Backend - Go (Gin/Echo)

When to use this skill

• Building or updating Go HTTP APIs using Gin or Echo.
• Adding routes/handlers/middleware, validation, logging, or persistence.
• Improving performance, observability, security, or testing for Go services.

Quick start

1. Install deps: go mod tidy (or go mod download).
2. Env: copy .env.example -> .env if present; load via godotenv/config; set DB URLs, secrets, and service endpoints.
3. Run: go run ./... or service-specific make dev if provided.
4. Test: go test ./...; lint/format: golangci-lint run and gofmt -w/go fmt ./....
5. Build: go build ./cmd/... or project entry.

Project structure basics

• cmd/<service>/main.go: entrypoint; wire router, middleware, config, logger, DI.
• internal/ or pkg/: handlers, services/usecases, repositories, domain models, DTOs.
• configs/: config files; prefer typed config structs with validation.
• migrations/: SQL/DDL migrations if applicable.

Coding principles

• Keep handlers thin: parse/validate input, call services/usecases, map errors to HTTP responses.
• Services hold business logic; repositories isolate data access; prefer interfaces for tests.
• Validate inputs; return typed errors and map to consistent JSON error shapes.
• Use context-aware logging with request IDs; never log secrets.
• Prefer golangci-lint and go test ./... before merge (see scripts/dev-check.sh).

Patterns and snippets

• See references/snippets.md for Gin/Echo router setup, middleware, handlers, error mapping, and DI patterns.
• Centralize HTTP error responses; include correlation ID; avoid panics in request path.
• Use context.Context in all public methods; pass through layers.

Bundled resources

• scripts/dev-check.sh: run pre-commit/PR to enforce gofmt, lint, tests, and optional build.
• references/coding-standards.md: guardrails on layering, validation, errors, logging, and testing.
• references/best-practices.md: deeper guidance for Gin/Echo routing, middleware, observability, performance, and security.
• references/snippets.md: ready-to-copy snippets for Gin and Echo (routing, middleware, handlers, errors).
• assets/pr-template.md: PR checklist with testing evidence and API notes.
• assets/migration-checklist.md: use when adding DB schema changes.

Delivery checklist

• gofmt/go fmt clean; golangci-lint run passes; go test ./... green.
• Config validated; secrets not logged; env vars documented.
• HTTP errors normalized; correlation/request IDs propagated.
• Migrations applied/documented if DB changes; API contracts/docs updated if endpoints change.