socket error Errno 48 Address already in use

Question

I m trying to set up a server with python from mac terminal    I navigate to folder location an use    python -m SimpleHTTPServer   But this gives me error    socket error   Errno 48  Address already in use   I had previously open a connection using the same command  for a different website in a different location in my machine

User · Answer

This commonly happened use case for any developer.

It is better to have it as function in your local system. (So better to keep this script in one of the shell profile like ksh/zsh or bash profile based on the user preference)

function killport {
   kill -9 `lsof -i tcp:"$1" | grep LISTEN | awk '{print $2}'`
}

Usage:

killport port_number

Example:

killport 8080

User · Answer

You can allow the server to reuse an address with allow reuse address      Whether the server will allow the reuse of an address  This defaults to False  and can be set in subclasses to change the policy    import SimpleHTTPServer  SocketServer PORT   8000 httpd   SocketServer TCPServer      PORT   SimpleHTTPServer SimpleHTTPRequestHandler  httpd allow reuse address   True print  Serving at port   PORT httpd serve forever

User · Answer

You already have a process bound to the default port  8000   If you already ran the same module before  it is most likely that process still bound to the port  Try and locate the other process first     ps -fA   grep python   501 81651 12648   0  9 53PM ttys000    0 00 16 python -m SimpleHTTPServer   The command arguments are included  so you can spot the one running SimpleHTTPServer if more than one python process is active  You may want to test if http   localhost 8000  still shows a directory listing for local files   The second number is the process number  stop the server by sending it a signal   kill 81651   This sends a standard SIGTERM signal  if the process is unresponsive you may have to resort to tougher methods like sending a SIGKILL  kill -s KILL  lt pid gt  or kill -9  lt pid gt   signal instead  See Wikipedia for more details   Alternatively  run the server on a different port  by specifying the alternative port on the command line     python -m SimpleHTTPServer 8910 Serving HTTP on 0 0 0 0 port 8910       then access the server as http   localhost 8910  where 8910 can be any number from 1024 and up  provided the port is not already taken

User · Answer

You can also serve on the next-highest available port doing something like this in Python   import SimpleHTTPServer import SocketServer  Handler   SimpleHTTPServer SimpleHTTPRequestHandler  port   8000 while True      try          httpd   SocketServer TCPServer      port   Handler          print  Serving on port   port         httpd serve forever       except SocketServer socket error as exc          if exc args 0     48              raise         print  Port   port   already in use          port    1     else          break   If you need to do the same thing for other utilities  it may be more convenient as a bash script      usr bin env bash  MIN PORT   1 -1025  MAX PORT   2 -65535    netstat -atn   awk   printf   s n s n    4   4     grep -oE   0-9      seq   MIN PORT    MAX PORT     sort -R   head -n 1   Set that up as a executable with the name get-free-port and you can do something like this   someprogram --port   get-free-port    That s not as reliable as the native Python approach because the bash script doesn t capture the port -- another process could grab the port before your process does  race condition  -- but still may be useful enough when using a utility that doesn t have a try-try-again approach of its own

User · Answer

Just in case above solutions didn t work    Get the port your process is listening to     ps ax   grep python Kill the Process    kill PROCESS NAME

User · Answer

Simple solution   Find the process using port 8080    sudo lsof -i 8080    Kill the process on that port    kill  PID   PID is got from step 1 s output

User · Answer

Use   sudo lsof -i 5000   This will give you a list of processes using the port if any   Once the list of processes is given  use the id on the PID column to terminate the process use   kill 379  use the provided PID

User · Answer

I am new to Python  but after my brief research I found out that this is typical of sockets being binded  It just so happens that the socket is still being used and you may have to wait to use it  Or  you can just add   tcpSocket setsockopt socket SOL SOCKET  socket SO REUSEADDR  1    This should make the port available within a shorter time  In my case  it made the port available almost immediately

User · Answer

I have a raspberry pi  and I am using python web server  using Flask   I have tried everything above  the only solution is to close the terminal shell  and open it again  Or restart the raspberry pi  because nothing stops that webserver

User · Answer

Simple one line command to get rid of it  type below command in terminal   ps -a   This will list out all process  checkout which is being used by Python and type bellow command in terminal   kill -9  processID     For example kill -9 33178

User · Answer

By the way  to prevent this from happening in the first place  simply press Ctrl C in terminal while SimpleHTTPServer is still running normally  This will  properly  stop the server and release the port so you don t have to find and kill the process again before restarting the server    Mods  I did try to put this comment on the best answer where it belongs  but I don t have enough reputation

[python] socket.error: [Errno 48] Address already in use

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