MigrateDBConfig does not support pre-existing client and ensureDatabaseExists at the same time

[Tethik]

I noticed the createDb was marked as deprecated, so I moved to refactor my code to support the newer syntax.

In my client I'd like to do the following:

  client = await createPostgresPool(); 
  const config: MigrateDBConfig = {
    client,
    ensureDatabaseExists: true,
    defaultDatabase: databaseName,
  };
  await migrate(config, "src/data/migrations");

However, the type defined for MigrateDBConfig does not allow for ensureDatabaseExists at the same time with an existing client: https://github.com/ThomWright/postgres-migrations/blob/5a73373160b4e95200b1578c42101d67b9d28a6f/src/types.ts#L51-L55

[ThomWright]

Yeah, honestly I'm not sure there's much value in supporting using existing clients - I can't even remember why I introduced it! I guess in case people want to use connection strings for the credentials or something?

Thanks for the issue. I'll see if I can find some time to look into supporting this combination of parameters.

[Tethik]

In my case it means I don't have to write the same code twice for e.g. fetching the secrets and setting up the connection to the database (with properties such as pinned CA etc).

[Tethik]

I can potentially try for a PR later this week too, but very hesitant to promise anything :)

[bruceharrison1984]

The current shortfall of not allowing a custom client is this library doesn't support the ssl setting of the client. If removing the ability to use a custom client, the ssl setting should be made available through the client config object.

Another potential issue with removing it, I currently use the aws-xray-sdk to wrap the pg library so I get trace data. Removing the ability to pass in a client would make this impossible(or much mroe difficult).