logger

logger — structured, context-aware logging

import "github.com/downsized-devs/sdk-go/logger"

Stability: Stable — see STABILITY.md

Thin wrapper over rs/zerolog that pulls request metadata from appcontext and enriches error logs via errors.

Features

• Eight log levels: Trace, Debug, Debugf, Info, Warn, Error, Fatal, Panic
• Automatic context-field extraction (request ID, user ID, service version, etc.)
• Stack-trace + caller info enrichment on Panic
• DefaultLogger() bootstrap for tests and pre-config code paths
• Single Interface — trivial to mock with gomock

Installation

go get github.com/downsized-devs/sdk-go/logger

Quick Start

package main

import (
    "context"

    "github.com/downsized-devs/sdk-go/logger"
)

func main() {
    log := logger.Init(logger.Config{Level: "info"})
    ctx := context.Background()

    log.Info(ctx, "service started")
    log.Debugf(ctx, "loaded %d feature flags", 42)
}

API Reference

Construction

Interface

Configuration

Examples

HTTP middleware that propagates request ID

log := logger.Init(logger.Config{Level: "info"})

func handler(w http.ResponseWriter, r *http.Request) {
    ctx := appcontext.SetRequestId(r.Context(), uuid.NewString())
    log.Info(ctx, "received request") // request_id field auto-attached
}

Log a wrapped error with its code

if err := repo.Save(ctx, user); err != nil {
    err = errors.WrapWithCode(err, codes.CodeSQLTxRollback, "save user")
    log.Error(ctx, err) // includes stack trace + code
}

Use the default logger in a TestMain

func TestMain(m *testing.M) {
    log := logger.DefaultLogger()
    log.Info(context.Background(), "starting test suite")
    os.Exit(m.Run())
}

Error Handling

Methods do not return errors — logger writes and continues. Panic deliberately re-panics so the caller's recover policy applies.

Dependencies

• Internal: appcontext, errors
• External: github.com/rs/zerolog

Testing

go test ./logger/...

Two test files cover every level plus context-field extraction.

Contributing

See CONTRIBUTING.md. Adding a method to Interface is a breaking change — coordinate before merging.

Related Packages

• appcontext — populates the fields this logger reads.
• errors — supplies the codes/stack traces shown in log lines.
• instrument — Prometheus metrics; logs say what, metrics say how often.
• audit — durable business events vs ephemeral log lines.