Azure Cosmos DB

This health check verifies the ability to communicate with Azure Cosmos DB. It uses the provided CosmosClient.

Installation

• .NET CLI
• Package Reference
• Nuget

dotnet add package AspNetCore.Pulse.CosmosDb --version 8.0.4

Defaults

By default, the CosmosClient instance is resolved from service provider. AzureCosmosDbHealthCheckOptions does not provide any specific containers or database ids, the health check just calls CosmosClient.ReadAccountAsync.

void Configure(IHealthChecksBuilder builder)
{
    builder.Services.AddSingleton(sp => new CosmosClient(
        "endpoint-from-portal",
        new DefaultAzureCredential()));
    builder.AddHealthChecks().AddAzureCosmosDB();
}

Customization

You can additionally add the following parameters:

• clientFactory: A factory method to provide CosmosClient instance.
• optionsFactory: A factory method to provide AzureCosmosDbHealthCheckOptions instance. It allows to specify the database id and/or container id(s).
• name: The health check name. The default is azure_cosmosdb.
• failureStatus: The HealthStatus that should be reported when the health check fails. Default is HealthStatus.Unhealthy.
• tags: A list of tags that can be used to filter sets of health checks.
• timeout: A System.TimeSpan representing the timeout of the check.

void Configure(IHealthChecksBuilder builder)
{
    builder.Services.AddSingleton(sp => new CosmosClient(
        "endpoint-from-portal",
        new DefaultAzureCredential(),
        new CosmosClientOptions()
        {
            ApplicationRegion = Regions.EastUS2,
        }));
    builder.AddHealthChecks().AddAzureCosmosDB(
        optionsFactory: sp => new AzureCosmosDbHealthCheckOptions()
        {
            DatabaseId = "demo"
        });
}

Breaking changes

In the prior releases, CosmosDbHealthCheck was a part of Pulse.CosmosDb package. It had a dependency on not just Microsoft.Azure.Cosmos, but also Azure.Data.Tables. The packages have been split to avoid bringing unnecessary dependencies. Moreover, CosmosDbHealthCheck was letting the users specify how CosmosClient should be created (from raw connection string or from endpoint and managed identity credentials), at a cost of maintaining an internal, static client instances cache. Now the type does not create client instances nor maintain an internal cache and it’s the caller responsibility to provide the instance of CosmosClient (please see #2040 for more details). Since Azure SDK recommends treating clients as singletons and client instances can be expensive to create, it’s recommended to register a singleton factory method for Azure SDK clients. So the clients are created only when needed and once per whole application lifetime.