# BaseCsc¶

class lsst.ts.salobj.BaseCsc(name, index=None, initial_state=<State.STANDBY: 5>, settings_to_apply='', simulation_mode=0)

Base class for a Commandable SAL Component (CSC)

To implement a CSC in Python define a subclass of this class.

Parameters: name : str Name of SAL component. index : SAL component index, or 0 or None if the component is not indexed. initial_state : State or int, optional Initial state for this CSC. Typically State.STANDBY (or State.OFFLINE for an externally commandable CSC) but can also be State.DISABLED, or State.ENABLED, in which case you may also want to specify settings_to_apply for a configurable CSC. settings_to_apply : str, optional Settings to apply if initial_state is State.DISABLED or State.ENABLED. Ignored if the CSC is not configurable. simulation_mode : int, optional Simulation mode. The default is 0: do not simulate. ValueError If initial_state is invalid. salobj.ExpectedError If simulation_mode is invalid. Note: you will only see this error if you await start_task.

Notes

Constructor

The constructor does the following, beyond the parent class constructor:

• For each command defined for the component, find a do_<name> method (which must be present) and add it as a callback to the cmd_<name> attribute.

• The base class provides asynchronous do_<name> methods for the standard CSC commands. The default implementation is as follows (if any step fails then the remaining steps are not performed):

• Check for validity of the requested state change; if the change is valid then:
• Call begin_<name>. This is a no-op in the base class, and is available for the subclass to override. If this fails, then log an error and acknowledge the command as failed.
• Change self.summary_state.
• Call end_<name>. Again, this is a no-op in the base class, and is available for the subclass to override. If this fails then revert self.summary_state, log an error, and acknowledge the command as failed.
• Call handle_summary_state and report_summary_state to handle report the new summary state. If this fails then leave the summary state updated (since the new value may have been reported), but acknowledge the command as failed.
• Acknowledge the command as complete.
• Set the summary state.

• Run start asynchronously.

Attributes: default_initial_state : State A class attribute. Default initial state. Leave at State.STANDBY for most CSCs; set to State.OFFLINE for externally commandable CSCs. enable_cmdline_state : State A class attribute. If True then add --state and (if a subclass of ConfigurableCsc) --settings command-line arguments. The default is False because CSCs should start in default_initial_state unless we have good reason to do otherwise. require_settings : bool A class attribute. Controls whether the --settings command-line argument is required if --state is specified. Ignored unless enable_cmdline_state is True and the CSC is a subclass of ConfigurableCsc. valid_simulation_modes : A class attribute. If not None has the following effect: simulation_mode will be checked in the constructor implement_simulation_mode will be a no-op. The amain command parser will have a --simulate argument. The default value will be 0 if that is a valid simulation mode (and it certainly should be). Otherwise the default value will be the first entry. heartbeat_interval : float Interval between heartbeat events, in seconds;

Attributes Summary

 default_initial_state disabled_or_enabled Return True if the summary state is State.DISABLED or State.ENABLED. domain enable_cmdline_state require_settings simulation_mode Get the current simulation mode. summary_state Get the summary state as a State enum. valid_simulation_modes

Methods Summary

 add_arguments(parser) Add arguments to the parser created by make_from_cmd_line. add_kwargs_from_args(args, kwargs) Add constructor keyword arguments based on parsed arguments. amain(index, **kwargs) Make a CSC from command-line arguments and run it. assert_enabled([action]) Assert that an action that requires ENABLED state can be run. begin_disable(data) Begin do_disable; called before state changes. begin_enable(data) Begin do_enable; called before state changes. begin_exitControl(data) Begin do_exitControl; called before state changes. begin_standby(data) Begin do_standby; called before the state changes. begin_start(data) Begin do_start; called before state changes. close([exception, cancel_start]) Shut down, clean up resources and set done_task done. close_tasks() Shut down pending tasks. do_disable(data) Transition from State.ENABLED to State.DISABLED. do_enable(data) Transition from State.DISABLED to State.ENABLED. do_exitControl(data) Transition from State.STANDBY to State.OFFLINE and quit. do_setAuthList(data) Update the authorization list. do_setLogLevel(data) Set logging level. do_standby(data) Transition from State.DISABLED or State.FAULT to State.STANDBY. do_start(data) Transition from State.STANDBY to State.DISABLED. end_disable(data) End do_disable; called after state changes but before command acknowledged. end_enable(data) End do_enable; called after state changes but before command acknowledged. end_exitControl(data) End do_exitControl; called after state changes but before command acknowledged. end_standby(data) End do_standby; called after state changes but before command acknowledged. end_start(data) End do_start; called after state changes but before command acknowledged. fault(code, report[, traceback]) Enter the fault state and output the errorCode event. handle_summary_state() Called when the summary state has changed. implement_simulation_mode(simulation_mode) Implement going into or out of simulation mode. make_from_cmd_line(index, **kwargs) Construct a CSC from command line arguments. put_log_level() Output the logLevel event. report_summary_state() Report a new value for summary_state, including current state. set_simulation_mode(simulation_mode) Set the simulation mode. start() Finish constructing the CSC.

Attributes Documentation

default_initial_state = 5
disabled_or_enabled

Return True if the summary state is State.DISABLED or State.ENABLED.

This is useful in handle_summary_state to determine if you should start or stop a telemetry loop, and connect to or disconnect from an external controller

domain
enable_cmdline_state = False
require_settings = False
simulation_mode

Get the current simulation mode.

0 means normal operation (no simulation).

Raises: ExpectedError If the new simulation mode is not a supported value.
summary_state

Get the summary state as a State enum.

valid_simulation_modes = None

Methods Documentation

classmethod add_arguments(parser)

Add arguments to the parser created by make_from_cmd_line.

Parameters: parser : argparse.ArgumentParser The argument parser.

Notes

If you override this method then you should almost certainly override add_kwargs_from_args as well.

classmethod add_kwargs_from_args(args, kwargs)

Add constructor keyword arguments based on parsed arguments.

Parameters: args : argparse.namespace Parsed command. kwargs : dict Keyword argument dict for the constructor. Update this based on args. The index argument will already be present if relevant.

Notes

If you override this method then you should almost certainly override add_arguments as well.

classmethod amain(index, **kwargs)

Make a CSC from command-line arguments and run it.

Parameters: index : If the CSC is indexed: specify True make index a required command-line argument that accepts any index, or an enum.IntEnum class to make index a required command-line argument that only accepts the enum values. If the CSC is not indexed specify None or 0. **kwargs : dict, optional Additional keyword arguments for your CSC’s constructor.
assert_enabled(action='')

Assert that an action that requires ENABLED state can be run.

Parameters: action : str, optional Action attempted. Not needed if this is called at the beginning of a do_... method, since the user will know what command was called.
begin_disable(data)

Begin do_disable; called before state changes.

Parameters: data : DataType Command data
begin_enable(data)

Begin do_enable; called before state changes.

Parameters: data : DataType Command data
begin_exitControl(data)

Begin do_exitControl; called before state changes.

Parameters: data : DataType Command data
begin_standby(data)

Begin do_standby; called before the state changes.

Parameters: data : DataType Command data
begin_start(data)

Begin do_start; called before state changes.

Parameters: data : DataType Command data
close(exception=None, cancel_start=True)

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. cancel_start : bool, optional Cancel the start task? Leave this true unless calling this from the start task.

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.

do_disable(data)

Transition from State.ENABLED to State.DISABLED.

Parameters: data : cmd_disable.DataType Command data
do_enable(data)

Transition from State.DISABLED to State.ENABLED.

Parameters: data : cmd_enable.DataType Command data
do_exitControl(data)

Transition from State.STANDBY to State.OFFLINE and quit.

Parameters: data : cmd_exitControl.DataType Command data
do_setAuthList(data)

Update the authorization list.

Parameters: data : cmd_setAuthList.DataType Authorization lists.

Notes

Add items if the data string starts with “+”, ignoring duplicates (both with respect to the existing items and within the data string). Remove items if the data string starts with “-“, ignoring missing items (items specified for removal that do not exist). Ignore whitespace after each comma and after the +/- prefix.

do_setLogLevel(data)

Set logging level.

Parameters: data : cmd_setLogLevel.DataType Logging level.
do_standby(data)

Transition from State.DISABLED or State.FAULT to State.STANDBY.

Parameters: data : cmd_standby.DataType Command data
do_start(data)

Transition from State.STANDBY to State.DISABLED.

Parameters: data : cmd_start.DataType Command data
end_disable(data)

End do_disable; called after state changes but before command acknowledged.

Parameters: data : DataType Command data
end_enable(data)

End do_enable; called after state changes but before command acknowledged.

Parameters: data : DataType Command data
end_exitControl(data)

End do_exitControl; called after state changes but before command acknowledged.

Parameters: data : DataType Command data
end_standby(data)

End do_standby; called after state changes but before command acknowledged.

Parameters: data : DataType Command data
end_start(data)

End do_start; called after state changes but before command acknowledged.

Parameters: data : DataType Command data
fault(code, report, traceback='')

Enter the fault state and output the errorCode event.

Parameters: code : int Error code for the errorCode event. If None then errorCode is not output and you should output it yourself. Specifying None is deprecated; please always specify an integer error code. report : str Description of the error. traceback : str, optional Description of the traceback, if any.
handle_summary_state()

Called when the summary state has changed.

Override to perform tasks such as starting and stopping telemetry (example).

Notes

The versions in BaseCsc and ConfigurableCsc do nothing, so if you subclass one of those you do not need to call await super().handle_summary_state().

implement_simulation_mode(simulation_mode)

Implement going into or out of simulation mode.

Deprecated. See simulation mode for details.

Parameters: simulation_mode : int Requested simulation mode; 0 for normal operation. ExpectedError If simulation_mode is not a supported value.
classmethod make_from_cmd_line(index, **kwargs)

Construct a CSC from command line arguments.

Parameters: index : If the CSC is indexed: specify True make index a required command-line argument that accepts any index, or an enum.IntEnum class to make index a required command-line argument that only accepts the enum values. If the CSC is not indexed specify None or 0. **kwargs : dict, optional Additional keyword arguments for your CSC’s constructor. csc : cls The CSC.

Notes

To add additional command-line arguments, override add_arguments and add_kwargs_from_args.

put_log_level()

Output the logLevel event.

report_summary_state()

Report a new value for summary_state, including current state.

Subclasses may wish to override for code that depends on the current state (rather than the state transition command that got it into that state).

set_simulation_mode(simulation_mode)

Set the simulation mode.

Await implement_simulation_mode, update the simulation mode property and report the new value.

Parameters: simulation_mode : int Requested simulation mode; 0 for normal operation.
start()

Finish constructing the CSC.