PersistentActor

Defined in: src/persistence/PersistentActor.ts:58

Classic-style event-sourced actor. Subclasses override onCommand (which decides what to persist), onEvent (pure state update from the event), and optionally onRecoveryComplete. Commands are automatically stashed while persist(...) is pending, so user code can assume the state is caught up by the time its callback fires.

class AccountActor extends PersistentActor<Cmd, Event, State> { readonly persistenceId = ‘account-42’; initialState(): State { return { balance: 0 }; } onEvent(state: State, e: Event): State { if (e.kind === ‘deposited’) return { balance: state.balance + e.amount }; return state; } onCommand(state: State, cmd: Cmd): void { if (cmd.kind === ‘deposit’) { this.persist({ kind: ‘deposited’, amount: cmd.amount }, (s) => { this.sender?.tell({ ok: s.balance }); }); } } }

Extends

Actor<Cmd>

Extended by

PersistentFSM

Type Parameters

Cmd

Cmd

Event

Event

State

State

Constructors

Constructor

new PersistentActor<Cmd, Event, State>(): PersistentActor<Cmd, Event, State>

Returns

PersistentActor<Cmd, Event, State>

Inherited from

Actor.constructor

Properties

persistenceId

abstract readonly persistenceId: string

Defined in: src/persistence/PersistentActor.ts:59

Methods

compression()

compression(): CompressionConfig | undefined

Defined in: src/persistence/PersistentActor.ts:106

Per-actor compression — overrides the plugin default for THIS actor’s snapshots. Stores that don’t compress (in-memory, SQLite, Cassandra) ignore the value. Returning undefined (the default) defers to the plugin’s resolver / configured default.

Returns

CompressionConfig | undefined

encryption()

encryption(): EncryptionConfig | undefined

Defined in: src/persistence/PersistentActor.ts:114

Per-actor encryption — overrides the plugin default for THIS actor’s snapshots. Honoured by stores that encrypt at rest (object-storage); other stores ignore it. Used on both the write path (encrypt) and the read path (derive subkey from master to decrypt).

Returns

EncryptionConfig | undefined

eventAdapter()

eventAdapter(): EventAdapter<Event, Event> | undefined

Defined in: src/persistence/PersistentActor.ts:90

Optional event adapter for schema evolution. When defined, every persisted event is wrapped into a { _v, _t, _e } envelope on the write path and unwrapped (with up-casting through the adapter) on the read path. Recovery is strict when an adapter is set: a raw, non-envelope event in the journal will throw MigrationError. See src/persistence/migration/.

Returns

EventAdapter<Event, Event> | undefined

initialState()

abstract initialState(): State

Defined in: src/persistence/PersistentActor.ts:62

Default initial state when no snapshot and no events exist.

Returns

State

onCommand()

abstract onCommand(state, cmd): void | Promise<void>

Defined in: src/persistence/PersistentActor.ts:68

Handle an incoming command — typically calls persist(event, cb).

Parameters

state

State

cmd

Cmd

Returns

void | Promise<void>

onEvent()

abstract onEvent(state, event): State

Defined in: src/persistence/PersistentActor.ts:65

Pure state-update function — MUST be deterministic.

Parameters

state

State

event

Event

Returns

State

onReceive()

onReceive(message): Promise<void>

Defined in: src/persistence/PersistentActor.ts:209

Main message handler. Receives each envelope dequeued from the mailbox. A thrown error (sync or async) is caught by the supervisor.

Parameters

message

Cmd

Returns

Promise<void>

Overrides

Actor.onReceive

onRecoveryComplete()

onRecoveryComplete(_state): void | Promise<void>

Defined in: src/persistence/PersistentActor.ts:71

Called once recovery finishes, with the final replayed state.

Parameters

_state

State

Returns

void | Promise<void>

onRecoveryFailure()

onRecoveryFailure(reason): void

Defined in: src/persistence/PersistentActor.ts:74

Called when recovery itself throws. Default = propagate to supervision.

Parameters

reason

Error

Returns

void

postRestart()

postRestart(_reason): void | Promise<void>

Defined in: src/Actor.ts:55

Called on the fresh instance after a restart. Default: call preStart().

Parameters

_reason

Error

Returns

void | Promise<void>

Inherited from

Actor.postRestart

postStop()

postStop(): void | Promise<void>

Defined in: src/Actor.ts:44

Called after the actor has been terminated. Children are already stopped.

Returns

void | Promise<void>

Inherited from

Actor.postStop

preRestart()

preRestart(_reason, _message?): void | Promise<void>

Defined in: src/Actor.ts:50

Called before a restart, on the instance about to be thrown away. The default stops children and then calls postStop().

Parameters

_reason

Error

_message?

Cmd

Returns

void | Promise<void>

Inherited from

Actor.preRestart

preStart()

preStart(): Promise<void>

Defined in: src/persistence/PersistentActor.ts:138

Called after construction and before the first message is processed.

Returns

Promise<void>

Overrides

Actor.preStart

snapshotAdapter()

snapshotAdapter(): SnapshotAdapter<State, State> | undefined

Defined in: src/persistence/PersistentActor.ts:98

Optional snapshot adapter — same semantics as eventAdapter, but applied to the state blob persisted by the snapshot store. When a snapshot adapter is set and a stored snapshot is not an envelope, recovery throws.