go-pubsub

Lightweight, in-process Pub/Sub for Go—perfect for transient data flows like real-time streaming-media packets. It’s pure fire-and-forget: zero persistence, no delivery guarantees, just ultra-fast, one-way messaging.

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Installation

go get github.com/F2077/go-pubsub

Quick Start

package main

import (
	"fmt"
	"github.com/F2077/go-pubsub/pubsub"
	"time"
)

func main() {
	// 1. Create a broker (supports generics)
	broker, _ := pubsub.NewBroker[string]()

	// 2. Create a publisher
	publisher := pubsub.NewPublisher[string](broker)

	// 3. Create a subscriber
	subscriber := pubsub.NewSubscriber[string](broker)

	// 4. Subscribe to a topic with buffer size and timeout
	sub, _ := subscriber.Subscribe("alerts",
		pubsub.WithChannelSize[string](pubsub.Medium), // Buffer 100 messages
		pubsub.WithTimeout[string](5*time.Second),     // Auto-close if idle
	)
	defer func(sub *pubsub.Subscription[string]) {
		_ = sub.Close()
	}(sub)

	// 5. Publish a message
	go func() {
		_ = publisher.Publish("alerts", "CPU over 90%!")
	}()

	// 6. Listen for messages or timeouts
	select {
	case msg := <-sub.Ch:
		fmt.Println("Received:", msg) // Output: "CPU over 90%!"
	case err := <-sub.ErrCh:
		fmt.Println("Error:", err)
	}
}

Key Features

• 🚀 Zero Persistence: Messages vanish if channels are full or subscribers time out.
• ⏱️ Auto-Expiry: Idle subscriptions close automatically (configurable timeout).
• 🔒 Concurrency-Safe: Efficient locking for high concurrency.
• 📦 Capacity Control: Set max subscriptions per broker (prevents memory leaks).
• 📡 Topic-Based: Simple publish/subscribe with string topics.

Advanced Configuration

Custom Broker

broker, _ := pubsub.NewBroker[string](
pubsub.WithCapacity(5000), // Max 5000 topics
pubsub.WithLogger(customLogger), // Inject your logger
pubsub.WithId("broker-1"), // Custom broker ID
)

Subscriber Options

// Subscribe with custom settings
sub, _ := subscriber.Subscribe("metrics",
pubsub.WithChannelSize[string](pubsub.Huge), // 1000-message buffer
pubsub.WithTimeout[string](10 * time.Second), // Timeout after 10s inactivity
)

When to Use

• ✅ Real-time pub-sub
• ✅ Low-latency gaming/live events
• ❌ Not for: Persistent queues, guaranteed delivery.

Performance Notes

• 🔥 Fast fan-out: Optimized for many subscribers per topic.
• ⚠️ No backpressure: Full channels drop messages silently.

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Benchmark Results

All benchmarks run on goos: windows, goarch: amd64, pkg: github.com/F2077/go-pubsub, cpu: Intel(R) Core(TM) i7-10700F CPU @ 2.90GHz

Benchmark	Iterations	ns/op	B/op	allocs/op
BenchmarkPublishSingleSubscriber-16	5 188 107	233.0 ns/op	96	2
BenchmarkMultipleSubscribers-16	143 594	8 089 ns/op	96	2
BenchmarkMultiPublisherSingleSubscriber-16	259 663	4 732 ns/op	776	21
BenchmarkMultiPublisherMultipleSubscribers-16	67 593	17 823 ns/op	776	21
BenchmarkUltraLargeSubscribersSinglePublisher-16	471	2 846 125 ns/op	96	2
BenchmarkPublishChannelSizes/Small-16	5 271 156	230.2 ns/op	96	2
BenchmarkPublishChannelSizes/Medium-16	5 134 640	229.5 ns/op	96	2
BenchmarkPublishChannelSizes/Large-16	5 238 266	231.8 ns/op	96	2
BenchmarkPublishWithTimeout-16	1 345 124	861.1 ns/op	507	7
BenchmarkHighLoadParallel-16	14 728	83 785 ns/op	100	2

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Contributions welcome! Report bugs or suggest features via issues.