Class RotatingFileSink

packages/agent-core/src/logging/sinks.ts:33–221

}

export class RotatingFileSink implements Sink {
  private readonly queue = new AsyncSerialQueue();
  private pending: string[] = [];
  private dropped = 0;
  private closed = false;
  private lastStderrNotice = 0;
  private currentBytes = -1;
  private directorySynced = false;

  constructor(private readonly options: RotatingFileSinkOptions) {}

  enqueue(line: string): void {
    if (this.closed) return;
    if (this.pending.length >= PENDING_MAX) {
      this.pending.shift();
      this.dropped++;
    }
    this.pending.push(line);
    this.scheduleDrain();
  }

  async flush(): Promise<boolean> {
    return this.queue.run(() => this.drain());
  }

  async close(): Promise<void> {
    if (this.closed) return;
    this.closed = true;
    try {
      await this.flush();
    } catch {
      // swallow — close must not throw
    }
  }

  flushSync(): void {
    if (this.closed || this.pending.length === 0) return;
    try {
      mkdirSync(dirname(this.options.path), { recursive: true });
      const body = this.pending.join('') + this.takeDroppedNotice();
      this.pending = [];
      appendFileSync(this.options.path, body);
    } catch (error) {
      this.noteFailure(error);
    }
  }

  private scheduleDrain(): void {
    if (this.closed) return;
    queueMicrotask(() => {
      if (this.closed || this.pending.length === 0) return;
      this.queue.run(() => this.drain()).catch(() => {});
    });
  }

  private async drain(): Promise<boolean> {
    if (this.pending.length === 0) return true;
    const droppedLine = this.takeDroppedNotice();