From cbbb2ff24c2d549926b21a94680361af74d30281 Mon Sep 17 00:00:00 2001
From: Bryan Boreham <bjboreham@gmail.com>
Date: Wed, 25 Sep 2019 20:05:40 +0000
Subject: [PATCH] performance: in Docker reporter, reduce IP type conversions.

The code was converting IP addresses to strings and back again.
---
 probe/docker/container.go | 16 +++++++---------
 probe/docker/reporter.go  | 13 ++++++++-----
 2 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/probe/docker/container.go b/probe/docker/container.go
index 9c81a250f..f4c7f7d8a 100644
--- a/probe/docker/container.go
+++ b/probe/docker/container.go
@@ -226,19 +226,14 @@ func (c *container) NetworkMode() (string, bool) {
 	return "", false
 }
 
-func addScopeToIPs(hostID string, ips []string) []string {
+func addScopeToIPs(hostID string, ips []net.IP) []string {
 	ipsWithScopes := []string{}
 	for _, ip := range ips {
-		ipsWithScopes = append(ipsWithScopes, report.MakeAddressNodeID(hostID, ip))
+		ipsWithScopes = append(ipsWithScopes, report.MakeAddressNodeIDB(hostID, ip))
 	}
 	return ipsWithScopes
 }
 
-func isIPv4(addr string) bool {
-	ip := net.ParseIP(addr)
-	return ip != nil && ip.To4() != nil
-}
-
 func (c *container) NetworkInfo(localAddrs []net.IP) report.Sets {
 	c.RLock()
 	defer c.RUnlock()
@@ -278,13 +273,16 @@ func (c *container) NetworkInfo(localAddrs []net.IP) report.Sets {
 
 	// Filter out IPv6 addresses; nothing works with IPv6 yet
 	ipv4s := []string{}
+	ipv4ips := []net.IP{}
 	for _, ip := range ips {
-		if isIPv4(ip) {
+		ipaddr := net.ParseIP(ip)
+		if ipaddr != nil && ipaddr.To4() != nil {
 			ipv4s = append(ipv4s, ip)
+			ipv4ips = append(ipv4ips, ipaddr)
 		}
 	}
 	// Treat all Docker IPs as local scoped.
-	ipsWithScopes := addScopeToIPs(c.hostID, ipv4s)
+	ipsWithScopes := addScopeToIPs(c.hostID, ipv4ips)
 
 	s := report.MakeSets()
 	if len(networks) > 0 {
diff --git a/probe/docker/reporter.go b/probe/docker/reporter.go
index b41899d60..70dade7df 100644
--- a/probe/docker/reporter.go
+++ b/probe/docker/reporter.go
@@ -192,16 +192,19 @@ func (r *Reporter) Report() (report.Report, error) {
 	return result, nil
 }
 
-func getLocalIPs() ([]string, error) {
+// Get local addresses both as strings and IP addresses, in matched slices
+func getLocalIPs() ([]string, []net.IP, error) {
 	ipnets, err := report.GetLocalNetworks()
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 	ips := []string{}
+	addrs := []net.IP{}
 	for _, ipnet := range ipnets {
 		ips = append(ips, ipnet.IP.String())
+		addrs = append(addrs, ipnet.IP)
 	}
-	return ips, nil
+	return ips, addrs, nil
 }
 
 func (r *Reporter) containerTopology(localAddrs []net.IP) report.Topology {
@@ -222,10 +225,10 @@ func (r *Reporter) containerTopology(localAddrs []net.IP) report.Topology {
 	// is recursive to deal with people who decide to be clever.
 	{
 		hostNetworkInfo := report.MakeSets()
-		if hostIPs, err := getLocalIPs(); err == nil {
+		if hostStrs, hostIPs, err := getLocalIPs(); err == nil {
 			hostIPsWithScopes := addScopeToIPs(r.hostID, hostIPs)
 			hostNetworkInfo = hostNetworkInfo.
-				Add(ContainerIPs, report.MakeStringSet(hostIPs...)).
+				Add(ContainerIPs, report.MakeStringSet(hostStrs...)).
 				Add(ContainerIPsWithScopes, report.MakeStringSet(hostIPsWithScopes...))
 		}