GunDB Integration with Fiber: Building fibergun

The modern web is moving towards decentralization, and traditional centralized databases are increasingly showing their limitations. Data silos, single points of failure, and vendor lock-in are pushing developers to seek alternatives that offer true data ownership and resilience. This is where GunDB shines – a decentralized, real-time database that enables applications to work offline-first while maintaining eventual consistency across distributed peers.

Fibergun was born from our need to bring GunDB’s revolutionary decentralized database capabilities to Fiber applications. This comprehensive post details our complete technical implementation, the architectural decisions we made, and the challenges we faced in creating a seamless integration between these two powerful technologies.

The Centralization Problem

Before diving into our solution, it’s important to understand why traditional centralized databases are becoming inadequate for modern applications:

Single Points of Failure: Centralized databases create bottlenecks and vulnerability points. When the central server goes down, the entire application becomes unavailable, regardless of how many users are online and could potentially share data with each other.

Data Ownership Issues: Users don’t truly own their data when it’s stored in centralized systems. Companies can change terms of service, go out of business, or restrict access, leaving users without their information.

Scalability Limitations: Traditional databases require expensive infrastructure scaling, often leading to vendor lock-in and increasing costs as applications grow.

Network Dependency: Users must be online and connected to the central server to access their data, making applications unusable in areas with poor connectivity.

Privacy Concerns: Centralized systems create attractive targets for hackers and government surveillance, compromising user privacy.

Why GunDB?

GunDB addresses these fundamental issues through its unique architecture and design principles:

Real-time Data Synchronization

GunDB provides instant data synchronization across all connected peers without requiring a central authority. Changes propagate automatically through the network, ensuring that all users see updates in real-time, regardless of which peer initiated the change.

Offline-first Capabilities

Applications built with GunDB work seamlessly offline. Users can read, write, and modify data locally, and all changes automatically synchronize when connectivity is restored. This offline-first approach ensures applications remain functional regardless of network conditions.

Graph-based Data Structure

Unlike traditional relational or document databases, GunDB uses a graph-based structure that naturally represents relationships between data. This approach provides more flexibility in data modeling and enables powerful querying capabilities.

Peer-to-peer Networking Support

GunDB’s built-in P2P networking eliminates the need for centralized servers. Peers can connect directly to each other, creating resilient networks that become stronger as more users join.

Cryptographic Security

GunDB incorporates cryptographic principles to ensure data integrity and enable user authentication without central authorities. Each piece of data is cryptographically signed, providing tamper-proof storage.

Understanding GunDB’s Architecture

Before implementing our Fiber integration, we need to understand how GunDB works at a fundamental level:

The Graph Structure

GunDB stores all data as a graph where each node represents a piece of data and edges represent relationships. This structure is more flexible than traditional schemas and allows for dynamic data modeling:

// Traditional JSON structure
{
  "users": {
    "john": {
      "name": "John Doe",
      "email": "[email protected]",
      "posts": ["post1", "post2"]
    }
  }
}

// GunDB graph structure
{
  "users": {"john": {"#": "user_john_ref"}},
  "user_john_ref": {
    "name": "John Doe",
    "email": "[email protected]",
    "posts": {"#": "posts_ref"}
  },
  "posts_ref": {
    "post1": {"#": "post1_ref"},
    "post2": {"#": "post2_ref"}
  }
}

Conflict Resolution

GunDB uses a conflict-free replicated data type (CRDT) approach to handle conflicts when multiple peers modify the same data simultaneously. The resolution algorithm prioritizes the most recent timestamp while maintaining consistency across all peers.

Storage Layers

GunDB supports multiple storage layers that can be combined:

  • In-memory storage for fast access
  • Local file system storage for persistence
  • Cloud storage (S3, etc.) for backup and scaling
  • Custom storage adapters for specific needs

Technical Implementation

Now let’s dive into the actual implementation of our Fiber-GunDB integration. Our goal was to create a middleware that would be intuitive for Fiber developers while providing full access to GunDB’s capabilities.

1. Core Architecture and Design Patterns

The foundation of fibergun is built on several key design patterns that ensure scalability and maintainability:

// Core interfaces that define our abstractions
type GunDB interface {
    Get(path string) Node
    Put(path string, data interface{}) error
    On(path string, callback func(data interface{}, key string)) Subscription
    Off(subscription Subscription)
    Map(path string) MapNode
    Set(path string) SetNode
    Close() error
}

type Node interface {
    Val() interface{}
    Put(data interface{}) error
    On(callback func(data interface{}, key string)) Subscription
    Off(subscription Subscription)
    Map() MapNode
    Set() SetNode
}

// Main GunDB implementation
type gunDB struct {
    peers          []string
    graph          *Graph
    options        *Options
    handlers       map[string]Handler
    subscriptions  *SubscriptionManager
    storage        []StorageAdapter
    eventBus       *EventBus
    metrics        *Metrics
}

type Options struct {
    Peers        []string          // List of peer addresses
    File         string           // Local file storage path
    Radisk       bool            // Enable local disk storage
    S3           *S3Config       // S3 storage configuration
    WebSocket    bool           // Enable WebSocket transport
    Port         int            // Port for peer connections
    Timeout      time.Duration  // Connection timeout
    MaxPeers     int           // Maximum number of peer connections
    StorageQuota int64         // Storage quota in bytes
    LogLevel     LogLevel      // Logging level
}

func NewGunDB(opts *Options) (GunDB, error) {
    if opts == nil {
        opts = &Options{}
    }
    
    // Set defaults
    if opts.Timeout == 0 {
        opts.Timeout = 30 * time.Second
    }
    if opts.MaxPeers == 0 {
        opts.MaxPeers = 100
    }
    if opts.Port == 0 {
        opts.Port = 8080
    }
    
    gun := &gunDB{
        options:       opts,
        handlers:      make(map[string]Handler),
        subscriptions: NewSubscriptionManager(),
        eventBus:      NewEventBus(),
        metrics:       NewMetrics(),
    }
    
    // Initialize graph
    gun.graph = NewGraph()
    
    // Setup storage layers
    if err := gun.setupStorage(); err != nil {
        return nil, fmt.Errorf("failed to setup storage: %w", err)
    }
    
    // Initialize peer connections
    if err := gun.initializePeers(); err != nil {
        return nil, fmt.Errorf("failed to initialize peers: %w", err)
    }
    
    return gun, nil
}

2. Storage Layer Implementation

One of GunDB’s key strengths is its flexible storage system. Our implementation supports multiple storage backends that can be used simultaneously:

type StorageAdapter interface {
    Get(key string) ([]byte, error)
    Put(key string, value []byte) error
    Del(key string) error
    List(prefix string) ([]string, error)
    Close() error
}

// File system storage adapter
type FileSystemStorage struct {
    basePath string
    mutex    sync.RWMutex
}

func NewFileSystemStorage(basePath string) (*FileSystemStorage, error) {
    if err := os.MkdirAll(basePath, 0755); err != nil {
        return nil, err
    }
    
    return &FileSystemStorage{
        basePath: basePath,
    }, nil
}

func (fs *FileSystemStorage) Get(key string) ([]byte, error) {
    fs.mutex.RLock()
    defer fs.mutex.RUnlock()
    
    filePath := filepath.Join(fs.basePath, fs.keyToPath(key))
    return os.ReadFile(filePath)
}

func (fs *FileSystemStorage) Put(key string, value []byte) error {
    fs.mutex.Lock()
    defer fs.mutex.Unlock()
    
    filePath := filepath.Join(fs.basePath, fs.keyToPath(key))
    if err := os.MkdirAll(filepath.Dir(filePath), 0755); err != nil {
        return err
    }
    
    return os.WriteFile(filePath, value, 0644)
}

// S3 storage adapter for cloud backup
type S3Storage struct {
    client *s3.Client
    bucket string
    prefix string
}

func NewS3Storage(config *S3Config) (*S3Storage, error) {
    cfg, err := awsconfig.LoadDefaultConfig(context.TODO(),
        awsconfig.WithRegion(config.Region),
    )
    if err != nil {
        return nil, err
    }
    
    return &S3Storage{
        client: s3.NewFromConfig(cfg),
        bucket: config.Bucket,
        prefix: config.Prefix,
    }, nil
}

func (s3s *S3Storage) Get(key string) ([]byte, error) {
    result, err := s3s.client.GetObject(context.TODO(), &s3.GetObjectInput{
        Bucket: aws.String(s3s.bucket),
        Key:    aws.String(s3s.prefix + key),
    })
    if err != nil {
        return nil, err
    }
    defer result.Body.Close()
    
    return io.ReadAll(result.Body)
}

func (s3s *S3Storage) Put(key string, value []byte) error {
    _, err := s3s.client.PutObject(context.TODO(), &s3.PutObjectInput{
        Bucket: aws.String(s3s.bucket),
        Key:    aws.String(s3s.prefix + key),
        Body:   bytes.NewReader(value),
    })
    return err
}

3. WebSocket Transport Implementation

Real-time synchronization is crucial for GunDB’s functionality. Our WebSocket implementation provides efficient, bidirectional communication between peers:

type WebSocketTransport struct {
    connections map[string]*WebSocketConnection
    upgrader    websocket.Upgrader
    gun         *gunDB
    mutex       sync.RWMutex
}

type WebSocketConnection struct {
    conn        *websocket.Conn
    peerID      string
    gun         *gunDB
    sendQueue   chan []byte
    recvQueue   chan []byte
    closeChan   chan struct{}
    metrics     *ConnectionMetrics
}

func (g *gunDB) setupWebSocket() error {
    if !g.options.WebSocket {
        return nil
    }
    
    transport := &WebSocketTransport{
        connections: make(map[string]*WebSocketConnection),
        upgrader: websocket.Upgrader{
            CheckOrigin: func(r *http.Request) bool {
                // Implement proper origin checking in production
                return true
            },
            ReadBufferSize:  1024,
            WriteBufferSize: 1024,
        },
        gun: g,
    }
    
    g.wsTransport = transport
    return nil
}

func (wst *WebSocketTransport) HandleConnection(c *fiber.Ctx) error {
    conn, err := wst.upgrader.Upgrade(c.Response(), c.Request(), nil)
    if err != nil {
        return err
    }
    
    peerID := generatePeerID()
    wsConn := &WebSocketConnection{
        conn:      conn,
        peerID:    peerID,
        gun:       wst.gun,
        sendQueue: make(chan []byte, 1000),
        recvQueue: make(chan []byte, 1000),
        closeChan: make(chan struct{}),
        metrics:   NewConnectionMetrics(),
    }
    
    wst.mutex.Lock()
    wst.connections[peerID] = wsConn
    wst.mutex.Unlock()
    
    // Start connection handlers
    go wsConn.handleSend()
    go wsConn.handleReceive()
    go wsConn.handleMessages()
    
    // Wait for connection to close
    <-wsConn.closeChan
    
    // Cleanup
    wst.mutex.Lock()
    delete(wst.connections, peerID)
    wst.mutex.Unlock()
    
    return nil
}

func (wsc *WebSocketConnection) handleReceive() {
    defer close(wsc.recvQueue)
    
    for {
        select {
        case <-wsc.closeChan:
            return
        default:
            messageType, data, err := wsc.conn.ReadMessage()
            if err != nil {
                if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
                    log.Printf("WebSocket error: %v", err)
                }
                close(wsc.closeChan)
                return
            }
            
            if messageType == websocket.TextMessage {
                wsc.metrics.MessagesReceived++
                wsc.metrics.BytesReceived += int64(len(data))
                
                select {
                case wsc.recvQueue <- data:
                case <-wsc.closeChan:
                    return
                }
            }
        }
    }
}

func (wsc *WebSocketConnection) handleSend() {
    ticker := time.NewTicker(54 * time.Second) // WebSocket ping interval
    defer ticker.Stop()
    
    for {
        select {
        case <-wsc.closeChan:
            return
        case <-ticker.C:
            if err := wsc.conn.WriteMessage(websocket.PingMessage, nil); err != nil {
                close(wsc.closeChan)
                return
            }
        case message := <-wsc.sendQueue:
            if err := wsc.conn.WriteMessage(websocket.TextMessage, message); err != nil {
                close(wsc.closeChan)
                return
            }
            wsc.metrics.MessagesSent++
            wsc.metrics.BytesSent += int64(len(message))
        }
    }
}

4. Data Synchronization Engine

The heart of GunDB is its synchronization engine, which ensures data consistency across all peers:

type SyncEngine struct {
    gun           *gunDB
    pendingWrites map[string]*PendingWrite
    conflictQueue chan *ConflictEvent
    syncQueue     chan *SyncEvent
    peerStates    map[string]*PeerState
    mutex         sync.RWMutex
}

type PendingWrite struct {
    Key       string
    Value     interface{}
    Timestamp int64
    PeerID    string
    Retries   int
}

type ConflictEvent struct {
    Key       string
    LocalVal  interface{}
    RemoteVal interface{}
    LocalTime int64
    RemoteTime int64
    PeerID    string
}

type SyncEvent struct {
    Type      SyncEventType
    Key       string
    Value     interface{}
    Timestamp int64
    PeerID    string
}

func NewSyncEngine(gun *gunDB) *SyncEngine {
    se := &SyncEngine{
        gun:           gun,
        pendingWrites: make(map[string]*PendingWrite),
        conflictQueue: make(chan *ConflictEvent, 1000),
        syncQueue:     make(chan *SyncEvent, 1000),
        peerStates:    make(map[string]*PeerState),
    }
    
    // Start sync processors
    go se.processConflicts()
    go se.processSyncEvents()
    go se.processRetries()
    
    return se
}

func (se *SyncEngine) Put(key string, value interface{}) error {
    timestamp := time.Now().UnixNano()
    peerID := se.gun.GetPeerID()
    
    // Check for local conflicts
    if existing, exists := se.gun.graph.Get(key); exists {
        if existingTime, ok := existing["_"][">"]; ok {
            if timestamp <= existingTime.(int64) {
                return ErrStaleWrite
            }
        }
    }
    
    // Prepare write with metadata
    writeData := map[string]interface{}{
        "_": map[string]interface{}{
            ">": timestamp,
            "#": peerID,
        },
    }
    
    // Merge value with metadata
    if valueMap, ok := value.(map[string]interface{}); ok {
        for k, v := range valueMap {
            writeData[k] = v
        }
    } else {
        writeData["="] = value
    }
    
    // Store locally
    se.gun.graph.Put(key, writeData)
    
    // Add to pending writes for peer synchronization
    se.mutex.Lock()
    se.pendingWrites[key] = &PendingWrite{
        Key:       key,
        Value:     writeData,
        Timestamp: timestamp,
        PeerID:    peerID,
        Retries:   0,
    }
    se.mutex.Unlock()
    
    // Trigger sync
    se.syncQueue <- &SyncEvent{
        Type:      SyncEventPut,
        Key:       key,
        Value:     writeData,
        Timestamp: timestamp,
        PeerID:    peerID,
    }
    
    return nil
}

func (se *SyncEngine) processConflicts() {
    for conflict := range se.conflictQueue {
        // Implement last-write-wins with vector clock comparison
        if conflict.RemoteTime > conflict.LocalTime {
            // Remote write is newer, accept it
            se.gun.graph.Put(conflict.Key, conflict.RemoteVal)
            se.gun.eventBus.Publish("data.updated", map[string]interface{}{
                "key":   conflict.Key,
                "value": conflict.RemoteVal,
                "peer":  conflict.PeerID,
            })
        } else if conflict.RemoteTime == conflict.LocalTime {
            // Same timestamp, use deterministic resolution based on peer ID
            localPeerID := se.gun.GetPeerID()
            if conflict.PeerID > localPeerID {
                se.gun.graph.Put(conflict.Key, conflict.RemoteVal)
                se.gun.eventBus.Publish("data.updated", map[string]interface{}{
                    "key":   conflict.Key,
                    "value": conflict.RemoteVal,
                    "peer":  conflict.PeerID,
                })
            }
        }
        // If local time is newer, keep local value (do nothing)
    }
}

5. Integration with Fiber Applications

Making fibergun easy to use in Fiber applications was a primary design goal. Here’s how developers can integrate it:

package main

import (
    "log"
    "time"
    
    "github.com/gofiber/fiber/v2"
    "github.com/gofiber/fiber/v2/middleware/cors"
    "github.com/gofiber/fiber/v2/middleware/logger"
    "github.com/gofiber/websocket/v2"
    "your-package/fibergun"
)

func main() {
    app := fiber.New(fiber.Config{
        ErrorHandler: func(c *fiber.Ctx, err error) error {
            code := fiber.StatusInternalServerError
            if e, ok := err.(*fiber.Error); ok {
                code = e.Code
            }
            return c.Status(code).JSON(fiber.Map{
                "error": err.Error(),
            })
        },
    })
    
    // Middleware
    app.Use(logger.New())
    app.Use(cors.New(cors.Config{
        AllowOrigins:     "*",
        AllowCredentials: true,
    }))
    
    // Initialize GunDB
    gun, err := fibergun.New(&fibergun.Options{
        Peers:        []string{"ws://peer1.com/gun", "ws://peer2.com/gun"},
        Radisk:       true,
        File:         "./data",
        WebSocket:    true,
        Port:         8080,
        MaxPeers:     50,
        StorageQuota: 1024 * 1024 * 1024, // 1GB
    })
    if err != nil {
        log.Fatal(err)
    }
    defer gun.Close()
    
    // WebSocket upgrade middleware
    app.Use("/gun", websocket.New(func(c *websocket.Conn) {
        gun.HandleWebSocket(c)
    }))
    
    // REST API endpoints
    setupAPIRoutes(app, gun)
    
    // Static file serving
    app.Static("/", "./public")
    
    log.Fatal(app.Listen(":3000"))
}

func setupAPIRoutes(app *fiber.App, gun fibergun.GunDB) {
    api := app.Group("/api/v1")
    
    // Get data
    api.Get("/data/*", func(c *fiber.Ctx) error {
        path := c.Params("*")
        node := gun.Get(path)
        value := node.Val()
        
        if value == nil {
            return c.Status(fiber.StatusNotFound).JSON(fiber.Map{
                "error": "Data not found",
            })
        }
        
        return c.JSON(fiber.Map{
            "data": value,
            "path": path,
        })
    })
    
    // Put data
    api.Put("/data/*", func(c *fiber.Ctx) error {
        path := c.Params("*")
        
        var data interface{}
        if err := c.BodyParser(&data); err != nil {
            return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{
                "error": "Invalid JSON",
            })
        }
        
        if err := gun.Put(path, data); err != nil {
            return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{
                "error": err.Error(),
            })
        }
        
        return c.JSON(fiber.Map{
            "status": "success",
            "path":   path,
        })
    })
    
    // Subscribe to data changes
    api.Get("/subscribe/*", websocket.New(func(c *websocket.Conn) {
        path := c.Params("*")
        
        subscription := gun.On(path, func(data interface{}, key string) {
            message := map[string]interface{}{
                "type": "update",
                "path": path,
                "key":  key,
                "data": data,
            }
            
            if err := c.WriteJSON(message); err != nil {
                gun.Off(subscription)
                c.Close()
            }
        })
        
        defer gun.Off(subscription)
        
        // Keep connection alive
        for {
            _, _, err := c.ReadMessage()
            if err != nil {
                break
            }
        }
    }))
}

Advanced Features and Use Cases

1. Real-time Collaborative Applications

Fibergun excels at building real-time collaborative applications:

// Real-time chat implementation
func setupChatRoutes(app *fiber.App, gun fibergun.GunDB) {
    chat := app.Group("/chat")
    
    // Send message
    chat.Post("/send", func(c *fiber.Ctx) error {
        var message struct {
            Room    string `json:"room"`
            User    string `json:"user"`
            Message string `json:"message"`
        }
        
        if err := c.BodyParser(&message); err != nil {
            return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{
                "error": "Invalid message format",
            })
        }
        
        messageID := generateMessageID()
        messageData := map[string]interface{}{
            "user":      message.User,
            "message":   message.Message,
            "timestamp": time.Now().UnixNano(),
        }
        
        // Store message in room
        path := fmt.Sprintf("chat/rooms/%s/messages/%s", message.Room, messageID)
        if err := gun.Put(path, messageData); err != nil {
            return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{
                "error": "Failed to send message",
            })
        }
        
        return c.JSON(fiber.Map{
            "status":    "sent",
            "messageId": messageID,
        })
    })
    
    // Subscribe to room messages
    chat.Get("/room/:room/subscribe", websocket.New(func(c *websocket.Conn) {
        room := c.Params("room")
        path := fmt.Sprintf("chat/rooms/%s/messages", room)
        
        subscription := gun.Map(path).On(func(message interface{}, messageID string) {
            response := map[string]interface{}{
                "type":      "message",
                "room":      room,
                "messageId": messageID,
                "data":      message,
            }
            
            if err := c.WriteJSON(response); err != nil {
                gun.Off(subscription)
                c.Close()
            }
        })
        
        defer gun.Off(subscription)
        
        // Keep connection alive
        for {
            _, _, err := c.ReadMessage()
            if err != nil {
                break
            }
        }
    }))
}

2. Offline-first Todo Application

// Todo application with offline support
type Todo struct {
    ID          string    `json:"id"`
    Title       string    `json:"title"`
    Description string    `json:"description"`
    Completed   bool      `json:"completed"`
    CreatedAt   time.Time `json:"createdAt"`
    UpdatedAt   time.Time `json:"updatedAt"`
    UserID      string    `json:"userId"`
}

func setupTodoRoutes(app *fiber.App, gun fibergun.GunDB) {
    todos := app.Group("/todos")
    
    // Create todo
    todos.Post("/", func(c *fiber.Ctx) error {
        var todo Todo
        if err := c.BodyParser(&todo); err != nil {
            return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{
                "error": "Invalid todo format",
            })
        }
        
        todo.ID = generateTodoID()
        todo.CreatedAt = time.Now()
        todo.UpdatedAt = time.Now()
        
        // Store in user's todo list
        userTodosPath := fmt.Sprintf("users/%s/todos/%s", todo.UserID, todo.ID)
        if err := gun.Put(userTodosPath, todo); err != nil {
            return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{
                "error": "Failed to create todo",
            })
        }
        
        return c.Status(fiber.StatusCreated).JSON(todo)
    })
    
    // Get user's todos
    todos.Get("/user/:userId", func(c *fiber.Ctx) error {
        userID := c.Params("userId")
        todosPath := fmt.Sprintf("users/%s/todos", userID)
        
        todosNode := gun.Get(todosPath)
        todosData := todosNode.Val()
        
        if todosData == nil {
            return c.JSON([]Todo{})
        }
        
        var todos []Todo
        if todosMap, ok := todosData.(map[string]interface{}); ok {
            for _, todoData := range todosMap {
                if todoData != nil {
                    var todo Todo
                    if err := mapstructure.Decode(todoData, &todo); err == nil {
                        todos = append(todos, todo)
                    }
                }
            }
        }
        
        return c.JSON(todos)
    })
    
    // Update todo
    todos.Put("/:id", func(c *fiber.Ctx) error {
        todoID := c.Params("id")
        userID := c.Query("userId")
        
        var updates map[string]interface{}
        if err := c.BodyParser(&updates); err != nil {
            return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{
                "error": "Invalid update format",
            })
        }
        
        updates["updatedAt"] = time.Now()
        todoPath := fmt.Sprintf("users/%s/todos/%s", userID, todoID)
        
        // Get existing todo and merge updates
        existing := gun.Get(todoPath).Val()
        if existing == nil {
            return c.Status(fiber.StatusNotFound).JSON(fiber.Map{
                "error": "Todo not found",
            })
        }
        
        // Merge updates with existing data
        if existingMap, ok := existing.(map[string]interface{}); ok {
            for key, value := range updates {
                existingMap[key] = value
            }
            
            if err := gun.Put(todoPath, existingMap); err != nil {
                return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{
                    "error": "Failed to update todo",
                })
            }
            
            return c.JSON(existingMap)
        }
        
        return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{
            "error": "Invalid todo data",
        })
    })
}

Performance Optimization Strategies

Building a performant distributed database requires careful optimization at multiple levels:

1. Connection Pooling and Management

type ConnectionPool struct {
    connections chan *Connection
    factory     func() (*Connection, error)
    maxSize     int
    currentSize int
    mutex       sync.Mutex
}

func NewConnectionPool(maxSize int, factory func() (*Connection, error)) *ConnectionPool {
    return &ConnectionPool{
        connections: make(chan *Connection, maxSize),
        factory:     factory,
        maxSize:     maxSize,
    }
}

func (cp *ConnectionPool) Get() (*Connection, error) {
    select {
    case conn := <-cp.connections:
        return conn, nil
    default:
        cp.mutex.Lock()
        defer cp.mutex.Unlock()
        
        if cp.currentSize < cp.maxSize {
            conn, err := cp.factory()
            if err != nil {
                return nil, err
            }
            cp.currentSize++
            return conn, nil
        }
        
        // Wait for available connection
        return <-cp.connections, nil
    }
}

func (cp *ConnectionPool) Put(conn *Connection) {
    select {
    case cp.connections <- conn:
    default:
        // Pool is full, close connection
        conn.Close()
        cp.mutex.Lock()
        cp.currentSize--
        cp.mutex.Unlock()
    }
}

2. Intelligent Caching System

type CacheLayer struct {
    memory    *lru.Cache
    disk      *DiskCache
    metrics   *CacheMetrics
    mutex     sync.RWMutex
}

func NewCacheLayer(memorySize int, diskPath string) (*CacheLayer, error) {
    memCache, err := lru.New(memorySize)
    if err != nil {
        return nil, err
    }
    
    diskCache, err := NewDiskCache(diskPath)
    if err != nil {
        return nil, err
    }
    
    return &CacheLayer{
        memory:  memCache,
        disk:    diskCache,
        metrics: NewCacheMetrics(),
    }, nil
}

func (cl *CacheLayer) Get(key string) (interface{}, bool) {
    cl.mutex.RLock()
    defer cl.mutex.RUnlock()
    
    // Try memory cache first
    if value, ok := cl.memory.Get(key); ok {
        cl.metrics.MemoryHits++
        return value, true
    }
    
    // Try disk cache
    if value, ok := cl.disk.Get(key); ok {
        cl.metrics.DiskHits++
        // Promote to memory cache
        cl.memory.Add(key, value)
        return value, true
    }
    
    cl.metrics.Misses++
    return nil, false
}

func (cl *CacheLayer) Put(key string, value interface{}) {
    cl.mutex.Lock()
    defer cl.mutex.Unlock()
    
    // Store in both memory and disk
    cl.memory.Add(key, value)
    cl.disk.Put(key, value)
}

3. Message Batching and Compression

type MessageBatcher struct {
    messages    []Message
    batchSize   int
    flushTimer  *time.Timer
    flushPeriod time.Duration
    compressor  Compressor
    sender      MessageSender
    mutex       sync.Mutex
}

func NewMessageBatcher(batchSize int, flushPeriod time.Duration) *MessageBatcher {
    mb := &MessageBatcher{
        messages:    make([]Message, 0, batchSize),
        batchSize:   batchSize,
        flushPeriod: flushPeriod,
        compressor:  NewGzipCompressor(),
    }
    
    mb.flushTimer = time.AfterFunc(flushPeriod, mb.flush)
    return mb
}

func (mb *MessageBatcher) Add(message Message) {
    mb.mutex.Lock()
    defer mb.mutex.Unlock()
    
    mb.messages = append(mb.messages, message)
    
    if len(mb.messages) >= mb.batchSize {
        mb.flushLocked()
    }
}

func (mb *MessageBatcher) flushLocked() {
    if len(mb.messages) == 0 {
        return
    }
    
    // Create batch
    batch := MessageBatch{
        Messages:  mb.messages,
        Timestamp: time.Now().UnixNano(),
    }
    
    // Compress batch
    compressed, err := mb.compressor.Compress(batch)
    if err != nil {
        log.Printf("Failed to compress message batch: %v", err)
        return
    }
    
    // Send batch
    go mb.sender.Send(compressed)
    
    // Reset batch
    mb.messages = mb.messages[:0]
    mb.flushTimer.Reset(mb.flushPeriod)
}

Testing and Quality Assurance

Comprehensive testing is crucial for a distributed database system:

1. Unit Testing

func TestGunDBBasicOperations(t *testing.T) {
    // Setup test environment
    tmpDir, err := os.MkdirTemp("", "gundb_test")
    require.NoError(t, err)
    defer os.RemoveAll(tmpDir)
    
    gun, err := NewGunDB(&Options{
        File:   tmpDir,
        Radisk: true,
    })
    require.NoError(t, err)
    defer gun.Close()
    
    // Test basic put/get operations
    testData := map[string]interface{}{
        "name": "John Doe",
        "age":  30,
    }
    
    err = gun.Put("users/john", testData)
    require.NoError(t, err)
    
    node := gun.Get("users/john")
    value := node.Val()
    require.NotNil(t, value)
    
    // Verify data integrity
    if valueMap, ok := value.(map[string]interface{}); ok {
        assert.Equal(t, "John Doe", valueMap["name"])
        assert.Equal(t, float64(30), valueMap["age"]) // JSON numbers are float64
    } else {
        t.Fatal("Expected map[string]interface{}")
    }
}

func TestConflictResolution(t *testing.T) {
    // Create two GunDB instances
    gun1, err := NewGunDB(&Options{})
    require.NoError(t, err)
    defer gun1.Close()
    
    gun2, err := NewGunDB(&Options{})
    require.NoError(t, err)
    defer gun2.Close()
    
    // Simulate concurrent writes
    key := "test/conflict"
    
    // Write to gun1
    err = gun1.Put(key, map[string]interface{}{"value": "from_gun1"})
    require.NoError(t, err)
    
    // Write to gun2 slightly later
    time.Sleep(time.Millisecond)
    err = gun2.Put(key, map[string]interface{}{"value": "from_gun2"})
    require.NoError(t, err)
    
    // Sync between instances
    err = gun1.Sync(gun2)
    require.NoError(t, err)
    
    // Both should have the later write (from gun2)
    value1 := gun1.Get(key).Val()
    value2 := gun2.Get(key).Val()
    
    assert.Equal(t, value1, value2)
    
    if valueMap, ok := value1.(map[string]interface{}); ok {
        assert.Equal(t, "from_gun2", valueMap["value"])
    }
}

2. Integration Testing

func TestPeerSynchronization(t *testing.T) {
    // Start multiple peer instances
    peers := make([]*gunDB, 3)
    ports := []int{8081, 8082, 8083}
    
    for i := 0; i < 3; i++ {
        gun, err := NewGunDB(&Options{
            Port:      ports[i],
            WebSocket: true,
            Peers:     getPeerURLs(ports, i),
        })
        require.NoError(t, err)
        peers[i] = gun
    }
    
    // Cleanup
    defer func() {
        for _, peer := range peers {
            peer.Close()
        }
    }()
    
    // Wait for peers to connect
    time.Sleep(2 * time.Second)
    
    // Write data to first peer
    testData := map[string]interface{}{
        "message": "Hello from peer 0",
        "timestamp": time.Now().Unix(),
    }
    
    err := peers[0].Put("sync/test", testData)
    require.NoError(t, err)
    
    // Wait for synchronization
    time.Sleep(1 * time.Second)
    
    // Verify data is available on all peers
    for i, peer := range peers {
        value := peer.Get("sync/test").Val()
        require.NotNil(t, value, "Peer %d should have synced data", i)
        
        if valueMap, ok := value.(map[string]interface{}); ok {
            assert.Equal(t, "Hello from peer 0", valueMap["message"])
        }
    }
}

func getPeerURLs(ports []int, exclude int) []string {
    var urls []string
    for i, port := range ports {
        if i != exclude {
            urls = append(urls, fmt.Sprintf("ws://localhost:%d/gun", port))
        }
    }
    return urls
}

3. Load Testing

func TestHighLoadOperations(t *testing.T) {
    gun, err := NewGunDB(&Options{
        MaxPeers: 100,
    })
    require.NoError(t, err)
    defer gun.Close()
    
    // Test concurrent writes
    numRoutines := 100
    numWrites := 1000
    
    var wg sync.WaitGroup
    errors := make(chan error, numRoutines*numWrites)
    
    for i := 0; i < numRoutines; i++ {
        wg.Add(1)
        go func(routineID int) {
            defer wg.Done()
            
            for j := 0; j < numWrites; j++ {
                key := fmt.Sprintf("load/test/%d/%d", routineID, j)
                data := map[string]interface{}{
                    "routine": routineID,
                    "write":   j,
                    "time":    time.Now().UnixNano(),
                }
                
                if err := gun.Put(key, data); err != nil {
                    errors <- err
                    return
                }
            }
        }(i)
    }
    
    wg.Wait()
    close(errors)
    
    // Check for errors
    var errorCount int
    for err := range errors {
        t.Logf("Write error: %v", err)
        errorCount++
    }
    
    assert.Equal(t, 0, errorCount, "No errors should occur during load test")
    
    // Verify some random keys exist
    for i := 0; i < 10; i++ {
        routineID := rand.Intn(numRoutines)
        writeID := rand.Intn(numWrites)
        key := fmt.Sprintf("load/test/%d/%d", routineID, writeID)
        
        value := gun.Get(key).Val()
        assert.NotNil(t, value, "Random key %s should exist", key)
    }
}

Monitoring and Observability

Production distributed systems require comprehensive monitoring:

type Metrics struct {
    // Operation counters
    ReadOperations  prometheus.Counter
    WriteOperations prometheus.Counter
    SyncOperations  prometheus.Counter
    
    // Performance metrics
    OperationDuration prometheus.HistogramVec
    SyncLatency      prometheus.Histogram
    
    // System metrics
    ConnectedPeers   prometheus.Gauge
    StorageUsage     prometheus.Gauge
    MemoryUsage      prometheus.Gauge
    
    // Error metrics
    OperationErrors prometheus.CounterVec
    SyncErrors      prometheus.Counter
}

func NewMetrics() *Metrics {
    m := &Metrics{
        ReadOperations: prometheus.NewCounter(prometheus.CounterOpts{
            Name: "gundb_read_operations_total",
            Help: "Total number of read operations",
        }),
        WriteOperations: prometheus.NewCounter(prometheus.CounterOpts{
            Name: "gundb_write_operations_total",
            Help: "Total number of write operations",
        }),
        OperationDuration: prometheus.NewHistogramVec(prometheus.HistogramOpts{
            Name: "gundb_operation_duration_seconds",
            Help: "Duration of operations",
        }, []string{"operation", "status"}),
        ConnectedPeers: prometheus.NewGauge(prometheus.GaugeOpts{
            Name: "gundb_connected_peers",
            Help: "Number of connected peers",
        }),
    }
    
    // Register metrics
    prometheus.MustRegister(
        m.ReadOperations,
        m.WriteOperations,
        m.OperationDuration,
        m.ConnectedPeers,
    )
    
    return m
}

func (m *Metrics) RecordOperation(operation string, duration time.Duration, err error) {
    status := "success"
    if err != nil {
        status = "error"
    }
    
    m.OperationDuration.WithLabelValues(operation, status).Observe(duration.Seconds())
    
    switch operation {
    case "read":
        m.ReadOperations.Inc()
    case "write":
        m.WriteOperations.Inc()
    }
}

Future Roadmap and Improvements

Our Fiber-GunDB integration continues to evolve. Here are some planned improvements:

1. Enhanced Security Features

  • End-to-end encryption for sensitive data
  • User authentication and authorization layers
  • Audit logging and compliance features
  • Advanced key management systems

2. Performance Optimizations

  • Improved caching strategies with intelligent prefetching
  • Better compression algorithms for network traffic
  • Optimized storage backends for different use cases
  • Enhanced conflict resolution algorithms

3. Developer Experience

  • Comprehensive documentation with interactive examples
  • Developer tools for debugging and profiling
  • Code generation tools for common patterns
  • Integration with popular development frameworks

4. Enterprise Features

  • Multi-tenant support with data isolation
  • Advanced monitoring and alerting
  • Backup and disaster recovery solutions
  • Compliance tools for regulatory requirements

Resources and Community

To learn more about GunDB and our Fiber integration:

Conclusion

Integrating GunDB with Fiber provides developers with a powerful foundation for building distributed, real-time applications that work seamlessly offline and online. The combination of Fiber’s performance and simplicity with GunDB’s decentralized architecture creates unique opportunities for building resilient, user-centric applications.

Our implementation demonstrates that decentralized databases can be successfully integrated into modern web frameworks without sacrificing performance or developer experience. The modular design allows for easy customization and extension while maintaining the core benefits of decentralization.

As we continue to develop fibergun, we remain committed to improving both performance and developer experience, making it easier for developers to build the distributed applications of tomorrow.

The future of web applications lies not in centralized architectures, but in systems that empower users with true data ownership and work reliably regardless of network conditions. GunDB and Fiber together provide the foundation for building these next-generation applications.


This integration represents our ongoing commitment to advancing decentralized web technologies and empowering developers to build more resilient, user-centric applications.