Seeding in .Net Core

Question

I'm currently building a .NET core Identity Server application that uses migrations and wondered what the best method of seeding a database would be in regards to .NET core.

Currently I have a DbInitializer class that is called on startup (see below) but wondered if I should be doing this as a migration?

  public static void Seed(IApplicationBuilder applicationBuilder)
    {
        ConfigurationDbContext context =
            applicationBuilder.ApplicationServices.GetRequiredService<ConfigurationDbContext>();
        IConfiguration oConfig =
            applicationBuilder.ApplicationServices.GetRequiredService<IConfiguration>();

        string sSeedingConfig = GetSeedingConfiguration(oConfig);

        SeedConfigurationDb(ref context, sSeedingConfig);
    }

    private static void SeedConfigurationDb(ref ConfigurationDbContext oContext, string sSeedingConfig)
    {
        if (!oContext.ApiResources.Any())
        {
            var oApis = GetSeedingConfigElements(sSeedingConfig, "Apis");
            List<ApiResource> lApis = null;
            if (oApis != null)
            {
                lApis = JsonConvert.DeserializeObject<List<ApiResource>>(oApis.ToString());
            }
            if (lApis != null)
            {
                foreach (var api in lApis)
                {
                   oContext.ApiResources.Add(api.ToEntity());
                }
            }
        }

        if (!oContext.Clients.Any())
        {
            var oClients = GetSeedingConfigElements(sSeedingConfig, "Clients");
            List<Client> lClients = null;
            if (oClients != null)
            {
                lClients = JsonConvert.DeserializeObject<List<Client>>(oClients.ToString());
            }
            if (lClients != null)
            {
                foreach (var client in lClients)
                {
                    oContext.Clients.Add(client.ToEntity());
                }
            }
        }

        if (!oContext.IdentityResources.Any())
        {
            var oIdentityResources = GetSeedingConfigElements(sSeedingConfig, "IdentityResources");
            List<IdentityResource> lIdentityResources = null;
            if (oIdentityResources != null)
            {
                lIdentityResources = JsonConvert.DeserializeObject<List<IdentityResource>>(oIdentityResources.ToString());
            }
            if (lIdentityResources != null)
            {
                foreach (var identityresource in lIdentityResources)
                {
                    oContext.IdentityResources.Add(identityresource.ToEntity());
                }
            }
        }

        oContext.SaveChanges();
    }

Answer 1

When you enable your migrations, you get a class file named "Configuration". This class has a seed method that gets run every time you update the database trough a migration.

So you could seed your initial update trough there, and then comment it out.