golang-concurrency

Golang concurrency patterns. Use when writing or reviewing concurrent Go code involving goroutines, channels, select, locks, sync primitives, errgroup, singleflight, worker pools, or fan-out/fan-in pipelines. Also triggers when you detect goroutine leaks, race conditions, channel ownership issues, or need to choose between channels and mutexes.

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Repository: samber/cc-skills-golang
Last source activity: July 5, 2026 at 18:43
Detected SKILL.md language: English
Stars: 2,997
Forks: 196

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golang-lint

Linting best practices and golangci-lint configuration for Golang projects — running linters, configuring .golangci.yml, suppressing warnings with nolint directives, interpreting lint output, and selecting linters. Use when configuring golangci-lint, asking about lint warnings or nolint suppressions, setting up code quality tooling, or choosing linters. Also use when the user mentions golangci-lint, go vet, staticcheck, or revive.

2026-08-13

golang-how-to

Golang skills orchestrator — always active on any Golang coding, review, debug, or setup task. Reads the task context and loads the most relevant skills from samber/cc-skills-golang, often multiple at once: writing a gRPC service loads golang-grpc + golang-testing + golang-error-handling; debugging a panic loads golang-troubleshooting + golang-safety; auditing security loads golang-security + golang-lint + golang-safety. Also: disambiguates competing clusters when two skills seem to overlap (performance vs benchmark vs troubleshooting, samber/lo vs mo vs ro, DI cluster, safety vs security), and configures CLAUDE.md or AGENTS.md to force-trigger skills in a project (/golang-how-to configure).

2026-07-27

golang-project-layout

Provides a guide for setting up Golang project layouts and workspaces. Use when starting a new Go project, organizing an existing codebase, setting up a monorepo with multiple packages, creating CLI tools with multiple main packages, deciding between cmd/internal/pkg directory conventions, or discussing package restructuring, package splits, or module splits.

2026-07-27

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Scenario	Use	Why
Passing data between goroutines	Channel	Communicates ownership transfer
Coordinating goroutine lifecycle	Channel + context	Clean shutdown with select
Protecting shared struct fields	`sync.Mutex` / `sync.RWMutex`	Simple critical sections
Simple counters, flags	`sync/atomic`	Lock-free, lower overhead
Many readers, few writers on a map	`sync.Map`	Optimized for read-heavy workloads. Concurrent map read/write causes a hard crash
Caching expensive computations	`sync.Once` / `singleflight`	Execute once or deduplicate

Need	Use	Why
Wait for goroutines, errors not needed	`sync.WaitGroup`	Fire-and-forget
Wait + collect first error	`errgroup.Group`	Error propagation
Wait + cancel siblings on first error	`errgroup.WithContext`	Context cancellation on error
Wait + limit concurrency	`errgroup.SetLimit(n)`	Built-in worker pool

Primitive	Use case	Key notes
`sync.Mutex`	Protect shared state	Keep critical sections short; never hold across I/O
`sync.RWMutex`	Many readers, few writers	Never upgrade RLock to Lock (deadlock)
`sync/atomic`	Simple counters, flags	Prefer typed atomics (Go 1.19+): `atomic.Int64`, `atomic.Bool`
`sync.Map`	Concurrent map, read-heavy	No explicit locking; use `RWMutex`+map when writes dominate
`sync.Pool`	Reuse temporary objects	Always `Reset()` before `Put()`; reduces GC pressure
`sync.Once`	One-time initialization	Go 1.21+: `OnceFunc`, `OnceValue`, `OnceValues`
`sync.WaitGroup`	Waiting for simple goroutines	Go 1.25+: prefer `wg.Go(func(){ ... })` for fire-and-wait tasks that do not panic and do not need error propagation. For Go <1.25 use `Add`/`Done`. For errors/cancellation/limits, use `errgroup` with context.
`x/sync/singleflight`	Deduplicate concurrent calls	Cache stampede prevention
`x/sync/errgroup`	Goroutine group + errors	`SetLimit(n)` replaces hand-rolled worker pools

Mistake	Fix
Fire-and-forget goroutine	Provide stop mechanism (context, done channel)
Closing channel from receiver	Only the sender closes
`time.After` in hot loop	Reuse `time.NewTimer` + `Reset`
Missing `ctx.Done()` in select	Always select on context to allow cancellation
Unbounded goroutine spawning	Use `errgroup.SetLimit(n)` or semaphore
Sharing pointer via channel	Send copies or immutable values
`wg.Add` inside goroutine	Call `Add` before `go` — `Wait` may return early otherwise
Forgetting `-race` in CI	Always run `go test -race ./...`
Mutex held across I/O	Keep critical sections short

curl http://localhost:6060/debug/pprof/goroutineleak?debug=2
go tool pprof http://localhost:6060/debug/pprof/goroutineleak

name	golang-concurrency
description	Golang concurrency patterns. Use when writing or reviewing concurrent Go code involving goroutines, channels, select, locks, sync primitives, errgroup, singleflight, worker pools, or fan-out/fan-in pipelines. Also triggers when you detect goroutine leaks, race conditions, channel ownership issues, or need to choose between channels and mutexes.
user-invocable	true
license	MIT
compatibility	Designed for Claude Code or similar AI coding agents, and for projects using Golang.
metadata	{"author":"samber","version":"1.1.5","openclaw":{"emoji":"⚡","homepage":"https://github.com/samber/cc-skills-golang","requires":{"bins":["go"]},"install":[]}}
allowed-tools	Read Edit Write Glob Grep Bash(go:) Bash(golangci-lint:) Bash(git:*) Agent AskUserQuestion

name	golang-concurrency
description	Golang concurrency patterns. Use when writing or reviewing concurrent Go code involving goroutines, channels, select, locks, sync primitives, errgroup, singleflight, worker pools, or fan-out/fan-in pipelines. Also triggers when you detect goroutine leaks, race conditions, channel ownership issues, or need to choose between channels and mutexes.
user-invocable	true
license	MIT
compatibility	Designed for Claude Code or similar AI coding agents, and for projects using Golang.
metadata	{"author":"samber","version":"1.1.5","openclaw":{"emoji":"⚡","homepage":"https://github.com/samber/cc-skills-golang","requires":{"bins":["go"]},"install":[]}}
allowed-tools	Read Edit Write Glob Grep Bash(go:) Bash(golangci-lint:) Bash(git:*) Agent AskUserQuestion

golang-concurrency

Install options

Review the source files

Go Concurrency Best Practices

Core Principles

Channel vs Mutex vs Atomic

WaitGroup vs errgroup

Sync Primitives Quick Reference

Concurrency Checklist

Pipelines and Worker Pools

Parallelizing Concurrency Audits

Common Mistakes

Cross-References

Go 1.26 experimental goroutine leak profile

References

golang-concurrency

Source facts

Install options

Review the source files

More from this repository

More from this repository

Go Concurrency Best Practices

Core Principles

Channel vs Mutex vs Atomic

WaitGroup vs errgroup

Sync Primitives Quick Reference

Concurrency Checklist

Pipelines and Worker Pools

Parallelizing Concurrency Audits

Common Mistakes

Cross-References

Go 1.26 experimental goroutine leak profile

References