The hex.pm source has a really good audit logging implementation that is worth looking at. I’ve been running a (heavily modified) variant of it in production for the last couple of years and it hasn’t failed me yet. It has a Task-based audit function that can be used for writing to the audit log on reads. I’m sure it wouldn’t be hard to write your error handling to use the audit function if, say, a multi operation failed.

If you need videos my search was successful and found a lot but that specific one eludes me as well.

In any case if you want eleixir conf videos this is what I found https://www.youtube.com/results?search_query=elixir+conf
Maybe this might help:

• Also I am wondering if not the ecto multi, can be used here. https://hexdocs.pm/ecto/Ecto.Multi.html.(can make several repo actions like multiple inserts)

• The changeset also can prepare queries and add to them.

  Ecto.Changeset — Ecto v3.14.0(modify structures and validate them)

I’m not sure if this is a good way of doing it, but you could create a custom repo module, and require the user id to be passed along:

defmodule MyApp.AuditedRepo do
  alias MyApp.Repo

  @spec insert(Ecto.Changeset.t(), binary() | nil, keyword()) :: {:ok, map()} | {:error, Ecto.Changeset.t()}
  def insert(changeset, user_id, opts \\ []) do
    Repo.transaction(fn ->
      # set session here
      Repo.insert(changeset, opts)
    end)
  end

  # all other methods, e.g. using defdelegate for the actions that doesn't need user id
end

So in the context methods you’ll have to pass along the user id:

defmodule MyApp.Posts do
  alias MyApp.{AuditedRepo, Posts.Post}

  def create_post(user_id, attrs) do
    %Post{}
    |> Post.changeset(attrs)
    |> AuditedRepo.insert(user_id)
  end

  # ...
end