Azure Function With Queues

In this blog, you will learn how to use azure function with queues, tips and tricks.

Azure functions usage

The azure function can be used under the following circumstances,

1. Use the Azure function where the application needs to execute small code/logic repeatedly.
2. Code that needs to scale quickly or that runs sporadically.

Azure function triggers

The azure function can be triggered from the following,

1. Queue
2. Timer
3. Event Grid
4. HTTP

I was working on the azure function with service bus queue triggers and would like to share some observations,

1. Once the azure function picks the message from the queue, the function should finish the processing within 5 minutes because the queue message lock duration is 5 min. If a function takes more than 5 min to execute and the Max delivery count is more than 1, then the message will be re-queued and picked up by another function instance.
2. The azure function can be hosted in 3 different plans,
    
   • Consumption Plan - Scales automatically can have 200 instances in windows with a 10-minute max time of execution.
   • Premium Plan - Scales automatically can have 100 instances in windows with an unlimited max time of execution.
   • Dedicate Plan - Manual/autoscale can have 10-20 instances in windows with an unlimited max time of execution.

Tips

1. If the queue is used as a function trigger and a premium or dedicated plan are used, function execution should finish within 5 min only. Otherwise, the message will be re-queued and picked again by another function instance.
2. If you need more than 200 instances at any given time and are using queues, separate the message into multiple queues, which triggers different function deployments.