From 5696cdc7648dbefa14282d919fa0d97a653b4f70 Mon Sep 17 00:00:00 2001
From: Seena Fallah <seenafallah@gmail.com>
Date: Tue, 20 Aug 2024 22:20:19 +0200
Subject: [PATCH] memberlist: respect interface names config for advertise addr

If interface names are specified in common config, use this to
fulfill the instance_addr with it.

Signed-off-by: Seena Fallah <seenafallah@gmail.com>
---
 pkg/loki/modules.go | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/pkg/loki/modules.go b/pkg/loki/modules.go
index 60e2683b599ff..70e45b5880266 100644
--- a/pkg/loki/modules.go
+++ b/pkg/loki/modules.go
@@ -33,6 +33,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus/collectors/version"
 	"github.com/prometheus/common/model"
 
+	"github.com/grafana/dskit/netutil"
 	"github.com/grafana/loki/v3/pkg/analytics"
 	"github.com/grafana/loki/v3/pkg/bloombuild/builder"
 	"github.com/grafana/loki/v3/pkg/bloombuild/planner"
@@ -1449,6 +1450,15 @@ func (t *Loki) initMemberlistKV() (services.Service, error) {
 	)
 	dnsProvider := dns.NewProvider(util_log.Logger, dnsProviderReg, dns.GolangResolverType)
 
+	var err error
+	t.Cfg.MemberlistKV.AdvertiseAddr, err = GetInstanceAddr(
+		t.Cfg.MemberlistKV.AdvertiseAddr,
+		t.Cfg.Common.InstanceInterfaceNames,
+		util_log.Logger,
+	)
+	if err != nil {
+		return nil, err
+	}
 	t.MemberlistKV = memberlist.NewKVInitService(&t.Cfg.MemberlistKV, util_log.Logger, dnsProvider, reg)
 
 	t.Cfg.CompactorConfig.CompactorRing.KVStore.MemberlistKV = t.MemberlistKV.GetMemberlistKV
@@ -2042,3 +2052,16 @@ func schemaHasBoltDBShipperConfig(scfg config.SchemaConfig) bool {
 
 	return false
 }
+
+func GetInstanceAddr(addr string, netInterfaces []string, logger log.Logger) (string, error) {
+	if len(netInterfaces) == 0 {
+		return addr, nil
+	}
+
+	addr, err := netutil.GetFirstAddressOf(netInterfaces, logger, false)
+	if err != nil {
+		return "", err
+	}
+
+	return addr, nil
+}