I'm using EntityFramework in .NET to handle DB migrations. For example, dotnet ef migrations list --project My.Project --context MyDbContext.
However, some of these entity framework commands require a connection string, to connect to the DB and see what's what:
Build started...
Build succeeded.
Args are:
Schema Name: myschema
Connection string:
Connection string not set up. No connection string works when adding a migration (EF compares to the snapshot.cs file) but you will need a connection string to apply a migration.
Connection string not set up in environment variable: 'ConnectionString:SchemaAdmin'. Set the connection string in the Package Manager Console first: $env:ConnectionString:SchemaAdmin='<replace with connection string>'
So I need to set up an environment variable called ConnectionString:SchemaAdmin containing the connection string for my DB.
However, this is not easy, since there is a colon in the name of the environment variable:
$ fo:o=bar
bash: fo:o=bar: command not found
$ fo\:o=bar; echo $foo
bash: fo:o=bar: command not found
How am I supposed to do this?
The way that I found to resolve this was to use AddJsonFile in a builder at Startup (which allows it to find the configuration stored in the appsettings.json file) and then use that to set a private _config variable
public Startup(IHostingEnvironment env)
{
var builder = new ConfigurationBuilder()
.SetBasePath(env.ContentRootPath)
.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
.AddEnvironmentVariables();
_config = builder.Build();
}
And then I could set the configuration string as follows:
var connectionString = _config.GetConnectionString("DbContextSettings:ConnectionString");