Dotnet core 1.1 on linux: Any particular way thats better than others when seeding data with EF Core?

Question

I was thinking about just doing a migration, and seeding the data in that migration. I am not sure if i want seeding to be part of my migrations, maybe there comes a time when i want a clean slate.

Last time i did asp.net about a year ago on windows i had the following implementation:

using System.Collections.Generic;
using System.Data.Entity.Validation;
using Mentor.Models;
using Microsoft.AspNet.Identity;
using Microsoft.AspNet.Identity.EntityFramework;
/**
 * Author: matti
 */
namespace Mentor.Migrations
{
    using System;
    using System.Data.Entity;
    using System.Data.Entity.Migrations;
    using System.Linq;

    internal sealed class Configuration : DbMigrationsConfiguration<Mentor.Models.ApplicationDbContext>
    {
        public Configuration()
        {
            /*if (System.Diagnostics.Debugger.IsAttached == false)
               System.Diagnostics.Debugger.Launch();*/
            AutomaticMigrationsEnabled = true;
            AutomaticMigrationDataLossAllowed = true;
            ContextKey = "Mentor.Models.ApplicationDbContext";
        }

        protected override void Seed(Mentor.Models.ApplicationDbContext context)
        {
            try
            {
                var passwordHasher = new PasswordHasher();
                User user1 = new User()
                {
                    UserName = "[email protected]",
                    PasswordHash = passwordHasher.HashPassword("Denherpderp21!"),
                    FirstName = "Matti andreas",
                    LastName = "Nielsen",
                    Age = 24,
                    ProfileText = "Lorem ipsum dolor sit amet, minimum delicatissimi ad eos, " +
                                  "ne veniam eirmod voluptatibus vel, ne eam facilisi inciderint. " +
                                  "Ex eleifend recteque delicatissimi eos, ut erat posse etiam pri." +
                                  " Ei qui commune vivendum legendos, augue accusata in vim, mei at" +
                                  " bonorum pericula definitionem. Has ornatus aliquando vulputate " +
                                  "at, nonumes docendi in mel. Ne duo recusabo percipitur, et nam " +
                                  "vitae nostrud cotidieque, cibo liber mel te.",
                    IsMentor = true,
                    IsMentee = false,
                    UndefinedInterests = new List<Interest>
                    {

                    },
                    MentorInterests = new List<Interest>
                    {

                    },
                    ... blabla alot of entities ...
                context.SaveChanges();
            }
            catch (DbEntityValidationException e)
            {
                //some error handling
            }
        }
    }
}

So i want something like a seed method, so i was thinking about making my own seed method being called in startup.cs depending on some environment variable like development. My question is, how do you guys do it - or how would you do it??

EDIT:

I am considering doing it like this, when creating the model:

protected override void OnModelCreating(ModelBuilder modelBuilder) 
  {
    //One-to-one
     modelBuilder.Entity<Account>().HasOne(a => a.Player).WithOne(p =>   p.Account).HasForeignKey<Player>(p => p.AccountForeignKey);
     modelBuilder.Entity<Group>().HasOne(g => g.Role).WithOne(r => r.Group).HasForeignKey<Role>(r => r.GroupForeignKey);
    modelBuilder.Entity<GameEvent>().HasOne(e => e.Event);
    modelBuilder.Entity<GameEvent>().HasOne(e => e.Game);
    modelBuilder.Entity<TeamEvent>().HasOne(e => e.Event);
    modelBuilder.Entity<TeamEvent>().HasOne(e => e.Team);
    modelBuilder.Entity<GroupEvent>().HasOne(e => e.Event);
    modelBuilder.Entity<GroupEvent>().HasOne(e => e.Group);

    //one-to-many
    modelBuilder.Entity<Player>().HasMany(p => p.Integrations).WithOne(i => i.Player);
    modelBuilder.Entity<Player>().HasMany(p => p.Followers);
    modelBuilder.Entity<Player>().HasMany(p => p.Activities).WithOne(a => a.Player);
    modelBuilder.Entity<Game>().HasMany(g => g.GameEvents).WithOne(ge => ge.Game);
    modelBuilder.Entity<Game>().HasMany(g => g.Teams).WithOne(t => t.Game);
    modelBuilder.Entity<Team>().HasMany(t => t.TeamEvents).WithOne(te => te.Team);
    modelBuilder.Entity<Group>().HasMany(g => g.GroupEvents);

    //many to many
    modelBuilder.Entity<PlayerGames>().HasKey(pg => new {pg.PlayerId, pg.GameId});
    modelBuilder.Entity<PlayerTeams>().HasKey(pt => new {pt.PlayerId, pt.TeamId});
    modelBuilder.Entity<PlayerGroups>().HasKey(pg => new {pg.PlayerId, pg.GroupId});

    //discriminator values
    modelBuilder.Entity<Event>()
        .HasDiscriminator<string>("Type")
        .HasValue<GameEvent>("GameEvent")
        .HasValue<GroupEvent>("GroupEvent")
        .HasValue<TeamEvent>("TeamEvent");

    CALLING SEED DATA DOWN HERE, that should be fine???
}

Answer 1

The recommended approach is to run the seeding code within a service scope in Startup.Configure().

It's like this :

using (var serviceScope = app.ApplicationServices.GetRequiredService<IServiceScopeFactory>().CreateScope())
{
       var context = serviceScope.ServiceProvider.GetService<MyContext>();       
       context.Database.Migrate();
       context.EnsureSeedData();
 }

You can see more details about this on below link.

Implementing Seeding EF Core 1.0