🚀 MemoryStore

MemoryStore is a high-performance, thread-safe, in-memory key-value store implemented in Go. It features automatic key expiration, JSON serialization support, batch operations, metrics, and an agnostic Publish/Subscribe system (supporting In-Memory and Google Cloud PubSub).

Features

• 🔄 Thread-safe operations
• ⏰ Automatic key expiration
• 🧹 Background cleanup of expired keys
• 📦 Support for both raw bytes and JSON data
• 💪 High-performance using go-json
• 🚀 Batch operations (SetMulti, GetMulti)
• 📊 Built-in Metrics and Monitoring
• 📡 Agnostic Publish/Subscribe system (In-Memory & GCP PubSub)
• 🔒 Clean shutdown mechanism
• 📝 Comprehensive documentation

Installation

go get github.com/BryceWayne/MemoryStore

Quick Start

Here's a simple example demonstrating basic usage:

package main

import (
    "log"
    "time"
    "github.com/BryceWayne/MemoryStore/memorystore"
)

func main() {
    // Create a new store instance (defaults to In-Memory PubSub)
    store := memorystore.NewMemoryStore()
    defer store.Stop()

    // Store a string (converted to bytes)
    err := store.Set("greeting", []byte("Hello, World!"), 1*time.Minute)
    if err != nil {
        log.Fatal(err)
    }

    // Retrieve the value
    if value, exists := store.Get("greeting"); exists {
        log.Printf("Value: %s", string(value))
    }
}

PubSub Usage

MemoryStore supports an agnostic PubSub interface. By default, it uses an in-memory implementation. To use Google Cloud PubSub, simply provide your Project ID configuration.

Using In-Memory PubSub (Default)

package main

import (
    "log"
    "time"
    "github.com/BryceWayne/MemoryStore/memorystore"
)

func main() {
    store := memorystore.NewMemoryStore()
    defer store.Stop()

    // Subscribe to a topic
    msgs, err := store.Subscribe("user-updates")
    if err != nil {
        log.Fatal(err)
    }

    // Listen in background
    go func() {
        for msg := range msgs {
            log.Printf("Received: %s", string(msg))
        }
    }()

    // Publish to the topic
    err = store.Publish("user-updates", []byte("User 123 logged in"))
    if err != nil {
        log.Fatal(err)
    }

    // Give time for message delivery
    time.Sleep(1 * time.Second)
}

Using Google Cloud PubSub

package main

import (
    "log"
    "time"
    "github.com/BryceWayne/MemoryStore/memorystore"
)

func main() {
    // Configure with GCP Project ID
    config := memorystore.Config{
        GCPProjectID: "my-gcp-project-id",
    }
    store := memorystore.NewMemoryStoreWithConfig(config)
    defer store.Stop()

    // Subscribe to a topic
    // Note: GCP PubSub creates a subscription for this topic
    msgs, err := store.Subscribe("user-updates")
    if err != nil {
        log.Fatal(err)
    }

    // Listen in background
    go func() {
        for msg := range msgs {
            log.Printf("Received: %s", string(msg))
        }
    }()

    // Publish to the topic
    err = store.Publish("user-updates", []byte("User 123 logged in"))
    if err != nil {
        log.Fatal(err)
    }

    // Give time for message delivery
    time.Sleep(1 * time.Second)
}

Or simply set GOOGLE_CLOUD_PROJECT environment variable:

export GOOGLE_CLOUD_PROJECT=my-project-id

store := memorystore.NewMemoryStore() // Automatically picks up GCP PubSub

Advanced Usage

Working with JSON

MemoryStore provides convenient methods for JSON serialization:

type User struct {
    Name  string `json:"name"`
    Email string `json:"email"`
}

func main() {
    store := memorystore.NewMemoryStore()
    defer store.Stop()

    // Store JSON data
    user := User{Name: "Alice", Email: "alice@example.com"}
    err := store.SetJSON("user:123", user, 1*time.Hour)
    if err != nil {
        log.Fatal(err)
    }

    // Retrieve JSON data
    var retrievedUser User
    exists, err := store.GetJSON("user:123", &retrievedUser)
    if err != nil {
        log.Fatal(err)
    }
    if exists {
        log.Printf("User: %+v", retrievedUser)
    }
}

Batch Operations

Efficiently set or get multiple items at once:

items := map[string][]byte{
    "key1": []byte("val1"),
    "key2": []byte("val2"),
}
store.SetMulti(items, time.Minute)

results := store.GetMulti([]string{"key1", "key2"})

Metrics

Monitor cache performance:

metrics := store.GetMetrics()
log.Printf("Hits: %d, Misses: %d, Items: %d", metrics.Hits, metrics.Misses, metrics.Items)

Expiration and Cleanup

Keys automatically expire after their specified duration:

// Set a value that expires in 5 seconds
store.Set("temp", []byte("temporary value"), 5*time.Second)

// The background cleanup routine will automatically remove expired items
// You can also manually check if an item exists
time.Sleep(6 * time.Second)
if _, exists := store.Get("temp"); !exists {
    log.Println("Key has expired")
}

Proper Shutdown

Always ensure proper cleanup by calling Stop():

store := memorystore.NewMemoryStore()
defer func() {
    if err := store.Stop(); err != nil {
        log.Printf("Error stopping store: %v", err)
    }
}()

Architecture

Here's an overview of how MemoryStore is architected:

graph TD
    subgraph Client Layer
        User[User Application]
    end

    subgraph MemoryStore System
        API[MemoryStore API]

        subgraph "Storage Engine"
            Shards[Sharded Storage Map]
            Metrics[Metrics Collector]
        end

        subgraph "Background Services"
            Cleaner[Cleanup Routine]
        end

        subgraph "Pub/Sub System"
            PS_Interface[PubSub Interface]
            PS_Mem[In-Memory Broker]
            PS_GCP[Google Cloud PubSub]
        end
    end

    User -->|Set/Get| API
    User -->|Subscribe| API

    API -->|Read/Write| Shards
    API -->|Record| Metrics
    API -->|Publish| PS_Interface

    Cleaner -->|Periodically Scan| Shards
    Cleaner -->|Remove Expired| Shards

    PS_Interface -->|Default| PS_Mem
    PS_Interface -->|Configured| PS_GCP

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PubSub Data Flow

sequenceDiagram
    participant P as Publisher
    participant MS as MemoryStore
    participant S as Subscriber

    S->>MS: Subscribe("topic-A")
    activate MS
    MS-->>S: Returns Channel
    deactivate MS

    P->>MS: Publish("topic-A", "payload")
    activate MS
    MS->>S: Sends "payload" to Channel
    deactivate MS

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Performance Considerations

• Uses github.com/goccy/go-json for faster JSON operations
• Minimizes lock contention with RWMutex
• Efficient background cleanup of expired items
• Memory-efficient storage using byte slices

Building and Testing

Use the provided Makefile:

# Build the project
make build

# Run tests (with race detection)
make test

# Run benchmarks
make bench

# Run linter
make lint

# Format code
make fmt

# Show all targets
make help

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Thanks to the Go team for the amazing standard library
• go-json for high-performance JSON operations

Support

If you have any questions or need help integrating MemoryStore, please:

1. Check the documentation
2. Open an issue with a detailed description
3. Reach out through the discussions tab