diff --git a/pkg/myfsm/fsm.go b/pkg/myfsm/fsm.go
new file mode 100644
index 0000000..6d980ac
--- /dev/null
+++ b/pkg/myfsm/fsm.go
@@ -0,0 +1,160 @@
+package fsm
+
+import (
+	"fmt"
+	"log"
+	"time"
+)
+
+type EventName string
+
+const (
+	EventEntry EventName = "EventEntry"
+	EventExit  EventName = "EventExit"
+
+	EventOK     EventName = "EventOK"
+	EventNoProc EventName = "EventNoProc"
+)
+
+type Callback func(fsm *FSM, event EventName, arg interface{}) EventName
+
+type Callbacks map[string]Callback
+
+type FSMState struct {
+	name      string
+	parent    string
+	initState string
+	processor Callback
+}
+
+type FSM struct {
+	name         string
+	currentState *FSMState
+	eventNames   *[]string
+	fsmStats     map[string]*FSMState
+}
+
+type Event struct {
+	FSM        *FSM
+	Event      string
+	Src        string
+	Dst        string
+	Err        error
+	Args       []interface{}
+	canceled   bool
+	async      bool
+	cancelFunc func()
+}
+
+func NewFSMState(name string, parent, initState string, processor Callback) *FSMState {
+	return &FSMState{
+		name:      name,
+		parent:    parent,
+		initState: initState,
+		processor: processor,
+	}
+}
+
+func NewFSM(name string, eventNames *[]string, fsmStats ...*FSMState) (*FSM, error) {
+	if len(fsmStats) == 0 {
+		return nil, fmt.Errorf("initial state cannot be nil")
+	}
+	fsm := &FSM{
+		name:         name,
+		currentState: fsmStats[0],
+		eventNames:   eventNames,
+		fsmStats:     make(map[string]*FSMState),
+	}
+
+	for index := range fsmStats {
+		fsm.fsmStats[fsmStats[index].name] = fsmStats[index]
+	}
+
+	// Execute ENTRY event for initial state and its sub-states
+	for tempState := fsm.currentState; tempState != nil; tempState = fsm.fsmStats[tempState.initState] {
+		fsm.currentState = tempState
+		if err := fsm.ExecuteEvent(EventEntry, nil); err != nil {
+			return nil, err
+		}
+	}
+
+	return fsm, nil
+}
+
+func (fsm *FSM) ExecuteEvent(event EventName, arg interface{}) error {
+	if fsm == nil {
+		return fmt.Errorf("FSM is nil")
+	}
+
+	log.Printf("%d %-23s STATE:%-23s EVENT:%s\n", time.Now().UnixMilli(), fsm.name, fsm.currentState.name, event)
+
+	tmpState := fsm.currentState
+	if tmpState == nil {
+		return fmt.Errorf("current state is nil")
+	}
+
+	result := tmpState.processor(fsm, event, arg)
+	for result == EventNoProc && fsm.fsmStats[tmpState.parent] != nil {
+		tmpState = fsm.fsmStats[tmpState.parent]
+		result = tmpState.processor(fsm, event, arg)
+	}
+
+	return nil
+}
+
+func (fsm *FSM) ChangeState(newState string, arg interface{}) error {
+	if newState == "" {
+		return fmt.Errorf("new state cannot be nil")
+	}
+
+	curState := fsm.currentState
+
+	for tempState := curState; tempState != nil; tempState = fsm.fsmStats[tempState.parent] {
+		fsm.currentState = tempState
+		if err := fsm.ExecuteEvent(EventExit, nil); err != nil {
+			return err
+		}
+
+		if newState == tempState.name {
+			if err := fsm.ExecuteEvent(EventEntry, arg); err != nil {
+				return err
+			}
+			break
+		}
+
+		if found, ok := fsm.findState(fsm.fsmStats[newState], tempState); ok {
+			for end := len(found) - 1; end >= 0; end-- {
+				fsm.currentState = found[end]
+				if err := fsm.ExecuteEvent(EventEntry, arg); err != nil {
+					return err
+				}
+			}
+			break
+		}
+	}
+
+	// Enter sub-states of the new state
+	for tempState := fsm.fsmStats[newState].initState; fsm.fsmStats[tempState] != nil; tempState = fsm.fsmStats[tempState].initState {
+		fsm.currentState = fsm.fsmStats[tempState]
+		if err := fsm.ExecuteEvent(EventEntry, arg); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (fsm *FSM) findState(targetState, findState *FSMState) ([]*FSMState, bool) {
+	var fsmStateList []*FSMState
+
+	for tempState := targetState; tempState != nil; tempState = fsm.fsmStats[tempState.parent] {
+
+		fsmStateList = append(fsmStateList, tempState)
+
+		if findState.parent == tempState.parent {
+			return fsmStateList, true
+		}
+	}
+
+	return fsmStateList, false
+}
diff --git a/pkg/myfsm/fsm_test.go b/pkg/myfsm/fsm_test.go
new file mode 100644
index 0000000..4ca568e
--- /dev/null
+++ b/pkg/myfsm/fsm_test.go
@@ -0,0 +1,87 @@
+package fsm
+
+import (
+	"log"
+	"testing"
+	"time"
+)
+
+type myFsm struct {
+	fsm *FSM
+}
+
+func state1(fsm *FSM, event EventName, arg interface{}) EventName {
+	switch event {
+	case EventEntry:
+		log.Println("state1", event)
+	case EventExit:
+		log.Println("state1", event)
+	default:
+		log.Println("state1", event)
+		return EventNoProc
+	}
+
+	return EventOK
+}
+
+func state2(fsm *FSM, event EventName, arg interface{}) EventName {
+	switch event {
+	case EventEntry:
+		log.Println("state2", event)
+	case EventExit:
+		log.Println("state2", event)
+	default:
+		log.Println("state2", event)
+		return EventNoProc
+	}
+
+	return EventOK
+}
+
+func state3(fsm *FSM, event EventName, arg interface{}) EventName {
+	switch event {
+	case EventEntry:
+		log.Println("state3", event)
+	case EventExit:
+		log.Println("state3", event)
+	case "test event":
+		log.Println("state3", event)
+	default:
+		log.Println("state3", event)
+		return EventNoProc
+	}
+
+	return EventOK
+}
+
+func newMyFsm() *myFsm {
+	state1 := NewFSMState("State1", "", "State2", state1)
+	state2 := NewFSMState("State2", "State1", "", state2)
+	state3 := NewFSMState("State3", "State1", "", state3)
+
+	fsm, err := NewFSM("MyFSM", &[]string{string(EventEntry), string(EventExit)}, state2, state1, state3)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	return &myFsm{fsm: fsm}
+}
+
+func Test_fsm(t *testing.T) {
+	myfsm := newMyFsm()
+
+	if err := myfsm.fsm.ChangeState("State3", nil); err != nil {
+		log.Fatal(err)
+	}
+
+	myfsm.fsm.ExecuteEvent("test event", nil)
+
+	// Start a timer (example)
+	// timerHandle := &ReactorTimerHandle{}
+	// if err := fsm.StartReactorTimer(timerHandle, 0, 1000, EventEntry, nil); err != nil {
+	// 	log.Fatal(err)
+	// }
+
+	// Keep the program running to observeinterior
+	time.Sleep(2 * time.Second)
+}