Azure.ResourceManager.CosmosDB (.NET)

Authentication

using Azure.Identity;
using Azure.ResourceManager;
using Azure.ResourceManager.CosmosDB;

// Always use DefaultAzureCredential
var credential = new DefaultAzureCredential();
var armClient = new ArmClient(credential);

// Get subscription
var subscriptionId = Environment.GetEnvironmentVariable("AZURE_SUBSCRIPTION_ID");
var subscription = armClient.GetSubscriptionResource(
    new ResourceIdentifier($"/subscriptions/{subscriptionId}"));

Resource Hierarchy

ArmClient
└── SubscriptionResource
    └── ResourceGroupResource
        └── CosmosDBAccountResource
            ├── CosmosDBSqlDatabaseResource
            │   └── CosmosDBSqlContainerResource
            │       ├── CosmosDBSqlStoredProcedureResource
            │       ├── CosmosDBSqlTriggerResource
            │       └── CosmosDBSqlUserDefinedFunctionResource
            ├── CassandraKeyspaceResource
            ├── GremlinDatabaseResource
            ├── MongoDBDatabaseResource
            └── CosmosDBTableResource

Core Workflow

1. Create Cosmos DB Account

using Azure.ResourceManager.CosmosDB;
using Azure.ResourceManager.CosmosDB.Models;

// Get resource group
var resourceGroup = await subscription
    .GetResourceGroupAsync("my-resource-group");

// Define account
var accountData = new CosmosDBAccountCreateOrUpdateContent(
    location: AzureLocation.EastUS,
    locations: new[]
    {
        new CosmosDBAccountLocation
        {
            LocationName = AzureLocation.EastUS,
            FailoverPriority = 0,
            IsZoneRedundant = false
        }
    })
{
    Kind = CosmosDBAccountKind.GlobalDocumentDB,
    ConsistencyPolicy = new ConsistencyPolicy(DefaultConsistencyLevel.Session),
    EnableAutomaticFailover = true
};

// Create account (long-running operation)
var accountCollection = resourceGroup.Value.GetCosmosDBAccounts();
var operation = await accountCollection.CreateOrUpdateAsync(
    WaitUntil.Completed,
    "my-cosmos-account",
    accountData);

CosmosDBAccountResource account = operation.Value;

2. Create SQL Database

var databaseData = new CosmosDBSqlDatabaseCreateOrUpdateContent(
    new CosmosDBSqlDatabaseResourceInfo("my-database"));

var databaseCollection = account.GetCosmosDBSqlDatabases();
var dbOperation = await databaseCollection.CreateOrUpdateAsync(
    WaitUntil.Completed,
    "my-database",
    databaseData);

CosmosDBSqlDatabaseResource database = dbOperation.Value;

3. Create SQL Container

var containerData = new CosmosDBSqlContainerCreateOrUpdateContent(
    new CosmosDBSqlContainerResourceInfo("my-container")
    {
        PartitionKey = new CosmosDBContainerPartitionKey
        {
            Paths = { "/partitionKey" },
            Kind = CosmosDBPartitionKind.Hash
        },
        IndexingPolicy = new CosmosDBIndexingPolicy
        {
            Automatic = true,
            IndexingMode = CosmosDBIndexingMode.Consistent
        },
        DefaultTtl = 86400 // 24 hours
    });

var containerCollection = database.GetCosmosDBSqlContainers();
var containerOperation = await containerCollection.CreateOrUpdateAsync(
    WaitUntil.Completed,
    "my-container",
    containerData);

CosmosDBSqlContainerResource container = containerOperation.Value;

4. Configure Throughput

// Manual throughput
var throughputData = new ThroughputSettingsUpdateData(
    new ThroughputSettingsResourceInfo
    {
        Throughput = 400
    });

// Autoscale throughput
var autoscaleData = new ThroughputSettingsUpdateData(
    new ThroughputSettingsResourceInfo
    {
        AutoscaleSettings = new AutoscaleSettingsResourceInfo
        {
            MaxThroughput = 4000
        }
    });

// Apply to database
await database.CreateOrUpdateCosmosDBSqlDatabaseThroughputAsync(
    WaitUntil.Completed,
    throughputData);

5. Get Connection Information

// Get keys
var keys = await account.GetKeysAsync();
Console.WriteLine($"Primary Key: {keys.Value.PrimaryMasterKey}");

// Get connection strings
var connectionStrings = await account.GetConnectionStringsAsync();
foreach (var cs in connectionStrings.Value.ConnectionStrings)
{
    Console.WriteLine($"{cs.Description}: {cs.ConnectionString}");
}

Key Types Reference

Best Practices

1. Use WaitUntil.Completed for operations that must finish before proceeding
2. Use WaitUntil.Started when you want to poll manually or run operations in parallel
3. Always use DefaultAzureCredential — never hardcode keys
4. Handle RequestFailedException for ARM API errors
5. Use CreateOrUpdateAsync for idempotent operations
6. Navigate hierarchy via Get* methods (e.g., account.GetCosmosDBSqlDatabases())

Error Handling

using Azure;

try
{
    var operation = await accountCollection.CreateOrUpdateAsync(
        WaitUntil.Completed, accountName, accountData);
}
catch (RequestFailedException ex) when (ex.Status == 409)
{
    Console.WriteLine("Account already exists");
}
catch (RequestFailedException ex)
{
    Console.WriteLine($"ARM Error: {ex.Status} - {ex.ErrorCode}: {ex.Message}");
}

Reference Files

Related SDKs