From de0ef498258e724ecd7c7c2ba2a426513eb57c23 Mon Sep 17 00:00:00 2001
From: kompotkot <zenitsws@gmail.com>
Date: Tue, 11 Jan 2022 21:04:21 +0000
Subject: [PATCH] Extended client nodebalancer with additional comments

---
 nodes/node_balancer/cmd/clients.go      | 31 +++++++++++++++----------
 nodes/node_balancer/cmd/server.go       |  3 +--
 nodes/node_balancer/configs/settings.go |  2 +-
 3 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/nodes/node_balancer/cmd/clients.go b/nodes/node_balancer/cmd/clients.go
index 703e5fee..4942070a 100644
--- a/nodes/node_balancer/cmd/clients.go
+++ b/nodes/node_balancer/cmd/clients.go
@@ -1,7 +1,6 @@
 package cmd
 
 import (
-	"fmt"
 	"log"
 	"reflect"
 	"time"
@@ -11,9 +10,12 @@ import (
 
 var clientPool ClientPool
 
+// Add client node and client itself if doesn't exist
+// TODO(kompotkot): Add mutes as for balancer
 func (cpool *ClientPool) AddClientNode(ip, blockchain string, node *Node) {
 	ts := time.Now().Unix()
 
+	// Find in list clint with same IP
 	var client *Client
 	for _, c := range cpool.Clients {
 		if c.IP == ip {
@@ -21,8 +23,8 @@ func (cpool *ClientPool) AddClientNode(ip, blockchain string, node *Node) {
 		}
 	}
 
+	// Add new client if doesn't exist
 	if client == nil {
-		fmt.Println("Adding new client")
 		client = &Client{
 			IP: ip,
 		}
@@ -46,6 +48,8 @@ func (cpool *ClientPool) AddClientNode(ip, blockchain string, node *Node) {
 	}
 }
 
+// Get client hot node if exists
+// TODO(kompotkot): Add mutes as for balancer
 func (cpool *ClientPool) GetClientNode(blockchain, ip string) *Node {
 	ts := time.Now().Unix()
 
@@ -54,13 +58,14 @@ func (cpool *ClientPool) GetClientNode(blockchain, ip string) *Node {
 			for j, cn := range c.ClientNodes {
 				if cn.Blockchain == blockchain {
 					if ts-cn.LastCallTs < configs.NB_CLIENT_NODE_KEEP_ALIVE {
-						cn.LastCallTs = ts
-						fmt.Printf("Hot client node found: %s, re-use it", cn.Node.GethURL)
-						return cn.Node
-					} else {
-						fmt.Println("Client node outdated, remove it")
-						c.ClientNodes = append(c.ClientNodes[:j], c.ClientNodes[j+1:]...)
+						// Hot node for client found, use it
+						if cn.Node.IsAlive() {
+							cn.LastCallTs = ts
+							return cn.Node
+						}
 					}
+					// Remove outdated hot node from client hot nodes list
+					c.ClientNodes = append(c.ClientNodes[:j], c.ClientNodes[j+1:]...)
 				}
 			}
 		}
@@ -69,22 +74,24 @@ func (cpool *ClientPool) GetClientNode(blockchain, ip string) *Node {
 	return nil
 }
 
+// Clean client list of hot nodes from outdated
+// TODO(kompotkot): Add mutes as for balancer
 func (cpool *ClientPool) CleanInactiveClientNodes() {
 	ts := time.Now().Unix()
 
 	for i, c := range cpool.Clients {
 		for j, cn := range c.ClientNodes {
 			if ts-cn.LastCallTs >= configs.NB_CLIENT_NODE_KEEP_ALIVE {
-				fmt.Println("Removing client node")
+				// Remove client's node
 				c.ClientNodes = append(c.ClientNodes[:j], c.ClientNodes[j+1:]...)
 			}
 		}
+
+		// If there are no hot nodes under client, remove client
 		if len(c.ClientNodes) == 0 {
-			fmt.Println("Removing client itself")
 			cpool.Clients = append(cpool.Clients[:i], cpool.Clients[i+1:]...)
 		}
 	}
-}
-func (cpool *ClientPool) StatusLog() {
+
 	log.Printf("Active clients: %d", len(cpool.Clients))
 }
diff --git a/nodes/node_balancer/cmd/server.go b/nodes/node_balancer/cmd/server.go
index 13e00717..257bd39c 100644
--- a/nodes/node_balancer/cmd/server.go
+++ b/nodes/node_balancer/cmd/server.go
@@ -29,8 +29,7 @@ func initHealthCheck(debug bool) {
 			blockchainPool.HealthCheck()
 			clientPool.CleanInactiveClientNodes()
 			if debug {
-				// blockchainPool.StatusLog()
-				clientPool.StatusLog()
+				blockchainPool.StatusLog()
 			}
 		}
 	}
diff --git a/nodes/node_balancer/configs/settings.go b/nodes/node_balancer/configs/settings.go
index a2c917f6..664995b6 100644
--- a/nodes/node_balancer/configs/settings.go
+++ b/nodes/node_balancer/configs/settings.go
@@ -96,7 +96,7 @@ var NB_HEALTH_CHECK_INTERVAL = time.Second * 5
 var NB_HEALTH_CHECK_CALL_TIMEOUT = time.Second * 2
 
 // Client config
-var NB_CLIENT_NODE_KEEP_ALIVE = int64(5) // Seconds
+var NB_CLIENT_NODE_KEEP_ALIVE = int64(5) // How long to store node in hot list for client in seconds
 
 // Humbug config
 var HUMBUG_REPORTER_NODE_BALANCER_TOKEN = os.Getenv("HUMBUG_REPORTER_NODE_BALANCER_TOKEN")