A convenience behaviour to ease the use of a database instance within an OTP application while also promoting best practices.

Firstly the configuration for the behaviour must be set and is designed in such a way that it can be changed for each environment:

config :example, Example.Foundation,
  cluster: "./fdb.cluster",  # Path to the cluster file
  directory: "example",      # The directory the application should operate under

The behaviour can then be used to create and manage a database instance.

defmodule Example.Foundation do
  use FDBC.Foundation,
    otp_app: :example,
    options: [
      transaction_retry_limit: 100,
      transaction_timeout: 60_000
    ]
end

The module must be added to the applications supervision tree, once this is done it can then be used to easily transact with FoundationDB.

defmodule Example.App do
  alias FDBC.{Directory, Subspace, Transaction}
  alias Example.Foundation

  def get_value(key) do
    Foundation.transact(fn tr, dir ->
      key = Directory.subspace(dir) |> Subspace.pack([key])
      Transaction.get(tr, key)
    end)
  end

  def set_value(key, value) do
    Foundation.transact(fn tr, dir ->
      key = Directory.subspace(dir) |> Subspace.pack([key])
      Transaction.set(tr, key, value)
    end)
  end
end