Using a single master Repo for library where library contains it's own migrations (or alternatively how to test in this situation)

[clemensm]

@LostKobrakai

In my opinion the requirement of keeping migrations strictly in “accounts” is a bad idea. Provide any user of your library (a.k.a. “master”) with a quick way to integrate your libraries migration needs into their own migrations and use the repo provided by them in your library. This allows “master” to be fully in charge of it’s db schema without any surprises.

Thanks @LostKobrakai, that gave me the right idea. For anyone stumbling upon the same question and looking for an answer:

I’ve now setup the “accounts” library as described here Setting Up Testing for Library and use a config setting like this to set the repo for the “accounts” lib:

config :accounts, repo: Master.Repo

I then create the migrations this way:

MIX_ENV=test mix ecto.gen.migration xxx

And finally I’ve created a simple mix task that copies those migrations into the priv/repo/migrations folder of the “master” app, which is aliased to mix deps.get and mix deps.update, i.e.:

in mix.exs:

def project do
    [
      ....
      aliases: aliases()
    ]
end

defp aliases do
    [
      "deps.update": ["deps.update", "migrations.merge"],
      "deps.get": ["deps.get", "migrations.merge"]
    ]
end