EF Core - 无源运行迁移 - 等效于 EF6 的 migrate.exe

Question

Is it possible to run an ef migration from DLL containing migrations and dbcontext? I'd like to run dotnet ef database update against my build artefacts without need of project.json and source codes.

In other words I'm looking for an equivalent of migrate.exe https://msdn.microsoft.com/en-us/data/jj618307.aspx from EF6

Answer 1

My team colleague found a way which allows you to run migrations on build artefacts without sources. Following command replace migrate.exe for us:

dotnet exec 
  --runtimeconfig ./HOST.runtimeconfig.json 
  --depsfile ./HOST.deps.json Microsoft.EntityFrameworkCore.Design.dll
  --assembly ./DB_CONTEXT_DLL.dll 
  --startup-assembly ./HOST.dll --data-dir ./ 
  --root-namespace DB_CONTEXT_NAMESPACE 
  --verbose database update --context DB_CONTEXT_CLASS -e development 

Update for 2.1.x version:

dotnet exec 
   --runtimeconfig ./HOST.runtimeconfig.json 
   --depsfile ./HOST.deps.json /PATH/TO/microsoft.entityframeworkcore.tools/.../ef.dll 
   --verbose database update --context DB_CONTEXT_CLASS
   --assembly ./DB_CONTEXT_DLL.dll 
   --startup-assembly ./HOST.dll --data-dir ./

Answer 2

Seems not possible run dotnet ef database update only with the DLL, and if you use the docker, the actual version of runtime microsoft/dotnet:1.1.0-preview1-runtime do not have the sdk installed (with the dotnet ef database update command).

One option to update database without use dotnet ef database update is execute the command bellow in some default action or startup routine.

_dbContext.Database.Migrate();

Answer 3

I happen to use a factory to obtain a context, so based on Richardo's answer created a class like this. I use it as a singleton and call its ApplyMigrations method at service startup.

using System;
using Microsoft.EntityFrameworkCore;

namespace Nhs.Digital.Cwt.MultiStreamPublisher
{
    public class MigrationApplier
    {
        private IMyContextFactory _contextFactory;

        public MigrationApplier(IMyContextFactory contextFactory)
        {
            _contextFactory = contextFactory ?? throw new ArgumentNullException($"{nameof(contextFactory)} was null");
        }

        public void ApplyMigrations()
        {
            if (_contextFactory != null)
            {
                using (var context = _contextFactory.Create())
                {
                    _contextFactory = null;
                    context.Database.Migrate();
                }
            }
        }
    }
}

Damn ran into problems though as my deployment scripts expected the DB to be there so that DB permissions can be added to it. So it looks like I'll have to write a small console app just for the deploy script to use to make the DB ahead of adding DB permissions. Code on through the pain.

Answer 4

I just created a small utility to solve this problem. It will works with any providers out of the box. The only requirements is your assembly must have a public implementation of IDesignTimeDbContextFactory .

The usage is very simple, just execute the src/EFMigrate project with the first argument is a path to your published assembly.