I have an ASP.NET Core 2 application hosted on Azure, and I added a new Application Settings MyNewSetting for my App in the Azure Portal.
How do I access that setting from a controller?
My code bellow:
public void ConfigureServices(IServiceCollection services)
{
services.AddOptions();
services.Configure<AppSecrets>(Configuration);
services.AddSingleton<ITableRepositories, TableClientOperationsService>();
//...
My Controller:
public class RecordController : Controller
{
const int MyNewSetting = 7; // this one to replace with Azure Setting one
private readonly ITableRepositories repository;
public RecordController(ITableRepositories rep) {
repository = rep;
}
Here, I need probably to add FromServices injection, but I am not sure if it will work...
EDIT:
Folowing the #dee_zg answer, the following code could probably do the job:
public class RecordController : Controller
{
int MyNewSetting = 7;
private readonly ITableRepositories repository;
public RecordController(ITableRepositories rep) {
repository = rep;
int myInt;
if (int.TryParse(System.Environment.GetEnvironmentVariable("MY_NEW_SETTING"),
out myInt)) {
MyNewSetting = myInt;
};
}
You can choose to either get them from AppSettings["your-key"] collection or as environment variables: Environment.GetEnvironmentVariable("your-key").
From there you can map them to your custom IOptions and inject wherever you need them.
There's quite a few things you can do.
Use Options and configuration objects
The options pattern uses custom options classes to represent a group of related settings. We recommended that you create decoupled classes for each feature within your app.
Use an IOptionsSnapshot.
IOptionsSnapshot supports reloading configuration data when the configuration file has changed. It has minimal overhead. Using IOptionsSnapshot with reloadOnChange: true, the options are bound to Configuration and reloaded when changed.
... (see documentation)
In short, have a look at Configuration in ASP.NET Core, determine the scenario that best fits your needs and have at it!
Hope this helps.
Related
ServiceStack uses a dialect of Funq (no support for metadata), where Kephas uses one of MEF/Autofac (requires metadata support). My question has two parts:
How to make ServiceStack and Kephas use one DI container, if this is possible?
Depending on the answer above: how to make ServiceStack services (like IClientCache) available to Kephas components, knowing that such services may not be annotated with [AppServiceContract]?
You can make ASP.NET and Kephas use one container by choosing to work with Autofac. However, as #mythz pointed out, you will need to provide the Autofac IoC Adapter to the ServiceStack. I don't think you will have any problems with ASP.NET in doing so, as Autofac is the first recommendation of the ASP.NET Core team.
For ASP.NET Core, reference the Kephas.AspNetCore package and inherit from the StartupBase class if you need to be all setup. However, if you need to be in control, have a look at https://github.com/kephas-software/kephas/blob/master/src/Kephas.AspNetCore/StartupBase.cs and write your own Startup class. Another resource that you might find useful is the Kephas.ServiceStack integration package.
Then, additionally to annotating service contracts and service implementations, Kephas allows you to provide service definitions by implementing the IAppServiceInfoProvider interface. These classes are automatically discovered, so this is pretty much everything you have to do.
public class ServiceStackAppServiceInfoProvider : IAppServiceInfoProvider
{
public IEnumerable<(Type contractType, IAppServiceInfo appServiceInfo)> GetAppServiceInfos(IList<Type> candidateTypes, ICompositionRegistrationContext registrationContext)
{
yield return (typeof(IUserAuthRepository),
new AppServiceInfo(
typeof(IUserAuthRepository),
AppServiceLifetime.Singleton));
yield return (typeof(ICacheClient),
new AppServiceInfo(
typeof(ICacheClient),
ctx => new MemoryCacheClient(),
AppServiceLifetime.Singleton));
}
}
Note in the above example that for IUserAuthRepository there is no implementation provided. This indicates Kephas to auto-discover the implementation in the types registered for composition. Alternatively, feel free to use an instance or a factory in the registration, if you need to be deterministic.
I've never heard of Kephas before, but if you're referring to this Kephas Framework on GitHub it says it uses ASP.NET Core in which case it's best if you get them to both use ASP.NET Core's IOC which you can do by either registering your dependencies in ConfigureServices in your App's Startup:
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
//...
}
}
Or alternatively in ServiceStack's latest v5.6 release for Modular Startup change your ASP.NET Core Startup class to inherit from ModularStartup, e.g:
public class Startup : ModularStartup
{
public Startup(IConfiguration configuration) : base(configuration){}
public new void ConfigureServices(IServiceCollection services)
{
//...
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
//...
}
}
In which case you'll be able to Register ASP.NET Core dependencies in AppHost by registering them in your AppHost's Configure(IServiceCollection) where they can be resolved through both ASP.NET Core's IOC + ServiceStack's IOC, e.g:
public class AppHost : AppHostBase
{
public override void Configure(IServiceCollection services)
{
services.AddSingleton<IRedisClientsManager>(
new RedisManagerPool(Configuration.GetConnectionString("redis")));
}
public override void Configure(Container container)
{
var redisManager = container.Resolve<IRedisClientsManager>();
//...
}
}
I have a Azure Mobile Services project. When running locally everything works fine, the Application_Start() method gets called which in turn calls my WebApiConfig.Register() method.
However, when published to a live Azure Mobile Services server the Application_Start() does not get called along with the WebApiConfig.Register().
In the servers log I have the following entry:
No bootstrapper found -- using default bootstrapper. A bootstrapper can be specified in one of two ways: Either by defining a public, static class with name 'WebApiConfig' having a public parameter-less member called 'Register', or using the 'IBootstrapper' attribute to define a public class with a default constructor.
Why is Azure Mobile Services not picking up my BootStrapping WebApiConfig?
public static class WebApiConfig
{
public static void Register()
{
Trace.TraceInformation("Hello from WebApiConfig Register().");
// Use this class to set configuration options for your mobile service
ConfigOptions options = new ConfigOptions();
// Use this class to set WebAPI configuration options
HttpConfiguration config = ServiceConfig.Initialize(new ConfigBuilder(options));
// To display errors in the browser during development, uncomment the following
// line. Comment it out again when you deploy your service for production use.
// config.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always;
}
}
public class WebApiApplication : System.Web.HttpApplication
{
public WebApiApplication()
{
Trace.TraceInformation("Hello from WebApiApplication ctor!");
}
protected void Application_Start()
{
Trace.TraceInformation("Hello from Application_Start()");
//RouteConfig.RegisterRoutes(RouteTable.Routes);
WebApiConfig.Register();
var dataContext = new DataContext();
dataContext.Database.Initialize(false);
}
}
Help is much appreciated!
That is bizarre... It really looks like you got it right. After working with .net backend azure mobile service for few weeks, I might suggest just maybe restart the service in portal and republish. I have hit some weird unexplained stuff just like you are and somehow fix like that.
I am doing some stuff in Service Stack self host in windows service. The link gave me some hint. But in the code, what is StarterTemplateAppListenerHost then?
It is a class which extends AppHostHttpListenerBase (Source here) which is used to provide the http listener and application configuration.
public class StarterTemplateAppListenerHost : AppHostHttpListenerBase
{
static readonly IAppSettings AppSettings = new AppSettings();
public StarterTemplateAppListenerHost()
: base(AppSettings.GetString("ServiceName") ?? "StarterTemplate HttpListener", typeof(HelloService).Assembly) { }
public override void Configure(Funq.Container container)
{
container.Register(new TodoRepository());
}
}
This is demonstrated also in the official documentation here.
I just wonder why the link doesn't have OnStart() etc
The example has two different compilation modes. When it's run in debug, it will not run as a service, and solely uses StarterTemplateAppListenerHost.
When it is run in release mode then it will create a service around the instance of StarterTemplateAppListenerHost. The WinService class provides the OnStart and OnStop methods which are expected of Windows Services by extending System.ServiceProcess.ServiceBase.
So to get it running as a Windows Service you will need to include these 3 files:
Program.cs
WinService.cs
StarterTemplateAppListenerHost.cs
I'm currently using AutoFac as the DI container for our ServiceStack web services app. I'm able to configure the wiring and everything, but after reading the section on Scopes, I'm at a loss at which scope would be best to use when registering my components. In our particular case, I think a PerHttpRequest scope would be OK since (please correct me if im wrong) I would want to dispose the dependencies as soon as the request ends.
My question is, how do I set this up in the container? I can't seem to find the "PerHttpRequest" lifetime scope within the included methods in autofac. I'm also unsure if ServiceStack does some kind of automagic to do this for me behind the scenes.
I'm using Autofac 3.0.1 on ServiceStack 3.9.35 on .Net 4 (running as a regular ASP host, not MVC). I'm also using the class described here as the IContainer adapter.
I wanted to avoid the overhead of the dependency on MVC, so the first answer didn't quite work for me.
Instead I used Funq to register a PerRequest ILifetimeScope, and resolve the ILifetimeScope in the ConatinerAdaptor before resolving the dependency.
public class AutofacLifetimeScopeIocAdapter : IContainerAdapter
{
private readonly Container _requestContainer;
public AutofacLifetimeScopeIocAdapter(Funq.Container requestContainer)
{
_requestContainer = requestContainer;
}
public T Resolve<T>()
{
var currentContainer = _requestContainer.Resolve<ILifetimeScope>();
return currentContainer.Resolve<T>();
}
public T TryResolve<T>()
{
var currentContainer = _requestContainer.Resolve<ILifetimeScope>();
T result;
if (currentContainer.TryResolve<T>(out result))
{
return result;
}
return default(T);
}
}
Then initialise with this
_autofacContainerRoot = builder.Build();
IContainerAdapter adapter = new AutofacLifetimeScopeIocAdapter(container);
container.Register<ILifetimeScope>((c) => _autofacContainerRoot.BeginLifetimeScope())
.ReusedWithin(ReuseScope.Request);
container.Adapter = adapter;
Then cleanup with
public override void OnEndRequest()
{
var currentContainer = _container.Resolve<ILifetimeScope>();
currentContainer.Dispose();
base.OnEndRequest();
}
This seems to behave as required for Autofac - SingleInstance, InstancePerDependency, and now InstancePerLifetimeScope which is perRequest.
Mythz response on the HostContext.Instance.Items collection can likely be used to remove the need for the
var currentContainer = _container.Resolve<ILifetimeScope>();
resolution, which should improve performance.
I think I have figured out how to make this work (using Autofac 2.6, which I am stuck on right now.) It involves using the following adapter and the Autofac.Mvc3 package:
public class AutofacIocAdapter : IContainerAdapter
{
private readonly IContainer _autofacRootContainer;
private readonly Container _funqContainer;
public AutofacIocAdapter(IContainer autofacRootContainer, Container funqContainer)
{
// Register a RequestLifetimeScopeProvider (from Autofac.Integration.Mvc) with Funq
var lifetimeScopeProvider = new RequestLifetimeScopeProvider(autofacRootContainer,null);
funqContainer.Register<ILifetimeScopeProvider>(x => lifetimeScopeProvider);
// Store the autofac application (root) container, and the funq container for later use
_autofacRootContainer = autofacRootContainer;
_funqContainer = funqContainer;
}
public T Resolve<T>()
{
return ActiveScope.Resolve<T>();
}
public T TryResolve<T>()
{
T result;
if (ActiveScope.TryResolve(out result))
{
return result;
}
return default(T);
}
private ILifetimeScope ActiveScope
{
get
{
// If there is an active HttpContext, retrieve the lifetime scope by resolving
// the ILifetimeScopeProvider from Funq. Otherwise, use the application (root) container.
return HttpContext.Current == null
? _autofacRootContainer
: _funqContainer.Resolve<ILifetimeScopeProvider>().GetLifetimeScope();
}
}
}
Steps to implement:
Add the Autofac.Mvc3 NuGet package to your web project (NOTE: does
not matter that your project isn't using MVC. The solution might be slightly different with Autofac 3, which cannot use Mvc3 integration.)
Follow the ServiceStack IoC page in hooking up a custom IContainerAdapter
for Autofac, using the following implementation
Note the RequestScope in ServiceStack's IOC only refers to ServiceStack's built-in Funq IOC.
To use RequestScope in another IOC Container like AutoFac you generally need to notify AutoFac at the end of the request so it can clean up all its request-scoped instances. To do this, ServiceStack provides the AppHostBase.OnEndRequest() hook you can override to get execute custom logic at the end of each request.
I'm not familiar with how AutoFac's custom lifetime scope works but more details about it can be found in:
AutoFac's InstanceScope wiki page
Primer on AutoFac's Lifetime scopes
Answer on how to manage AutoFac' request scope in MVC
Other info that might be useful for managing instances in ServiceStack is that every instance in put in the HostContext.Instance.Items dictionary or disposable added to HostContext.Instance.TrackDisposable are automatically disposed at the end of each request.
Update 2015-11-25: I changed the implementation by using global request and response filters. I put both ServiceStack V3 and V4 solutions into this repository and both versions are available as nuget packages.
I solved this problem by opening a new scope in Application_BeginRequest and disposing in Application_EndRequest. In the container adapter I check if this scope exists and use it, if not, I use the container. This allows using .InstancePerRequest() registration scope.
Described with gists here.
Here are my parameters:
Simple NServiceBus Saga implementation using the default builder
In-house ORM on top of SQL Server
Multitenancy - I have two ASP.NET MVC 4 domains running on the same website, each with their own databases
We configure our ORM using a static method like so:
public class EndpointConfig: IConfigureThisEndpoint, IWantCustomInitialization {
public void Init() {
var bus = Configure.With()
.AutofacBuilder()
.UnicastBus().LoadMessageHandlers().DoNotAutoSubscribe()
.XmlSerializer()
.MsmqTransport().IsTransactional(true).PurgeOnStartup(false)
.MsmqSubscriptionStorage()
.Sagas().RavenSagaPersister().InstallRavenIfNeeded()
.UseInMemoryTimeoutPersister()
.CreateBus()
.Start();
SlenderConfiguration.Init(bus);
}
}
public class SlenderCofnigruation {
private static ORMScope scope { get; set; }
public static void Init(IBus bus)
{
ORMConfig.GetScope = () =>
{
var environment = "dev";
if (bus.CurrentMessageContext.Headers.ContainsKey("Environment"))
environment = bus.CurrentMessageContext.Headers["Environment"];
if (scope == null)
scope = new SlenderScope(ConfigurationManager.ConnectionStrings[environment].ConnectionString);
return scope;
};
}
}
This works fine in our single-tenant Beta environment - it's fine for that static scope to get re-used because the environment header is always the same for a given deployment.
It's my understanding that this won't work for the multitenant situation described above, because NServiceBus will reuse threads across messages. The same scope would then be used, causing problems if the message was intended for a different environment.
What I think I want is a single scope per message, but I'm really not sure how to get there.
I've seen Unit Of Work Implementation for RavenDB, and the unit of work implementation in the full duplex sample, but I'm not sure that's the right path.
I've also seen the DependencyLifecycle enum, but I'm not sure how I can use that to resolve the scope given the way I have to set up the GetScope func.
Obviously I have no idea what's going on here. Any suggestions?
If you need to do something on a per-message basis, consider using message mutators (IMutateIncomingMessages) in addition to your unit-of-work management with some thread-static state.