run_collector.ts

import { BaseRun, Run } from "langsmith/schemas";
import { BaseTracer } from "./base.js";

/**
 * A callback handler that collects traced runs and makes it easy to fetch the traced run object from calls through any langchain object.
 * For instance, it makes it easy to fetch the run ID and then do things with that, such as log feedback.
 */
export class RunCollectorCallbackHandler extends BaseTracer {
  /** The name of the callback handler. */
  name = "run_collector";

  /** The ID of the example. */
  exampleId?: string;

  /** An array of traced runs. */
  tracedRuns: Run[];

  /**
   * Creates a new instance of the RunCollectorCallbackHandler class.
   * @param exampleId The ID of the example.
   */
  constructor({ exampleId }: { exampleId?: string } = {}) {
    super({ _awaitHandler: true });
    this.exampleId = exampleId;
    this.tracedRuns = [];
  }

  /**
   * Persists the given run object.
   * @param run The run object to persist.
   */
  protected async persistRun(run: BaseRun): Promise<void> {
    const run_ = { ...run } as Run;
    run_.reference_example_id = this.exampleId;
    this.tracedRuns.push(run_);
  }
}