Cairn

Small OTP helpers for message delivery and supervised task callbacks.

Cairn tries not to become a framework for OTP. It is a thin layer for starting lightweight processes, passing messages, running supervised work, and waiting on refs.

Try it

cd cairn
mix deps.get
iex -S mix

Paste this into IEx:

{:ok, pid} = Cairn.Function.start_link(fn value -> value * 2 end)

msg = Cairn.dispatch(pid, 21)

{:ok, %Cairn.Message{payload: {:ok, 42}}} =
  Cairn.Await.message(msg.ref)

API

• Cairn.Message
• Cairn.deliver/2
• Cairn.Server
• Cairn.Function
• Cairn.Task
• Cairn.Await

Many Processes

{:ok, pids} =
  1..1_000
  |> Enum.map(fn n -> fn input -> {n, input * n} end end)
  |> Cairn.Function.start_many()

msgs = Cairn.dispatch(pids, 21)
refs = Enum.map(msgs, & &1.ref)

{:ok, replies} = Cairn.Await.all(refs)

Use as many processes as your BEAM node can actually afford. Cairn does not add a pool or scheduler above OTP. If your node can handle one million processes, pids can be one million processes.

AI orchestration

{:ok, classifier} =
  Cairn.Function.start_link(fn text ->
    MyApp.LLM.classify_ticket(text)
  end)

msg = Cairn.dispatch(classifier, "payment failed after upgrade")

{:ok, %Cairn.Message{payload: {:ok, %{team: team, summary: summary}}}} =
  Cairn.Await.message(msg.ref)

{:ok, pids} =
  Cairn.Function.start_many([
    fn topic -> MyApp.Search.notes(topic) end,
    fn topic -> MyApp.LLM.outline(topic) end,
    fn topic -> MyApp.LLM.risks(topic) end
  ])

refs =
  pids
  |> Cairn.dispatch("elixir lightweight processes")
  |> Enum.map(& &1.ref)

{:ok, replies} = Cairn.Await.all(refs)

pids
|> Cairn.dispatch("index my release notes")
|> Enum.map(& &1.ref)
|> Cairn.Await.stream()
|> Enum.each(fn msg -> IO.inspect(msg.payload) end)

Install

def deps do
  [
    {:cairn, "~> 0.1.1"}
  ]
end