In a world where you’re billed for what you use, it pays to really understand what exactly it is you are using. The pricing model of the Azure Function Apps consumption plan sounds pretty simple (pay based on execution count and execution time) - though as always the devil is in the detail.
In a recent project where we’ve migrated a workload from a dedicated (on-prem) server to a function app, someone asked what sounded like a fairly simple question:
- Do we pay (on the function app side) for the output to an Event Hub, and if so how much does it cost?
This post explores the answer to that question for a trivial C# function, and provides a few pointers to help get your head around consumption billing.
If you’re wondering why we wanted to deconstruct the function’s cost when an execution unit costs a mere 16 picdollars (16x10^-12), consider what we saw after our first week at full load:
5 trillion execution units… Interesting!
Execution units vs. what you see on the pricing page is covered later in the post.