# 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.

- **Type:** Skill
- **Install:** `agentstack add skill-samber-cc-skills-golang-golang-concurrency`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [samber](https://agentstack.voostack.com/s/samber)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [samber](https://github.com/samber)
- **Source:** https://github.com/samber/cc-skills-golang/tree/main/skills/golang-concurrency
- **Website:** https://skills.sh/samber/cc-skills-golang

## Install

```sh
agentstack add skill-samber-cc-skills-golang-golang-concurrency
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

**Persona:** You are a Go concurrency engineer. You assume every goroutine is a liability until proven necessary — correctness and leak-freedom come before performance.

**Modes:**

- **Write mode** — implement concurrent code (goroutines, channels, sync primitives, worker pools, pipelines). Follow the sequential instructions below.
- **Review mode** — reviewing a PR's concurrent code changes. Focus on the diff: check for goroutine leaks, missing context propagation, ownership violations, and unprotected shared state. Sequential.
- **Audit mode** — auditing existing concurrent code across a codebase. Use up to 5 parallel sub-agents as described in the "Parallelizing Concurrency Audits" section.

> **Community default.** A company skill that explicitly supersedes `samber/cc-skills-golang@golang-concurrency` skill takes precedence.

# Go Concurrency Best Practices

Go's concurrency model is built on goroutines and channels. Goroutines are cheap but not free — every goroutine you spawn is a resource you must manage. The goal is structured concurrency: every goroutine has a clear owner, a predictable exit, and proper error propagation.

## Core Principles

1. **Every goroutine must have a clear exit** — without a shutdown mechanism (context, done channel, WaitGroup), they leak and accumulate until the process crashes
2. **Share memory by communicating** — channels transfer ownership explicitly; mutexes protect shared state but make ownership implicit
3. **Send copies, not pointers** on channels — sending pointers creates invisible shared memory, defeating the purpose of channels
4. **Only the sender closes a channel** — closing from the receiver side panics if the sender writes after close
5. **Specify channel direction** (`chan See `samber/cc-skills-golang@golang-performance` skill for false sharing, cache-line padding, `sync.Pool` hot-path patterns
- -> See `samber/cc-skills-golang@golang-context` skill for cancellation propagation and timeout patterns
- -> See `samber/cc-skills-golang@golang-safety` skill for concurrent map access and race condition prevention
- -> See `samber/cc-skills-golang@golang-troubleshooting` skill for debugging goroutine leaks and deadlocks
- -> See `samber/cc-skills-golang@golang-design-patterns` skill for graceful shutdown patterns
- -> See `samber/cc-skills-golang@golang-continuous-integration` skill for automated AI-driven code review in CI using these guidelines

### Go 1.26 experimental goroutine leak profile

For Go 1.26 diagnostics, there is an experimental goroutine leak profile. It is useful for production-oriented leak investigation, but is gated by `GOEXPERIMENT=goroutineleakprofile`; do not rely on it as default stable behavior.

Typical usage when the experiment is enabled:

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

Keep existing tools:

- tests: `go.uber.org/goleak`
- runtime count: `runtime.NumGoroutine()`
- stack dump: `/debug/pprof/goroutine?debug=2`
- race checks: `go test -race ./...`

## References

- [Go Concurrency Patterns: Pipelines](https://go.dev/blog/pipelines)
- [Effective Go: Concurrency](https://go.dev/doc/effective_go#concurrency)

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [samber](https://github.com/samber)
- **Source:** [samber/cc-skills-golang](https://github.com/samber/cc-skills-golang)
- **License:** MIT
- **Homepage:** https://skills.sh/samber/cc-skills-golang

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** yes
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-samber-cc-skills-golang-golang-concurrency
- Seller: https://agentstack.voostack.com/s/samber
- Browse the marketplace: https://agentstack.voostack.com/browse

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Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.