machinery v0.12.1 Machinery View Source

This is the main Machinery module.

It keeps most of the Machinery logics, it’s the module that will be imported with use on the module responsible for the state machine.

Declare the states as an argument when importing Machinery on the module that will control your states transitions.

Machinery expects a Keyword as argument with two keys states and transitions.

Parameters

  • opts: A Keyword including states and transitions.

    • states: A List of Strings representing each state.
    • transitions: A Map for each state and it allowed next state(s).

Example

  defmodule YourProject.UserStateMachine do
    use Machinery,
      # The first state declared will be considered
      # the intial state
      states: ["created", "partial", "complete"],
      transitions: %{
        "created" =>  ["partial", "complete"],
        "partial" => "completed"
      }
  end

Link to this section Summary

Functions

Main macro function that will be executed upon the load of the module using it

Start function that will trigger a supervisor for the Machinery.Transitions, a GenServer that controls the state transitions and also starts another process, if the interface config is set to true, for Machinery.Endpoint, a module that uses Phoenix.Endpoint to expose new routes related to Machinery

Triggers the transition of a struct to a new state, accordinly to a specific state machine module, if it passes any existing guard functions. It also runs any before or after callbacks and returns a tuple with {:ok, struct}, or {:error, "reason"}

Link to this section Functions

Link to this macro __using__(opts) View Source (macro)

Main macro function that will be executed upon the load of the module using it.

It basically stores the states and transitions.

It expects a Keyword as argument with two keys states and transitions.

  • states: A List of Strings representing each state.
  • transitions: A Map for each state and it allowed next state(s).

P.S. The first state declared will be considered the intial state

Start function that will trigger a supervisor for the Machinery.Transitions, a GenServer that controls the state transitions and also starts another process, if the interface config is set to true, for Machinery.Endpoint, a module that uses Phoenix.Endpoint to expose new routes related to Machinery.

Link to this function transition_to(struct, state_machine_module, next_state) View Source
transition_to(struct(), module(), String.t()) ::
  {:ok, struct()} |
  {:error, String.t()}

Triggers the transition of a struct to a new state, accordinly to a specific state machine module, if it passes any existing guard functions. It also runs any before or after callbacks and returns a tuple with {:ok, struct}, or {:error, "reason"}.

Parameters

  • struct: The struct you want to transit to another state.
  • state_machine_module: The module that holds the state machine logic, where Machinery as imported.
  • next_state: String of the next state you want to transition to.

Examples

Machinery.transition_to(%User{state: :partial}, UserStateMachine, :completed)
{:ok, %User{state: :completed}}