Poll Failure Tracker

Track poll failures for the PaSD bus and report them as a snapshot.

class PollFailureSnapshot(fndh_total, fncc_total, smartbox_totals, fndh_in_window, fncc_in_window, smartbox_in_window)

Immutable snapshot of poll-failure state.

Carries both cumulative counts (since the tracker was created) and the number of failures observed within the most recent sliding window.

__init__(fndh_total, fncc_total, smartbox_totals, fndh_in_window, fncc_in_window, smartbox_in_window)

class PollFailureTracker(window, prune_interval, logger, on_changed)

Track and report poll failures for the PaSD bus.

Whenever state changes (a new failure is recorded or a sliding window value is re-calculated), a single PollFailureSnapshot is delivered to the on_changed callback.

__init__(window, prune_interval, logger, on_changed)

Initialise a new instance.

Parameters:

• window (float) – sliding-window length in seconds.

• prune_interval (float) – how often (seconds) to prune expired timestamps.

• logger (Logger) – logger for this object to use.

• on_changed (Callable[[PollFailureSnapshot], None]) – callable invoked with a fresh snapshot whenever the cumulative or windowed counts change.

cleanup()

Stop the prune timer and prevent further rescheduling.

Return type:

None

record_poll_failure(device_id)

Record a failed poll for a PaSD device.

Increments the cumulative counter for the device, appends a timestamp to its sliding window, and emits a snapshot if the resulting state differs from the previous one.

Parameters:

device_id (int) – id of the PaSD device whose poll just failed.

Return type:

None