Keycloak authentication extension (auth adapter) with predefined configuration and authorization policies requirements. It's simplify integration with auth service, all you needs it's just drop the installation keycloak client's file (keycloak.json) in root application folder.

1. Allow to application reads client installation file from the root directory

public class Program
{
    public static void Main(string[] args)
    {
        CreateWebHostBuilder(args).Build().Run();
    }

    public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
                // New line 
                .UseKeycloak()
                .UseStartup<Startup>();
}

2. Add Keycloak authentication functionality and authorization policies

public void ConfigureServices(IServiceCollection services)
{  
    // New line 
    services.AddKeycloakAuthentication(Configuration);

    services.AddAuthorization(config => /* ... */);
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.UseAuthentication();
    app.UseAuthorization();
}

3. Enjoy

1. Do first two steps from Authentication section
2. Configure http client

public void ConfigureServices(IServiceCollection services)
{

    services.AddKeycloakHttpClient<IMicroserviceTwo, MicroserviceTwo>(c => { /* ... */ });
    services.AddKeycloakHttpClient<IMicroserviceThree, MicroserviceThree>(c => { /* ... */ });
}

3. Done. Just invoke IMicroserviceTwo or IMicroserviceThree whenever and don't think about auth tokens.

1. Authentication with autosetup through keycloak.json file
2. HttpClient with auto obtaining and refreshing access_token
3. Predefined authorization policy requirements
   3.1. ResourceAccess - allows to check roles from different resources

[ ] More predefined policy requirements
[ ] Importing Authorization configuration from Keycloak ([service-id]-authz-config.json)