Is Azure function with http triggers a replacement for the web api with Azure APP service?

Question

Hi Team:

I am aware that Azure function supports http triggers. Does this mean we can build full fledged apis with azure functions instead of using .net core API with APP service? Basically we have already developed around 20 APIS using .net core web API and we would like to deploy them in Azure. I see that we can deploy to Azure APP service? But Azure function also supports http trigger so which one we should use APP service/ Azure function? Currently we have containerized and deployed to Azure VM. But we would like to go for Azure PAAS offering for better scalability and maintenance.

Basically, When should we go for Azure Functions with http trigger? and when should we go for the Azure APP service with respective web API development? Could you please clarify? what is the Microsoft recommendation?

Thanks
Rajesh

Answer 1

Hi @Naga Rajesh Kotaprolu ,

There isn't a best practices doc available that lists pros and cons of using Azure Functions vs App Services.

Having said that it really depends on your REST API and your goals and objectives. I would suggest reviewing performance considerations to ensure that you won't encounter any limitations. I would also consider reviewing open issues to see what others have been running into.

If you don't see stumbling blocks, then in my opinion, I would try transitioning a resource at a time. While it's possible to create REST APIs using Azure Functions, you may discover it doesn't fit very well in your existing workflow/codebase. On the other hand, you may discover it's a perfect candidate and a easy transition. There is no wrong answer but if you happen to run into issues, feel free to post your question here on Q&A or on the Azure Function repo.

Regards,
Ryan

Answer 2

This is a pretty complete guide to choose a computing service, it includes Azure Functions.
https://learn.microsoft.com/en-us/azure/architecture/guide/technology-choices/compute-decision-tree

I've been following a microservice architecture with Azure Functions in my projects for over a year now, and I haven't found any major blocker.

Probably the biggest issue is the delays when keeping up with .NET versions. Ex.: .NET 5 won't be supported out-of-the-box and support for .NET 6 probably won't arrive right after release... meaning you cannot use the latest features of your dependencies like Entity Framework, etc.

Outside APIs, they are definitely a great approach to reduce complexity when integrating with other systems.

Answer 3

Hi,

In addition to what has been provided above, you might find this comparison helpful to choose
https://learn.microsoft.com/en-us/azure/azure-functions/functions-compare-logic-apps-ms-flow-webjobs#comparison-table