OpenEvidence Observability

OpenEvidence Observability

Overview

Set up comprehensive observability for OpenEvidence clinical AI integrations in healthcare environments.

Prerequisites

• Prometheus or compatible metrics backend
• OpenTelemetry SDK installed
• Grafana or similar dashboarding tool
• AlertManager or PagerDuty configured

Key Metrics

Instructions

Step 1: Prometheus Metrics

// src/​monitoring/​metrics.ts
import { Registry, Counter, Histogram, Gauge, Summary } from 'prom-client';

const registry = new Registry();

// Request metrics
export const requestCounter = new Counter({
  name: 'openevidence_requests_total',
  help: 'Total OpenEvidence API requests',
  labelNames: ['method', 'specialty', 'status'],
  registers: [registry],
});

export const requestDuration = new Histogram({
  name: 'openevidence_request_duration_seconds',
  help: 'OpenEvidence request duration',
  labelNames: ['method', 'specialty'],
  buckets: [0.5, 1, 2, 5, 10, 15, 30, 60],
  registers: [registry],
});

// Error metrics
export const errorCounter = new Counter({
  name: 'openevidence_errors_total',
  help: 'OpenEvidence errors by type',
  labelNames: ['error_type', 'specialty'],
  registers: [registry],
});

// Cache metrics
export const cacheHits = new Counter({
  name: 'openevidence_cache_hits_total',
  help: 'Cache hit count',
  registers: [registry],
});

export const cacheMisses = new Counter({
  name: 'openevidence_cache_misses_total',
  help: 'Cache miss count',
  registers: [registry],
});

// Rate limit metrics
export const rateLimitRemaining = new Gauge({
  name: 'openevidence_rate_limit_remaining',
  help: 'Remaining rate limit',
  registers: [registry],
});

export const rateLimitPercent = new Gauge({
  name: 'openevidence_rate_limit_usage_percent',
  help: 'Rate limit usage percentage',
  registers: [registry],
});

// DeepConsult metrics
export const deepConsultActive = new Gauge({
  name: 'openevidence_deepconsult_active',
  help: 'Active DeepConsult requests',
  registers: [registry],
});

export const deepConsultDuration = new Histogram({
  name: 'openevidence_deepconsult_duration_seconds',
  help: 'DeepConsult completion time',
  labelNames: ['specialty', 'status'],
  buckets: [30, 60, 120, 180, 300, 600],
  registers: [registry],
});

// Confidence metrics
export const confidenceScore = new Summary({
  name: 'openevidence_confidence_score',
  help: 'Response confidence score distribution',
  labelNames: ['specialty'],
  percentiles: [0.5, 0.9, 0.95, 0.99],
  registers: [registry],
});

export { registry };

Step 2: Instrumented Client Wrapper

// src/​monitoring/​instrumented-client.ts
import { OpenEvidenceClient } from '@openevidence/​sdk';
import {
  requestCounter,
  requestDuration,
  errorCounter,
  cacheHits,
  cacheMisses,
  rateLimitRemaining,
  rateLimitPercent,
  confidenceScore,
} from './​metrics';
import { trace, SpanStatusCode, Span } from '@opentelemetry/​api';

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

export class InstrumentedOpenEvidenceClient {
  private client: OpenEvidenceClient;
  private cache: ClinicalQueryCache;

  constructor(config: any, cache: ClinicalQueryCache) {
    this.client = new OpenEvidenceClient(config);
    this.cache = cache;
  }

  async query(request: ClinicalQueryRequest): Promise<ClinicalQueryResponse> {
    const { specialty } = request.context;

    return tracer.startActiveSpan('openevidence.query', async (span: Span) => {
      const timer = requestDuration.startTimer({ method: 'query', specialty });

      try {
        // Add span attributes
        span.setAttribute('openevidence.specialty', specialty);
        span.setAttribute('openevidence.urgency', request.context.urgency);

        // Check cache first
        const cached = await this.cache.get(request.question, request.context);
        if (cached) {
          cacheHits.inc();
          span.setAttribute('cache.hit', true);
          timer({ cached: 'true' });
          requestCounter.inc({ method: 'query', specialty, status: 'cache_hit' });
          return cached;
        }
        cacheMisses.inc();
        span.setAttribute('cache.hit', false);

        // Make API request
        const response = await this.client.query(request);

        // Update rate limit metrics from headers
        this.updateRateLimitMetrics(response.headers);

        // Record confidence score
        confidenceScore.observe({ specialty }, response.confidence);

        // Cache response
        await this.cache.set(request.question, request.context, response);

        // Record success
        timer({ cached: 'false' });
        requestCounter.inc({ method: 'query', specialty, status: 'success' });
        span.setStatus({ code: SpanStatusCode.OK });

        return response;
      } catch (error: any) {
        // Record error
        timer({ cached: 'false' });
        requestCounter.inc({ method: 'query', specialty, status: 'error' });
        errorCounter.inc({ error_type: error.code || 'unknown', specialty });

        span.setStatus({ code: SpanStatusCode.ERROR, message: error.message });
        span.recordException(error);

        throw error;
      } finally {
        span.end();
      }
    });
  }

  private updateRateLimitMetrics(headers: any): void {
    const remaining = parseInt(headers['x-ratelimit-remaining'] || '0');
    const limit = parseInt(headers['x-ratelimit-limit'] || '100');

    rateLimitRemaining.set(remaining);
    rateLimitPercent.set(((limit - remaining) / limit) * 100);
  }
}

Step 3: Distributed Tracing Setup

// src/​monitoring/​tracing.ts
import { NodeSDK } from '@opentelemetry/​sdk-node';
import { Resource } from '@opentelemetry/​resources';
import { SemanticResourceAttributes } from '@opentelemetry/​semantic-conventions';
import { TraceExporter } from '@google-cloud/​opentelemetry-cloud-trace-exporter';
import { HttpInstrumentation } from '@opentelemetry/​instrumentation-http';
import { ExpressInstrumentation } from '@opentelemetry/​instrumentation-express';

export function initTracing(): void {
  const sdk = new NodeSDK({
    resource: new Resource({
      [SemanticResourceAttributes.SERVICE_NAME]: 'clinical-evidence-api',
      [SemanticResourceAttributes.SERVICE_VERSION]: process.env.npm_package_version,
      [SemanticResourceAttributes.DEPLOYMENT_ENVIRONMENT]: process.env.NODE_ENV,
    }),
    traceExporter: new TraceExporter(),
    instrumentations: [
      new HttpInstrumentation({
        requestHook: (span, request) => {
          // Don't trace health checks
          if (request.url?.includes('/​health')) {
            span.setAttribute('http.skip', true);
          }
        },
      }),
      new ExpressInstrumentation(),
    ],
  });

  sdk.start();

  process.on('SIGTERM', () => {
    sdk.shutdown().catch(console.error);
  });
}

Step 4: Structured Logging

// src/​monitoring/​logger.ts
import pino from 'pino';

export const logger = pino({
  name: 'clinical-evidence-api',
  level: process.env.LOG_LEVEL || 'info',
  formatters: {
    level: (label) => ({ level: label }),
  },
  // Redact PHI fields
  redact: {
    paths: ['patient.*', 'patientId', 'mrn', '*.ssn'],
    censor: '[REDACTED]',
  },
});

// OpenEvidence-specific logger
export const oeLogger = logger.child({ service: 'openevidence' });

export function logClinicalQuery(
  queryId: string,
  specialty: string,
  duration: number,
  cached: boolean,
  confidence?: number
): void {
  oeLogger.info({
    event: 'clinical_query',
    queryId,
    specialty,
    durationMs: duration,
    cached,
    confidence,
  });
}

export function logDeepConsult(
  consultId: string,
  specialty: string,
  status: string,
  duration?: number
): void {
  oeLogger.info({
    event: 'deep_consult',
    consultId,
    specialty,
    status,
    durationMs: duration,
  });
}

export function logError(
  error: Error,
  context: Record<string, any>
): void {
  oeLogger.error({
    event: 'error',
    errorType: error.name,
    errorMessage: error.message,
    ...context,
  });
}

Step 5: Alert Rules

# prometheus/​openevidence_alerts.yaml
groups:
  - name: openevidence_alerts
    rules:
      # High error rate
      - alert: OpenEvidenceHighErrorRate
        expr: |
          rate(openevidence_errors_total[5m]) /
          rate(openevidence_requests_total[5m]) > 0.05
        for: 5m
        labels:
          severity: warning
          service: openevidence
        annotations:
          summary: "OpenEvidence error rate > 5%"
          description: "Error rate is {{ $value | humanizePercentage }}"

      # Critical error rate
      - alert: OpenEvidenceCriticalErrorRate
        expr: |
          rate(openevidence_errors_total[5m]) /
          rate(openevidence_requests_total[5m]) > 0.20
        for: 2m
        labels:
          severity: critical
          service: openevidence
        annotations:
          summary: "OpenEvidence error rate > 20%"
          description: "Critical error rate - possible outage"

      # High latency
      - alert: OpenEvidenceHighLatency
        expr: |
          histogram_quantile(0.95,
            rate(openevidence_request_duration_seconds_bucket[5m])
          ) > 15
        for: 5m
        labels:
          severity: warning
          service: openevidence
        annotations:
          summary: "OpenEvidence P95 latency > 15s"
          description: "95th percentile latency is {{ $value | humanizeDuration }}"

      # Low cache hit rate
      - alert: OpenEvidenceLowCacheHitRate
        expr: |
          rate(openevidence_cache_hits_total[1h]) /
          (rate(openevidence_cache_hits_total[1h]) + rate(openevidence_cache_misses_total[1h])) < 0.5
        for: 30m
        labels:
          severity: warning
          service: openevidence
        annotations:
          summary: "OpenEvidence cache hit rate < 50%"
          description: "Consider reviewing cache configuration"

      # Rate limit warning
      - alert: OpenEvidenceRateLimitWarning
        expr: openevidence_rate_limit_remaining < 10
        for: 1m
        labels:
          severity: warning
          service: openevidence
        annotations:
          summary: "OpenEvidence rate limit < 10 remaining"
          description: "Consider throttling requests"

      # Service down
      - alert: OpenEvidenceDown
        expr: up{job="openevidence"} == 0
        for: 1m
        labels:
          severity: critical
          service: openevidence
        annotations:
          summary: "OpenEvidence integration is down"
          description: "No successful health checks for 1 minute"

Step 6: Grafana Dashboard

{
  "dashboard": {
    "title": "OpenEvidence Clinical AI",
    "panels": [
      {
        "title": "Request Rate",
        "type": "stat",
        "targets": [{
          "expr": "sum(rate(openevidence_requests_total[5m]))",
          "legendFormat": "req/​s"
        }]
      },
      {
        "title": "Error Rate",
        "type": "gauge",
        "targets": [{
          "expr": "sum(rate(openevidence_errors_total[5m])) / sum(rate(openevidence_requests_total[5m])) * 100"
        }],
        "fieldConfig": {
          "defaults": {
            "max": 100,
            "thresholds": {
              "mode": "absolute",
              "steps": [
                {"color": "green", "value": 0},
                {"color": "yellow", "value": 5},
                {"color": "red", "value": 20}
              ]
            }
          }
        }
      },
      {
        "title": "Latency Distribution",
        "type": "heatmap",
        "targets": [{
          "expr": "sum(rate(openevidence_request_duration_seconds_bucket[5m])) by (le)"
        }]
      },
      {
        "title": "Cache Hit Rate",
        "type": "timeseries",
        "targets": [{
          "expr": "sum(rate(openevidence_cache_hits_total[5m])) / (sum(rate(openevidence_cache_hits_total[5m])) + sum(rate(openevidence_cache_misses_total[5m])))",
          "legendFormat": "Hit Rate"
        }]
      },
      {
        "title": "Rate Limit Usage",
        "type": "gauge",
        "targets": [{
          "expr": "openevidence_rate_limit_usage_percent"
        }],
        "fieldConfig": {
          "defaults": {
            "max": 100,
            "thresholds": {
              "mode": "absolute",
              "steps": [
                {"color": "green", "value": 0},
                {"color": "yellow", "value": 70},
                {"color": "red", "value": 90}
              ]
            }
          }
        }
      },
      {
        "title": "Confidence Score Distribution",
        "type": "histogram",
        "targets": [{
          "expr": "openevidence_confidence_score"
        }]
      }
    ]
  }
}

Metrics Endpoint

// src/​routes/​metrics.ts
import { Router } from 'express';
import { registry } from '../​monitoring/​metrics';

const router = Router();

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

export default router;

Output

• Prometheus metrics collection
• Distributed tracing with OpenTelemetry
• Structured logging with PHI redaction
• Alert rules for critical conditions
• Grafana dashboard

Observability Checklist

• Metrics endpoint exposed
• Request counters and histograms
• Error counters with labels
• Cache hit/​miss tracking
• Rate limit monitoring
• Distributed tracing enabled
• Structured logging configured
• Alert rules deployed
• Dashboard created

Resources

• Prometheus Best Practices
• OpenTelemetry Documentation
• Grafana Dashboards

Next Steps

For incident response, see openevidence-incident-runbook.