LazyAgent

LazyAgent wraps Elixir's Agent library to allow delayed execution of the initial state generator function until the first time the Agent process is accessed.

It is intended to be used in test environments of applications with agents that have initialization functions that take hundreds of milliseconds or more to execute. When developing and running a subset of the test suite, these type of agents can significantly increase the time it takes to run tests, which slows down development. Using LazyAgent allows execution of only the initialization functions necessary to run the test subset.

Installation

Install LazyAgent by adding lazy_agent to your list of dependencies in mix.exs:

def deps do
  [
    {:lazy_agent, "~> 0.1.0"}
  ]
end

Configuration

To enable or disable LazyAgent, add the following to an environment configuration file:

use Mix.Config

config :lazy_agent, enabled?: true

Usage

Currently, LazyAgent supports the lazy equivalents of:

• Agent.start/2
• Agent.start_link/2
• Agent.get/3
• Agent.update/3
• Agent.get_and_update/3
• Agent.stop/3

iex> {:ok, pid} = LazyAgent.start_link(fn -> 42 end)
iex> LazyAgent.get(pid, fn state -> state end)
42

iex> LazyAgent.start_link(fn -> 42 end, name: :lazy)
iex> LazyAgent.update(:lazy, fn state -> state + 5 end)
:ok
iex> LazyAgent.get(:lazy, fn state -> state end)
47

iex> {:ok, pid} = LazyAgent.start(fn -> 42 end)
iex> LazyAgent.get_and_update(pid, fn state -> {state, state + 5} end)
42
iex> LazyAgent.get(pid, fn state -> state end)
47
iex> LazyAgent.stop(pid)
:ok