MonEx.Ecto (MonEx v0.2.1)

Ecto extensions for MonEx.

use MonEx.Ecto inside an Ecto.Repo to add Option-returning lookups and a Multi result repacker. Requires the consumer app to depend on :ecto.

Usage

defmodule MyApp.Repo do
  use Ecto.Repo, otp_app: :my_app, adapter: Ecto.Adapters.Postgres
  use MonEx.Ecto
end

This injects one_option/2, get_option/3, and get_by_option/3 into the host Repo and exposes repack_multi/1,2. The *_option helpers wrap the standard nil-returning Repo callbacks into MonEx.Option:

MyApp.Repo.get_option(User, user_id)
|> map(&do_something/1)
|> get_or_else(default_user())

repack_multi/2 normalises the outcome of Repo.transaction/1 on an Ecto.Multi into a MonEx.Result, handling both the success shape ({:ok, changes}) and the failure shape ({:error, operation, value, changes_so_far}).

Summary

Functions

repack_multi(result, opts \\ [])

Repacks the result of Repo.transaction/1 on an Ecto.Multi into a MonEx.Result.

Functions

repack_multi(result, opts \\ [])

@spec repack_multi(
  {:ok, map()}
  | {:error, Ecto.Multi.name(), any(), %{required(Ecto.Multi.name()) => any()}},
  Keyword.t()
) :: MonEx.Result.t(any(), any())

Repacks the result of Repo.transaction/1 on an Ecto.Multi into a MonEx.Result.

On success, the changes map is normalised: entries shaped as {value, ret} tuples (the convention used by Ecto.Multi.run/3 callbacks) are unwrapped to either value or ret depending on whether ret is nil.

Options

:error — what to surface when the Multi failed:
- :all (default) — {operation, value, changes_so_far} tuple
- :operation — just the failed operation's name
- :value — just the failed operation's value (e.g. a changeset)
- :changes — just the changes accumulated before the failure
:result — what to surface on success:
- :all (default) — the full normalised changes map
- an operation name — just that operation's value, looked up in the changes map (returns ok(nil) if absent)

Examples

iex> MonEx.Ecto.repack_multi({:ok, %{a: 1, b: 2}})
{:ok, %{a: 1, b: 2}}

iex> MonEx.Ecto.repack_multi({:ok, %{a: 1, b: 2}}, result: :a)
{:ok, 1}

iex> MonEx.Ecto.repack_multi({:error, :step, :boom, %{}})
{:error, {:step, :boom, %{}}}

iex> MonEx.Ecto.repack_multi({:error, :step, :boom, %{}}, error: :value)
{:error, :boom}