#44 Implemented the round robin routing strategy

pkg/routers/routing/round_robin.go

@@ -0,0 +1,45 @@
+package routing
+
+import (
+	"glide/pkg/providers"
+	"sync/atomic"
+)
+
+const (
+	RoundRobin Strategy = "round-robin"
+)
+
+// RoundRobinRouting routes request to the next model in the list in cycle
+type RoundRobinRouting struct {
+	idx    atomic.Uint64
+	models []*providers.LangModel
+}
+
+func NewRoundRobinRouting(models []*providers.LangModel) *RoundRobinRouting {
+	return &RoundRobinRouting{
+		models: models,
+	}
+}
+
+func (r *RoundRobinRouting) Iterator() LangModelIterator {
+	return r
+}
+
+func (r *RoundRobinRouting) Next() (*providers.LangModel, error) {
+	modelLen := len(r.models)
+
+	// in order to avoid infinite loop in case of no healthy model is available,
+	// we need to track whether we made a whole cycle around the model slice looking for a healthy model
+	for i := 0; i < modelLen; i++ {
+		idx := r.idx.Add(1)
+		model := r.models[idx%uint64(modelLen)]
+
+		if !model.Healthy() {
+			continue
+		}
+
+		return model, nil
+	}
+
+	return nil, ErrNoHealthyModels
+}