Using IdentityServer4 with custom DBContext config

You don't need to create a custom ConfigurationDbContext

or event IDbContextFactory

to switch to use different databases. Since IdentityServer4.EntityFramework

version 2.3.2 you can do:

namespace DL.STS.Host
{
    public class Startup
    {
        ...

        public void ConfigureServices(IServiceCollection services)
        {
            string connectionString = _configuration.GetConnectionString("appDbConnection");

            string migrationsAssembly = typeof(Startup).GetTypeInfo().Assembly
                .GetName().Name;

            services
               .AddIdentityServer()
               .AddConfigurationStore(options =>
               {
                   options.ConfigureDbContext = builder =>
                       // I made up this extension method "UseOracle",
                       // but this is where you plug your database in
                       builder.UseOracle(connectionString,
                           sql => sql.MigrationsAssembly(migrationsAssembly));
               })
               ...;

            ...
        }

        ...
    }
}

      

        
        
        
      

    

Serve config / live storage to your own project / assembly?

What if you want to neatly decompose your solution and want to split the configuration store and operational store (as well as the user ID store) into their own class library / assembly?

According to the documentation, you can use -o

to specify the destination of the migration output folder:

dotnet ef migrations add InitialIdentityServerPersistedGrantDbMigration -c PersistedGrantDbContext -o Data/Migrations/IdentityServer/PersistedGrantDb
dotnet ef migrations add InitialIdentityServerConfigurationDbMigration -c ConfigurationDbContext -o Data/Migrations/IdentityServer/ConfigurationDb

      

        
        
        
      

    

But who likes to memorize / type such a long way when doing migrations? Then you might be thinking: how about a custom ConfigurationDbContext

one inherited from IdentityServer and a separate project:

using IdentityServer4.EntityFramework.DbContexts;
using IdentityServer4.EntityFramework.Options;
using Microsoft.EntityFrameworkCore;

namespace DL.STS.Data.ConfigurationStore.EFCore
{
    public class AppConfigurationDbContext : ConfigurationDbContext
    {
        public AppConfigurationDbContext(DbContextOptions<ConfigurationDbContext> options, 
            ConfigurationStoreOptions storeOptions) : base(options, storeOptions)
        {
        }
    }
}

      

        
        
        
      

    

Common mistakes

I think this is where people get into trouble. When you do Add-Migration

, you may encounter:

Unable to create object of type AppConfigurationDbContext

. For the various templates supported at design time see https://go.microsoft.com/fwlink/?linkid=851728 .

or

Failed to resolve service for type Microsoft.EntityFrameworkCore.DbContextOptions<IdentityServer4.EntityFramework.DbContexts.ConfigurationDbContext>

when trying to activate DL.STS.Data.ConfigurationStore.EFCore.AppConfigurationDbContext

.

I don't think there is a way to fix this right now.

Are there other ways?

It turns out it's actually pretty simple. It looks like you cannot have your own DbContext

inherited from IdentityServer. So get rid of that and create an extension method in this separate library / assembly:

using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using System.Reflection;

namespace DL.STS.Data.ConfigurationStore.EFCore.Extensions
{
    public static class IdentityServerBuilderExtensions
    {
        public static IIdentityServerBuilder AddEFConfigurationStore(
            this IIdentityServerBuilder builder, string connectionString)
        {
            string assemblyNamespace = typeof(IdentityServerBuilderExtensions)
                .GetTypeInfo()
                .Assembly
                .GetName()
                .Name;

            builder.AddConfigurationStore(options =>
                options.ConfigureDbContext = b =>
                    b.UseSqlServer(connectionString, optionsBuilder =>
                        optionsBuilder.MigrationsAssembly(assemblyNamespace)
                    )
            );

            return builder;
        }
    }
}

      

        
        
        
      

    

Then on Startup.cs

in your web project:

public void ConfigureServices(IServiceCollection services)
{
    ...

    string connectionString = _configuration.GetConnectionString("appDbConnection");

    services
        .AddIdentityServer()
        .AddDeveloperSigningCredential()
        .AddEFConfigurationStore(connectionString)
        ...;

    ...
}

      

        
        
        
      

    

And when you do PM> Add-Migration AddConfigurationTables -Context ConfigurationDbContext

with the default project, which is a separate library / assembly: