Clock#

class lsst.ts.watcher.rules.Clock(config, log=None)#

Bases: BaseRule

Monitor the system clock of a SAL component using the heartbeat event.

Set alarm severity WARNING if the absolute value of the clock error is above the configured threshold for min_errors sequential heartbeat events. The clock error is computed as the difference between the time the heartbeat event was sent and received; thus some delay is inevitable.

Parameters:

config (types.SimpleNamespace) – Rule configuration, as validated by the schema.
log (logging.Logger, optional) – Parent logger.

Notes

The alarm name is f”Clock.{name}:{index}”, where name and index are derived from config.name.

Attributes Summary

min_errors

Number of sequential errors required for a failure

Methods Summary

`compute_alarm_severity`(data[, topic_callback])	Compute and set alarm severity and reason.
`get_schema`()	Return a jsonschema as a `dict`, to validate configuration.

Attributes Documentation

min_errors = 3#: Number of sequential errors required for a failure

Methods Documentation

compute_alarm_severity(data, topic_callback=None)#

Compute and set alarm severity and reason.

Parameters:

**kwargs (dict [str, typing.Any]) –

Keyword arguments. If triggered by TopicCallback calling update_alarm_severity, the arguments will be as follows:

data : salobj.BaseMsgType Message from the topic described by topic_callback.
topic_callback : TopicCallback Topic callback wrapper.

Return type:

tuple[AlarmSeverity, str] | None

Returns:

None, if no change or unknown, or a tuple of two values
severity (lsst.ts.xml.enums.Watcher.AlarmSeverity) – The new alarm severity.
reason (str) – Detailed reason for the severity, e.g. a string describing what value is out of range, and what the range is. If severity is NONE then this value is ignored (but still required) and the old reason is retained until the alarm is reset to nominal state.

Notes

You may return NoneNoReason if the alarm state is NONE.

Parameters:

data (BaseMsgType)
topic_callback (TopicCallback | None, default: None)

classmethod get_schema()#

Return a jsonschema as a dict, to validate configuration.

Notes

Please provide default values for all fields for which defaults make sense. This makes watcher configuration files easier to write.

If your rule has no configuration then return None.

We recommend that you write the schema as yaml, for compactness, then use yaml.safe_load to convert it to a dict. For example:

schema_yaml = """
    $schema: http://json-schema.org/draft-07/schema#
    description: Configuration for MyRule
    type: object
    properties:
    ...
    required: [...]
    additionalProperties: false
"""
return yaml.safe_load(schema_yaml)