Demo for usage of StateMachine

Author: JeroenSoeters

demo/apps/myapp/mystatemachine.go

@@ -0,0 +1,93 @@
+package myapp
+
+import (
+	"fmt"
+	"time"
+
+	"ergo.services/ergo/act"
+	"ergo.services/ergo/gen"
+)
+
+// Order with the states: new, processing, shipped, delivered, canceled
+
+type OrderData struct {
+	items     []string
+	processed time.Time
+	shipped   time.Time
+	delivered time.Time
+	canceled  time.Time
+}
+
+type Order struct {
+	act.StateMachine[OrderData]
+}
+
+func factoryOrder() gen.ProcessBehavior {
+	return &Order{}
+}
+
+func (order *Order) Init(args ...any) (act.StateMachineSpec[OrderData], error) {
+	spec := act.NewStateMachineSpec(gen.Atom("new"),
+		// new
+		act.WithStateCallback(gen.Atom("new"), process),
+		act.WithStateCallback(gen.Atom("new"), cancel),
+		// processing
+		act.WithStateCallback(gen.Atom("processing"), ship),
+		act.WithStateCallback(gen.Atom("processing"), cancel),
+		// shipped
+		act.WithStateCallback(gen.Atom("shipped"), deliver),
+	)
+
+	return spec, nil
+}
+
+type Process struct{}
+
+type Ship struct {
+	priority bool
+}
+
+type Deliver struct{}
+
+type Cancel struct {
+	reason string
+}
+
+func process(sm *act.StateMachine[OrderData], message Process) error {
+	data := sm.Data()
+	if len(data.items) < 1 {
+		return fmt.Errorf("can't process order as there are no items added yet")
+	}
+	sm.Log().Info("processing order...")
+	data.processed = time.Now()
+	sm.SetData(data)
+	sm.SetCurrentState(gen.Atom("processing"))
+	return nil
+}
+
+func ship(sm *act.StateMachine[OrderData], message Ship) error {
+	data := sm.Data()
+	sm.Log().Info("shiping order...")
+	data.shipped = time.Now()
+	sm.SetData(data)
+	sm.SetCurrentState(gen.Atom("shipped"))
+	return nil
+}
+
+func deliver(sm *act.StateMachine[OrderData], message Deliver) error {
+	data := sm.Data()
+	sm.Log().Info("delivering order...")
+	data.delivered = time.Now()
+	sm.SetData(data)
+	sm.SetCurrentState(gen.Atom("delivered"))
+	return nil
+}
+
+func cancel(sm *act.StateMachine[OrderData], message Cancel) error {
+	data := sm.Data()
+	sm.Log().Info("canceling order...")
+	data.canceled = time.Now()
+	sm.SetData(data)
+	sm.SetCurrentState(gen.Atom("canceled"))
+	return nil
+}