From a4261243fcb5a9f2d1f7cfabe960b4111667428e Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@nspcc.ru>
Date: Mon, 21 Mar 2022 15:02:27 +0300
Subject: [PATCH] [#1157] network/cache: Cache multiclients based on public key
 only

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
---
 pkg/network/cache/client.go | 21 +++++----------------
 pkg/network/cache/multi.go  | 26 ++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 16 deletions(-)

diff --git a/pkg/network/cache/client.go b/pkg/network/cache/client.go
index 67ede4be..598f4352 100644
--- a/pkg/network/cache/client.go
+++ b/pkg/network/cache/client.go
@@ -2,12 +2,10 @@ package cache
 
 import (
 	"crypto/ecdsa"
-	"encoding/hex"
 	"sync"
 	"time"
 
 	clientcore "github.com/nspcc-dev/neofs-node/pkg/core/client"
-	"github.com/nspcc-dev/neofs-node/pkg/network"
 	"github.com/nspcc-dev/neofs-sdk-go/client"
 )
 
@@ -16,7 +14,7 @@ type (
 	// already created clients.
 	ClientCache struct {
 		mu      *sync.RWMutex
-		clients map[string]clientcore.Client
+		clients map[string]*multiClient
 		opts    ClientCacheOpts
 	}
 
@@ -32,7 +30,7 @@ type (
 func NewSDKClientCache(opts ClientCacheOpts) *ClientCache {
 	return &ClientCache{
 		mu:      new(sync.RWMutex),
-		clients: make(map[string]clientcore.Client),
+		clients: make(map[string]*multiClient),
 		opts:    opts,
 	}
 }
@@ -40,22 +38,12 @@ func NewSDKClientCache(opts ClientCacheOpts) *ClientCache {
 // Get function returns existing client or creates a new one.
 func (c *ClientCache) Get(info clientcore.NodeInfo) (clientcore.Client, error) {
 	netAddr := info.AddressGroup()
-
-	// multiaddr is used as a key in client cache since
-	// same host may have different connections(with tls or not),
-	// therefore, host+port pair is not unique
-
-	// FIXME: #1157 we should calculate map key regardless of the address order,
-	//  but network.StringifyGroup is order-dependent.
-	//  This works until the same mixed group is transmitted
-	//  (for a network map, it seems to be true).
-	cacheKey := hex.EncodeToString(info.PublicKey()) + network.StringifyGroup(netAddr)
+	cacheKey := string(info.PublicKey())
 
 	c.mu.RLock()
 	if cli, ok := c.clients[cacheKey]; ok {
-		// todo: check underlying connection neofs-api-go#196
 		c.mu.RUnlock()
-
+		cli.updateGroup(netAddr)
 		return cli, nil
 	}
 
@@ -67,6 +55,7 @@ func (c *ClientCache) Get(info clientcore.NodeInfo) (clientcore.Client, error) {
 	// check once again if client is missing in cache, concurrent routine could
 	// create client while this routine was locked on `c.mu.Lock()`.
 	if cli, ok := c.clients[cacheKey]; ok {
+		// No need to update address group as the client has just been created.
 		return cli, nil
 	}
 
diff --git a/pkg/network/cache/multi.go b/pkg/network/cache/multi.go
index f08e246f..bb36b2ab 100644
--- a/pkg/network/cache/multi.go
+++ b/pkg/network/cache/multi.go
@@ -67,6 +67,32 @@ func (x *multiClient) createForAddress(addr network.Address) clientcore.Client {
 	return &c
 }
 
+// updateGroup replaces current multiClient addresses with a new group.
+// Old addresses not present in group are removed.
+func (x *multiClient) updateGroup(group network.AddressGroup) {
+	// Firstly, remove old clients.
+	cache := make([]string, 0, group.Len())
+	group.IterateAddresses(func(a network.Address) bool {
+		cache = append(cache, a.String())
+		return false
+	})
+
+	x.mtx.Lock()
+	defer x.mtx.Unlock()
+loop:
+	for a := range x.clients {
+		for i := range cache {
+			if cache[i] == a {
+				continue loop
+			}
+		}
+		delete(x.clients, a)
+	}
+
+	// Then add new clients.
+	x.addr = group
+}
+
 func (x *multiClient) iterateClients(ctx context.Context, f func(clientcore.Client) error) error {
 	var firstErr error