Monitoring & Observability

The monitoring utilities provide comprehensive observability features specifically designed for edge environments, including metrics collection, structured logging, distributed tracing, and health checks.

Features

Metrics Collection: Performance metrics, custom counters, histograms
Structured Logging: JSON-formatted logs with redaction and filtering
Distributed Tracing: Request tracing across edge functions and services
Health Checks: Automated health monitoring and reporting
Performance Monitoring: Response times, throughput, error rates
Log Aggregation: Centralized log collection and analysis
Edge Optimized: Low-overhead monitoring for edge environments
Real-time Dashboards: Live metrics and alerting

Quick Start

const { MetricsCollector, StructuredLogger, TracingManager, HealthCheckManager } = require('edge-utils/monitoring');

// Metrics collection
const metrics = new MetricsCollector({ storage: kvStorage });
metrics.increment('requests_total', 1, { method: 'GET', status: '200' });
metrics.histogram('request_duration', 150, { endpoint: '/api/users' });

// Structured logging
const logger = new StructuredLogger({
  level: 'info',
  format: 'json',
  redaction: ['password', 'apiKey']
});
logger.info('User login successful', { userId: 123, ip: '192.168.1.1' });

// Distributed tracing
const tracer = new TracingManager({
  serviceName: 'edge-api',
  sampler: () => Math.random() < 0.1 // 10% sampling
});
const span = tracer.startSpan('handle_request');

// Health checks
const health = new HealthCheckManager();
health.addCheck('database', async () => {
  const isHealthy = await checkDatabase();
  return { healthy: isHealthy, latency: 5 };
});

MetricsCollector

Comprehensive metrics collection with support for counters, gauges, histograms, and summaries.

Constructor Options

const metrics = new MetricsCollector({
  storage: kvStorage,                   // Optional distributed storage
  prefix: 'edge_',                      // Metric name prefix
  labels: {                            // Global labels
    service: 'edge-api',
    version: '1.0.0',
    region: 'us-east'
  },
  flushInterval: 60000,                // Flush interval in ms (1 minute)
  retention: 7 * 24 * 60 * 60 * 1000,   // Data retention (7 days)
  compression: true,                   // Enable data compression
  aggregation: {                       // Metric aggregation settings
    interval: 60000,                   // Aggregation interval
    functions: ['sum', 'avg', 'min', 'max', 'count']
  }
});

Counter Metrics

// Increment counter
metrics.increment('requests_total', 1, {
  method: 'GET',
  status: '200',
  endpoint: '/api/users'
});

// Increment by custom amount
metrics.increment('bytes_transferred', 1024, {
  direction: 'upload',
  user: 'user123'
});

// Get counter value
const requestCount = await metrics.getCounter('requests_total', {
  method: 'GET',
  status: '200'
});

Gauge Metrics

// Set gauge value
metrics.gauge('active_connections', 42, {
  region: 'us-east',
  instance: 'worker-1'
});

// Update gauge (add/subtract)
metrics.gauge('memory_usage', -50, { type: 'heap' });  // Decrease by 50
metrics.gauge('cpu_usage', 85, { core: '0' });        // Set to 85%

// Get gauge value
const connections = await metrics.getGauge('active_connections');

Histogram Metrics

// Record histogram observation
metrics.histogram('request_duration', 150.5, {
  method: 'POST',
  endpoint: '/api/users',
  status: '200'
});

metrics.histogram('response_size', 2048, {
  contentType: 'application/json'
});

// Get histogram statistics
const stats = await metrics.getHistogram('request_duration', {
  method: 'POST'
});
console.log({
  count: stats.count,
  sum: stats.sum,
  mean: stats.mean,
  median: stats.median,
  p95: stats.p95,
  p99: stats.p99,
  min: stats.min,
  max: stats.max
});

Summary Metrics

// Record summary observation
metrics.summary('api_latency', 250, {
  service: 'user-service',
  operation: 'getUser'
});

// Get summary quantiles
const quantiles = await metrics.getSummary('api_latency', {
  service: 'user-service'
});
console.log({
  '0.5': quantiles.quantile_0_5,   // Median
  '0.9': quantiles.quantile_0_9,   // P90
  '0.95': quantiles.quantile_0_95, // P95
  '0.99': quantiles.quantile_0_99  // P99
});

Custom Metrics

// Define custom metric
metrics.defineMetric('custom_metric', 'histogram', {
  description: 'Custom business metric',
  unit: 'requests',
  buckets: [10, 50, 100, 500, 1000]
});

// Record custom metric
metrics.record('custom_metric', 75, {
  business_unit: 'sales',
  region: 'na'
});

StructuredLogger

JSON-formatted logging with redaction, filtering, and multiple output destinations.

Constructor Options

const logger = new StructuredLogger({
  level: 'info',                       // Log level (error, warn, info, debug)
  format: 'json',                      // Output format (json, text, pretty)
  redaction: ['password', 'apiKey', 'token', 'secret'], // Fields to redact
  filtering: {                         // Log filtering rules
    exclude: ['debug'],                // Exclude debug logs in production
    include: ['error', 'warn']         // Always include errors and warnings
  },
  destinations: [                      // Multiple output destinations
    { type: 'console' },
    { type: 'kv', storage: kvStorage, key: 'logs' },
    { type: 'http', url: 'https://logs.example.com/api/logs' }
  ],
  context: {                          // Global context
    service: 'edge-api',
    version: '1.0.0',
    environment: 'production'
  },
  buffering: {                        // Log buffering for performance
    enabled: true,
    size: 100,                        // Buffer size
    flushInterval: 5000               // Flush interval in ms
  }
});

Logging Methods

// Different log levels
logger.error('Database connection failed', {
  error: error.message,
  stack: error.stack,
  userId: 123
});

logger.warn('Rate limit approaching', {
  current: 95,
  limit: 100,
  userId: 456
});

logger.info('User login successful', {
  userId: 123,
  ip: '192.168.1.1',
  userAgent: 'Mozilla/5.0...'
});

logger.debug('Processing request', {
  requestId: 'req-123',
  params: { id: 123, type: 'user' }
});

Context and Correlation

// Add request context
const requestLogger = logger.child({
  requestId: 'req-123',
  userId: 456,
  sessionId: 'sess-789'
});

// All logs will include the context
requestLogger.info('Processing payment');
requestLogger.debug('Validating card', { cardType: 'visa' });
requestLogger.error('Payment failed', { error: 'insufficient_funds' });

Log Redaction

// Sensitive data is automatically redacted
logger.info('User registration', {
  username: 'john_doe',
  password: 'secret123',        // Will be logged as "[REDACTED]"
  email: 'john@example.com',
  apiKey: 'sk-1234567890'       // Will be logged as "[REDACTED]"
});

// Custom redaction patterns
const customLogger = new StructuredLogger({
  redaction: {
    patterns: [
      /token_[a-zA-Z0-9]+/,     // Redact tokens
      /\b\d{4}-\d{4}-\d{4}-\d{4}\b/  // Redact credit cards
    ],
    replacement: '[SENSITIVE]'
  }
});

Log Filtering

// Filter logs based on conditions
const filteredLogger = new StructuredLogger({
  filtering: {
    include: (log) => log.level === 'error' || log.userId === 'admin',
    exclude: (log) => log.endpoint === '/health',
    sampling: {
      rate: 0.1,  // Sample 10% of debug logs
      levels: ['debug']
    }
  }
});

TracingManager

Distributed tracing with span creation, context propagation, and sampling.

Constructor Options

const tracer = new TracingManager({
  serviceName: 'edge-api',             // Service name
  serviceVersion: '1.0.0',             // Service version
  sampler: (context) => {              // Sampling function
    // Sample 10% of requests
    return Math.random() < 0.1;
  },
  exporter: {                         // Trace export configuration
    type: 'http',
    url: 'https://tracing.example.com/api/traces',
    headers: { 'Authorization': 'Bearer token' }
  },
  propagation: {                      // Context propagation
    formats: ['w3c', 'b3'],           // Supported formats
    extract: true,                    // Extract context from requests
    inject: true                      // Inject context into requests
  },
  storage: kvStorage                  // Optional distributed storage
});

Span Creation

// Start root span
const rootSpan = tracer.startSpan('handle_request', {
  attributes: {
    'http.method': 'GET',
    'http.url': '/api/users',
    'user.id': 123
  }
});

// Create child spans
const dbSpan = tracer.startSpan('database_query', {
  parent: rootSpan,
  attributes: {
    'db.statement': 'SELECT * FROM users',
    'db.table': 'users'
  }
});

// Add events to spans
tracer.addEvent(rootSpan.spanId, 'request_started');
tracer.addEvent(dbSpan.spanId, 'query_executed', {
  rowCount: 42
});

// Set span attributes
tracer.setAttributes(rootSpan.spanId, {
  'http.status_code': 200,
  'response.size': 2048
});

// End spans
tracer.endSpan(dbSpan.spanId);
tracer.endSpan(rootSpan.spanId);

Context Propagation

// Extract context from incoming request
const extractedContext = tracer.extract(request.headers);

// Start span with extracted context
const span = tracer.startSpan('process_request', {
  parentContext: extractedContext
});

// Inject context into outgoing request
const headers = {};
tracer.inject(span.spanId, headers);

// Make request with trace context
const response = await fetch('https://api.example.com', {
  headers: {
    ...headers,
    'Content-Type': 'application/json'
  }
});

Sampling Strategies

// Probabilistic sampling
const probabilisticSampler = (context) => Math.random() < 0.1; // 10%

// Rate-limited sampling
let sampleCount = 0;
const rateLimitedSampler = (context) => {
  sampleCount++;
  return sampleCount % 10 === 0; // Sample every 10th request
};

// Dynamic sampling based on attributes
const dynamicSampler = (context) => {
  if (context.attributes['http.status_code'] >= 500) {
    return true; // Always sample errors
  }
  if (context.attributes['user.tier'] === 'premium') {
    return Math.random() < 0.5; // 50% for premium users
  }
  return Math.random() < 0.05; // 5% for regular users
};

const tracer = new TracingManager({
  serviceName: 'edge-api',
  sampler: dynamicSampler
});

HealthCheckManager

Automated health monitoring with configurable checks and reporting.

Constructor Options

const health = new HealthCheckManager({
  timeout: 5000,                      // Check timeout in ms
  interval: 30000,                    // Check interval in ms
  retries: 2,                         // Number of retries on failure
  failureThreshold: 3,                // Failures before marking unhealthy
  successThreshold: 2,                // Successes before marking healthy
  storage: kvStorage,                 // Optional distributed storage
  alerting: {                         // Alert configuration
    enabled: true,
    webhook: 'https://alerts.example.com/webhook',
    thresholds: {
      responseTime: 1000,             // Alert if > 1s
      errorRate: 0.05                 // Alert if > 5% error rate
    }
  }
});

Adding Health Checks

// Database health check
health.addCheck('database', async () => {
  try {
    const startTime = Date.now();
    await database.ping();
    const latency = Date.now() - startTime;

    return {
      healthy: true,
      latency,
      details: { connectionPoolSize: 10 }
    };
  } catch (error) {
    return {
      healthy: false,
      error: error.message,
      latency: 0
    };
  }
});

// External API health check
health.addCheck('external-api', async () => {
  const response = await fetch('https://api.example.com/health');
  const isHealthy = response.ok;

  return {
    healthy: isHealthy,
    latency: 0,  // Could measure response time
    statusCode: response.status
  };
});

// Cache health check
health.addCheck('cache', async () => {
  try {
    await cache.set('health-check', 'ok', { ttl: 10 });
    const value = await cache.get('health-check');

    return {
      healthy: value === 'ok',
      latency: 0
    };
  } catch (error) {
    return {
      healthy: false,
      error: error.message
    };
  }
});

Health Check Execution

// Run all health checks
const results = await health.runChecks();
console.log(results);
// Output:
// {
//   database: { healthy: true, latency: 5, timestamp: 1234567890 },
//   'external-api': { healthy: true, latency: 150, timestamp: 1234567890 },
//   cache: { healthy: true, latency: 2, timestamp: 1234567890 }
// }

// Run specific check
const dbResult = await health.runCheck('database');

// Get overall health status
const overallHealth = health.getOverallHealth();
console.log(overallHealth);
// Output: { healthy: true, checks: 3, healthyChecks: 3, unhealthyChecks: 0 }

Health Endpoints

// Create health endpoint
const healthEndpoint = async (request) => {
  if (request.url.endsWith('/health')) {
    const results = await health.runChecks();
    const overall = health.getOverallHealth();

    const status = overall.healthy ? 200 : 503;

    return new Response(JSON.stringify({
      status: overall.healthy ? 'healthy' : 'unhealthy',
      timestamp: Date.now(),
      checks: results,
      summary: {
        total: overall.checks,
        healthy: overall.healthyChecks,
        unhealthy: overall.unhealthyChecks
      }
    }), {
      status,
      headers: { 'Content-Type': 'application/json' }
    });
  }

  if (request.url.endsWith('/health/live')) {
    // Liveness probe - just check if service is running
    return new Response('OK', { status: 200 });
  }

  if (request.url.endsWith('/health/ready')) {
    // Readiness probe - check if service is ready to serve traffic
    const overall = health.getOverallHealth();
    const status = overall.healthy ? 200 : 503;
    return new Response(overall.healthy ? 'Ready' : 'Not Ready', { status });
  }

  return new Response('Not found', { status: 404 });
};

Middleware Integration

Complete Monitoring Middleware

const {
  MetricsCollector,
  StructuredLogger,
  TracingManager,
  HealthCheckManager
} = require('edge-utils/monitoring');

// Initialize monitoring components
const metrics = new MetricsCollector({
  labels: { service: 'edge-api', version: '1.0.0' }
});

const logger = new StructuredLogger({
  level: 'info',
  redaction: ['password', 'apiKey']
});

const tracer = new TracingManager({
  serviceName: 'edge-api',
  sampler: () => Math.random() < 0.1
});

const health = new HealthCheckManager();
health.addCheck('self', async () => ({ healthy: true, latency: 0 }));

// Monitoring middleware
const monitoringMiddleware = async (request, context) => {
  const startTime = Date.now();

  // Extract or create trace context
  const traceContext = tracer.extract(request.headers) || {};
  const rootSpan = tracer.startSpan('handle_request', {
    attributes: {
      'http.method': request.method,
      'http.url': request.url,
      'http.user_agent': request.headers.get('user-agent'),
      'http.scheme': new URL(request.url).protocol.replace(':', '')
    }
  });

  // Add trace context to request
  const traceHeaders = {};
  tracer.inject(rootSpan.spanId, traceHeaders);
  context.traceHeaders = traceHeaders;

  try {
    // Continue to next middleware
    const response = await context.next();

    const duration = Date.now() - startTime;

    // Record metrics
    metrics.increment('requests_total', 1, {
      method: request.method,
      status: response.status.toString(),
      endpoint: new URL(request.url).pathname
    });

    metrics.histogram('request_duration', duration, {
      method: request.method,
      status: response.status.toString()
    });

    // Log successful request
    logger.info('Request completed', {
      method: request.method,
      url: request.url,
      status: response.status,
      duration,
      userId: context.user?.id
    });

    // Add trace events
    tracer.addEvent(rootSpan.spanId, 'request_completed', {
      status: response.status,
      duration
    });

    // Set response headers
    tracer.setAttributes(rootSpan.spanId, {
      'http.status_code': response.status,
      'response.duration': duration
    });

    return response;

  } catch (error) {
    const duration = Date.now() - startTime;

    // Record error metrics
    metrics.increment('requests_total', 1, {
      method: request.method,
      status: '500',
      error: error.name
    });

    metrics.histogram('request_duration', duration, {
      method: request.method,
      status: '500'
    });

    // Log error
    logger.error('Request failed', {
      method: request.method,
      url: request.url,
      error: error.message,
      stack: error.stack,
      duration,
      userId: context.user?.id
    }, error);

    // Add trace error
    tracer.addEvent(rootSpan.spanId, 'request_failed', {
      error: error.message,
      stack: error.stack
    });

    throw error;

  } finally {
    // End trace span
    tracer.endSpan(rootSpan.spanId);
  }
};

// Error tracking middleware
const errorTrackingMiddleware = async (request, context) => {
  try {
    return await context.next();
  } catch (error) {
    // Track unhandled errors
    metrics.increment('errors_total', 1, {
      type: error.name,
      endpoint: new URL(request.url).pathname
    });

    throw error;
  }
};

// Performance monitoring middleware
const performanceMiddleware = async (request, context) => {
  const startTime = performance.now();
  const startMemory = performance.memory?.usedJSHeapSize;

  try {
    const response = await context.next();

    const endTime = performance.now();
    const endMemory = performance.memory?.usedJSHeapSize;

    // Record performance metrics
    if (endMemory && startMemory) {
      metrics.gauge('memory_usage', endMemory - startMemory, {
        type: 'delta'
      });
    }

    metrics.histogram('processing_time', endTime - startTime, {
      endpoint: new URL(request.url).pathname
    });

    return response;
  } catch (error) {
    throw error;
  }
};

// Apply monitoring middleware
const monitoredHandler = applyMiddleware([
  monitoringMiddleware,
  errorTrackingMiddleware,
  performanceMiddleware
], baseHandler);

Advanced Examples

Real-time Metrics Dashboard

const { MetricsCollector, StructuredLogger } = require('edge-utils/monitoring');

const metrics = new MetricsCollector({ storage: kvStorage });
const logger = new StructuredLogger({ level: 'info' });

// Metrics dashboard endpoint
const dashboardHandler = async (request) => {
  if (!request.url.includes('/metrics')) {
    return new Response('Not found', { status: 404 });
  }

  // Get current metrics
  const currentMetrics = await metrics.getAllMetrics();

  // Calculate derived metrics
  const derivedMetrics = {
    errorRate: currentMetrics.errors_total / currentMetrics.requests_total,
    averageResponseTime: currentMetrics.request_duration_sum / currentMetrics.request_duration_count,
    throughput: currentMetrics.requests_total / ((Date.now() - startTime) / 1000), // requests per second
    availability: (currentMetrics.requests_total - currentMetrics.errors_total) / currentMetrics.requests_total
  };

  // Get recent logs
  const recentLogs = await logger.getRecentLogs({
    limit: 100,
    since: new Date(Date.now() - 5 * 60 * 1000) // Last 5 minutes
  });

  // Generate dashboard HTML
  const html = generateDashboardHTML({
    metrics: { ...currentMetrics, ...derivedMetrics },
    logs: recentLogs,
    alerts: await getActiveAlerts()
  });

  return new Response(html, {
    headers: { 'Content-Type': 'text/html' }
  });
};

Distributed Tracing Across Services

const tracer = new TracingManager({
  serviceName: 'edge-gateway',
  exporter: { type: 'jaeger', endpoint: 'http://jaeger:14268/api/traces' }
});

// Gateway tracing middleware
const gatewayTracing = async (request, context) => {
  const span = tracer.startSpan('gateway_request', {
    attributes: {
      'http.method': request.method,
      'http.url': request.url,
      'gateway.service': 'edge-gateway'
    }
  });

  // Inject trace context
  const headers = { ...request.headers };
  tracer.inject(span.spanId, headers);

  // Forward request to backend
  const backendResponse = await fetch('https://backend.example.com', {
    method: request.method,
    headers,
    body: request.body
  });

  // Record backend call
  const backendSpan = tracer.startSpan('backend_call', {
    parent: span,
    attributes: {
      'http.status_code': backendResponse.status,
      'backend.service': 'user-service'
    }
  });

  tracer.endSpan(backendSpan.spanId);
  tracer.endSpan(span.spanId);

  return backendResponse;
};

Health Check with Dependencies

const health = new HealthCheckManager();

// Check database connectivity
health.addCheck('database', async () => {
  const client = new DatabaseClient();
  try {
    await client.connect();
    const result = await client.query('SELECT 1');
    await client.disconnect();

    return {
      healthy: result.length > 0,
      latency: client.getLastQueryTime(),
      details: {
        connectionTime: client.getConnectionTime(),
        queryTime: client.getLastQueryTime()
      }
    };
  } catch (error) {
    return {
      healthy: false,
      error: error.message,
      details: { errorCode: error.code }
    };
  }
});

// Check external service dependencies
health.addCheck('payment-service', async () => {
  const startTime = Date.now();

  try {
    const response = await fetch('https://api.payment.com/health', {
      timeout: 3000
    });

    const latency = Date.now() - startTime;

    return {
      healthy: response.ok,
      latency,
      details: {
        statusCode: response.status,
        responseTime: latency
      }
    };
  } catch (error) {
    return {
      healthy: false,
      error: error.message,
      latency: Date.now() - startTime
    };
  }
});

// Check cache availability
health.addCheck('cache', async () => {
  try {
    const testKey = `health-check-${Date.now()}`;
    await cache.set(testKey, 'ok', { ttl: 10 });
    const value = await cache.get(testKey);

    return {
      healthy: value === 'ok',
      latency: 0,
      details: { cacheType: cache.constructor.name }
    };
  } catch (error) {
    return {
      healthy: false,
      error: error.message
    };
  }
});

Performance Considerations

Metrics Collection Overhead

// Use sampling for high-volume metrics
const sampledMetrics = new MetricsCollector({
  sampling: {
    enabled: true,
    rate: 0.1,  // Sample 10% of requests
    metrics: ['request_duration', 'response_size']
  }
});

// Batch metric updates
const batchMetrics = new MetricsCollector({
  batching: {
    enabled: true,
    size: 100,  // Batch 100 metrics before flushing
    interval: 5000  // Flush every 5 seconds
  }
});

Log Performance

// Asynchronous logging
const asyncLogger = new StructuredLogger({
  async: true,  // Don't block on log writes
  buffering: {
    enabled: true,
    size: 1000,
    flushInterval: 1000
  }
});

// Log level filtering for performance
const productionLogger = new StructuredLogger({
  level: 'warn',  // Only log warnings and errors in production
  filtering: {
    exclude: ['debug']  // Never log debug messages
  }
});

Tracing Overhead

// Adaptive sampling based on load
const adaptiveTracer = new TracingManager({
  sampler: (context) => {
    const load = getCurrentLoad(); // 0-1 scale
    const baseRate = 0.1; // 10% base sampling

    // Reduce sampling under high load
    return Math.random() < (baseRate * (1 - load));
  }
});

// Lightweight tracing for edge environments
const lightweightTracer = new TracingManager({
  lightweight: true,  // Minimal span data
  noStackTraces: true, // Don't capture stack traces
  maxSpans: 10  // Limit spans per request
});

Platform-Specific Notes

Cloudflare Workers

Use Cloudflare Analytics Engine for metrics
Compatible with Cloudflare Logs for structured logging
Leverage Cloudflare’s distributed tracing

Vercel Edge Functions

Compatible with Vercel’s analytics
Use Vercel Log Drain for centralized logging
Support for Vercel’s performance monitoring

Deno Deploy

Native performance with Deno runtime
Compatible with Deno KV for metrics storage
Support for Web APIs for monitoring

Best Practices

Metrics Naming

// Good metric names
const goodMetrics = {
  requests_total: 'Total number of requests',
  request_duration_seconds: 'Request duration in seconds',
  active_connections: 'Number of active connections',
  error_rate: 'Rate of errors per second'
};

// Avoid
const badMetrics = {
  req: 'Too vague',
  requestTimeMS: 'Inconsistent naming',
  errorsPerMin: 'Inconsistent units'
};

Logging Levels

// Appropriate use of log levels
logger.error('Database connection failed', { error: error.message });  // System errors
logger.warn('Rate limit exceeded', { userId: 123, limit: 100 });       // Warnings
logger.info('User logged in', { userId: 123, ip: '1.2.3.4' });         // Important events
logger.debug('Processing step completed', { step: 'validation' });     // Debug info

Tracing Guidelines

// Meaningful span names
const spans = {
  'handle_request': 'Overall request handling',
  'authenticate_user': 'User authentication',
  'validate_input': 'Input validation',
  'database_query': 'Database operation',
  'external_api_call': 'External service call'
};

// Useful span attributes
const attributes = {
  'http.method': 'GET',
  'http.status_code': 200,
  'db.statement': 'SELECT * FROM users',
  'user.id': 123,
  'error.message': 'Connection timeout'
};

Testing

Run monitoring tests with:

npm test -- --testPathPattern=monitoring.test.js

API Reference

MetricsCollector Methods

increment(name, value, labels) - Increment counter
gauge(name, value, labels) - Set gauge value
histogram(name, value, labels) - Record histogram observation
summary(name, value, labels) - Record summary observation
getCounter(name, labels) - Get counter value
getGauge(name, labels) - Get gauge value
getHistogram(name, labels) - Get histogram statistics
getSummary(name, labels) - Get summary quantiles

StructuredLogger Methods

error(message, meta, error) - Log error message
warn(message, meta) - Log warning message
info(message, meta) - Log info message
debug(message, meta) - Log debug message
child(meta) - Create child logger with additional context

TracingManager Methods

startSpan(name, options) - Start new span
endSpan(spanId) - End span
addEvent(spanId, name, attributes) - Add event to span
setAttributes(spanId, attributes) - Set span attributes
extract(headers) - Extract trace context
inject(spanId, headers) - Inject trace context

HealthCheckManager Methods

addCheck(name, checkFn) - Add health check
runChecks() - Run all health checks
runCheck(name) - Run specific health check
getOverallHealth() - Get overall health status

Contributing

When contributing to monitoring utilities:

Maintain observability best practices
Add comprehensive monitoring tests
Update documentation for monitoring features
Consider performance impact of monitoring
Test across all supported platforms

License

MIT

​Monitoring & Observability

​Features

​Quick Start

​MetricsCollector

​Constructor Options

​Counter Metrics

​Gauge Metrics

​Histogram Metrics

​Summary Metrics

​Custom Metrics

​StructuredLogger

​Constructor Options

​Logging Methods

​Context and Correlation

​Log Redaction

​Log Filtering

​TracingManager

​Constructor Options

​Span Creation

​Context Propagation

​Sampling Strategies

​HealthCheckManager

​Constructor Options

​Adding Health Checks

​Health Check Execution

​Health Endpoints

​Middleware Integration

​Complete Monitoring Middleware

​Advanced Examples

​Real-time Metrics Dashboard

​Distributed Tracing Across Services

​Health Check with Dependencies

​Performance Considerations

​Metrics Collection Overhead

​Log Performance

​Tracing Overhead

​Platform-Specific Notes

​Cloudflare Workers

​Vercel Edge Functions

​Deno Deploy

​Best Practices

​Metrics Naming

​Logging Levels

​Tracing Guidelines

​Testing

​API Reference

​MetricsCollector Methods

​StructuredLogger Methods

​TracingManager Methods

​HealthCheckManager Methods

​Contributing

​License

Monitoring & Observability

Features

Quick Start

MetricsCollector

Constructor Options

Counter Metrics

Gauge Metrics

Histogram Metrics

Summary Metrics

Custom Metrics

StructuredLogger

Constructor Options

Logging Methods

Context and Correlation

Log Redaction

Log Filtering

TracingManager

Constructor Options

Span Creation

Context Propagation

Sampling Strategies

HealthCheckManager

Constructor Options

Adding Health Checks

Health Check Execution

Health Endpoints

Middleware Integration

Complete Monitoring Middleware

Advanced Examples

Real-time Metrics Dashboard

Distributed Tracing Across Services

Health Check with Dependencies

Performance Considerations

Metrics Collection Overhead

Log Performance

Tracing Overhead

Platform-Specific Notes

Cloudflare Workers

Vercel Edge Functions

Deno Deploy

Best Practices

Metrics Naming

Logging Levels

Tracing Guidelines

Testing

API Reference

MetricsCollector Methods

StructuredLogger Methods

TracingManager Methods

HealthCheckManager Methods

Contributing

License