Logging

Context

The log package provides simple logging. For structured logging, use log/slog (Go 1.21+). Logging is essential for CLI tools to output status, errors, and debug information.

Example

Use log and slog to log messages.

Code example

package main

import (
    "log"
    "log/slog"
    "os"
)

func main() {
    // Standard log
    log.Println("This is a log message")

    // Structured logging with slog
    slog.Info("Server started", "port", 8080)
    slog.Warn("Disk usage high", "usage", "85%")
    slog.Error("Failed to connect", "error", "timeout")
}

Output

2025/01/01 12:00:00 This is a log message
2025-01-01T12:00:00.000 INFO Server started port=8080
2025-01-01T12:00:00.000 WARN Disk usage high usage=85%
2025-01-01T12:00:00.000 ERROR Failed to connect error=timeout

Useful links

• log package
• log/slog package