clerk-observability by jeremylongshore

---
name: clerk-observability
description: |
  Implement monitoring, logging, and observability for Clerk authentication.
  Use when setting up monitoring, debugging auth issues in production,
  or implementing audit logging.
  Trigger with phrases like "clerk monitoring", "clerk logging",
  "clerk observability", "clerk metrics", "clerk audit log".
allowed-tools: Read, Write, Edit, Bash(npm:*), Grep
version: 1.0.0
license: MIT
author: Jeremy Longshore <[email protected]>
---

# Clerk Observability

## Overview
Implement comprehensive monitoring, logging, and observability for Clerk authentication.

## Prerequisites
- Clerk integration working
- Monitoring platform (DataDog, New Relic, Sentry, etc.)
- Logging infrastructure

## Instructions

### Step 1: Authentication Event Logging
```typescript
// lib/auth-logger.ts
import { auth, currentUser } from '@clerk/nextjs/server'

interface AuthEvent {
  type: string
  userId: string | null
  timestamp: string
  metadata: Record<string, any>
}

class AuthLogger {
  private events: AuthEvent[] = []

  log(type: string, metadata: Record<string, any> = {}) {
    const event: AuthEvent = {
      type,
      userId: null, // Set after auth
      timestamp: new Date().toISOString(),
      metadata
    }

    this.events.push(event)
    console.log('[Auth Event]', JSON.stringify(event))

    // Send to monitoring service
    this.sendToMonitoring(event)
  }

  async logWithAuth(type: string, metadata: Record<string, any> = {}) {
    const { userId, sessionId } = await auth()

    const event: AuthEvent = {
      type,
      userId,
      timestamp: new Date().toISOString(),
      metadata: {
        ...metadata,
        sessionId,
        hasUser: !!userId
      }
    }

    this.events.push(event)
    console.log('[Auth Event]', JSON.stringify(event))
    this.sendToMonitoring(event)
  }

  private sendToMonitoring(event: AuthEvent) {
    // DataDog example
    if (process.env.DD_API_KEY) {
      fetch('https://http-intake.logs.datadoghq.com/v1/input', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'DD-API-KEY': process.env.DD_API_KEY
        },
        body: JSON.stringify({
          ddsource: 'clerk',
          ddtags: 'env:production',
          message: event
        })
      }).catch(console.error)
    }
  }
}

export const authLogger = new AuthLogger()
```

### Step 2: Middleware Monitoring
```typescript
// middleware.ts
import { clerkMiddleware, createRouteMatcher } from '@clerk/nextjs/server'
import { NextResponse } from 'next/server'

const isPublicRoute = createRouteMatcher(['/', '/sign-in(.*)', '/sign-up(.*)'])

export default clerkMiddleware(async (auth, request) => {
  const start = performance.now()
  const { userId, sessionId } = await auth()

  // Log auth check
  const authDuration = performance.now() - start

  // Add monitoring headers
  const response = NextResponse.next()
  response.headers.set('x-auth-duration', String(authDuration.toFixed(2)))
  response.headers.set('x-auth-user', userId || 'anonymous')

  // Log slow auth
  if (authDuration > 100) {
    console.warn('[Clerk Perf] Slow auth check:', {
      duration: authDuration,
      path: request.nextUrl.pathname,
      userId
    })
  }

  // Metrics
  recordMetric('clerk.auth.duration', authDuration)
  recordMetric('clerk.auth.success', userId ? 1 : 0)

  return response
})

function recordMetric(name: string, value: number) {
  // Send to your metrics provider
  console.log(`[Metric] ${name}: ${value}`)
}
```

### Step 3: Session Analytics
```typescript
// lib/session-analytics.ts
import { clerkClient } from '@clerk/nextjs/server'

interface SessionMetrics {
  totalSessions: number
  activeSessions: number
  averageSessionDuration: number
  sessionsByDevice: Record<string, number>
}

export async function getSessionMetrics(userId: string): Promise<SessionMetrics> {
  const client = await clerkClient()

  const sessions = await client.sessions.getSessionList({
    userId,
    status: 'active'
  })

  const sessionsByDevice: Record<string, number> = {}
  let totalDuration = 0

  for (const session of sessions.data) {
    // Parse user agent for device type
    const device = parseDeviceType(session.userAgent || '')
    sessionsByDevice[device] = (sessionsByDevice[device] || 0) + 1

    // Calculate duration
    const duration = Date.now() - new Date(session.createdAt).getTime()
    totalDuration += duration
  }

  return {
    totalSessions: sessions.totalCount,
    activeSessions: sessions.data.length,
    averageSessionDuration: totalDuration / sessions.data.length || 0,
    sessionsByDevice
  }
}

function parseDeviceType(userAgent: string): string {
  if (/mobile/i.test(userAgent)) return 'mobile'
  if (/tablet/i.test(userAgent)) return 'tablet'
  return 'desktop'
}
```

### Step 4: Webhook Event Tracking
```typescript
// app/api/webhooks/clerk/route.ts
import { Webhook } from 'svix'
import { headers } from 'next/headers'
import { WebhookEvent } from '@clerk/nextjs/server'

const webhookMetrics = {
  received: 0,
  processed: 0,
  failed: 0,
  byType: {} as Record<string, number>
}

export async function POST(req: Request) {
  webhookMetrics.received++

  const start = performance.now()
  const headerPayload = await headers()
  const svix_id = headerPayload.get('svix-id')!

  // ... verification code ...

  try {
    const evt = wh.verify(body, headers) as WebhookEvent
    const eventType = evt.type

    // Track by type
    webhookMetrics.byType[eventType] = (webhookMetrics.byType[eventType] || 0) + 1

    // Process event
    await processEvent(evt)

    webhookMetrics.processed++

    // Log success
    console.log('[Webhook]', {
      type: eventType,
      id: svix_id,
      duration: performance.now() - start,
      status: 'success'
    })

    return Response.json({ success: true })
  } catch (error) {
    webhookMetrics.failed++

    console.error('[Webhook Error]', {
      id: svix_id,
      error: error.message,
      duration: performance.now() - start
    })

    return Response.json({ error: 'Processing failed' }, { status: 500 })
  }
}

// Expose metrics endpoint
export async function GET() {
  return Response.json(webhookMetrics)
}
```

### Step 5: Error Tracking with Sentry
```typescript
// lib/sentry-clerk.ts
import * as Sentry from '@sentry/nextjs'
import { auth, currentUser } from '@clerk/nextjs/server'

export async function initSentryWithClerk() {
  const { userId, orgId } = await auth()

  if (userId) {
    Sentry.setUser({
      id: userId,
      // Don't include email unless necessary for privacy
    })

    Sentry.setContext('clerk', {
      userId,
      orgId,
      hasOrg: !!orgId
    })
  }
}

// Wrapper for auth operations with error tracking
export async function withAuthErrorTracking<T>(
  operation: () => Promise<T>,
  context: string
): Promise<T> {
  try {
    return await operation()
  } catch (error) {
    Sentry.captureException(error, {
      tags: {
        component: 'clerk',
        operation: context
      }
    })
    throw error
  }
}

// Usage
const user = await withAuthErrorTracking(
  () => currentUser(),
  'get-current-user'
)
```

### Step 6: Health Check Endpoint
```typescript
// app/api/health/clerk/route.ts
import { auth, clerkClient } from '@clerk/nextjs/server'

interface HealthStatus {
  status: 'healthy' | 'degraded' | 'unhealthy'
  checks: {
    auth: { status: string; latency: number }
    api: { status: string; latency: number }
    webhooks: { status: string; lastReceived: string | null }
  }
  timestamp: string
}

export async function GET() {
  const health: HealthStatus = {
    status: 'healthy',
    checks: {
      auth: { status: 'unknown', latency: 0 },
      api: { status: 'unknown', latency: 0 },
      webhooks: { status: 'unknown', lastReceived: null }
    },
    timestamp: new Date().toISOString()
  }

  // Check auth function
  const authStart = performance.now()
  try {
    await auth()
    health.checks.auth = {
      status: 'ok',
      latency: performance.now() - authStart
    }
  } catch {
    health.checks.auth = {
      status: 'error',
      latency: performance.now() - authStart
    }
    health.status = 'degraded'
  }

  // Check API connectivity
  const apiStart = performance.now()
  try {
    const client = await clerkClient()
    await client.users.getUserList({ limit: 1 })
    health.checks.api = {
      status: 'ok',
      latency: performance.now() - apiStart
    }
  } catch {
    health.checks.api = {
      status: 'error',
      latency: performance.now() - apiStart
    }
    health.status = 'unhealthy'
  }

  return Response.json(health)
}
```

## Dashboard Metrics

Track these key metrics:
- Authentication success/failure rate
- Auth latency (p50, p95, p99)
- Active sessions over time
- Webhook processing time
- Error rate by type

## Output
- Authentication event logging
- Performance monitoring
- Error tracking integration
- Health check endpoints

## Error Handling
| Issue | Monitoring Action |
|-------|-------------------|
| High auth latency | Alert on p95 > 200ms |
| Failed webhooks | Alert on failure rate > 1% |
| Session anomalies | Track unusual session patterns |
| API errors | Capture with Sentry context |

## Resources
- [Clerk Dashboard Analytics](https://dashboard.clerk.com)
- [Sentry Integration](https://docs.sentry.io)
- [DataDog APM](https://docs.datadoghq.com/tracing)

## Next Steps
Proceed to `clerk-incident-runbook` for incident response procedures.