run at a time. Is there any way to achieve this?

Edit: After doing a little research, would this setting allow me to avoid concurrent executions of my HttpTriggers: https://docs.microsoft.com/en-us/azure/azure-functions/functions-app-settings#website_max_dynamic_application_scale_out?

If I set WEBSITE_MAX_DYNAMIC_APPLICATION_SCALE_OUT to 1, would that mean only one invocation could run at a time and the other HttpTriggers would wait?

Answer 1

Check out the full description of WEBSITE_MAX_DYNAMIC_APPLICATION_SCALE_OUT here. It says that:

WEBSITE_MAX_DYNAMIC_APPLICATION_SCALE_OUT sets a maximum number of instances that a function app can scale to. This limit is not yet fully supported - it does work to limit your scale out, but there are some cases where it might not be completely foolproof. We're working on improving this.

I believe this is not what you are looking for.

Logically, this can be made possible if we choose timer trigger times in such a way that they never collide within a day (24hrs). Please note, this depends on the business requirements of function app HttpTriggers - what is the required frequency of them.

Another solution can be to have separate consumption plans for different HttpTriggers. Infact, in this case, you will get a monthly free grant of 1 million requests and 4,00,000 GB-s of resource consumption per month per subscription in pay-as-you-go pricing across all function apps in that subscription.

As mentioned above, there can be different solutions for this, you need to choose as per what suits you the best.