Azure Cosmos DB trigger and bindings for Azure Functions 2.x and higher overview

Functions execute in an isolated C# worker process. To learn more, see Guide for running C# Azure Functions in an isolated worker process.

Functions execute in the same process as the Functions host. To learn more, see Develop C# class library functions using Azure Functions.

In a variation of this model, Functions can be run using C# scripting, which is supported primarily for C# portal editing. To update existing binding extensions for C# script apps running in the portal without having to republish your function app, see Update your extensions.

This section describes using a class library. For C# scripting, you would need to instead install the extension bundle, version 4.x.

This version of the Azure Cosmos DB bindings extension introduces the ability to connect using an identity instead of a secret. For a tutorial on configuring your function apps with managed identities, see the creating a function app with identity-based connections tutorial.

This version also changes the types that you can bind to, replacing the types from the v2 SDK Microsoft.Azure.DocumentDB with newer types from the v3 SDK Microsoft.Azure.Cosmos. Learn more about how these new types are different and how to migrate to them from the SDK migration guide, trigger, input binding, and output binding examples.

This extension version is available as a NuGet package, version 4.x.

This section describes using a class library. For C# scripting, you would need to instead install the extension bundle, version 2.x or 3.x.

Working with the trigger and bindings requires that you reference the appropriate NuGet package. Install the NuGet package, version 3.x.

This version of the Azure Cosmos DB bindings extension introduces the ability to connect using an identity instead of a secret. For a tutorial on configuring your function apps with managed identities, see the creating a function app with identity-based connections tutorial.

Add the extension to your project by installing the NuGet package, version 4.x.

If you're writing your application using F#, you must also configure this extension as part of the app's startup configuration. In the call to ConfigureFunctionsWorkerDefaults() or ConfigureFunctionsWebApplication(), add a delegate that takes an IFunctionsWorkerApplication parameter. Then within the body of that delegate, call ConfigureCosmosDBExtension() on the object:

let hostBuilder = new HostBuilder()
hostBuilder.ConfigureFunctionsWorkerDefaults(fun (context: HostBuilderContext) (appBuilder: IFunctionsWorkerApplicationBuilder) ->
    appBuilder.ConfigureCosmosDBExtension() |> ignore
) |> ignore

Add the extension to your project by installing the NuGet package, version 3.x.

This version of the bundle contains version 4.x of the Azure Cosmos DB bindings extension that introduces the ability to connect using an identity instead of a secret. For a tutorial on configuring your function apps with managed identities, see the creating a function app with identity-based connections tutorial.

You can add this version of the extension from the preview extension bundle v4 by adding or replacing the following code in your host.json file:

{
  "version": "2.0",
  "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle.Preview",
    "version": "[4.0.0, 5.0.0)"
  }
}

To learn more, see Update your extensions.

You can install this version of the extension in your function app by registering the extension bundle, version 2.x or 3.x.

{
    "version": "2.0",
    "extensionBundle": {
        "id": "Microsoft.Azure.Functions.ExtensionBundle",
        "version": "[3.3.0, 4.0.0)"
    }
}

An isolated worker process class library compiled C# function runs in a process isolated from the runtime.

An in-process class library is a compiled C# function runs in the same process as the Functions runtime.

The Azure Cosmos DB extension supports parameter types according to the table below.

¹ Documents containing JSON data can be deserialized into known plain-old CLR object (POCO) types.

Earlier versions of the extension exposed types from the now deprecated Microsoft.Azure.Documents namespace. Newer types from Microsoft.Azure.Cosmos are exclusive to extension 4.x and higher.

The isolated worker process supports parameter types according to the tables below. Support for binding to types from Microsoft.Azure.Cosmosis in preview.

Cosmos DB trigger

When you want the function to process a single document, the Cosmos DB trigger can bind to the following types:

When you want the function to process a batch of documents, the Cosmos DB trigger can bind to the following types:

Cosmos DB input binding

When you want the function to process a single document, the Cosmos DB input binding can bind to the following types:

When you want the function to process multiple documents from a query, the Cosmos DB input binding can bind to the following types:

¹ To use these types, you need to reference Microsoft.Azure.Functions.Worker.Extensions.CosmosDB 4.3.1-preview1 or later and the common dependencies for SDK type bindings.

Cosmos DB output binding

When you want the function to write to a single document, the Cosmos DB output binding can bind to the following types:

When you want the function to write to multiple documents, the Cosmos DB output binding can bind to the following types:

For other output scenarios, create and use types from Microsoft.Azure.Cosmos directly.

Earlier versions of extensions in the isolated worker process only support binding to JSON serializable types. Additional options are available to extension 4.x and higher.