I have a design where I have one "master" database and multiple "client" databases. When I get a request I lookup in the master database and setup the connection to the right client database.
I'm now trying to design the same in .net 5, where I setup the masterDB in StartUps ConfigureServices():
services.AddDbContext<Models.DataContext.MasterContext>(options =>
options.UseSqlServer("Name=MasterDB"));
I then on the request lookup in the MasterDB as the first thing in every controllers methods and find the connectionString for the clientDB.
But how do I then set it up at that point in time? While also not having to think about disposal of the connection, like when it's passed in using dependency injection, it's handled.
Any advice to do things slightly different are also encouraged.
Inject your MasterContext into a service that provides connection string lookups for your "client" databases (probably with caching). Then use that when resolving and configuring your "client" DbContext.
Something like this:
class ClientDatabaseService
{
MasterDbContext db;
IHttpContextAccessor context;
static Dictionary<string, string> cache = null;
public ClientDatabaseService(MasterDbContext db, IHttpContextAccessor context)
{
this.db = db;
this.context = context;
if (cache == null) RefreshCache();
}
public void RefreshCache()
{
cache = db.Clients.Select(c => new { c.ClientID, c.ConnectionString }).ToDictionary(c => c.ClientID, c => c.ConnectionString);
}
public string GetClientConnectionString()
{
var clientId = context.HttpContext.User.FindFirst("ClientID").Value;
return cache[clientId];
}
}
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
services.AddControllers();
services.AddDbContext<MasterDbContext>();
services.AddHttpContextAccessor();
services.AddScoped<ClientDatabaseService>();
services.AddDbContext<ClientDbContext>((services, options) =>
{
var constrService = services.GetRequiredService<ClientDatabaseService>();
var constr = constrService.GetClientConnectionString();
options.UseSqlServer(constr, o => o.UseRelationalNulls());
});
}
I want to run my blazor app as a service using TopShelf but now that i have configured a service i lost all css. it does still use Startup as it is supposed to but it just doesnt load my css? is this just a problem with paths? or is it something else?
I havent made any changes to the Startup class.
my main:
public static void Main(string[] args)
{
var exitCode = HostFactory.Run(x =>
{
x.Service(() => new Service(args));
x.SetServiceName("Print");
x.SetDescription("service");
x.StartAutomaticallyDelayed();
});
Environment.ExitCode = (int)Convert.ChangeType(exitCode, exitCode.GetTypeCode());
}
my Service:
public bool Start(HostControl hostControl)
{
Configuration.Settings settings = Program.initSettings();
new Task(() => CreateWebHostBuilder(args)
.UseKestrel()
.UseContentRoot(Directory.GetCurrentDirectory())
.UseIISIntegration()
.UseStartup<Startup>()
.UseStaticWebAssets()
.UseUrls(settings.BaseAddress)
.Build().Run()).Start();
return true;
}
public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.ConfigureLogging(logging =>
{
logging.ClearProviders();
logging.AddConsole();
});
//.UseStartup<Startup>();
}
So after a bit of trial and error i found it was a dumb mistake. I didn't change the properties of the css files to copy to output directory. Now my css is being loaded.
Is there any code to perform automatic migration in Entity Framework core code first in asp.net core project?
I do it simply in MVC4/5 by adding
Database.SetInitializer(new MigrateDatabaseToLatestVersion<AppDbContext, MyProject.Migrations.Configuration>());
public Configuration() {
AutomaticMigrationsEnabled = true;
}
This saves time when entities changed
You can call context.Database.Migrate()in your Startup.cs
eg:
using (var context = new MyContext(...))
{
context.Database.Migrate();
}
EF core doesn't support automatic migrations.So you have to do it manually.
From the perspective of automatic migrations as a feature, we are not
planning to implement it in EF Core as experience has showed code-base
migrations to be a more manageable approach.
You can read full story here : Not to implement Automatic Migrations
This is the way they do it in IdentityServer4 http://identityserver.io
public void ConfigureServices(IServiceCollection services)
{
var connectionString = Configuration.GetConnectionString("DefaultConnection");
var migrationsAssembly = typeof(Startup).GetTypeInfo().Assembly.GetName().Name;
// Add framework services.
services.AddDbContext<ApplicationDbContext>(options =>
options.UseSqlServer(connectionString));
...
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
// this will do the initial DB population
InitializeDatabase(app);
}
private void InitializeDatabase(IApplicationBuilder app)
{
using (var scope = app.ApplicationServices.GetService<IServiceScopeFactory>().CreateScope())
{
scope.ServiceProvider.GetRequiredService<ApplicationDbContext>().Database.Migrate();
scope.ServiceProvider.GetRequiredService<PersistedGrantDbContext>().Database.Migrate();
...
}
}
Automatic migrations is not supported in EF Core. Migration it is necessary to create hands. To automatically apply all existing handmade migrations need to add the following code in the class Program:
public class Program
{
public static void Main(string[] args)
{
var host = CreateWebHostBuilder(args).Build();
using (var scope = host.Services.CreateScope())
{
var services = scope.ServiceProvider;
try
{
var context = services.GetRequiredService<MyDbContext>();
context.Database.Migrate(); // apply all migrations
SeedData.Initialize(services); // Insert default data
}
catch (Exception ex)
{
var logger = services.GetRequiredService<ILogger<Program>>();
logger.LogError(ex, "An error occurred seeding the DB.");
}
}
host.Run();
}
public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseStartup<Startup>();
}
Following Microsoft's documentation
https://learn.microsoft.com/en-us/aspnet/core/data/ef-mvc/intro
If you are using dependency injection, first, you need to setup a static class Data/DbInitializer.cs and add the following code:
public static class DbInitializer
{
public static void Initialize(ApplicationDbContext context)
{
context.Database.Migrate();
// Add Seed Data...
}
}
Notice, this is also where you can add seed data.
Next, in your Program.cs file, add the following code
public static void Main(string[] args)
{
var host = BuildWebHost(args);
using (var scope = host.Services.CreateScope())
{
var services = scope.ServiceProvider;
try
{
var environment = services.GetRequiredService<IHostingEnvironment>();
if (!environment.IsDevelopment())
{
var context = services.GetRequiredService<ApplicationDbContext>();
DbInitializer.Initialize(context);
}
}
catch (Exception ex)
{
var logger = services.GetRequiredService<ILogger<Program>>();
logger.LogError(ex, "An error occurred while seeding the database.");
}
}
host.Run();
}
In my case, I'm checking the environment to make sure I'm in development so I can control the migrations/updates. However, in production, I want them to be automatic for continuous integration. As others have mentioned, this is probably not best practices but on small projects it works great.
My working automigration code Asp Net Core 2.0.7.
// startup.cs
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
// configure app
SeedData.Initialize(app.ApplicationServices);
}
// dbInitializer.cs
public static class SeedData
{
public static void Initialize(IServiceProvider serviceProvider)
{
using (var serviceScope = serviceProvider.CreateScope())
{
var context = serviceScope.ServiceProvider.GetService<ApplicationDbContext>();
// auto migration
context.Database.Migrate();
// Seed the database.
InitializeUserAndRoles(context);
}
}
private static void InitializeUserAndRoles(ApplicationDbContext context)
{
// init user and roles
}
}
You can call Database.Migrate() in db context constructor.
If the model changes a lot and you manage a medium - large team, migrations leads more problems than solution at least in development phase.
I published a nuget package with automatic migration for .net core, EFCore.AutomaticMigrations - https://www.nuget.org/packages/EFCore.AutomaticMigrations/, so manual migration not needed anymore.
You can call directly in Program class, like bellow:
public static void Main(string[] args)
{
var host = CreateWebHostBuilder(args);
using (var scope = host.Services.CreateScope())
{
var services = scope.ServiceProvider;
var loggerFactory = services.GetRequiredService<ILoggerFactory>();
var logger = loggerFactory.CreateLogger<Program>();
try
{
var environment = services.GetRequiredService<IWebHostEnvironment>();
if (environment.IsDevelopment())
{
var context = services.GetRequiredService<ApplicationContext>();
MigrateDatabaseToLatestVersion.ExecuteAsync(context).Wait();
}
}
catch (Exception ex)
{
logger.LogError(ex, "An error occurred creating/updating the DB.");
}
}
host.Run();
}
Frank Odoom's answer works even 4 years later in .net 5, but it is not the intended context to call the migration at runtime... And, it appears it never was because it requires us to mock the DbContext with DbContextOptions whos documentation explicitly states:
"The options to be used by a DbContext. You normally override OnConfiguring(DbContextOptionsBuilder) or use a DbContextOptionsBuilder to create instances of this class and it is not designed to be directly constructed in your application code."
Here is my suggestion:
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
// database provider is configured before runtime migration update is applied e.g:
optionsBuilder.UseSqlServer(ConnectionString);
Database.Migrate();
}
Edit:
My suggestion is actually horrible if you are using multiple DBContexts in the same project... It would migrate the database multiple times. Which would most likely not break anything, but it would slow startup considerably.
my best advice is not to use the automatic migration.It is always better to add migrations manually and also avoid bulk migration and stick to best practice for using manual migration
automatic migration is not a magic tool and there will be several occasions where you might want to add some addition changes to the migration. You only accomplish by using manual migration.
To enable migration, type "enable-migrations" in the package manager console
This way you will have full control of upgrading or downgrading your database and also easy to track migrations.
Just three simple steps in package manager console.
1) add-migrations [some name for your migration]
2) migrations is generated for the changes, you review them and also can
make changes to it
3) update-database your migration is complete now.
handling migration is less painful!
I'm using Autofac for injecting dependencies in Web Api.
I set InstancePerRequest scope for EF DBContext.
Autofac Wiring up configuration:
public void Configuration(IAppBuilder app)
{
ConfigureOAuth(app);
var config = new HttpConfiguration();
var builder = new ContainerBuilder();
builder.RegisterApiControllers(Assembly.GetExecutingAssembly()).InstancePerRequest();
var asmb = typeof (TrafficDataService).Assembly;
builder.RegisterAssemblyTypes(asmb).Where(t => t.Name.EndsWith("Service")).AsImplementedInterfaces().InstancePerRequest();
builder.RegisterType<TrafficServiceGlobalContext>().As<IUnitOfWork>().InstancePerRequest();
builder.RegisterType<EMSEntities>().As<IEmsDataModel>().InstancePerRequest();
builder.RegisterType<ViolationTrafficEntities>().As<IViolationDataModel>().InstancePerRequest();
builder.RegisterType<TrafficController>().As<IHttpController>().InstancePerRequest();
builder.Register(c => HttpContext.Current.GetOwinContext().Authentication).InstancePerRequest();
builder.Register(c => app.GetDataProtectionProvider()).InstancePerRequest();
var container = builder.Build();
config.DependencyResolver = new AutofacWebApiDependencyResolver(container);
app.UseAutofacMiddleware(container);
app.UseAutofacWebApi(config);
app.UseCors(Microsoft.Owin.Cors.CorsOptions.AllowAll);
app.UseWebApi(config);
WebApiConfig.Register(config);
}
After Service gets huge number of request, and when checking Active Sessions for my DB i see 500 Active Sessions over db.
Is really this a problem?
How to implement Connection Pooling?
Any idea?
Update:
All relevant classes depends on interfaces.
As Yacoub Massad asked in comments area, here is some of relevant classes signature and constructors:
public partial class ViolationTrafficEntities : DbContext, IViolationDataModel
{
.
.
.
}
public class TrafficDataService : ITrafficDataService
{
private readonly IViolationDataModel _violationDataModel;
public TrafficDataService(IViolationDataModel violationDataModel)
{
_violationDataModel = violationDataModel;
}
}
I recently upgraded to a new version of Hangfire and I am struggeling trying to setup my webapi with autofac and Hangfire. I'm using Autofac Hangfire integration version 1.1 and Hangfire 1.4.2. I'm using Owin to host. I keep getting following error:
The requested service 'IFoo' has not been registered. To avoid this exception, either register a component to provide the service, check for service registration using IsRegistered(), or use the ResolveOptional() method to resolve an optional dependency.
Here is my owin startup configuration. All my registrations are made in the AutofacStandardModule class
public class Startup
{
public void Configuration(IAppBuilder app)
{
//we will have the firewall block all CE endpoints from the outside instead
//ConfigureOAuthTokenConsumption(app);
var storage = new SqlServerStorage("connection string");
JobStorage.Current = storage;
app.UseHangfireServer(new BackgroundJobServerOptions(),storage);
app.UseHangfireDashboard("/Hangfire",new DashboardOptions(),storage);
var builder = new ContainerBuilder();
builder.RegisterModule(new AutofacStandardModule());
var container = builder.Build();
GlobalConfiguration.Configuration.UseAutofacActivator(container);
}
}
Also, here is my web api config class. I dont see how I should be configuring Hangfire here also though..
public static class WebApiConfig
{
public static void Register(HttpConfiguration config, Autofac.Module moduleToAppend)
{
config.MapHttpAttributeRoutes();
config.EnableCors();
config.EnableSystemDiagnosticsTracing();
var builder = new ContainerBuilder();
builder.RegisterAssemblyTypes(
Assembly.GetExecutingAssembly())
.Where(t =>
!t.IsAbstract && typeof(ApiController).IsAssignableFrom(t))
.InstancePerLifetimeScope();
builder.RegisterModule(
new AutofacStandardModule());
if (moduleToAppend != null)
{
builder.RegisterModule(moduleToAppend);
}
var container = builder.Build();
config.DependencyResolver = new AutofacWebApiDependencyResolver(
container);
//Hangfire.GlobalConfiguration.Configuration.UseAutofacActivator(container);
//JobActivator.Current = new AutofacJobActivator(container);
}
}
I solved the issue, it seemed I hadn't specified clearly enough which type my job was when enqueuing.
What is did was to change
_jobClient.Enqueue(
() => _foo.Bar(fooId, fooId2));
..into..
_jobClient.Enqueue<IFoo>(x => x.Bar(fooId, fooId2));