Programming Ecto

Safely Sharing Connections with Allowances

To work around the limitations of shared mode, Ecto provides a mechanism called allowances. This allows us to pick and choose which processes we share our database connection with. We can keep a single database connection for all processes needed for our test, and be sure that the database state is isolated from any other tests running concurrently.

Let’s go back to the test we looked at in the last section:

priv/examples/sandboxes_03.exs

test "insert album" do
  task = Task.async(fn ->
    album = MusicDB.Repo.insert!(%MusicDB.Album{title: "Giant Steps"})
    album.id
  end)

  album_id = Task.await(task)
 assert MusicDB.Repo.get(MusicDB.Album, album_id).title ...