s3: register the advertised ip with the master (#10482)

* s3: register the advertised ip with the master

The cluster address came from the bind ip, falling back to the
auto-detected interface, so -ip never reached the S3 registration.
weed mini -ip=localhost binds the wildcard and ended up registering
whatever interface happened to sort first -- on a host with VPN
interfaces, an address that stops routing once the tunnel drops.

IAM changes are pushed to registered S3 servers over gRPC, so every
mutation then blocked the full 10s propagation deadline before logging
a failure, and cluster.ps and the admin UI listed a node nothing could
reach. Identities still arrived through the /etc/iam metadata
subscription, so this cost latency and visibility, not credentials.

Add an advertise ip to the gateway option, preferring it over the bind
address, and wire the parent -ip through server, filer and mini.

* s3: treat any unspecified bind address as a wildcard

net.ParseIP + IsUnspecified covers ::, [::] and the expanded IPv6 forms
instead of only the 0.0.0.0 literal, so an IPv6 wildcard bind no longer
registers an address peers cannot dial. Host names parse as nil and stay
addresses in their own right. Apply the same guard to the advertised ip.

weed/s3api/s3api_server.go

@@ -58,9 +58,10 @@ type S3ApiServerOption struct {
 	IamConfig                 string // Advanced IAM configuration file path
 	ConcurrentUploadLimit     int64
 	ConcurrentFileUploadLimit int64
-	EnableIam                 bool // Enable embedded IAM API on the same port
-	IamReadOnly               bool // Disable IAM write operations on this server
-	Cipher                    bool // encrypt data on volume servers
+	EnableIam                 bool   // Enable embedded IAM API on the same port
+	IamReadOnly               bool   // Disable IAM write operations on this server
+	Cipher                    bool   // encrypt data on volume servers
+	Ip                        string // address advertised to the cluster; empty falls back to BindIp
 	BindIp                    string
 	GrpcPort                  int
 	ExternalUrl               string // external URL clients use, for signature verification behind a reverse proxy
@@ -132,6 +133,30 @@ func NewS3ApiServer(router *mux.Router, option *S3ApiServerOption) (s3ApiServer
 	return NewS3ApiServerWithStore(router, option, "")
 }
 
+// advertisedHost is the address this server registers with the master, which is
+// how peers reach it — IAM changes are pushed to it over gRPC. It must be the
+// advertised -ip, not the bind address: binding 0.0.0.0 and registering the
+// auto-detected interface makes those pushes dial a host that may not route
+// back here at all (a VPN address, a container-internal IP), and the push then
+// fails silently after a 10s deadline.
+func (option *S3ApiServerOption) advertisedHost() string {
+	if option.Ip != "" && !isWildcardHost(option.Ip) {
+		return option.Ip
+	}
+	if option.BindIp != "" && !isWildcardHost(option.BindIp) {
+		return option.BindIp
+	}
+	return util.DetectedHostAddress()
+}
+
+// isWildcardHost reports whether host is an unspecified address (0.0.0.0, ::,
+// [::]) — one that accepts connections but tells a peer nothing about where to
+// reach us. Host names parse as nil and are addresses in their own right.
+func isWildcardHost(host string) bool {
+	ip := net.ParseIP(strings.TrimSuffix(strings.TrimPrefix(host, "["), "]"))
+	return ip != nil && ip.IsUnspecified()
+}
+
 func NewS3ApiServerWithStore(router *mux.Router, option *S3ApiServerOption, explicitStore string) (s3ApiServer *S3ApiServer, err error) {
 	if len(option.Filers) == 0 {
 		return nil, fmt.Errorf("at least one filer address is required")
@@ -174,10 +199,7 @@ func NewS3ApiServerWithStore(router *mux.Router, option *S3ApiServerOption, expl
 		for i, addr := range option.Masters {
 			masterMap[fmt.Sprintf("master%d", i)] = addr
 		}
-		clientHost := option.BindIp
-		if clientHost == "0.0.0.0" || clientHost == "" {
-			clientHost = util.DetectedHostAddress()
-		}
+		clientHost := option.advertisedHost()
 		masterClient = wdclient.NewMasterClient(option.GrpcDialOption, option.FilerGroup, cluster.S3Type, pb.ServerAddress(util.JoinHostPort(clientHost, option.GrpcPort)), option.DataCenter, "", *pb.NewServiceDiscoveryFromMap(masterMap))
 		// Build the object-write lock client and subscribe to the master's
 		// lock-ring updates BEFORE starting the master loop, so the initial