ControllerTelemetry

class lsst.ts.salobj.topics.ControllerTelemetry(salinfo, name)

Bases: lsst.ts.salobj.topics.WriteTopic

Write a specific telemetry topic.

Parameters:
salinfo : SalInfo

SAL component information

name : str

Command 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]) Output this topic.
set(**kwargs) Set one or more fields of message data cache self.data.
set_put(**kwargs) Set zero or more fields of self.data and put the result.

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()

A synchronous and possibly less thorough version of close.

Intended for exit handlers and constructor error handlers.

close()

Shut down and release resources.

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

put(data=None)

Output this topic.

Parameters:
data : self.DataType, optional

New message data to replace self.data, if any.

Raises:
TypeError

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

set(**kwargs)

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

Parameters:
**kwargs : dict [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_change : bool

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(**kwargs)

Set zero or more fields of self.data and put the result.

Parameters:
**kwargs : dict [str, any]

The keyword arguments are field name = new value for that field. See set for more information about values.

Returns:
did_change : bool

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.