Structured JSON Logging

The logger writes structured log entries as JSON, making logs easy to parse, search, and process in production environments.

Each log entry is stored as a single JSON object containing standardized fields such as timestamp, level, and message.

Example log entry:

{
  "time": "2026-05-11T11:08:42.135294+02:00",
  "level": "INFO",
  "msg": "server started"
}

JSON logging is enabled automatically when file logging is active.

package main

import (
	"log/slog"

	"github.com/netlifeguru/logger"
)

func main() {
	closer, err := logger.Init(logger.Config{
		Dir:      "./logs",
		MinLevel: slog.LevelInfo,
	})

	if err != nil {
		slog.Error(err.Error())
	}

	defer closer.Close()

	slog.Info("server started")
	slog.Warn("high memory usage")
	slog.Error("database connection failed")
}

Generated log file:

logs/2026-05-11-0001.log

Structured JSON logs are useful for:

centralized log aggregation
observability platforms
production monitoring
analytics pipelines
machine parsing and indexing

Additional structured fields can be attached directly through the standard slog API:

slog.Info("user authenticated",
slog.Int("user_id", 42),
slog.String("role", "admin"),
)

File output:

{
  "time": "2026-05-11T12:23:38.592038+02:00",
  "level": "INFO",
  "msg": "user authenticated",
  "user_id": 42,
  "role": "admin"
}

Terminal output

2026-05-11 12:23:38 [INFO] user authenticated user_id=42 role=admin