fsm-go's Introduction

fsm-go

Golang finite-state machine.

Examples

Comprehensive

In this example we do the following:

utilize a back-reference to our state maching using MachineProvider;
use Expiring state handler to timeout a state;
create custom state handlers that print the states and terminate the app;
join the handlers using Compose.

Simple

In this example we start with stInit, and then send evInitialized, which switches the state into stFinal.

const (
	stInit        fsm.StateType = "stInit"
	stFinal       fsm.StateType = "stFinal"
	evInitialized fsm.EventType = "evInitialized"
)

transitions := fsm.Transitions{
	fsm.When(stInit, evInitialized): stFinal,
}

fsm := fsm.New(stInit, transitions, nil, nil)
fsm.Send(evInitialized)

Expiring states

In this example we use an Expiring state handler, which sends events to the FSM with a delay. Since timer events are asynchronous, we recommend to use the asynchronous FSM implementation.

const (
	stInit         StateType = "stInit"
	stWaitTimeout  StateType = "stWaitTimeout"
	stFinal        StateType = "stFinal"
	evInitialized  EventType = "evInitialized"
	evTimeout      EventType = "evTimeout"
)

transitions := Transitions{
	When(stInit, evInitialized):    stWaitTimeout,
	When(stWaitTimeout, evTimeout): stFinal,
}

provider := new(MachineProvider)

states := States{
	stWaitTimeout: NewExpiring(provider, After(time.Second), evTimeout),
}

fsm := fsm.NewAsync(stInit, transitions, states, nil)
provider.Set(fsm)
fsm.Send(evInitialized)
fsm.Run()

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