Communicator

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

Bases: lsst.ts.MTMount.ClientServerPair

Read and write BaseMessages using Tekniker’s communication protocol.

Data is written to the client socket and read from the (single) server socket.

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.

read_replies : bool

If True then read replies, else read commands, on the server port.

connect_client : bool (optional)

Connect the client at construction time?

connect_callback : callable (optional)

Synchronous function to call when a connection is made or dropped.

Notes

Tekniker’s OperationManager software connects to each component (PXI, EUI and HHD) using two TCP/IP sockets:

• A client socket for output; data is only written to this socket.

  For the PXI this is used to send commands. For EUI and HDD this is used to send replies.

• A server socket for input; data is only read from this socket.

  For the PXI this is used to read replies. For EUI and HDD this is used to read commands.

Attributes Summary

client_connected	Is the client connected?
connect_retry_interval
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.
monitor_client_reader()	Monitor the client reader; if it closes then close the writer.
read()	Read and return a message.
wait_server_port()	Wait for the server to start, then return the port.
write(message)	Write a message.

Attributes Documentation

client_connected

Is the client connected?

connect_retry_interval = 0.1

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.

monitor_client_reader()

Monitor the client reader; if it closes then close the writer.

read()

Read and return a message. Waits indefinitely.

Returns:

message : BaseMessage

The message read.

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.

write(message)

Write a message.

Parameters:

message : BaseMessage

Message to write.