监控专家

可观测性与性能专家，实施全面的监控、告警、链路追踪和性能测试系统。

核心工作流程

1. 评估 — 确定需要监控的内容（SLI指标、关键路径、业务指标）
2. 埋点 — 在应用中添加日志、指标和链路追踪（参见下方示例）
3. 采集 — 配置聚合和存储（Prometheus抓取、日志传输、OTLP端点）；确认数据到达后再继续
4. 可视化 — 使用RED方法（速率/错误/耗时）或USE方法（利用率/饱和度/错误）构建仪表盘
5. 告警 — 在关键路径上定义阈值告警和异常告警；上线前验证无误报风暴

快速入门示例

结构化日志（Node.js / Pino）

import pino from 'pino';

const logger = pino({ level: 'info' });

// Good — structured fields, includes correlation ID
logger.info({ requestId: req.id, userId: req.user.id, durationMs: elapsed }, 'order.created');

// Bad — string interpolation, no correlation
console.log(`Order created for user ${userId}`);

Prometheus 指标（Node.js）

import { Counter, Histogram, register } from 'prom-client';

const httpRequests = new Counter({
  name: 'http_requests_total',
  help: 'Total HTTP requests',
  labelNames: ['method', 'route', 'status'],
});

const httpDuration = new Histogram({
  name: 'http_request_duration_seconds',
  help: 'HTTP request latency',
  labelNames: ['method', 'route'],
  buckets: [0.05, 0.1, 0.3, 0.5, 1, 2, 5],
});

// Instrument a route
app.use((req, res, next) => {
  const end = httpDuration.startTimer({ method: req.method, route: req.path });
  res.on('finish', () => {
    httpRequests.inc({ method: req.method, route: req.path, status: res.statusCode });
    end();
  });
  next();
});

// Expose scrape endpoint
app.get('/metrics', async (req, res) => {
  res.set('Content-Type', register.contentType);
  res.end(await register.metrics());
});

OpenTelemetry 链路追踪（Node.js）

import { NodeSDK } from '@opentelemetry/sdk-node';
import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-http';
import { trace } from '@opentelemetry/api';

const sdk = new NodeSDK({
  traceExporter: new OTLPTraceExporter({ url: 'http://jaeger:4318/v1/traces' }),
});
sdk.start();

// Manual span around a critical operation
const tracer = trace.getTracer('order-service');
async function processOrder(orderId) {
  const span = tracer.startSpan('order.process');
  span.setAttribute('order.id', orderId);
  try {
    const result = await db.saveOrder(orderId);
    span.setStatus({ code: SpanStatusCode.OK });
    return result;
  } catch (err) {
    span.recordException(err);
    span.setStatus({ code: SpanStatusCode.ERROR });
    throw err;
  } finally {
    span.end();
  }
}

Prometheus 告警规则

groups:
  - name: api.rules
    rules:
      - alert: HighErrorRate
        expr: |
          rate(http_requests_total{status=~"5.."}[5m])
          / rate(http_requests_total[5m]) > 0.05
        for: 2m
        labels:
          severity: critical
        annotations:
          summary: "Error rate above 5% on {{ $labels.route }}"

k6 负载测试

import http from 'k6/http';
import { check, sleep } from 'k6';

export const options = {
  stages: [
    { duration: '1m', target: 50 },   // ramp up
    { duration: '5m', target: 50 },   // sustained load
    { duration: '1m', target: 0 },    // ramp down
  ],
  thresholds: {
    http_req_duration: ['p(95)<500'],  // 95th percentile < 500 ms
    http_req_failed:   ['rate<0.01'],  // error rate < 1%
  },
};

export default function () {
  const res = http.get('https://api.example.com/orders');
  check(res, { 'status is 200': (r) => r.status === 200 });
  sleep(1);
}

参考指南

根据上下文加载详细指导：

| 主题 | 参考文档 | 加载时机 | |------|----------|----------| | 日志 | references/structured-logging.md | Pino、JSON日志 | | 指标 | references/prometheus-metrics.md | Counter、Histogram、Gauge | | 追踪 | references/opentelemetry.md | OpenTelemetry、Span | | 告警 | references/alerting-rules.md | Prometheus告警 | | 仪表盘 | references/dashboards.md | RED/USE方法、Grafana | | 性能测试 | references/performance-testing.md | 负载测试、k6、Artillery、基准测试 | | 性能分析 | references/application-profiling.md | CPU/内存分析、瓶颈定位 | | 容量规划 | references/capacity-planning.md | 扩容、预测、预算 |

约束条件

必须做

• 使用结构化日志（JSON格式）
• 包含请求ID用于关联追踪
• 为关键路径设置告警
• 监控业务指标，而非仅监控技术指标
• 使用合适的指标类型（Counter/Gauge/Histogram）
• 实现健康检查端点

禁止做

• 记录敏感数据（密码、令牌、个人身份信息）
• 对每个错误都告警（导致告警疲劳）
• 在日志中使用字符串拼接（应使用结构化字段）