go-fsm

It is a lightweight finite state machine (FSM) implementation in Golang. It has been inspired by the FSM used in Apache Hadoop YARN:

• Thread safe
• Multiple destination states
• Dynamic destination state determination

Installation

go get github.com/zjshen14/go-fsm

Usage

package main

import (
	"fmt"

	"github.com/zjshen14/go-fsm"
)

type evt struct {
	t fsm.EventType
}

func (e *evt) Type() fsm.EventType { return e.t }

func main() {
	fsm, _ := fsm.NewBuilder().
		AddInitialState("s1").
		AddStates("s2", "s3").
		AddTransition("s1", "e1", func(event fsm.Event) (fsm.State, error) { return "s2", nil }, []fsm.State{"s2"}).
		AddTransition("s2", "e2", func(event fsm.Event) (fsm.State, error) { return "s3", nil }, []fsm.State{"s3"}).
		AddTransition("s3", "e3", func(event fsm.Event) (fsm.State, error) { return "s1", nil }, []fsm.State{"s1"}).
		Build()

	fmt.Println(fsm.CurrentState())
	fsm.Handle(&evt{t: "e1"})
	fmt.Println(fsm.CurrentState())
	fsm.Handle(&evt{t: "e2"})
	fmt.Println(fsm.CurrentState())
	fsm.Handle(&evt{t: "e3"})
	fmt.Println(fsm.CurrentState())
}

License

go-fsm is under the Apache 2.0 license. See the LICENSE file for details.