Add multiple remotes and round robin

constmap.go

@@ -0,0 +1,36 @@
+package domainrouter
+
+import "sync"
+
+// ThreadMap for disallowing change of elements during runtime, for threadsafty
+type ThreadMap[K comparable, V any] struct {
+	dirty   map[K]V
+	rwMutex sync.RWMutex
+}
+
+func NewThreadMap[K comparable, V any](m map[K]V) *ThreadMap[K, V] {
+	return &ThreadMap[K, V]{
+		dirty:   m,
+		rwMutex: sync.RWMutex{},
+	}
+}
+
+func (m *ThreadMap[K, V]) Get(key K) (value V, ok bool) {
+	m.rwMutex.RLock()
+	defer m.rwMutex.RUnlock()
+	value, ok = m.dirty[key]
+	return value, ok
+}
+
+func (m *ThreadMap[K, V]) SetValue(key K, change func(old V) V) bool {
+	m.rwMutex.Lock()
+	defer m.rwMutex.Unlock()
+
+	value, ok := m.dirty[key]
+	if !ok {
+		return ok
+	}
+
+	m.dirty[key] = change(value)
+	return ok
+}