Fix IPv6 address handling in LAN <-> WAN join flooder

tkren · tkren · commit 8fa216aa27dc · 2025-03-15T00:22:10.000+01:00
When `advertise_addr` is an IPv6 address, Consul WAN federation breaks and we get a constant stream of warnings: ``` [WARN] agent.server.memberlist.wan: memberlist: Failed to resolve i-02a3c94b46768b01f.aws-eu-west-1/2a05:d018:18a3:f202:64d9:1621:ab22:df45:8302: lookup 2a05:d018:18a3:f202:64d9:1621:ab22:df45:8302: no such host ``` The LAN <-> WAN join flooder creates IPv6 addresses without square brackets with `fmt.Sprintf("%s:%d", addr, s.WanJoinPort)`, which confuses `net.SplitHostPort` in `memberlist.resolveAddr`. Fixes hashicorp#22225
diff --git a/agent/consul/server.go b/agent/consul/server.go
@@ -781,7 +781,7 @@ func NewServer(config *Config, flat Deps, externalGRPCServer *grpc.Server,
 			if err != nil {
 				return "", err
 			}
-			return fmt.Sprintf("%s:%d", addr, s.WanJoinPort), nil
+			return net.JoinHostPort(addr, strconv.Itoa(s.WanJoinPort)), nil
 		}
 		go s.Flood(addrFn, s.serfWAN)
 	}

Original file line number	Diff line number	Diff line change
`@@ -781,7 +781,7 @@ func NewServer(config Config, flat Deps, externalGRPCServer grpc.Server,`
`781`	`781`	`if err != nil {`
`782`	`782`	`return "", err`
`783`	`783`	`}`
`784`		`- return fmt.Sprintf("%s:%d", addr, s.WanJoinPort), nil`
	`784`	`+ return net.JoinHostPort(addr, strconv.Itoa(s.WanJoinPort)), nil`
`785`	`785`	`}`
`786`	`786`	`go s.Flood(addrFn, s.serfWAN)`
`787`	`787`	`}`