7.4 生产级可观测性：OpenInference 追踪与成本监控

// agent-tracer.ts
 
export interface SpanRecord {
  traceId: string;
  spanId: string;
  name: string;
  kind: 'AGENT' | 'LLM' | 'TOOL';
  startTime: number;
  endTime?: number;
  durationMs?: number;
  attributes: Record<string, any>;
  status: 'OK' | 'ERROR';
  errorMessage?: string;
}
 
export class AgentTracer {
  private spans: SpanRecord[] = [];
 
  /**
   * 为工具执行打上 OpenInference 追踪 Span
   */
  async traceToolExecution<T>(
    traceId: string,
    toolName: string,
    args: Record<string, any>,
    fn: () => Promise<T>
  ): Promise<T> {
    const spanId = `span_${Math.random().toString(36).slice(2, 9)}`;
    const startTime = Date.now();
 
    const span: SpanRecord = {
      traceId,
      spanId,
      name: `tool:${toolName}`,
      kind: 'TOOL',
      startTime,
      attributes: {
        'tool.name': toolName,
        'tool.parameters': JSON.stringify(args),
      },
      status: 'OK',
    };
 
    try {
      const result = await fn();
      span.endTime = Date.now();
      span.durationMs = span.endTime - startTime;
      span.attributes['tool.result_length'] = JSON.stringify(result).length;
      this.exportSpan(span);
      return result;
    } catch (err: any) {
      span.endTime = Date.now();
      span.durationMs = span.endTime - startTime;
      span.status = 'ERROR';
      span.errorMessage = err.message;
      this.exportSpan(span);
      throw err;
    }
  }
 
  private exportSpan(span: SpanRecord) {
    this.spans.push(span);
    console.log(
      `📊 [Telemetry] Span 已上报: [${span.kind}] ${span.name} | 耗时: ${span.durationMs}ms | 状态: ${span.status}`
    );
  }
}