Utilary - TypeScript Utility Library

A comprehensive TypeScript utility library featuring Redis distributed locking and more. Designed for scalable applications requiring reliable concurrency control and data management utilities.

Features

• 🔒 Distributed Locking: Redis-based distributed locks with RedLock algorithm
• 🔄 Auto-Retry & Extension: Smart retry mechanism and lock extension for long operations
• ⚡ Timeout Management: Sophisticated timeout handling with automatic error recovery
• 🛡️ Error Resilience: Comprehensive error handling with customizable callbacks
• 🚀 High Performance: Optimized for high-concurrency environments
• 📦 TypeScript First: Full type safety with zero external dependencies

Installation

npm install utilary redis

Quick Start

import { createClient } from 'redis'
import { RedLock } from 'utilary'

// Initialize Redis client
const client = createClient({
  url: 'redis://localhost:6379',
})
await client.connect()

// Create RedLock instance with advanced configuration
const redlock = new RedLock(client, {
  retryCount: 5,        // Maximum retry attempts
  retryDelay: 100,      // Base delay between retries (ms)
  retryJitter: 50,      // Random delay variation
  driftFactor: 0.01,    // Clock drift compensation
  automaticExtensionThreshold: 500,  // Auto-extension threshold
  onError: error => {
    console.error('🚨 RedLock operation failed:', error.message)
  },
})

📚 View Complete Examples →

Core Features

1. Automatic Lock Management

// Simple operations with automatic lock handling
await redlock.lock('payment-processing', 3000, async () => {
  await processPayment()
  // Lock is automatically released after completion
})

2. Auto-Extending Locks with Smart Limits

// Long-running operations with controlled extensions
await redlock.autoExtendLock('report-generation', 2000, async () => {
  await generateLargeReport()
  // Lock automatically extends up to 5 times
}, { maxExtensions: 5 })

// Payment processing with strict limit
await redlock.autoExtendLock('payment-critical', 1500, async () => {
  await processPayment()
  // Only 1 extension allowed for predictable timing
}, { maxExtensions: 1 })

// Background sync with unlimited extensions
await redlock.autoExtendLock('data-sync', 3000, async () => {
  await syncLargeDataset()
  // Unlimited extensions for unpredictable operations
}, { maxExtensions: -1 })

// Custom extension threshold for early triggers
await redlock.autoExtendLock('custom-operation', 2000, async () => {
  await performOperation()
  // Extend when 1000ms left instead of default 500ms
}, {
  maxExtensions: 3,
  extensionThreshold: 1000
})

3. Manual Lock Control

// Fine-grained control over lock lifecycle
const lock = await redlock.acquire('user-data', 5000)
if (lock) {
  try {
    await performOperation()
    await redlock.extend(lock, 3000)  // Extend if needed
    await continueOperation()
  } finally {
    await redlock.release(lock)
  }
}

Advanced Features

Smart Extension Management

RedLock provides intelligent extension control with flexible configuration:

Extension Policies

1. Unlimited Extensions (default behavior)

   await redlock.autoExtendLock('operation', 2000, fn) // No options = unlimited
   await redlock.autoExtendLock('operation', 2000, fn, { maxExtensions: -1 })

2. Limited Extensions

   await redlock.autoExtendLock('payment', 3000, fn, { maxExtensions: 2 })
   // Will extend maximum 2 times, then let TTL expire naturally

3. No Extensions

   await redlock.autoExtendLock('quick-task', 1000, fn, { maxExtensions: 0 })
   // Behaves like regular lock() with fixed TTL

Custom Extension Thresholds

Control when extensions are triggered:

await redlock.autoExtendLock('operation', 5000, fn, {
  maxExtensions: 3,
  extensionThreshold: 1500  // Extend when 1500ms left (vs default 500ms)
})

Use Case Recommendations

• Payment Processing: maxExtensions: 1-2 (predictable timing)
• Data Migration: maxExtensions: 5-10 (reasonable safety margin)
• Background Jobs: maxExtensions: -1 (unlimited for reliability)
• Critical Operations: maxExtensions: 0 (strict time bounds)

Smart Retry System

RedLock implements an intelligent retry mechanism with:

1. Exponential Backoff

   • Increasing delays between retries
   • Prevents system overload
   • Example: 100ms → 200ms → 400ms → 800ms

2. Random Jitter

   • Prevents thundering herd problem
   • Improves concurrent operation handling
   • Reduces network congestion

Error Handling & Timeouts

try {
  await redlock.lock('critical-operation', 2000, async () => {
    await criticalTask()
  })
} catch (error) {
  if (error instanceof LockTimeoutError) {
    // Handle timeout - operation exceeded duration
    await handleTimeout()
  } else if (error instanceof LockAcquisitionError) {
    // Handle acquisition failure - retries exhausted
    await handleAcquisitionFailure()
  }
}

Production Monitoring

const redlock = new RedLock(client, {
  onError: (error) => {
    if (error instanceof LockTimeoutError) {
      metrics.increment('lock.timeouts')
      logger.warn('Lock timeout', {
        resource: error.resource,
        duration: error.duration
      })
    }
  }
})

Real-World Examples

💡 Want more examples? Check out our complete example collection with detailed use cases and advanced patterns.

High-Concurrency Payment Processing

async function processPaymentWithRetry(userId: string, amount: number) {
  const LOCK_DURATION = 5000
  const MAX_RETRIES = 3

  for (let attempt = 1; attempt <= MAX_RETRIES; attempt++) {
    try {
      await redlock.lock(`payment-${userId}`, LOCK_DURATION, async () => {
        await validateBalance(userId)
        await deductAmount(userId, amount)
        await createTransaction(userId, amount)
      })
      return true
    } catch (error) {
      if (error instanceof LockTimeoutError) {
        if (attempt === MAX_RETRIES) throw error
        await delay(1000 * attempt)  // Exponential backoff
      } else {
        throw error
      }
    }
  }
}

Distributed Data Updates with Extension Control

// Data migration with reasonable extension limits
await redlock.autoExtendLock('user-migration', 2000, async () => {
  const userData = await fetchUserData()
  await processLargeDataset(userData)
  await saveUpdatedData(userData)
}, { maxExtensions: 10 }) // Allow up to 10 extensions for large operations

// Critical financial operations with strict control
await redlock.autoExtendLock('financial-calc', 3000, async () => {
  await performComplexCalculation()
  await updateAccountBalances()
}, {
  maxExtensions: 2,        // Maximum 2 extensions
  extensionThreshold: 800  // Extend early for safety
})

Quick Reference

autoExtendLock() Options

| Parameter | Type | Default | Description | |-----------|------|---------|-------------| | maxExtensions | number | undefined | Maximum extensions allowed (-1 = unlimited, 0 = none, >0 = limit) | | extensionThreshold | number | 100 | Time remaining (ms) when extension is triggered |

Common Patterns

// 💳 Payment processing (predictable timing)
await redlock.autoExtendLock('payment', 3000, paymentFn, {
  maxExtensions: 1
})

// 📊 Data processing (reasonable safety)
await redlock.autoExtendLock('analytics', 5000, analyticsFn, {
  maxExtensions: 5
})

// 🔄 Background sync (maximum reliability)
await redlock.autoExtendLock('sync', 2000, syncFn, {
  maxExtensions: -1
})

// ⚡ Quick operations (no extensions)
await redlock.autoExtendLock('cache-refresh', 1000, cacheFn, {
  maxExtensions: 0
})

// 🎯 Custom threshold (extend early)
await redlock.autoExtendLock('critical', 4000, criticalFn, {
  maxExtensions: 2,
  extensionThreshold: 1500  // Extend when 1.5s left
})

Best Practices

Thread Safety & Error Handling

⚠️ CRITICAL: Always wrap RedLock operations in try-catch blocks to ensure proper thread handling when locks fail or expire.

// ✅ CORRECT: Proper error handling with cleanup
async function processWithLock(userId: string) {
  let transaction = null
  let timer = null

  try {
    // Start transaction
    transaction = await db.beginTransaction()

    // Set operation timeout
    timer = setTimeout(() => {
      throw new Error('Operation timeout')
    }, 30000)

    await redlock.lock(`user-${userId}`, 5000, async () => {
      await updateUserData(userId, transaction)
      await transaction.commit()
    })

  } catch (error) {
    // Handle lock failures, timeouts, or operation errors
    if (transaction) {
      await transaction.rollback()
      console.log('Transaction rolled back due to error')
    }

    if (error instanceof LockTimeoutError) {
      console.error('Lock operation timed out:', error.message)
      // Handle timeout-specific cleanup
    } else if (error instanceof LockAcquisitionError) {
      console.error('Failed to acquire lock:', error.message)
      // Handle acquisition failure
    } else {
      console.error('Unexpected error:', error.message)
    }

    throw error // Re-throw if needed
  } finally {
    // Always cleanup resources
    if (timer) {
      clearTimeout(timer)
    }

    // Close connections, cleanup resources, etc.
    await cleanupResources()
  }
}

// ❌ INCORRECT: No error handling - can cause resource leaks
async function unsafeProcess(userId: string) {
  const transaction = await db.beginTransaction()

  await redlock.lock(`user-${userId}`, 5000, async () => {
    await updateUserData(userId, transaction)
    await transaction.commit()
  })
  // If lock fails, transaction is never rolled back!
}

Essential Thread Safety Patterns

1. Database Transactions

   const transaction = await db.beginTransaction()
   try {
     await redlock.lock('resource', 3000, async () => {
       await performDatabaseOperations(transaction)
       await transaction.commit()
     })
   } catch (error) {
     await transaction.rollback()
     throw error
   }

2. Timeout Management

   const timer = setTimeout(() => controller.abort(), 30000)
   try {
     await redlock.lock('resource', 5000, async () => {
       await operationWithAbortSignal(controller.signal)
     })
   } finally {
     clearTimeout(timer)
   }

3. Resource Cleanup

   let fileHandle = null
   try {
     fileHandle = await openFile('data.txt')
     await redlock.lock('file-processing', 3000, async () => {
       await processFile(fileHandle)
     })
   } catch (error) {
     // Handle errors appropriately
     await handleProcessingError(error)
   } finally {
     if (fileHandle) {
       await fileHandle.close()
     }
   }

Lock-Specific Error Handling

try {
  await redlock.autoExtendLock('critical-operation', 2000, async () => {
    await performCriticalTask()
  }, { maxExtensions: 3 })
} catch (error) {
  if (error instanceof LockTimeoutError) {
    // Operation exceeded maximum time (initial TTL + extensions)
    await rollbackOperations()
    await notifyTimeout()
  } else if (error instanceof LockAcquisitionError) {
    // Could not acquire lock after retries
    await handleAcquisitionFailure()
    await scheduleRetry()
  } else if (error instanceof LockExtensionError) {
    // Lock extension failed (Redis connection issues, etc.)
    await handleExtensionFailure()
    await emergencyCleanup()
  }
}

1. Lock Duration & Extension Strategy

   • Set appropriate initial TTL based on expected operation time
   • Use maxExtensions to control resource usage:
     • Critical/Financial: maxExtensions: 1-2 for predictable timing
     • Data Processing: maxExtensions: 5-10 for reasonable safety
     • Background Tasks: maxExtensions: -1 for maximum reliability
   • Prefer shorter TTL with extensions over very long initial TTL
   • Include buffer for network latency

2. Resource Keys

   • Use descriptive, hierarchical keys
   • Include relevant identifiers (user ID, transaction ID, etc.)
   • Consider environment prefixes (prod:payment:, dev:sync:)

3. Extension Configuration

   • Set extensionThreshold based on operation criticality:
     • High-priority: 1000ms+ (extend early)
     • Normal operations: 500ms (default)
     • Quick tasks: 100-200ms (minimal extension window)
   • Monitor extension patterns to optimize thresholds

4. Error Handling & Thread Safety

   • ALWAYS wrap RedLock operations in try-catch blocks
   • Implement comprehensive error catching for all lock operations
   • Use proper cleanup in finally blocks for transactions, timers, and resources
   • Handle different error types appropriately (timeout, acquisition, extension failures)
   • Ensure database transactions are rolled back on lock failures
   • Clear timeouts and cleanup resources in finally blocks
   • Monitor and log lock failures, especially extension failures
   • Handle max extension limits gracefully

5. Performance

   • Keep lock durations minimal while allowing for extensions
   • Release locks as soon as possible
   • Use appropriate retry configurations
   • Monitor extension frequency to detect performance issues

Contributing

We welcome contributions! Please read our Contributing Guide for details.

💡 Feature Requests & Bug Reports

• Request Features: Open an issue on GitHub
• Report Bugs: Submit a bug report

License

Licensed under the Apache License, Version 2.0. See LICENSE for details.

Author

Developed by Hunandika - Building reliable utilities for modern applications.

Utilary: Where utility meets reliability