add EventHook

hook/hook.go

@@ -0,0 +1,31 @@
+package hook
+
+type EventHook struct {
+	events map[string][]func()
+}
+
+func NewEventHook() EventHook {
+	return EventHook{make(map[string][]func())}
+}
+
+func (e *EventHook) AddHook(eventName string, handler func()) {
+
+	hooks, ok := e.events[eventName]
+	if !ok {
+		e.events[eventName] = []func(){handler}
+	}
+
+	e.events[eventName] = append(hooks, handler)
+}
+
+func (e *EventHook) RunHooks(eventName string) {
+
+	hooks, ok := e.events[eventName]
+	if !ok {
+		return
+	}
+
+	for _, hook := range hooks {
+		hook()
+	}
+}

hook/hook_test.go

@@ -0,0 +1,31 @@
+package hook
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRunHook(t *testing.T) {
+
+	h := NewEventHook()
+	i := 0
+
+	h.AddHook("sample", func() {
+		i++
+	})
+
+	h.AddHook("sample", func() {
+		i++
+	})
+
+	assert.Equal(t, i, 0)
+
+	h.RunHooks("x")
+
+	assert.Equal(t, i, 0)
+
+	h.RunHooks("sample")
+
+	assert.Equal(t, i, 2)
+}