Lead Go Architect

Quick Reference

Core Principles

1. Standard library first -- Use net/http and the Go 1.22+ enhanced ServeMux for routing. Only reach for a framework (chi, echo, gin) when you have a concrete need the stdlib cannot satisfy (e.g., complex middleware chains, regex routes).
2. Dependency injection over globals -- Pass databases, loggers, and services through struct fields and constructors, never package-level var.
3. Explicit over magic -- No init() side effects, no framework auto-wiring. main.go is the composition root where everything is assembled visibly.
4. Small interfaces, big structs -- Define interfaces at the consumer, keep them narrow (1-3 methods). Concrete types carry the implementation.

Hard gates

Use this sequence when implementing or reviewing work that claims to follow this skill. Do not skip ahead; each step has a pass condition you can answer with tooling or a concrete file path.

1. Toolchain vs APIs — If the code uses Go 1.22+ ServeMux features (method+path patterns like "GET /x/{id}", r.PathValue, or {path...}): run go version and pass only if the reported toolchain is go1.22+. If the project must stay on an older Go, pass only by not using those APIs (use a compatible router or older patterns) and say so in the review or PR.
2. Composition root — Pass when main.go or cmd/.../main.go visibly constructs the server and injects shared dependencies (DB, logger, config). Fail if shared dependencies are wired in init() or package-level var instead of explicit construction in main (or a run() called from main).
3. Production HTTP shutdown — For a long-lived HTTP service, pass only if shutdown uses http.Server.Shutdown with a bounded context (e.g. context.WithTimeout) after waiting on signal.NotifyContext (or equivalent). Cite the file path when reporting; see references/graceful-shutdown.md for the full pattern.
4. No env/globals in handlers — Pass when handlers and domain code take dependencies via structs/arguments. Fail if handlers read os.Getenv for secrets or use package-level var for DB/clients (loading env in main or a dedicated config package is fine).

Go 1.22+ Enhanced Routing

Go 1.22 upgraded http.ServeMux with method-based routing and path parameters, eliminating the most common reason for third-party routers.

Method-Based Routing and Path Parameters