ExOperation
A library for making domain operations wrapped in a single database transaction.
Resources
- Documentation
- Hex package
- ExOperation: organizing business logic with operations in Elixir
- Talk about ExOperation at Elixir-Lang Moscow meetup (in Russian)
- Example Phoenix app
Example
An operation definition:
defmodule MyApp.Book.Update do
use ExOperation, params: %{
id!: :integer,
title!: :string,
author_id: :integer
}
def validate_params(changeset) do
changeset
|> Ecto.Changeset.validate_length(:title, min: 5)
end
def call(operation) do
operation
|> find(:book, schema: MyApp.Book, preload: [:author])
|> find(:author, schema: MyApp.Author, id_path: [:author_id], optional: true)
|> step(:result, &do_update(operation.context, &1, operation.params))
|> after_commit(&send_notifcation(&1))
end
defp do_update(context, txn, params) do
txn.book
|> Ecto.Changeset.cast(params, [:title])
|> Ecto.Changeset.put_assoc(:author, txn.author)
|> Ecto.Changeset.put_assoc(:updated_by, context.current_user)
|> MyApp.Repo.update()
end
defp send_notification(txn) do
# …
{:ok, txn}
end
endThe call:
context = %{current_user: current_user}
with {:ok, %{result: book}} <- MyApp.Book.Update |> ExOperation.run(context, params) do
# …
endUsage with Phoenix
An example Phoenix app can be found here: ex_operation_phoenix_example.
Features
- Railway oriented domain logic pipeline.
- Running all steps in a single database transaction. It uses Ecto.Multi inside.
- Params casting & validation with
Ecto.Changeset. Thanks to params library. - Convenient fetching of entitites from the database.
- Context passing. Useful for passing current user, current locale etc.
- Composable operations: one operation can call another through
suboperation/3function. - Changing operation scenario based on previous steps results with
defer/2. - Hooks:
before_transaction/1,after_commit/1.
Installation
Add the following to your mix.exs and then run mix deps.get:
def deps do
[
{:ex_operation, "~> 0.5.0"}
]
endAdd to your config/config.exs:
config :ex_operation,
repo: MyApp.Repowhere MyApp.Repo is the name of your Ecto.Repo module.