Building event-driven Serverless Apps with Azure Functions and Azure Cosmos DB
Rafat Sarosh

In this session, Rafat Sarosh explained how to make a completely serverless backend with only Azure Functions and Azure Cosmos DB (with its ChangeFeed feature).

Despite being a very trendy subject, I found this session to be a little boring.
Not enough demos, not really explaining why use Azure Cosmos DB, and the speaker was not dynamic enough.

Azure Functions is part of the new FaaS offering of Azure that help make truly serverless development.

Azure Functions has 2 runtimes available. Version 1.x which is already GA (General Availability) and 2.x which is currently in preview.

Rafat demoed the tooling in the func CLI, Visual Studio and the Azure Portal to create new functions from templates. Those have been around for quite some time now.

Despite Azure Functions being serverless, you still have the choice to host them on your own App Service in Azure. This has the advantage to control a few scaling/performance options like AlwaysOn. By default, the Hosting Plan (no App Service) will put your functions to sleep if not used for 5 min.


Azure Functions has a trigger for Azure Cosmos DB that allows it to monitor for changes with the ChangeFeed functionality of Azure Cosmos DB and call a function when new content is available.
That allows to create automated workflows.


At the end of the session, 2 companies (Johnson Controls and Asos) explained their usage of both Azure Functions and Azure Cosmos DB.