Aspire.Hosting.Azure.CosmosDB

Aspire.Hosting.Azure.Cosmos library

Provides extension methods and resource definitions for an Aspire AppHost to configure Azure CosmosDB.

Getting started

Prerequisites

• Azure subscription - create one for free

Install the package

In your AppHost project, install the Aspire Azure Cosmos DB Hosting library with NuGet:

dotnet add package Aspire.Hosting.Azure.CosmosDB

Configure Azure Provisioning for local development

Adding Azure resources to the Aspire application model will automatically enable development-time provisioning for Azure resources so that you don't need to configure them manually. Provisioning requires a number of settings to be available via .NET configuration. Set these values in user secrets in order to allow resources to be configured automatically.

{
    "Azure": {
      "SubscriptionId": "<your subscription id>",
      "ResourceGroupPrefix": "<prefix for the resource group>",
      "Location": "<azure location>"
    }
}

NOTE: Developers must have Owner access to the target subscription so that role assignments can be configured for the provisioned resources.

Usage example

Then, in the AppHost.cs file of AppHost, add a Cosmos DB connection and consume the connection using the following methods:

var cosmosdb = builder.AddAzureCosmosDB("cdb").AddCosmosDatabase("cosmosdb");

var myService = builder.AddProject<Projects.MyService>()
                       .WithReference(cosmosdb);

The WithReference method passes that connection information into a connection string named cosmosdb in the MyService project. In the Program.cs file of MyService, the connection can be consumed using the client library Aspire.Microsoft.Azure.Cosmos:

builder.AddAzureCosmosClient("cosmosdb");

Emulator usage

Aspire supports the usage of the Azure Cosmos DB emulator to use the emulator, add the following to your AppHost project:

// AppHost
var cosmosdb = builder.AddAzureCosmosDB("cosmos").RunAsEmulator();

When the AppHost starts up a local container running the Azure CosmosDB will also be started:

// Service code
builder.AddAzureCosmosClient("cosmos");

Connection Properties

When you reference Azure Cosmos DB resources using WithReference, the following connection properties are made available to the consuming project:

Cosmos DB account

The Cosmos DB account resource exposes the following connection properties:

Cosmos DB database

The Cosmos DB database resource inherits all properties from its parent Cosmos DB account and adds:

Cosmos DB container

The Cosmos DB container resource inherits all properties from its parent Cosmos DB database and adds:

Aspire exposes each property as an environment variable named [RESOURCE]_[PROPERTY]. For instance, the Uri property of a resource called db1 becomes DB1_URI.

Additional documentation

• https://learn.microsoft.com/azure/cosmos-db/nosql/sdk-dotnet-v3
• https://github.com/dotnet/aspire/tree/main/src/Components/README.md

Feedback & contributing

https://github.com/dotnet/aspire