Working with the Azure Cosmos DB Change Feed using Azure Functions and C#

The Change Feed in Azure Cosmos DB is a persistent record of changes to a container in the order that they occur. Essentially, the change feed will listen to a container in Azure Cosmos DB for any changes that occur, and it will then output those changes into a sorted list of documents that were changes in the order that they were modified.
Azure Functions is the simplest option to consume the change feed. As you’ll see from the demo, all you need to do is create a Function that uses a Cosmos DB Trigger and connect it to the container that we want to listen to.
In this video, I explain what the Change Feed is and how you can work with it, then I go through a basic demo on how you can consume the Change Feed using Azure Functions in C#
Azure Cosmos DB Change Feed: docs.microsoft...
Azure Functions Cosmos DB Trigger: docs.microsoft...
If you have any questions, feel free to ask in the comment section below or feel free to reach out to me on Twitter.
Twitter: / willvelida

[@sanda-dev72]

Excellent video!
Side note: In case someone else runs into this - make sure that the "Document" type is "Microsoft.Azure.Documents.Document" and NOT "System.Reflection.Metadata.Document". Otherwise you get a "Can't bind CosmosDBTrigger to type 'System.Collections.Generic.IReadOnlyList" error.

[@venkatesansrinivasan8108]

Thank you . This is crystal clear :)

[@willvelida]

Thank you 😊

[@BenBaik]

Subscribed

[@willvelida]

Thank you!

[@timthacker63]

This was very helpful thanks for the info.

[@willvelida]

Thanks for watching!

[@SafetyPartner]

Very thorough and exactly what I needed. Thank you! :)

[@willvelida]

Thanks for watching! 😊

[@avoxbg]

Thank you for the video. I have question. This function would be triggered if item in books container would be updated?

[@MerlynJohnson]

can you please share this demo code?

[@AllendavidMr]

Do you have an example for gremlin api too?

[@vishnums2436]

What is in Lease container. Is it a replica of books container?

[@zongyili569]

nice video. it will be very handy if you are able to share the demo code. Thanks

[@IchyeuT]

Hi Im trying to do the same think running at my local machine via VS, (Azure Cosmos DB Change Feed - Trigger Azure Functions) simple migration mixing the Cosmos DB Trigger (with StartFromBeginning to true) and the Cosmos DB Output binding like so: i would like to migrate a large container to new a database a new container with different partition key, however after several hours of on going migration i received an error
Lease 0 encountered an unhandled user exception during processing.
[2023-12-01T04:03:10.627Z] Microsoft.Azure.Cosmos.Client: Exception has been thrown by the change feed processor delegate. Anonymously Hosted DynamicMethods Assembly: The property or indexer 'Microsoft.Azure.Documents.Resource.Timestamp' cannot be used in this context because the set accessor is inaccessible.
Any idea what is wrong ?