惯性聚合 高效追踪和阅读你感兴趣的博客、新闻、科技资讯
阅读原文 在惯性聚合中打开

推荐订阅源

Simon Willison's Weblog
Simon Willison's Weblog
Google DeepMind News
Google DeepMind News
CTFtime.org: upcoming CTF events
CTFtime.org: upcoming CTF events
P
Proofpoint News Feed
Recent Announcements
Recent Announcements
MongoDB | Blog
MongoDB | Blog
U
Unit 42
云风的 BLOG
云风的 BLOG
Recorded Future
Recorded Future
G
Google Developers Blog
I
InfoQ
Blog — PlanetScale
Blog — PlanetScale
A
About on SuperTechFans
Jina AI
Jina AI
量子位
宝玉的分享
宝玉的分享
The Cloudflare Blog
让小产品的独立变现更简单 - ezindie.com
让小产品的独立变现更简单 - ezindie.com
博客园 - 聂微东
Last Week in AI
Last Week in AI
WordPress大学
WordPress大学
美团技术团队
The Hacker News
The Hacker News
Threat Intelligence Blog | Flashpoint
Threat Intelligence Blog | Flashpoint
D
Darknet – Hacking Tools, Hacker News & Cyber Security
T
Tailwind CSS Blog
博客园 - 司徒正美
博客园 - 叶小钗
Hugging Face - Blog
Hugging Face - Blog
P
Palo Alto Networks Blog
博客园_首页
阮一峰的网络日志
阮一峰的网络日志
博客园 - 【当耐特】
Spread Privacy
Spread Privacy
The GitHub Blog
The GitHub Blog
Y
Y Combinator Blog
Vercel News
Vercel News
Martin Fowler
Martin Fowler
cs.CL updates on arXiv.org
cs.CL updates on arXiv.org
Forbes - Security
Forbes - Security
Attack and Defense Labs
Attack and Defense Labs
Google DeepMind News
Google DeepMind News
Cyber Security Advisories - MS-ISAC
Cyber Security Advisories - MS-ISAC
Microsoft Azure Blog
Microsoft Azure Blog
P
Privacy International News Feed
G
GRAHAM CLULEY
The Last Watchdog
The Last Watchdog
C
Cyber Attacks, Cyber Crime and Cyber Security
AI
AI
V2EX - 技术
V2EX - 技术

DEV Community

Authentication Security Deep Dive: From Brute Force to Salted Hashing (With Java Examples) Why AI Systems Don’t Fail — They Drift Spilling beans for how i learn for exam😁"Reinforcement Learning Cheat Sheet" I Replaced Chrome with Safari for AI Browser Automation. Here's What Broke (and What Finally Worked) How Python Borrows Other People's Work The $40 Architecture: Processing 1 Billion API Requests with 99.99% Uptime Vibe Coding: A Workflow Guide (From Zero to SaaS) Most webhook security guides protect the wrong side. The scary part is delivery. Headless CMS for TanStack Start: Build a Blog with Cosmic EU Age Verification App "Hacked in 2 Minutes" — What Actually Happened Comfy Cloud’s delete function does not actually remove files Running AI Models on GPU Cloud Servers: A Beginner Guide Event-driven media intelligence with AWS Step Functions and Bedrock I scored 500 AI prompts across 8 quality dimensions — here's what broke How to Call Google Gemini API from Next.js (Free Tier, No Backend Needed) The Portal Protocol: Reclaiming Human Connection in the Age of AI How to Fix Your Team's Scattered Knowledge Problem With a Self-Hosted Forum Intro to tc Cloud Functors: A Graph-First Mental Model for the Modern Cloud Designing Multi-Tenant Backends With Both Ownership and Team Access I Built a Neumorphic CSS Library with 77+ Components — Here's What I Learned PostgreSQL Performance Optimization: Why Connection Pooling Is Critical at Scale Cómo construí un SaaS multi-rubro para gestionar expensas en Argentina con FastAPI + Vue 3 🚀 I Built an Ethical Hacking Scanner Tool – Open Source Project I Replaced /usage and /context in Claude Code With a Single Statusline A Pythonic Way to Handle Emails (IMAP/SMTP) with Auto-Discovery and AI-Ready Design I Collected 8.9 Million Polymarket Price Points — Here's What I Found About How Markets Really Move EcoTrack AI — Carbon Footprint Tracker & Dashboard Everyone's Using AI. No One Agrees How. 5 self-hosted ebook managers worth trying in 2026 Building Your First AI Agent with LangChain: From Chatbot to Autonomous Assistant Common SOC 2 Failures (Real World) Stop Vibe-Checking Your AI App: A Practical Guide to Evals How to Use SonarQube and SonarScanner Locally to Level Up Your Code Quality Your Next To-Do App Is Dead — I Replaced Mine with an OpenClaw AI Sign a Nostr event in 60 lines of Python using coincurve — no nostr-sdk, no nbxplorer, no rust toolchain ITGC Audit Explained Like You’re in Big 4 Patch Tuesday abril 2026: Microsoft parcha 163 vulnerabilidades y un zero-day en SharePoint Stop scraping everything: a better way to track competitor price changes Listing on MCPize + the Official MCP Registry while routing payments OUTSIDE the marketplace — how I kept 100% of my x402 revenue Building an AI-Powered Risk Intelligence System Using Serverless Architecture Why We Ripped Function Overloading Out of Our AI Toolchain Testing AI-Generated Code: How to Actually Know If It Works SaaS Churn Is Killing Your Business. Here Is What to Do About It (Without a Support Team) The Speed of AI Is No Longer Linear - And Self-Improving Models Are Why How to Implement RBAC for MCP Tools: A Practical Guide for Engineering Teams From Standard Quote to Persuasive Proposal: AI Automation for Arborists I built a CLI that scaffolds complete multi-tenant SaaS apps Axios CVE-2025–62718: The Silent SSRF Bug That Could Be Hiding in Your Node.js App Right Now The dashboard that ended our friendship Data Pipelines Explained Simply (and How to Build Them with Python) The Hidden Cost of AI Systems Nobody Talks About. undefined vs undeclared, and how typeof behaves Switching from file-based jobs to NATS/Kafka in Rust without changing code io_uring Adventures: Rust Servers That Love Syscalls Why Agentic AI is Killing the Traditional Database The POUR principles of web accessibility for developers and designers Quantum Neural Network 3D — A Deep Dive into Interactive WebGL Visualization How To Install Caveman In Codex On macOS And Windows Automation Pipeline Reliability: Why Your Workflow Breaks When Nobody Is Watching I Built an 'Open World' AI Coding Agent — It Works From ANY Folder From Freelancing to Product: A Tech Service Company's SaaS Transformation China's AI Giants: Adding Tencent Hunyuan & ByteDance Doubao to AI University (74 Providers) On the Vibe Coders and Their Lies clerk: Auto-Summarize Your Claude Code Sessions AI Weekly — 2026/04/10–04/17 | The Model Lockdown Is Here, but the Toolchain Is the Real Battleground AI 週報 — 2026/04/10–2026/04/17 模型封鎖潮來了,但工具鏈才是真戰場 Maybe this is how Open-Source apps are born... 🚀 Fine-Tune LLMs with LoRA and QLoRA: 2026 Guide tRPC v11 + Next.js App Router: End-to-End Type Safety Without the Boilerplate ShadCN UI in 2026: Why I Stopped Installing Component Libraries and Started Owning My Components SaaS Billing in React Server Components: Stripe + Supabase Without a Single `useEffect` Join our DEV Weekend Challenge — $1,000 in Prizes Across TEN winners! Submissions Due April 20 at 6:59 AM UTC. Implementing FSRS Spaced Repetition in Flutter + Supabase — Adding Memory Science to an AI Learning App "I Texted My Localhost From the Train — Claude Code Fixed the Bug Before I Got Home" I Built a Sales Prep AI and It Went Deeper Than Expected Design to Code #2: One JSON, Eleven Outputs Solving the 100M-Row Problem: A Summary Table Pattern for High-Volume Push Notification Logs Flutter Web With Wasm: What Actually Changes For Developers I Built 50 Royalty-Free Soundtracks for My Side Project in a Weekend Using AI Music Generation The Vibe Coding Security Checklist: 7 Things to Check Before You Ship Stop Letting Googlebot Guess Fix Your React App's SEO Right Desconstruindo o Streaming do LinkedIn: Como Criar um Engine de Extração de Vídeo de Alta Performance com HLS e FFmpeg (EDA Part-1) EDA (Exploratory Data Analysis) Explained With Real Life — Why Looking at Your Data Is the Most Important Step in Machine Learning Brand Relationship Management at Scale: Our 4-Touch Outreach System for 200+ Brands Why String.fromEnvironment() Might Return an Empty String in Dart JGuardrails 1.0.0 — Hardening Java LLM Apps Against Jailbreaks, Toxicity, and Prompt Injection Plan and Schedule a Full Week of Threads Content From One Claude Conversation Coding Cat Oran Ep3, Five Tables Changed Everything Updated: BFF Pattern I'm done watching freelancers get buried by 200 proposals. So I'm building the alternative. This is my first post BFS Algorithm in Java Step by Step Tutorial with Examples Tracking LLM Pricing Monthly: An Open Dataset for 22 AI Models How We Measure Content ROI on a Comparison Site: Revenue Attribution Without Perfect Data Introducing Nova AI Ops: The AI-Native Operating System for SRE Teams I built a free desktop video downloader for Windows — Grabbit How Talkie OCR Helps Vision-Impaired & Dyslexic Users Read the World Around Them VRCFaceTracking安装和iPhone面捕配置教程,有bug Even CrowdStrike Can't See Your Agents The Automation Gold Rush: What n8n Workflows and Claude Are Opening Up for Developers Right Now
Concurrency in Go: Goroutines and Channels Explained with Real Examples
Dishon Oketc · 2026-04-30 · via DEV Community

Concurrency in Go: Goroutines and Channels Explained with Real Examples

If you've been coding in Go for a while, you've probably heard the phrase "Don't communicate by sharing memory; share memory by communicating." Today, we're going to break that down — no fluff, just real code and real use cases.


What Is Concurrency?

Concurrency is the ability to handle multiple tasks at the same time — or at least, appear to. It doesn't mean things literally run in parallel (though they can). It means your program can juggle multiple things without waiting for each one to finish before starting the next.

Think of a chef preparing a meal: while the pasta boils, they chop vegetables and stir the sauce. That's concurrency.

Go makes concurrency a first-class citizen of the language through two core concepts: goroutines and channels.


Goroutines: Lightweight Threads

A goroutine is a function that runs concurrently with other functions. You launch one with the go keyword.

package main

import (
    "fmt"
    "time"
)

func greet(name string) {
    fmt.Printf("Hello, %s!\n", name)
}

func main() {
    go greet("Alice") // runs concurrently
    go greet("Bob")   // runs concurrently
    go greet("Carol") // runs concurrently

    time.Sleep(1 * time.Second) // give goroutines time to finish
}

Enter fullscreen mode Exit fullscreen mode

Output (order may vary):

Hello, Bob!
Hello, Alice!
Hello, Carol!

Enter fullscreen mode Exit fullscreen mode

Notice the order isn't guaranteed — that's concurrency in action.

⚠️ The time.Sleep hack is just for demonstration. In real code, use sync.WaitGroup or channels to coordinate.


WaitGroups: The Right Way to Wait

package main

import (
    "fmt"
    "sync"
)

func greet(name string, wg *sync.WaitGroup) {
    defer wg.Done() // signal that this goroutine is done
    fmt.Printf("Hello, %s!\n", name)
}

func main() {
    var wg sync.WaitGroup

    names := []string{"Alice", "Bob", "Carol"}

    for _, name := range names {
        wg.Add(1) // tell the WaitGroup to expect one more
        go greet(name, &wg)
    }

    wg.Wait() // block until all goroutines call Done()
    fmt.Println("All done!")
}

Enter fullscreen mode Exit fullscreen mode

sync.WaitGroup is your best friend when you want to fire off goroutines and wait for all of them to complete.


Channels: Goroutines Talking to Each Other

A channel is a typed pipe through which goroutines send and receive values. Think of it as a conveyor belt between workers.

ch := make(chan int)     // unbuffered channel of ints
ch := make(chan int, 5)  // buffered channel with capacity 5

Enter fullscreen mode Exit fullscreen mode

Simple Example: Passing a Value

package main

import "fmt"

func square(n int, ch chan int) {
    ch <- n * n // send result to channel
}

func main() {
    ch := make(chan int)

    go square(9, ch)

    result := <-ch // receive from channel (blocks until value arrives)
    fmt.Println("9 squared is:", result)
}

Enter fullscreen mode Exit fullscreen mode


Buffered vs Unbuffered Channels

Unbuffered Channel

Sending blocks until someone receives.

ch := make(chan string)
ch <- "hello" // 🚫 DEADLOCK — no one is receiving yet!

Enter fullscreen mode Exit fullscreen mode

Buffered Channel

Sending only blocks when the buffer is full.

ch := make(chan string, 3)
ch <- "first"   // OK
ch <- "second"  // OK
ch <- "third"   // OK
ch <- "fourth"  // 🚫 BLOCKS — buffer is full

Enter fullscreen mode Exit fullscreen mode


Real Example: Fetching Data Concurrently

Imagine you're fetching user profiles from an API — one at a time is slow. Let's do it concurrently.

package main

import (
    "fmt"
    "sync"
    "time"
)

type UserProfile struct {
    ID   int
    Name string
}

// Simulates an API call
func fetchProfile(id int, ch chan<- UserProfile, wg *sync.WaitGroup) {
    defer wg.Done()
    time.Sleep(100 * time.Millisecond) // simulate network delay

    ch <- UserProfile{
        ID:   id,
        Name: fmt.Sprintf("User_%d", id),
    }
}

func main() {
    ch := make(chan UserProfile, 10)
    var wg sync.WaitGroup

    userIDs := []int{1, 2, 3, 4, 5}

    for _, id := range userIDs {
        wg.Add(1)
        go fetchProfile(id, ch, &wg)
    }

    // Close channel once all goroutines are done
    go func() {
        wg.Wait()
        close(ch)
    }()

    // Collect results
    for profile := range ch {
        fmt.Printf("Fetched: ID=%d, Name=%s\n", profile.ID, profile.Name)
    }
}

Enter fullscreen mode Exit fullscreen mode

This fetches all 5 profiles concurrently instead of sequentially — roughly 5x faster.


Select: Listening on Multiple Channels

select lets a goroutine wait on multiple channel operations at once — like a switch for channels.

package main

import (
    "fmt"
    "time"
)

func main() {
    ch1 := make(chan string)
    ch2 := make(chan string)

    go func() {
        time.Sleep(1 * time.Second)
        ch1 <- "one"
    }()

    go func() {
        time.Sleep(2 * time.Second)
        ch2 <- "two"
    }()

    for i := 0; i < 2; i++ {
        select {
        case msg1 := <-ch1:
            fmt.Println("Received from ch1:", msg1)
        case msg2 := <-ch2:
            fmt.Println("Received from ch2:", msg2)
        }
    }
}

Enter fullscreen mode Exit fullscreen mode

This is especially useful for timeouts:

select {
case result := <-ch:
    fmt.Println("Got result:", result)
case <-time.After(3 * time.Second):
    fmt.Println("Timed out!")
}

Enter fullscreen mode Exit fullscreen mode


Common Pitfalls to Avoid

1. Goroutine Leaks

If a goroutine is blocked on a channel that nobody ever reads from, it runs forever.

// BAD: goroutine blocks forever
ch := make(chan int)
go func() {
    ch <- 42 // no one reads this
}()

Enter fullscreen mode Exit fullscreen mode

Always make sure every goroutine has a way to exit.

2. Race Conditions

Two goroutines writing to the same variable without synchronization = undefined behaviour.

// BAD
counter := 0
go func() { counter++ }()
go func() { counter++ }()

Enter fullscreen mode Exit fullscreen mode

Use sync.Mutex or channels to protect shared state.

var mu sync.Mutex
mu.Lock()
counter++
mu.Unlock()

Enter fullscreen mode Exit fullscreen mode

3. Closing a Closed Channel

Closing an already-closed channel causes a panic. Only close from the sender side, and only once.


Quick Reference

Concept Use When
go func() You want to run something concurrently
sync.WaitGroup You want to wait for multiple goroutines
Unbuffered channel You need tight synchronization between goroutines
Buffered channel You want to decouple sender and receiver
select You're waiting on multiple channels or implementing timeouts
sync.Mutex You're protecting shared mutable state

Wrapping Up

Go's concurrency model is elegant once it clicks. The key ideas:

  • Goroutines are cheap — you can spin up thousands
  • Channels are how goroutines communicate safely
  • Don't share memory to communicate — let channels do the talking
  • Watch out for leaks, race conditions, and double closes

The best way to get comfortable is to build something: a web scraper, a concurrent file processor, a worker pool. Pick one and run with it.


Are you using goroutines in your current project? What patterns have you found most useful? Drop a comment below 👇


Tags: #go #golang #concurrency #programming #beginners