Logging

The runtime reports through a Logger. Configure it when constructing the actor system; every actor can reach the same logger from a lifecycle Context via ctx.logger().

import { ActorSystem, JsonLogger, discardLogger } from "@tochemey/nodeakt";

const system = new ActorSystem("orders", {
  logger: new JsonLogger({ level: "debug" }),
});

Pass discardLogger to drop every entry. The worker pool stays quiet when the system logger is discardLogger.

Logger

Method	Meaning
debug / info / warn / error	Emit a message and optional structured fields.
level()	Minimum level this logger emits: a Level (debug, info, warn, error, or off). EntryLevel excludes off: the levels an entry can carry.
enabled(level)	Whether an entry at that level would be written.
with(fields)	Returns a logger whose every entry also carries those fields.

Fields is Record<string, unknown>. Per-entry fields are LazyFields: ready-made Fields, or a function that builds them; pass a function when building them is expensive, and it runs only if that level is enabled.

A call below the configured level returns without allocating. Implementations must keep disabled calls cheap.

JsonLogger

The default. Each entry is one JSON line on standard error at info and above. The constructor takes JsonLoggerOptions:

new JsonLogger({
  level: "info",          // default
  stream: process.stderr, // default
  fields: { service: "orders" },
});

Line shape: time (ISO 8601), level, and msg first, then bound fields and per-entry fields. Error values serialize as { name, message, stack }. A circular payload still produces a line carrying the message and unserializable: true instead of throwing into the caller.

defaultLogger is new JsonLogger(): info level, stderr, no bound fields.

From an actor

Context (handed to preStart and postStop) exposes the system logger:

preStart(ctx: Context): void {
  ctx.logger().info("starting", { actor: ctx.actorName() });
}