Setting up dotnet core with RavenDB - dependency-injection

Question

I'm currently facing a problem with setting up RavenDB with dotnet core for multiple environments.
In StartUp class I have configured Raven as a Singleton and used the IOptions pattern to bind the settings Raven to the RavenSettings object.
public virtual void ConfigureServices(IServiceCollection services)
{
Services.AddMvc()
//Add functionality to inject IOptions<T>
services.AddOptions();
// App Settings
services.Configure<RavenSettings>(Configuration.GetSection("Raven"));
//services.Configure<RavenSettings>(settings => Configuration.GetSection("Raven").Bind(settings));
// .NET core built in IOC
services.AddSingleton(DocumentStoreHolder.Store);
services.AddSingleton<IConfiguration>(Configuration);
}
This is my default app settings.
{
"Logging": {
"IncludeScopes": false,
"LogLevel": {
"Default": "Debug",
"System": "Information",
"Microsoft": "Information"
}
},
"Raven": {
"Url": "x",
"DefaultDatabase": "x"
}
}
This is the class that I have attempted to bind the setting from appsettings to ...
public class RavenSettings
{
public string Url { get; set; }
public string DefaultDatabase { get; set; }
}
The class below follows the Raven documents in generating the Raven document store. Because I am using a singleton, I am not hitting the constructor to inject the settings. Can anyone advise a way around this?
public sealed class DocumentStoreHolder
{
private static RavenSettings _ravenSettings;
public DocumentStoreHolder(IOptions<RavenSettings> ravenSettings)
{
_ravenSettings = ravenSettings.Value;
}
public static IDocumentStore Store => DocStore.Value;
private static readonly Lazy<IDocumentStore> DocStore = new Lazy<IDocumentStore>(CreateStore);
private static IDocumentStore CreateStore()
{
var store = new DocumentStore
{
Url = _ravenSettings.Url,
DefaultDatabase = _ravenSettings.DefaultDatabase
}.Initialize();
return store;
}
}

Answer 1

Building on Set's answer, I was able to resolve it by creating an IDocumentStoreHolder interface, and registering that in the IOC.
DocumentStoreHolder.cs
public class DocumentStoreHolder : IDocumentStoreHolder
{
public DocumentStoreHolder(IOptions<RavenSettings> ravenSettings)
{
var settings = ravenSettings.Value;
Store = new DocumentStore
{
Url = settings.Url,
DefaultDatabase = settings.DefaultDatabase
}.Initialize();
}
public IDocumentStore Store { get; }
}
IDocumentStoreHolder.cs
public interface IDocumentStoreHolder
{
IDocumentStore Store { get; }
}
Startup.cs (ConfigureServices)
services.AddSingleton<IDocumentStoreHolder, DocumentStoreHolder>();
SomeClass.cs
private readonly IDocumentStore _store;
public SomeClass(IDocumentStoreHolder documentStoreHolder)
{
_store = documentStoreHolder.Store;
}

Answer 2

ASP.NET Core DI already uses lazy loading with singleton:
Singleton lifetime services are created the first time they are requested (or when ConfigureServices is run if you specify an instance there) and then every subsequent request will use the same instance.
and moreover:
If your application requires singleton behavior, allowing the services container to manage the service's lifetime is recommended instead of implementing the singleton design pattern and managing your object's lifetime in the class yourself.
Therefore, you can do something like this:
services.AddSingleton<DocumentStoreHolder>();
by removing your own singleton implementation from DocumentStoreHolder class
public sealed class DocumentStoreHolder
{
public DocumentStoreHolder(IOptions<RavenSettings> ravenSettings)
{
var _ravenSettings = ravenSettings.Value;
Store = new DocumentStore
{
Url = _ravenSettings.Url,
DefaultDatabase = _ravenSettings.DefaultDatabase
}.Initialize();
}
public IDocumentStore Store {get; private set;}
}