systemd-socketserver

systemd-socketserver is a simple Python 3 package that provides the SystemdSocketServer class, a socket server implementation that works in tandem with systemd's socket activation feature.

Very useful for writing basic socket activated daemons.

Installation

Install from PyPi:

pip install systemd-socketserver

Or clone from Git and install from source:

setup.py install

Basic Usage

For a full example see the example directory.

The following Python module, when activated via .socket unit, will echo the first sent line to the socket then disconnect.

class EchoHandler(socketserver.StreamRequestHandler):
    def handle(self):
        self.data = self.rfile.readline()
        self.wfile.write(self.data.upper())
        
server = systemd_socketserver.listen_server(EchoHandler)

if server is None:
    print('this example only supports socket activation', file=sys.stderr)
    return
    
server.listen_forever()

Features:

• Supports and auto detects both listen and accept sockets (Accept=true|false in the .socket unit)

• Supports named file descriptors, making it easy to bind different handlers to different sockets.

  This feature relies on functionality currently not present in the most recent package release of python-systemd, namely the listen_fds_with_names function. Calling listen_servers_with_names will throw a NotImplementedException in this case.

  Building python-systemd from source will include support for listen_fds_with_names and hence this feature will work.

  For an example of this functionality see the code in the example directory.

Known Limitations

• This module has only been tested with INET sockets.
• Better documentation TODO.