Azure Search .NET SDK: SearchIndexClient & Dependency Injection

Question

What's the recommended way to register a SearchIndexClient into DI container? (let's say we only have a single index) Register it as singleton or transient?

Answer 1

The short answer is that you should register it as a singleton, as long as you make sure to avoid using properties and methods that aren't thread-safe. Most of them are thread-safe; just avoid setting mutable properties from multiple threads and you should be fine.

For a more in-depth discussion of why this is the recommended practice and how you can extend it for more complex scenarios, see this related question.

Answer 2

In an ASP.NET Core app, you can inject the client as follows.

Install the packages: Microsoft.Extensions.Azure, Azure.Search.Documents (this is the latest)

In the ConfigureServices method in startup.cs, register the client:

using Microsoft.Extensions.Azure;

public void ConfigureServices(IServiceCollection services)
{
    services.AddAzureClients(builder =>
    {
        builder.AddSearchIndexClient(new 
            Uri("my resource url"), new 
            AzureKeyCredential("my resource key"));
    });

    services.AddControllers();
}

Now say you want to use the client in your controller, you can inject it like so:

public class MyApiController : ControllerBase
{
    private readonly SearchIndexClient _searchIndexClient;
  
    public MyApiController(SearchIndexClient searchIndexClient)
    {
        _searchIndexClient = searchIndexClient;
    }

}

You may not want to put your credentials directly in ConfigureServices though, in which case you could store them in appsettings.Development.json (or appsettings.Production.json):

  "SearchDocument": {
    "endpoint": "my resource url",
    "credential": { "key": "my resource key" }
  }

and do this in ConfigureServices:

services.AddAzureClients(builder =>
{   
    builder.AddSearchIndexClient(
        Configuration.GetSection("SearchDocument")); 
});

Read more about Dependency injection with the Azure SDK for .NET.