pharos/alert_manager

Per-threshold alert state machine.

Wraps an eparch/state_machine running the four-state lifecycle Clear -> Pending -> Firing -> Cooling -> Clear. The state machine is registered under a deterministic Name so that supervisor restarts. keep AlertManager handles valid: callers send Breach / Recover casts to the registered name, which the OTP runtime resolves to the current pid on each call.

breach/1 and recover/1 map physical signals (threshold crossed up / down) to state transitions. The dispatcher is notified with AlertFiring and AlertResolved events on the relevant transitions.

Types

AlertManager

opaque </>

Restart-resilient handle to a per-threshold alert state machine.

pub opaque type AlertManager

Message

</>

Internal command messages.

pub type Message {
  Breach
  Recover
  Sample(value: Float)
}

Constructors

```
Breach
```
```
Recover
```
```
Sample(value: Float)
```
A windowed-rule sample. The manager appends it to its bounded window and derives a breach/recover decision from the aggregate.

Values

breach

</>

pub fn breach(manager: AlertManager) -> Nil

Signal that the threshold has been breached.

from_name

</>

pub fn from_name(name: process.Name(Message)) -> AlertManager

Wrap a registered name as an AlertManager. The supervisor uses this to build handles before the underlying state machine has been started, so that the handler-attacher can route breach/recover signals to a stable address.

recover

</>

pub fn recover(manager: AlertManager) -> Nil

Signal that the threshold is no longer breached.

sample

</>

pub fn sample(manager: AlertManager, value: Float) -> Nil

Feed a sample to a windowed rule. The manager folds it into its window and derives breach/recover from the aggregate.

start_link

</>

pub fn start_link(
  data: alert.AlertData,
  bus: event_bus.EventBus,
  name: process.Name(Message),
) -> Result(AlertManager, state_machine.StartError)

Start a state machine for data, registering it under name. Notifies bus with AlertFiring / AlertResolved events on the relevant transitions.