go-patterns_skill

Overview

This skill collects production-ready Go language patterns and best practices for Go 1.24+ focused on reliable services, concurrency, error handling, and tooling. It bundles idiomatic approaches for context propagation, errgroup concurrency, error wrapping, HTTP and gRPC servers, PostgreSQL access with pgx, testing, and building CLIs with Cobra. The guidance targets practical, maintainable code and real-world deployment considerations.

How this skill works

The skill inspects and documents common coding patterns, providing concrete examples and recipes you can paste into projects. It emphasizes mandatory context propagation for I/O, safe concurrent patterns using errgroup and cancellation, error wrapping with %w, and structured project layouts. It also covers database access choices, HTTP server setup with graceful shutdown, gRPC interceptors, testing strategies, and performance profiling.

When to use it

• Starting a new Go service or refactoring an existing one to follow idiomatic patterns
• Implementing concurrent processing that must respect cancellation and resource limits
• Designing HTTP or gRPC servers with graceful shutdown and observability
• Choosing a database strategy (pgx, GORM, sqlc) for performance or developer ergonomics
• Building command-line tools with consistent UX using Cobra

Best practices

• Always accept context.Context as the first parameter for I/O and long-running operations
• Use errgroup.WithContext and SetLimit to manage goroutine lifecycles and cap concurrency
• Wrap errors with fmt.Errorf(...%w...) and use errors.Is / errors.As for checks
• Follow the standard project layout (cmd/, internal/, pkg/) and keep internal packages unexported
• Profile before optimizing (pprof) and prefer pre-allocating slices and strings.Builder for hot paths

Example use cases

• Concurrent batch processing where items are processed with a maximum worker count and shared cancellation
• An HTTP API using chi with middleware, request IDs, and a graceful shutdown sequence
• A PostgreSQL-backed service using pgx connection pooling and explicit sql queries for performance
• A testable service design using interfaces for repositories and table-driven unit tests with mocks
• A multi-command CLI built with Cobra, including flags, subcommands, and validation