ClientServerPair

class lsst.ts.MTMount.ClientServerPair(name, client_host, client_port, server_host, server_port, log, connect_client=True, connect_callback=None)

Bases: object

A TCP/IP client and server combined.

This class exists because Tekniker’s OperationManager software connects to each component using a client and server pair of sockets. The client only writes data and the server only reads data. See Communicator for a higher level abstraction.

Parameters:

name : str

Name used for error messages.

client_host : str

IP address for the output client socket.

client_port : int

IP port for the output client socket.

server_host : str or None

IP address for the input socket server. If None then use all interfaces.

server_port : int

IP port for the input socket server. If 0 then use a random port.

log : logging.Logger

Logger.

connect_client : bool

Connect the client at construction time?

connect_callback : callable or None

Synchronous function to call when a connection is made or dropped. It receives one argument: this ClientServerPair.

Notes

Attributes

• client_host: client host name, a str.
• client_port: client port, an int.
• client_writer: client socket writer, an asyncio.StreamWriter, or None if not connected.
• client_reader: client socket reader, an asyncio.StreamReader or None if not connected.
• connect_task (only available if connect_client true): an asyncio.Task that is set done when connected.

Attributes Summary

client_connected	Is the client connected?
connect_retry_interval	Interval between client connection retries (sec).
connected	Are both the client and server connected?
server_connected	Is the server connected?
server_host
server_port
server_reader	Server reader, an asyncio.StreamReader or None if not connected.
server_writer	Server writer, an asyncio.StreamWriter or None if not connected.

Methods Summary

call_connect_callback(*args, **kwargs)	Call the connect_callback if it exists.
close()	Close both the server and the client, to clean up when finished.
close_client()	Close the client.
connect([port])	Connect the client socket and wait for a connection to the server.
wait_server_port()	Wait for the server to start, then return the port.

Attributes Documentation

client_connected

Is the client connected?

connect_retry_interval = 0.1

Interval between client connection retries (sec).

connected

Are both the client and server connected?

server_connected

Is the server connected?

server_host

server_port

server_reader

Server reader, an asyncio.StreamReader or None if not connected.

server_writer

Server writer, an asyncio.StreamWriter or None if not connected.

Methods Documentation

call_connect_callback(*args, **kwargs)

Call the connect_callback if it exists. Any arguments are ignored.

close()

Close both the server and the client, to clean up when finished.

Set the server done_task done.

close_client()

Close the client.

Warning: does NOT call the connect_callback.

connect(port=None)

Connect the client socket and wait for a connection to the server.

Parameters:

port : int or None (optional)

TCP/IP port. If None use the port specified in the constructor. Being able to specify a port here is primarily for unit tests.

Notes

This will wait forever for a connection.

wait_server_port()

Wait for the server to start, then return the port.

Useful when you have specified port=0, e.g. for unit tests.