From 378918a295ccb6a9c33ee327e35bb4d3ae3707b5 Mon Sep 17 00:00:00 2001
From: f18m <francesco.montorsi@gmail.com>
Date: Wed, 30 Oct 2024 22:24:39 +0100
Subject: [PATCH] Fix excessive logging when new "link" attribute is empty

---
 .../pkg/uibackend/types.go                    | 26 ++++++++++++-------
 .../pkg/uibackend/uibackend.go                |  4 +--
 .../pkg/uibackend/uibackend_test.go           |  4 +--
 3 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/dhcp-clients-webapp-backend/pkg/uibackend/types.go b/dhcp-clients-webapp-backend/pkg/uibackend/types.go
index 2c54a20..36aa3b4 100644
--- a/dhcp-clients-webapp-backend/pkg/uibackend/types.go
+++ b/dhcp-clients-webapp-backend/pkg/uibackend/types.go
@@ -86,7 +86,7 @@ type PastDhcpClientData struct {
 type DhcpClientFriendlyName struct {
 	MacAddress   net.HardwareAddr
 	FriendlyName string
-	Link         template.Template
+	Link         *template.Template // maybe nil
 }
 
 // IpAddressReservation represents a static IP configuration loaded from the addon configuration file
@@ -94,7 +94,7 @@ type IpAddressReservation struct {
 	Name string
 	Mac  net.HardwareAddr
 	IP   netip.Addr
-	Link template.Template
+	Link *template.Template // maybe nil
 }
 
 // AddonConfig is used to unmarshal HomeAssistant option file correctly
@@ -186,9 +186,12 @@ func (b *AddonConfig) UnmarshalJSON(data []byte) error {
 			return fmt.Errorf("invalid MAC address found inside 'ip_address_reservations': %s", r.Mac)
 		}
 
-		linkTemplate, err := template.New("linkTemplate").Parse(r.Link)
-		if err != nil {
-			return fmt.Errorf("invalid golang template found inside 'link': %s", r.Link)
+		var linkTemplate *template.Template
+		if r.Link != "" {
+			linkTemplate, err = template.New("linkTemplate").Parse(r.Link)
+			if err != nil {
+				return fmt.Errorf("invalid golang template found inside 'link': %s", r.Link)
+			}
 		}
 
 		// normalize the IP and MAC address format (e.g. to lowercase)
@@ -199,7 +202,7 @@ func (b *AddonConfig) UnmarshalJSON(data []byte) error {
 			Name: r.Name,
 			Mac:  macAddr,
 			IP:   ipAddr,
-			Link: *linkTemplate,
+			Link: linkTemplate,
 		}
 
 		b.ipAddressReservationsByIP[ipAddr] = ipReservation
@@ -213,15 +216,18 @@ func (b *AddonConfig) UnmarshalJSON(data []byte) error {
 			return fmt.Errorf("invalid MAC address found inside 'dhcp_clients_friendly_names': %s", client.Mac)
 		}
 
-		linkTemplate, err := template.New("linkTemplate").Parse(client.Link)
-		if err != nil {
-			return fmt.Errorf("invalid golang template found inside 'link': %s", client.Link)
+		var linkTemplate *template.Template
+		if client.Link != "" {
+			linkTemplate, err = template.New("linkTemplate").Parse(client.Link)
+			if err != nil {
+				return fmt.Errorf("invalid golang template found inside 'link': %s", client.Link)
+			}
 		}
 
 		b.friendlyNames[macAddr.String()] = DhcpClientFriendlyName{
 			MacAddress:   macAddr,
 			FriendlyName: client.Name,
-			Link:         *linkTemplate,
+			Link:         linkTemplate,
 		}
 	}
 
diff --git a/dhcp-clients-webapp-backend/pkg/uibackend/uibackend.go b/dhcp-clients-webapp-backend/pkg/uibackend/uibackend.go
index 6323666..0e3ad89 100644
--- a/dhcp-clients-webapp-backend/pkg/uibackend/uibackend.go
+++ b/dhcp-clients-webapp-backend/pkg/uibackend/uibackend.go
@@ -500,12 +500,12 @@ func (b *UIBackend) evaluateLink(hostname string, ip netip.Addr, mac net.Hardwar
 
 	r, hasFriendlyName := b.cfg.friendlyNames[mac.String()]
 	if hasFriendlyName {
-		theTemplate = &r.Link
+		theTemplate = r.Link
 		friendlyName = r.FriendlyName
 	} else {
 		r, hasReservation := b.cfg.ipAddressReservationsByIP[ip]
 		if hasReservation {
-			theTemplate = &r.Link
+			theTemplate = r.Link
 		}
 	}
 
diff --git a/dhcp-clients-webapp-backend/pkg/uibackend/uibackend_test.go b/dhcp-clients-webapp-backend/pkg/uibackend/uibackend_test.go
index b9bcc34..a503519 100644
--- a/dhcp-clients-webapp-backend/pkg/uibackend/uibackend_test.go
+++ b/dhcp-clients-webapp-backend/pkg/uibackend/uibackend_test.go
@@ -22,8 +22,8 @@ func MustParseMAC(s string) net.HardwareAddr {
 	return mac
 }
 
-func MustParseTemplate(s string) template.Template {
-	return *template.Must(template.New("test").Parse(s))
+func MustParseTemplate(s string) *template.Template {
+	return template.Must(template.New("test").Parse(s))
 }
 
 func getMockLeases() []*dnsmasq.Lease {