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/*
Copyright 2023 The KubeEdge Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package fsm
import (
"fmt"
"k8s.io/klog/v2"
api "github.com/kubeedge/api/fsm/v1alpha1"
)
type FSM struct {
id string
nodeName string
lastState api.State
currentFunc func(id, nodeName string) (api.State, error)
updateFunc func(id, nodeName string, state api.State, event Event) error
guard map[string]api.State
stageSequence map[api.State]api.State
}
func (F *FSM) NodeName(nodeName string) *FSM {
F.nodeName = nodeName
return F
}
type Event struct {
Type string
Action api.Action
Msg string
ExternalMessage string
}
func (e Event) UniqueName() string {
return e.Type + "/" + string(e.Action)
}
func (F *FSM) ID(id string) *FSM {
F.id = id
return F
}
func (F *FSM) LastState(lastState api.State) {
F.lastState = lastState
}
func (F *FSM) CurrentFunc(currentFunc func(id, nodeName string) (api.State, error)) *FSM {
F.currentFunc = currentFunc
return F
}
func (F *FSM) UpdateFunc(updateFunc func(id, nodeName string, state api.State, event Event) error) *FSM {
F.updateFunc = updateFunc
return F
}
func (F *FSM) Guard(guard map[string]api.State) *FSM {
F.guard = guard
return F
}
func (F *FSM) StageSequence(stageSequence map[api.State]api.State) *FSM {
F.stageSequence = stageSequence
return F
}
func (F *FSM) CurrentState() (api.State, error) {
if F.currentFunc == nil {
return "", fmt.Errorf("currentFunc is nil")
}
return F.currentFunc(F.id, F.nodeName)
}
func (F *FSM) transitCheck(event Event) (api.State, api.State, error) {
currentState, err := F.CurrentState()
if err != nil {
return "", "", err
}
if F.guard == nil {
return "", "", fmt.Errorf("guard is nil ")
}
nextState, ok := F.guard[string(currentState)+"/"+event.UniqueName()]
if !ok {
return "", "", fmt.Errorf(string(currentState)+"/"+event.UniqueName(), " unsupported event")
}
return currentState, nextState, nil
}
func (F *FSM) AllowTransit(event Event) error {
_, _, err := F.transitCheck(event)
return err
}
func (F *FSM) Transit(event Event) error {
currentState, nextState, err := F.transitCheck(event)
if err != nil {
return err
}
if F.updateFunc == nil {
return fmt.Errorf("updateFunc is nil")
}
err = F.updateFunc(F.id, F.nodeName, nextState, event)
if err != nil {
return err
}
F.lastState = currentState
return nil
}
func TaskFinish(state api.State) bool {
return state == api.TaskFailed || state == api.TaskSuccessful
}
func (F *FSM) TaskStagCompleted(state api.State) bool {
currentState, err := F.CurrentState()
if err != nil {
klog.Errorf("get %s current state failed: %s", F.id, err.Error())
return false
}
if F.stageSequence[currentState] == state || TaskFinish(state) {
return true
}
return false
}
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