loggie

loggie 🧠⚡️ — Context-Aware Logger for Go

Context-aware, pluggable logger for Go web applications.
No more passing logger through every function — just use context.Context.

🚀 What is loggie?

loggie helps you embed a structured logger inside context.Context, so you can log from any layer — service, repository, or handler — with a consistent trace_id, user_id, or any custom field.

It supports Zap (now), and is extensible to Logrus, Slog, and more.

✨ Features

✅ Structured logging with context.Context
✅ Auto-generated trace_id per request
✅ Custom fields via loggie.WithCustomField()
✅ Middleware for Fiber / Gin / Echo
✅ Pluggable backends (Zap, Logrus, Slog, etc.)
✅ Fallback logger included (safe in any context)
✅ Ready for Fx lifecycle and timeout-aware context.WithTimeout

📦 Installation

go get github.com/ditthkr/loggie

🧱 Architecture

               ┌────────────────────┐
               │ context.Context    │
               └────────┬───────────┘
                        │
                ┌───────▼────────┐
                │ loggie.Logger  │◄── (interface)
                └───────┬────────┘
                        │
        ┌───────────────┼────────────────┐
        ▼               ▼                ▼
  ZapLogger        LogrusLogger       SlogLogger
(implemented)     (planned)          (planned)

🔌 Logger Interface

type Logger interface {
    Info(msg string, fields ...any)
    Error(msg string, fields ...any)
    With(fields ...any) Logger
}

You can plug any logger backend by implementing this interface.

⚙️ Middleware Usage

Fiber + Zap (fully working)

import (
    "github.com/ditthkr/loggie"
    "github.com/ditthkr/loggie/middleware/fiberlog"
    "go.uber.org/zap"
    "github.com/gofiber/fiber/v3"
)

func main() {
    rawLogger, _ := zap.NewProduction()
    defer rawLogger.Sync()

    adapter := &loggie.ZapLogger{L: rawLogger}
    app := fiber.New()
    app.Use(fiberlog.Middleware(adapter))

    app.Get("/ping", func(c *fiber.Ctx) error {
        log := loggie.FromContext(c.UserContext())
        log.Info("Ping received", "path", c.Path())
        return c.SendString("pong")
    })

    app.Listen(":8080")
}

🧪 Sample Log Output:

{
  "level": "info",
  "msg": "Ping received",
  "trace_id": "b4a3f5a0...",
  "path": "/ping"
}

✍️ Custom Fields (e.g. user_id)

ctx = loggie.WithCustomField(ctx, "user_id", 42)

log := loggie.FromContext(ctx)
log.Info("Order created")

📤 Output:

{
  "msg": "Order created",
  "trace_id": "abc-xyz",
  "user_id": 42
}

🧰 Utilities

📁 Available Middleware

All middlewares are generic and accept any loggie.Logger.

🔌 Current and Planned Logger Adapters

🧪 Testing & Fallbacks

Even without injecting a logger, loggie will still work with a safe no-op fallback:

log := loggie.FromContext(context.Background())
log.Info("This is safe even without a logger")

📃 License

MIT © 2025 @ditthkr