From bb88e2c1cb89b66c2440eeda721ca719d1365a1d Mon Sep 17 00:00:00 2001
From: Oleksii Moskalenko <moskalenko.alexey@gmail.com>
Date: Wed, 27 Jan 2021 12:07:07 +0800
Subject: [PATCH] feast client pool

Signed-off-by: Oleksii Moskalenko <moskalenko.alexey@gmail.com>
---
 main.go | 59 ++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 40 insertions(+), 19 deletions(-)

diff --git a/main.go b/main.go
index 86eed9a..8f95976 100644
--- a/main.go
+++ b/main.go
@@ -18,11 +18,32 @@ import (
 )
 
 type Config struct {
-	FeastServingHost 	string `default:"localhost" split_words:"true"`
-	FeastServingPort 	int    `default:"6566" split_words:"true"`
-	ListenPort       	string `default:"8080" split_words:"true"`
-	ProjectName      	string `default:"default" split_words:"true"`
-	SpecificationPath 	string `default:"loadSpec.yml" split_words:"true"`
+	FeastServingHost  string `default:"localhost" split_words:"true"`
+	FeastServingPort  int    `default:"6566" split_words:"true"`
+	ListenPort        string `default:"8080" split_words:"true"`
+	ProjectName       string `default:"default" split_words:"true"`
+	SpecificationPath string `default:"loadSpec.yml" split_words:"true"`
+	ClientPoolSize    int    `default:"4" split_words:"true"`
+}
+
+type FeastClientPool struct {
+	clients []feast.Client
+}
+
+func newFeastClientPool(host string, port int, poolSize int) (*FeastClientPool, error) {
+	var clients []feast.Client
+	for i := 0; i < poolSize; i++ {
+		client, err := feast.NewGrpcClient(host, port)
+		if err != nil {
+			return nil, err
+		}
+		clients = append(clients, client)
+	}
+	return &FeastClientPool{clients}, nil
+}
+
+func (p *FeastClientPool) GetClient() feast.Client {
+	return p.clients[rand.Intn(len(p.clients))]
 }
 
 func main() {
@@ -34,21 +55,21 @@ func main() {
 	}
 
 	log.Printf("Creating client to connect to Feast Serving at %s:%d", c.FeastServingHost, c.FeastServingPort)
-	client, err := feast.NewGrpcClient(c.FeastServingHost, c.FeastServingPort)
+	pool, err := newFeastClientPool(c.FeastServingHost, c.FeastServingPort, c.ClientPoolSize)
 	if err != nil {
 		log.Fatalf("Could not connect to: %v", err)
 	}
 
 	log.Printf("Loading specification at %s", c.SpecificationPath)
 	yamlSpec, err := ioutil.ReadFile(c.SpecificationPath)
-    if err != nil {
-        log.Fatalf("Error reading specification file at %s", err)
-    }
-    loadSpec := generator.LoadSpec{}
-    err = yaml.Unmarshal(yamlSpec, &loadSpec)
-    if err != nil {
-        log.Fatalf("Unmarshal: %v", err)
-    }
+	if err != nil {
+		log.Fatalf("Error reading specification file at %s", err)
+	}
+	loadSpec := generator.LoadSpec{}
+	err = yaml.Unmarshal(yamlSpec, &loadSpec)
+	if err != nil {
+		log.Fatalf("Unmarshal: %v", err)
+	}
 	requestGenerator, err := generator.NewRequestGenerator(loadSpec, c.ProjectName)
 	if err != nil {
 		log.Fatalf("Unable to instantiate request requestGenerator: %v", err)
@@ -59,11 +80,11 @@ func main() {
 	}
 
 	http.HandleFunc("/send", func(w http.ResponseWriter, r *http.Request) {
-		ctx, cancel := context.WithTimeout(context.Background(), 60 * time.Second)
+		ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
 		defer cancel()
 		requests := requestsPool[rand.Intn(len(requestsPool))]
 		if len(requests) == 1 {
-			resp, err := client.GetOnlineFeatures(ctx, &requests[0])
+			resp, err := pool.GetClient().GetOnlineFeatures(ctx, &requests[0])
 			if err != nil {
 				w.WriteHeader(500)
 			} else {
@@ -82,7 +103,7 @@ func main() {
 				request := request
 				go func() {
 					defer wg.Done()
-					resp, err := client.GetOnlineFeatures(ctx, &request)
+					resp, err := pool.GetClient().GetOnlineFeatures(ctx, &request)
 					if err != nil {
 						fatalErrors <- err
 					}
@@ -113,10 +134,10 @@ func main() {
 	})
 
 	http.HandleFunc("/echo", func(w http.ResponseWriter, r *http.Request) {
-		ctx, cancel := context.WithTimeout(context.Background(), 60 * time.Second)
+		ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
 		defer cancel()
 		var req serving.GetFeastServingInfoRequest
-		_, err := client.GetFeastServingInfo(ctx, &req)
+		_, err := pool.GetClient().GetFeastServingInfo(ctx, &req)
 		if err != nil {
 			log.Fatalf("%v", err)
 		}