I have a question,
Is there any concern if I use ILogger in Serilog on behalf of Microsoft logger?
public void ConfigureServices(IServiceCollection services)
{
services.AddSingleton(Log.Logger);
}
Then use from ILogger in Serilog namespace.
_logger.Error(exception, "Error", exception.Message, exceptionId);
What is your idea?
Microsoft.Extensions.ILogger is an abstraction that decouples your application code (the code that writes log entries) from the underlying logging framework.
Using this abstraction brings the benefit, that you could easily change the Logging Framework underneath (e.g. replace Serilog with NLog) and don't have to update all references in your application code.
Also using Microsoft's abstractions also allows you to configure logging of your application code and logging of Microsoft SDKs you might use at a single place.
The downside of abstractions is that you have to aggree to a common minimum interface provided by all logging frameworks. It's not so easy to use Framework-Specific features this way.
So most of the time i would advise using the abstraction.
If you have very specific features from Serilog you would like to interact with you could think about using ILogger from Serilog directly.
However you can configure serilog in the provider registration as well to a high degree and probably get the best of both worlds.
You would configure Serilog factory interface to be used instead of built-in Logger factory for creating ILogger
First in program.cs, add the Serilog ILoggerFactory to your IHostBuilder with UserSerilog() method in CreateHostBuilder():
public static IHostBuilder CreateHostBuilder(string[] args) =>
new HostBuilder()
.ConfigureHostConfiguration(builder => { /* Host configuration */ })
.ConfigureAppConfiguration(builder => { /* App configuration */ })
.ConfigureServices(services => { /* Service configuration */})
.UseSerilog(); // <- Add this line
}
How the library works behind the scenes
On the face of it, completely replacing the default ASP.NET Core logging system to use a different one seems like a big deal. Luckily, thanks to the use of interfaces, loose coupling, and dependency injection, the code is remarkably simple! The whole extension method we used previously is shown below:
public static class SerilogHostBuilderExtensions
{
public static IHostBuilder UseSerilog(this IHostBuilder builder,
Serilog.ILogger logger = null, bool dispose = false)
{
builder.ConfigureServices((context, collection) =>
collection.AddSingleton<ILoggerFactory>(services => new
SerilogLoggerFactory(logger, dispose)));
return builder;
}
}
The UseSerilog() extension calls the ConfigureServices method on the IHostBuilder and adds an instance of the SerilogLoggerFactory as the application's ILoggerFactory. Whenever an ILoggerFactory is required by the app (to create an ILogger), the SerilogLoggerFactory will be used.
for more Information check this Link
"The downside of abstractions is that you have to aggree to a common minimum interface provided by all logging frameworks. It's not so easy to use Framework-Specific features this way."
I think we can always create extension methods to overcome this downside.
Related
I realize DI (ctor based) in .NET CORE is quite straight forward but if it comes to nested injections I struggle.
This is quite simple:
public void ConfigureServices(IServiceCollection services)
{
services.AddRavenDbDocStore(x => x.AfterInitializeDocStore = RavenConfiguration.AfterInitializeDocStore());
services.AddRavenDbAsyncSession();
services.AddSingleton(new ExceptionHelper());
services.AddScoped<ICompoundService>(x => new CompoundService(x.GetService<IAsyncDocumentSession>(), x.GetService<ExceptionHelper>()));
But whenever I need to register a type within e.g a lamba of another registration, I have problems resolving dependencies:
services.AddMvc(setup =>
{
ILogger logger; // how would I get that?
setup.Filters.Add(new ApiExceptionFilter(logger));
}).AddFluentValidation();
Is there a good way to deal with that?
I certainly do not want to call this in ConfigureServices
var sp = services.BuildServiceProvider();
I read about this in Resolving instances with ASP.NET Core DI from within ConfigureServices
but I do not reall see an elegant option here...
Update:
After reading comments I realized that you can register Filters per type:
setup.Filters.Add<ApiExceptionFilter>()
Then you would not have to pass dependencies in the first place.
Still I wonder if there is a best practice for similar scenarios where you cannot access ServiceProvider in the lambda.
Coming from a webforms background, I'm trying to understand how configuration and environment translation works in .net core 2.2 MVC web apps. Gone are the web.config files and the ConfigurationSettings.AppSettings property. I'm finding the documentation a little unclear.
The documentation states I need to call AddJsonFile or AddXmlFile during application startup. Like this:
public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.ConfigureAppConfiguration((hostingContext, config) =>
{
config.SetBasePath(Directory.GetCurrentDirectory());
config.AddJsonFile(
"config.json", optional: true, reloadOnChange: true);
})
.UseStartup<Startup>();
The project template I use already has the following logic:
public static void Main(string[] args)
{
CreateWebHostBuilder(args).Build().Run();
}
public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseStartup<Startup>();
My project has appsettings.json and appsettings.development.json files. When I put a breakpoint on the Startup method of the Startup class, I can inspect the configuration parameter and see the two json configuration files exposed as what looks to be a dictionary.
Questions
So do I have to explicitly call AddJSonFile, or is this actually done for me somehow by the framework?
How do I handle transforming configuration for different deployments?
What is the best way to access this configuration in a controller?
So do I have to explicitly call AddJSonFile, or is this actually done for me somehow by the framework?
This is done in the framework. Most notably the "DefaultBuilder" adds in both appsettings.json and appsettings.{Environment}.json, among other things. https://learn.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.webhost.createdefaultbuilder?view=aspnetcore-2.2
How do I handle transforming configuration for different deployments?
You need to set the Environment variable on the host machine (This is the easiest way althought here are other ways to do it). So for example if you set the environment to be Production, then it will first load appsettings.json, then it will load appsettings.Production.json and override the default settings. More info here : https://dotnetcoretutorials.com/2017/05/03/environments-asp-net-core/
What is the best way to access this configuration in a controller?
There are two ways. You can use the Options pattern built into the framework : https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/options?view=aspnetcore-2.2
Or you can use good old fashioned POCO's (https://dotnetcoretutorials.com/2016/12/26/custom-configuration-sections-asp-net-core/).
All you need to do there is load out your configuration in your ConfigureServices method and bind it to a singleton :
services.AddSingleton(Configuration.GetSection("myConfiguration").Get<MyConfiguration>());
Then you can simply request it in your controller via DI:
public class ValuesController : Controller
{
private readonly MyConfiguration _myConfiguration;
public ValuesController(MyConfiguration myConfiguration)
{
_myConfiguration = myConfiguration;
}
}
I am familiar with using ASP.NET Core with EF Core, where you just define your DBContext in the ConfigureServices method from Startup.cs for DI, like so:
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
services.AddDbContext<MyDbContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
}
However, I have been asked to add Dapper to this project (it will still use EF) but I can't even fetch the connection string. I found Brad Patton's answer here to be along the lines of what I had in mind, but he leaves the setup of the Configuration object up to the reader:
public void ConfigureServices(IServiceCollection services)
{
...
// Add the whole configuration object here.
services.AddSingleton<IConfiguration>(Configuration);
}
After googling around for a couple of hours, I still have no idea of how to implement the IConfiguration interface. Any help is appreciated.
With ASP.NET Core 2.x you no longer need to register the IConfiguration type yourself. Instead, the framework will already register it with the dependency injection container for you. So you can just inject IConfiguration in your services directly.
You can also take a look at the options pattern to see how to implement the configuration for your own service layer. So you could do it like this:
services.Configure<MyDatabaseOptions>(options =>
{
options.ConnectionString = Configuration.GetConnectionString("DefaultConnection");
});
Assuming a MyDatabaseOptions type that you inject into your service using the options pattern.
I am trying to upgrade our current .Net Core application from 1.1 to 2.0 and am getting this runtime error: "The DbContext of type 'CoreContext' cannot be pooled because it does not have a single public constructor accepting a single parameter of type DbContextOptions".
It is caused by using the new IServiceCollection.AddDbContextPool<> function. When I use IServiceCollection.AddDbContext<> it still works.
This application is DB-First, so I generate all our contexts using 'Scaffold-DbContext'. Due to that, and the need to inject other services I have an extension on every context like this:
public partial class CoreContext
{
public CoreContext(
DbContextOptions<CoreContext> options,
IUserService userService,
IAuditRepository auditRepository
) : base(options) {...}
}
Whenever I run the Scaffold-DbContext I just remove the autogenerated Constructor from CoreContext, but even if I put it in there I still get this error.
public partial class CoreContext : DbContext
{
public CoreContext(DbContextOptions<CoreContext> options) : base(options) {}
}
I've already updated Program.cs to the new style:
public class Program
{
public static void Main(string[] args)
{
BuildWebHost(args).Run();
}
public static IWebHost BuildWebHost(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseKestrel()
.UseContentRoot(Directory.GetCurrentDirectory())
.UseIISIntegration()
.UseStartup<Startup>()
.Build();
}
And the Startup.cs is pretty straightforward:
public IServiceProvider ConfigureServices(IServiceCollection services)
{
...
services.AddDbContextPool<CoreContext>(options => options.UseSqlServer(absConnectionString));
...
}
I am using Autofac for DI if that helps. For now I'll default back to the non-Pooling alternative, but it would be nice to take advantage of this feature.
When using DbContext Pooling, your own state (e.g. private fields) in your derived DbContext class will be preserved. Which means the lifetime of your services is now singleton. That's why you shouldn't have other injected services here.
But it's possible to query the required services this way:
First we should use the UseInternalServiceProvider method on DbContextOptionsBuilder to tell EF which service provider to use for its services. This service provider must have all the services configured for EF and any providers. So we should register EF Services manually:
services.AddEntityFrameworkSqlServer();
And then introduce the application's services provider which now includes the EF Services too:
services.AddDbContextPool<ApplicationDbContext>((serviceProvider, optionsBuilder) =>
{
optionsBuilder.UseSqlServer("...");
optionsBuilder.UseInternalServiceProvider(serviceProvider);
});
After that define these namespaces:
using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.Extensions.DependencyInjection;
And now you can access the registered services in the application within the
ApplicationDbContext class using the following methods
var siteSettings = this.GetService<IOptionsSnapshot<SiteSettings>>();
Or
var siteSettings = this.GetInfrastructure().GetRequiredService<IOptionsSnapshot<SiteSettings>>();
this is the current instance of the DbContext.
Remove the default constructor in the DbContext class, this worked for me
"because it does not have a single public constructor accepting a
single parameter of type DbContextOptions"
If you have any public constructors apart from one that accepts DbContextOptions, you need to remove them or make them non-public in order to use context pooling.
Also, there are restrictions on what can be done by overriding the OnConfiguring method. This is referenced in the documentation here but it isn't explicit about what those restrictions are: https://learn.microsoft.com/en-us/ef/core/what-is-new/index#dbcontext-pooling
This issue is mostly encountered when you "Scaffold-Dbcontext" and two constructors are generated.
Simple Solutions:
AddDbContextPool:
If you want to use AddDbContextPool, remove your empty constructor and maintain the one with the DbContextOptionsBuilder. Note that in this case you might have to provide the options, as suggested in the previous posts.
AddDbContext:
With AddDbContext, you can have both constructors/Overloads
Note: AddDbContextPool is preferred for performance reasons!
Try to use AddDbContext instead of AddDbContextPool. This helped me in the same situation.
services.AddDbContext<CoreContext>(options => options.UseSqlServer(absConnectionString));
in some case need to
remove the constractor with zero parameter
//public MyContext()
//{
//}
or use
"AddDbContext"
instead of
"AddDbContextPool"
in startup.cs => ConfigureServices()
services.AddDbContext(options =>
options.UseSqlServer(absConnectionString));
I have created the web application with the web api. The application contains some Controllers for example TodoController:
namespace TodoApi.Controllers
{
[Route("api/[controller]")]
public class TodoController : Controller
{
private readonly TodoContext _context;
public TodoController(TodoContext context)
{
_context = context;
}
[HttpGet]
public IEnumerable<TodoItem> GetAll()
{
return _context.TodoItems.ToList();
}
}
}
If I create the GET request - /api/todo - I get the list of Todos from database.
I have a list of controllers and api endpoints like above.
I would like distribute this api to another application ideally like middleware - my idea is register in Startup.cs like this:
public void ConfigureServices(IServiceCollection services)
{
services.AddTodoApi();
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
app.UseTodoApi();
}
This will be awesome use case for my api but I don't know how this controllers api endpoints rewrite like middleware and return same JSON data same approache like using classic Controllers.
How can I write the middleware in .NET Core for creating API endpoints?
Instead of the separate middleware, you may configure the MVC middleware to discovery controllers from another assembly:
// using System.Reflection;
public void ConfigureServices(IServiceCollection services)
{
...
services
.AddMvc()
.AddApplicationPart(typeof(TodoController).GetTypeInfo().Assembly);
Controllers are part of MVC middleware, they are not a separate part of request pipeline (but this is what middlewares are). When you register the custom middleware, it by default invokes on each request and you have HttpContext context as an input parameter to work with/edit
Request/Response data. But ASP.NET Core provides Map* extensions that are used as a convention for branching the pipeline.
Map branches the request pipeline based on matches of the given request path. If the request path starts with the given path, the branch is executed.
Example:
private static void HandleMapTodo(IApplicationBuilder app)
{
app.Run(async context =>
{
await context.Response.WriteAsync("/api/todo was handled");
});
}
public void Configure(IApplicationBuilder app)
{
app.Map("/api/todo", HandleMapTodo);
}
Note, that as middleware knows nothing about MVC middleware, you have only access to "raw" request and do not have features like model binding or MVC action filters.
Because it looks like the perfect microservices approach (similar than what my team is doing right now) I'd create a client assembly that can consume your API, the one that contains your TodoController, if you define a contract, and interface, for that API you can register it in your other assembly as it was a midleware and also you could mock that behaviour in your unit tests.
So, as I said, you could inject your client in ConfigureServices method, you can create:
public static IServiceCollection AddTodoRestClient(this IServiceCollection services)
{
services.AddSingleton<ITodoRestClient, TodoRestClient>();
return services;
}
Also consider that you will need to provide the enpoint so, it might looks like:
public static IServiceCollection AddConfiguredTodoClient(this IServiceCollection services, string todoEndpoint)
{
AddTodoClient(services);
ITodoRestClient todoRestClient = services.BuildServiceProvider().GetService<ITodoRestClient>();
// Imagine you have a configure method...
todoRestClient.Configure(services, todoEndpoint);
return services;
}
You can create those methods in a TodoRestClientInjector class and use them in Configure method on your startup.
I hope it helps
--- MORE DETAILS TO ANSWER COMMENTS ---
For me TodoClient is a Rest client library that implements calls to the ToDo API, (I've edited previous code to be TodoRestClient) methos like, i.e., CreateTodoItem(TodoDto todoItem) which implementation would call to the TodoController.Post([FromBody] item) or GetTodos() which wuold call TodoController.Get() and so on and so forth....
Regarding the enpoints... This approach implies to have (at least) two different applications (.NET Core apps), on the one hand the ASP NET Core app that has your TodoController and on the other hand a console application or another ASP NET Core API on which startup class you'll do the inyection adn the Rest client (the Todo Rest client) configuration ...
In a microservices approach using docker, in a dev environment, you'll use docker-compose-yml, but in a traditional approach you'll use concrete ports to define the endpoints...
So, imagine that you have in the second service a controller that need to use TodoController, to achieve so I'll use the above aproach and the "SecondController" would look like:
public class SecondController : Controller
{
private readonly SecondContext _context;
private readonly TodoRestClient _todoRestClient;
public TodoController(SecondContext context, ITodoRestClient todoRestClient)
{
_context = context;
_todoRestClient= todoRestClient;
}
// Whatever logic in this second controller... but the usage would be like:
_todoRestClient.GetTodos()
}
Just few final hints: it's key to minimize calls between services because it increases latency, and more and more if this happens on cascade. Also consider Docker usage, looks challenging but it is quite easy to start and, indeed, is thought to be used in scenarios that the one you presented and solutions like mine.
Again, I hope it helps.
Juan