ControllerEvent¶

class lsst.ts.salobj.topics.ControllerEvent(salinfo: SalInfo, name: str)¶

Bases: lsst.ts.salobj.topics.write_topic.WriteTopic

Write a specific event topic.

Parameters

salinfoSalInfo: SAL component information
namestr: Event topic name

Attributes Summary

`DataType`	The type (class) for a message of this topic.
`data`	Internally cached message.
`has_data`	Has `data` ever been set?
`metadata`	Get topic metadata as a `TopicMetadata`, if available,else None.
`volatile`	Does this topic have volatile durability?

Methods Summary

`basic_close`()	A synchronous and possibly less thorough version of `close`.
`close`()	Shut down and release resources.
`put`([data, priority])	Output this topic.
`set`(**kwargs)	Set one or more fields of message data cache `self.data`.
`set_put`(*[, force_output])	Set zero or more fields of `self.data` and put if changed or if `force_output` true.

Attributes Documentation

DataType¶

The type (class) for a message of this topic.

When you read or write a message for this topic you are reading or writing an instance of DataType.

Notes

The preferred way to write a message for a topic is:

RemoteCommand.set_start to start a command.
CommandEvent.set_put to write an event.
CommandTelemetry.set_put to write a telemetry message.

However, it is also possible to use DataType to create a message, then write, it as separate operations. For example, assuming we have a Remote for SAL component “Test”:

# The preferred way to issue a command:
await = remote.cmd_wait.set_put(duration=2, timeout=5)

# But an alternative is to first create the command,
# then send it, as two separate operations:
message = remote.cmd_wait.DataType(duration=2)
await remote.cmd_wait.start(message, timeout=5)

# Or, even more verbosely:
message = remote.cmd_wait.DataType()
message.duration = 2
await remote.cmd_wait.start(message, timeout=5)

data¶

Internally cached message.

Raises

TypeError: If data is not an instance of DataType

Notes

Do not assume the data will be constant. You can make a copy using copy.copy(data).

has_data¶: Has data ever been set?

metadata¶: Get topic metadata as a TopicMetadata, if available,else None.

volatile¶: Does this topic have volatile durability?

Methods Documentation

basic_close() → None¶

A synchronous and possibly less thorough version of close.

Intended for exit handlers and constructor error handlers.

async close() → None¶

Shut down and release resources.

Intended to be called by SalInfo.close(), since that tracks all topics.

put(data: Optional[lsst.ts.salobj.type_hints.BaseDdsDataType] = None, priority: int = 0) → None¶

Output this topic.

Parameters

dataself.DataType or None: New message data to replace self.data, if any.
priorityint, optional: Priority; used to set the priority field of events. Ignored for commands and telemetry.

Raises

TypeError: If data is not None and not an instance of DataType.

set(**kwargs: Any) → bool¶

Set one or more fields of message data cache self.data.

Parameters

**kwargsdict [str, any]

Dict of field name: new value for that field:

Any key whose value is None is checked for existence, but the value of the field is not changed.
If the field being set is an array then the value must either be an array of the same length or a scalar (which replaces every element of the array).

Returns

did_changebool: True if self.data was changed, or if this was the first call to set.

Raises

AttributeError: If the topic does not have the specified field.
ValueError: If the field cannot be set to the specified value.

Notes

If one or more fields cannot be set, the message data may be partially updated.

set_put(*, force_output: bool = False, **kwargs: Any) → bool¶

Set zero or more fields of self.data and put if changed or if force_output true.

The data is put if it has never been set (has_data False), or this call changes the value of any field, or force_output is true.

Parameters

force_outputbool, optional: If True then output the event, even if no fields have changed.
**kwargsdict [str, any]: The remaining keyword arguments are field name = new value for that field. See set for more information about values.

Returns

did_putbool: True if the data was output, False otherwise

Raises

AttributeError: If the topic does not have the specified field.
ValueError: If the field cannot be set to the specified value.

Navigation

ControllerEvent¶