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

const registry = new Registry();

const requestCounter = new Counter({
  name: 'exa_requests_total',
  help: 'Total Exa API requests',
  labelNames: ['method', 'status'],
  registers: [registry],
});

const requestDuration = new Histogram({
  name: 'exa_request_duration_seconds',
  help: 'Exa request duration',
  labelNames: ['method'],
  buckets: [0.05, 0.1, 0.25, 0.5, 1, 2.5, 5],
  registers: [registry],
});

const errorCounter = new Counter({
  name: 'exa_errors_total',
  help: 'Exa errors by type',
  labelNames: ['error_type'],
  registers: [registry],
});

async function instrumentedRequest<T>(
  method: string,
  operation: () => Promise<T>
): Promise<T> {
  const timer = requestDuration.startTimer({ method });

  try {
    const result = await operation();
    requestCounter.inc({ method, status: 'success' });
    return result;
  } catch (error: any) {
    requestCounter.inc({ method, status: 'error' });
    errorCounter.inc({ error_type: error.code || 'unknown' });
    throw error;
  } finally {
    timer();
  }
}

import { trace, SpanStatusCode } from '@opentelemetry/api';

const tracer = trace.getTracer('exa-client');

async function tracedExaCall<T>(
  operationName: string,
  operation: () => Promise<T>
): Promise<T> {
  return tracer.startActiveSpan(`exa.${operationName}`, async (span) => {
    try {
      const result = await operation();
      span.setStatus({ code: SpanStatusCode.OK });
      return result;
    } catch (error: any) {
      span.setStatus({ code: SpanStatusCode.ERROR, message: error.message });
      span.recordException(error);
      throw error;
    } finally {
      span.end();
    }
  });
}

import pino from 'pino';

const logger = pino({
  name: 'exa',
  level: process.env.LOG_LEVEL || 'info',
});

function logExaOperation(
  operation: string,
  data: Record<string, any>,
  duration: number
) {
  logger.info({
    service: 'exa',
    operation,
    duration_ms: duration,
    ...data,
  });
}

# exa_alerts.yaml
groups:
  - name: exa_alerts
    rules:
      - alert: ExaHighErrorRate
        expr: |
          rate(exa_errors_total[5m]) /
          rate(exa_requests_total[5m]) > 0.05
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "Exa error rate > 5%"

      - alert: ExaHighLatency
        expr: |
          histogram_quantile(0.95,
            rate(exa_request_duration_seconds_bucket[5m])
          ) > 2
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "Exa P95 latency > 2s"

      - alert: ExaDown
        expr: up{job="exa"} == 0
        for: 1m
        labels:
          severity: critical
        annotations:
          summary: "Exa integration is down"

{
  "panels": [
    {
      "title": "Exa Request Rate",
      "targets": [{
        "expr": "rate(exa_requests_total[5m])"
      }]
    },
    {
      "title": "Exa Latency P50/P95/P99",
      "targets": [{
        "expr": "histogram_quantile(0.5, rate(exa_request_duration_seconds_bucket[5m]))"
      }]
    }
  ]
}

app.get('/metrics', async (req, res) => {
  res.set('Content-Type', registry.contentType);
  res.send(await registry.metrics());
});