Server

Description

class lab_utils.socket_comm.Server(config_file: str = None, pid_file_name: str = None)

Daemon-like TCP server. The server connects to the specified host and port and locks a PID file to ensure it is the only instance running.

If successful, the server will then listen indefinitely, waiting for a client to connect. Upon connection, a message is received and passed to the parser. If the message is valid, the parser will call the respective method. The base class provides only the quit() method; users should create new methods suitable for their needs. These methods should always set an appropriate reply, which will be then sent back to the client.

If a message is not valid (i.e. the parser does not support it), an error message and a complete help string is sent back to the client. The help string by the argparse library is not complete and hence is overridden by the ArgumentParser.full_help() method.

TODO: Create some examples of message parsing.

Attributes

Server.address	TCP binding address.
Server.host	Host address.
Server.lock	LockFile object.
Server.logger	Single logger for the whole class.
Server.max_backlog	TCP connection queue.
Server.message	Message from the client.
Server.namespace	Container to hold message options.
Server.parser	Argument parser.
Server.pid_file_name	The PID file name
Server.port	Connection port.
Server.quit_flag	Internal flag to stop the daemon.
Server.reply	Reply to the client.
Server.sock	Connection socket.
Server.socket_timeout	Socket time-out, used for Ctrl+C handling
Server.sp	Argument subparser

Methods

Server.__init__	Initializes and runs the Server object.
Server.config	Loads the server configuration from a file.
Server.create_parser	Configures the message parser, which will call the appropriate method upon reception of a message.
Server.daemonize	Locks a PID file to ensure that a single instance of the server is running.
Server.quit	User-defined task example.
Server.signal_handler
Server.start_daemon	Starts the server.