leandrocp

# apps/sales/lib/client/support.ex
defmodule Sales.Client.Support do
  alias Sales.Domain

  def get_customer(%Domain.Customer{id: customer_id} = customer) do
    customer_has_support_ticket =
      customer_id
      |> Support.get_customer()
      |> has_support_ticket()
      

leandrocp

# apps/support/lib/support.ex
defmodule Support do
  def get_customer(customer_id) when is_integet(customer_id) do
    find(customer_id) # get customer from db
    |> Map.from_struct()
  end
end

leandrocp

# apps/sales/lib/domain/customer.ex
defmodule Sales.Domain.Customer do
  defstruct [:id, :name, :address, :score, :has_support_ticket]
end

# apps/support/lib/domain/customer.ex
defmodule Support.Domain.Customer do
  defstruct [:id, :name, :last_ticket_id, :email]
end

leandrocp

➜ tree
.
├── README.md
├── apps
│   ├── sales
│   │   ├── README.md
│   │   ├── config
│   │   │   └── config.exs
│   │   ├── lib
│   │   │   └── sales.ex

leandrocp

➜ cd system_x/apps
➜ mix new sales
➜ mix new support

leandrocp

➜ mix new system_x --umbrella
➜ cd system_x/apps
➜ mix new sales
➜ mix new support

leandrocp

iex> defmodule Example, do: use GenServer
iex> {:ok, pid} = GenServer.start_link(Example, %{ping: "pong"})
iex> Process.info pid
[
  current_function: {:gen_server, :loop, 7},
  initial_call: {:proc_lib, :init_p, 5},
  status: :waiting,
  message_queue_len: 0,
  messages: [],
  links: [#PID<0.610.0>],

leandrocp

iex>h Enum.map

                            def map(enumerable, fun)

    @spec map(t(), (element() -> any())) :: list()

Returns a list where each item is the result of invoking fun on each
corresponding item of enumerable.

For maps, the function expects a key-value tuple.

leandrocp

iex> :observer.start

leandrocp

iex> :sys.trace pid, true
:ok
iex> GenServer.call(pid, ​:next_number​)
*DBG* <0.69.0> got call next_number from <0.25.0>
*DBG* <0.69.0> sent 105 to <0.25.0>, new state 106
105

# Excerpt From: Dave Thomas. “Programming Elixir ≥ 1.6” iBooks.