Controller

class lsst.ts.salobj.Controller(name, index=None, *, do_callbacks=False)

Bases: object

A class that receives commands for a SAL component and sends telemetry and events from that component.

This class provides much of the behavior for BaseCsc, basically everything except the standard summary states and associated transition commands.

Parameters:

name : str

Name of SAL component.

index : int or None (optional)

SAL component index, or 0 or None if the component is not indexed. A value is required if the component is indexed.

do_callbacks : bool (optional)

Set do_<name> methods as callbacks for commands? If True then there must be exactly one do_<name> method for each command.

Notes

Writing a Controller

(To write a CSC see Writing a CSC, instead)

To write a controller that is not a CSC (one that does not provide the standard summary states and associated state transition commands):

• Inherit from this class.
• Provide all Required Logging Attributes; these are automatically provided to CSCs, but not other controllers.
• Implement close_tasks.

Here is an example that makes a Test controller and displays the topic-related attributes, but has no code to do anything useful with those topics (see TestCsc for that):

include salobj

# the index is arbitrary, but a remote must use the same index
# to talk to this controller
test_controller = salobj.Controller("Test", index=5)
print(dir(test_controller))

You should see the following topic-related attributes:

• Commands, each an instance of topics.ControllerCommand:

  • cmd_standby
  • cmd_start
  • … and so on for all other standard CSC commands
  • cmd_setArrays
  • cmd_setScalars

• Events, each an instance of topics.ControllerEvent:

  • evt_appliedSettingsMatchStart
  • evt_errorCode
  • … and so on for all other standard CSC events
  • evt_arrays
  • evt_scalars

• Telemetry, each an instance of topics.ControllerTelemetry (note that there are no standard CSC telemetry topics):

  • tel_arrays
  • tel_scalars

Required Logging Attributes

Each Controller must support the following topics, as specified in ts_xml in SALGenerics.xml:

• setLogLevel command
• logLevel event
• logMessage event

Attributes:

log : logging.Logger

A logger.

salinfo : SalInfo

SAL info.

cmd_<command_name> : topics.ControllerCommand

Controller command topic. There is one for each command supported by the SAL component.

evt_<event_name> : topics.ControllerEvent

Controller event topic. There is one for each event topic supported by the SAL component.

tel_<telemetry_name> : topics.ControllerTelemetry

Controller telemetry topic. There is one for each telemetry topic supported by the SAL component.

Attributes Summary

domain

Methods Summary

close([exception])	Shut down, clean up resources and set done_task done.
close_tasks()	Shut down pending tasks.
do_setLogLevel(data)	Set logging level.
put_log_level()	Output the logLevel event.
start()	Finish construction.

Attributes Documentation

domain

Methods Documentation

close(exception=None)

Shut down, clean up resources and set done_task done.

May be called multiple times. The first call closes the Controller; subsequent calls wait until the Controller is closed.

Subclasses should override close_tasks instead of close, unless you have a good reason to do otherwise.

Parameters:

exception : Exception (optional)

The exception that caused stopping, if any, in which case the self.done_task exception is set to this value. Specify None for a normal exit, in which case the self.done_task result is set to None.

Notes

Removes the SAL log handler, calls close_tasks to stop all background tasks, pauses briefly to allow final SAL messages to be sent, then closes the dds domain.

close_tasks()

Shut down pending tasks. Called by close.

Perform all cleanup other than disabling logging to SAL and closing the dds domain.

do_setLogLevel(data)

Set logging level.

Parameters:

data : cmd_setLogLevel.DataType

Logging level.

put_log_level()

Output the logLevel event.

start()

Finish construction.