Trace¶
zelos_sdk.trace
¶
TraceSourceCache(name, namespace=None)
¶
A TraceSource wrapper that caches the last value of each field.
Uses a Rust core for cache storage, condition evaluation, and emit decisions. Python layer provides Pythonic attribute navigation.
Example: source = TraceSourceCache("motor_controller") source.add_event("motor_stats", [ TraceEventFieldMetadata("rpm", DataType.Float64), TraceEventFieldMetadata("torque", DataType.Float64, "Nm") ]) source.log("motor_stats", {"rpm": 3500.0, "torque": 42.8}) assert source.motor_stats.rpm.get() == 3500.0
add_event(name, schema, conditions=None, event_type=None)
¶
Register schema (a field list or a class with FIELDS), as
TraceSource.add_event. conditions maps field name to its own
log condition; unlisted fields take the default.
add_value_table(name, field_name, data)
¶
Register a value table (enum mapping).
Register the event and field with add_event first: a key is typed
by the field it labels, so there is nothing to type it against
otherwise.
flush()
¶
Flush buffered rows to the router.
get_source()
¶
Not supported — use the cache API directly.
log(name, data)
¶
Log data and update cache. Auto-registers event if not yet registered.
log_at(time_ns, name, data)
¶
Log data at a specific timestamp. Raises ValueError when the
emit fails, as TraceSource.log_at does.
log_batch(event_name, data)
¶
Log a pyarrow.RecordBatch or Table, as TraceSource.log_batch.
Each column's last non-null value is cached.
log_many(events)
¶
Log (time_ns, name, data) rows in order, as TraceSource.log_many.
set_default_log_condition(condition=_DEFAULT)
¶
Default condition for fields without their own; each field takes a
copy. With no argument it is DefaultLogCondition(); None
removes it, so those fields log every row.
TraceSourceCacheLastEvent(name, cache, source, conditions=None)
¶
A cached event with attribute access to fields and submessages.
Example: event = source.motor_stats event.rpm.get() # field access event.thermal.temp.get() # submessage access event.log(rpm=3500) # log via event
time_ns
property
¶
Wall-clock timestamp of the last log call for this event, in
nanoseconds since the Unix epoch. None if the event hasn't
been logged yet. Symmetric with 
meth:TraceSourceCacheLastField.get.
TraceSourceCacheLastField(name, full_path, data_type, cache, event_name, condition=None, uses_default=False)
¶
A cached field that stores the last logged value.
Example: field = event.rpm field.get() # Get cached value field.name # Full path: "motor_stats.rpm"