Standardize -ip.bind flags to default to empty and fall back to -ip (#7945)

* Add documentation for issue #7941 fix

* rm FIX_ISSUE_7941.md

* Standardize -ip.bind flags to default to empty string and fall back to -ip option

- Change s3 command -ip.bind default logic to use -ip instead of localhost
- Change sftp command -ip.bind default to empty and fall back to 0.0.0.0
- Update help text for consistency

* Fix compilation error: add -ip flag to s3 command and update bindIp fallback

* Revert -ip flag addition for s3 command, set bindIp fallback to 0.0.0.0

* Update s3 command -ip.bind help text to reflect correct default behavior

weed/command/s3.go

@@ -68,7 +68,7 @@ type S3Options struct {
 func init() {
 	cmdS3.Run = runS3 // break init cycle
 	s3StandaloneOptions.filer = cmdS3.Flag.String("filer", "localhost:8888", "comma-separated filer server addresses for high availability")
-	s3StandaloneOptions.bindIp = cmdS3.Flag.String("ip.bind", "", "ip address to bind to. Default to localhost.")
+	s3StandaloneOptions.bindIp = cmdS3.Flag.String("ip.bind", "", "ip address to bind to. If empty, default to 0.0.0.0.")
 	s3StandaloneOptions.port = cmdS3.Flag.Int("port", 8333, "s3 server http listen port")
 	s3StandaloneOptions.portHttps = cmdS3.Flag.Int("port.https", 0, "s3 server https listen port")
 	s3StandaloneOptions.portGrpc = cmdS3.Flag.Int("port.grpc", 0, "s3 server grpc listen port")
@@ -302,7 +302,7 @@ func (s3opt *S3Options) startS3Server() bool {
 		*s3opt.portGrpc = 10000 + *s3opt.port
 	}
 	if *s3opt.bindIp == "" {
-		*s3opt.bindIp = "localhost"
+		*s3opt.bindIp = "0.0.0.0"
 	}
 
 	if runtime.GOOS != "windows" {

weed/command/sftp.go

@@ -60,7 +60,7 @@ func init() {
 	cmdSftp.Run = runSftp
 
 	sftpOptionsStandalone.filer = cmdSftp.Flag.String("filer", "localhost:8888", "filer server address (ip:port)")
-	sftpOptionsStandalone.bindIp = cmdSftp.Flag.String("ip.bind", "0.0.0.0", "ip address to bind SFTP server")
+	sftpOptionsStandalone.bindIp = cmdSftp.Flag.String("ip.bind", "", "ip address to bind to. If empty, default to 0.0.0.0.")
 	sftpOptionsStandalone.port = cmdSftp.Flag.Int("port", 2022, "SFTP server listen port")
 	sftpOptionsStandalone.sshPrivateKey = cmdSftp.Flag.String("sshPrivateKey", "", "path to the SSH private key file for host authentication")
 	sftpOptionsStandalone.hostKeysFolder = cmdSftp.Flag.String("hostKeysFolder", "", "path to folder containing SSH private key files for host authentication")
@@ -95,6 +95,9 @@ func runSftp(cmd *Command, args []string) bool {
 }
 
 func (sftpOpt *SftpOptions) startSftpServer() bool {
+	if *sftpOpt.bindIp == "" {
+		*sftpOpt.bindIp = "0.0.0.0"
+	}
 	filerAddress := pb.ServerAddress(*sftpOpt.filer)
 	grpcDialOption := security.LoadClientTLS(util.GetViper(), "grpc.client")