transitions

Documentation

Index

• Constants
• Variables
• type Option
  • func WithActionHandler(h OrderHandleAction) Option
  • func WithPersister(p OrderPersistState) Option
  • func WithTransitions(tr []OrderTransition) Option
• type Order
• type OrderHandleAction
• type OrderPersistState
• type OrderStateMachine
  • func NewOrderStateMachine(opts ...Option) *OrderStateMachine
  • func (m *OrderStateMachine) Can(state StateType, event string) bool
  • func (m *OrderStateMachine) ChangeState(ctx context.Context, event string, obj *Order) error
  • func (m *OrderStateMachine) FindTransitionForStates(from, to StateType) (OrderTransition, bool)
• type OrderTransition
• type StateType

Constants

const (
	// Order state machine events
	OrderEventFailOrder    = "fail_order"
	OrderEventPlaceOrder   = "place_order"
	OrderEventSuccessOrder = "success_order"

	// Order state machine actions
	OrderActionBook              = "book"
	OrderActionCallApiV2         = "call_api_v2"
	OrderActionCheckAvailability = "check_availability"
	OrderActionFailOrder         = "fail_order"
	OrderActionSendEmail         = "send_email"
)

Variables

var (
	ErrOrderFsmAction       = errors.New("OrderStateMachine action error")
	ErrOrderFsmBeforeAction = errors.New("OrderStateMachine before action error")
	// ErrOrderFsmSkip indicates that further processing not need
	// used in before_actions
	ErrOrderFsmSkip = errors.New("skip")
)

var OrderTransitions = []OrderTransition{
	{
		From: StateTypeUnknown,
		To:   Created,
	},
	{
		Event: OrderEventSuccessOrder,
		From:  StateTypeUnknown,
		To:    Finished,
	},
	{
		Event: OrderEventPlaceOrder,
		From:  Created,
		To:    Started,
		BeforeActions: []string{
			OrderActionCheckAvailability,
			OrderActionBook,
		},
	},
	{
		Event: OrderEventFailOrder,
		From:  Created,
		To:    Failed,
		Actions: []string{
			OrderActionFailOrder,
			OrderActionCallApiV2,
		},
	},
	{
		Event: OrderEventSuccessOrder,
		From:  Started,
		To:    Finished,
		Actions: []string{
			OrderActionSendEmail,
		},
	},
}

OrderTransitions generated from transitions.json

Types

type Option

type Option func(*OrderStateMachine)

func WithActionHandler

func WithActionHandler(h OrderHandleAction) Option

func WithPersister

func WithPersister(p OrderPersistState) Option

func WithTransitions

func WithTransitions(tr []OrderTransition) Option

type Order

type Order struct {
	ID    int
	State StateType
}

type OrderHandleAction

type OrderHandleAction func(ctx context.Context, action string, transition OrderTransition, obj *Order) error

OrderHandle handles transitions action

type OrderPersistState

type OrderPersistState func(ctx context.Context, obj *Order, state StateType) error

Save state to external storage

type OrderStateMachine

type OrderStateMachine struct {
	// contains filtered or unexported fields
}

OrderStateMachine is a FSM that can handle transitions of a lot of objects. eventHandler and transitions are configured before use them.

func NewOrderStateMachine

func NewOrderStateMachine(opts ...Option) *OrderStateMachine

NewOrderStateMachine creates a new state machine.

func (*OrderStateMachine) Can

func (m *OrderStateMachine) Can(state StateType, event string) bool

func (*OrderStateMachine) ChangeState

func (m *OrderStateMachine) ChangeState(ctx context.Context, event string, obj *Order) error

ChangeState fires a event and if event succeeded then change state.

func (*OrderStateMachine) FindTransitionForStates

func (m *OrderStateMachine) FindTransitionForStates(from, to StateType) (OrderTransition, bool)

type OrderTransition

type OrderTransition struct {
	Event         string
	From          StateType
	To            StateType
	BeforeActions []string
	Actions       []string
}

OrderTransition is a state transition and all data are literal values that simplifies FSM usage and make it generic.

type StateType

type StateType int

const (
	StateTypeUnknown StateType = iota
	Created
	Started
	Processing
	Finished
	Failed
)