Enables middleware support for Ecto.Repo modules.

Add use EctoMiddleware.Repo to your Repo to enable middleware pipelines for database operations.

Setup

defmodule MyApp.Repo do
  use Ecto.Repo, otp_app: :my_app
  use EctoMiddleware.Repo

  @impl EctoMiddleware.Repo
  def middleware(action, resource) when is_insert(action, resource) do
    [NormalizeEmail, HashPassword, AuditLog]
  end

  def middleware(action, resource) when is_delete(action, resource) do
    [SoftDelete, AuditLog]
  end

  def middleware(_action, _resource) do
    [AuditLog]
  end
end

Defining Middleware

Implement the middleware/2 callback to specify which middleware run for each operation.

Pattern Matching on Actions

The first argument is the action atom (function name without arity):

@impl EctoMiddleware.Repo
def middleware(:insert, _), do: [ValidateEmail]

def middleware(:get, _), do: [EnrichData]

def middleware(:delete, _), do: [SoftDelete]

Available actions:

• Read: :get, :get!, :get_by, :get_by!, :one, :one!, :all, :reload, :reload!, :preload
• Write: :insert, :insert!, :update, :update!, :delete, :delete!, :insert_or_update, :insert_or_update!

Pattern Matching on Resources

The second argument is the resource being operated on:

# Specific schema
def middleware(:insert, %User{}), do: [NormalizeEmail, HashPassword]

# Multiple schemas with same middleware
def middleware(:insert, %{__struct__: schema})
  when schema in [User, Admin], do: [AuditLog]

# Changesets
def middleware(:update, %Ecto.Changeset{data: %User{}}), do: [CheckOwnership]

Using Guards

You can use EctoMiddleware.Utils guards in your middleware/2 definitions:

@impl EctoMiddleware.Repo
def middleware(action, resource) when is_insert(action, resource) do
  [SetCreatedAt, AuditLog]
end

def middleware(action, resource) when is_update(action, resource) do
  [SetUpdatedAt, AuditLog]
end

def middleware(_action, _resource), do: []

See EctoMiddleware.Utils for available guards.

Default Middleware

Always provide a catch-all clause:

def middleware(_action, _resource), do: []

Middleware Execution

Middleware execute in the order specified. If any middleware returns {:halt, value}, execution stops immediately.