I'm attempting to use migrations EFCore2.0 in a .NET standard 2.0 class library, and so far I have something like
public class SomeContextFactory : IDesignTimeDbContextFactory<SomeContext>
{
private Configuration _configuration;
public SomeContextFactory(Configuration configuration)
{
_configuration = configuration;
}
public SomeContext CreateDbContext(string[] args)
{
var optionsBuilder = new DbContextOptionsBuilder<SomeContext>();
optionsBuilder.UseSqlServer(_configuration.ConnectionString);
return new SomeContext(optionsBuilder.Options);
}
}
public class SomeContext : DbContext
{
public DbSet<SomeDbModel> Some { get; set; }
public SomeContext(DbContextOptions<SomeContext> options) : base(options)
{
}
}
The point is that the connection string is different depending on the environment (dev,test,prod), and migrations should be performed on the database specified by the Configuration
.
How do instruct migrations to inject Configuration
into SomeContextFactory
?
By design, the IDesignTimeDbContextFactory
isn't supposed to work with DI.
One way to achieve this would be:
public class AppDbContextFactory : IDesignTimeDbContextFactory<AppDbContext>
{
public AppDbContext CreateDbContext(params string[] args)
{
var options = new DbContextOptionsBuilder<AppDbContext>();
var config = GetAppConfiguration();
options.UseSqlServer(config.GetConnectionString("DesignTimeAppDbConnection"));
return new AppDbContext(options.Options);
}
IConfiguration GetAppConfiguration()
{
var environmentName =
Environment.GetEnvironmentVariable(
"ASPNETCORE_ENVIRONMENT");
var dir = Directory.GetParent(AppContext.BaseDirectory);
if(EnvironmentName.Development.Equals(environmentName,
StringComparison.OrdinalIgnoreCase))
{
var depth = 0;
do
dir = dir.Parent;
while (++depth < 5 && dir.Name != "bin");
dir = dir.Parent;
}
var path = dir.FullName;
var builder = new ConfigurationBuilder()
.SetBasePath(path)
.AddJsonFile("appsettings.json")
.AddJsonFile($"appsettings.{environmentName}.json", true)
.AddEnvironmentVariables();
return builder.Build();
}
}