log

The log module encompasses methods for comprehensive logging, which comprises a variety of logging levels:

• Panic Panic typically signifies that something has gone unexpectedly awry. It's primarily utilized to swiftly halt on errors that shouldn't surface during regular operation, or those we aren't equipped to handle smoothly.

• Fatal Fatal corresponds to situations that are immensely disastrous for the application. The application is on the verge of terminating to avert any sort of corruption or severe problem, if feasible. Exit code is 1.

• Error An error represents a significant issue and depicts the failure of something crucial within an application. Contrary to FATAL, the application itself is not doomed.

• Warn This log level implies that an application might be experiencing a problem and an unusual situation has been detected. It's an unexpected and unusual issue, but no real damage is done, and it's uncertain whether the problem will persist or happen again.

• Info The messages at this level relate to standard application behavior and milestones. They offer a framework of the events that took place.

• Debug This level is meant to provide more detailed, diagnostic information than the INFO level.

• Trace This level offers incredibly detailed information, even more so than DEBUG. At this level, every possible detail about the application's behavior should be captured.

Installation

To install this module use go get as:

$ go get -u github.com/goloop/log

Quick Start

To use this module import it as:

package main

import (
	"os"

	"github.com/goloop/log"
	"github.com/goloop/log/layout"
	"github.com/goloop/log/level"

	// It is not necessary to import this module, the three-valued logic
	// constants can be represented using integers where: -1 is False,
	// 0 is Unknown, and 1 is True.
	"github.com/goloop/trit"
)

func main() {
	// Open the file in append mode. Create the file if it doesn't exist.
	// Use appropriate permissions in a production setting.
	file, err := os.OpenFile(
		"errors.log",
		os.O_APPEND|os.O_CREATE|os.O_WRONLY,
		0644,
	)

	if err != nil {
		log.Fatal(err)
	}

	// Defer the closing of the file until the function ends.
	defer file.Close()

	// Set the outputs of the log to our file.
	// We can set many different outputs to record
	// individual errors, debug or mixed data.
	err = log.SetOutputs(
		log.Output{
			Name:      "stdout",
			Writer:    os.Stdout,
			Levels:    level.Debug | level.Info | level.Warn | level.Error,
			Layouts:   layout.Default,
			WithColor: 1, // or trit.True, see github.com/goloop/trit
		},
		log.Output{
			Name:      "errorsJSONFile",
			Writer:    file,
			Levels:    level.Warn | level.Error, // only errors and warnings
			Layouts:   layout.Default,
			TextStyle: trit.False, // or just -1
		},
	)

	if err != nil {
		log.Fatal(err)
	}

	// A message will be output to a file and to the console.
	// * stdout and errorsJSONFile has Error level.
	log.Errorln("This is a test log message with ERROR.")

	// A message will be output to the console only.
	// * stdout has Debug level, but errorsJSONFile has not.
	log.Debugln("This is a test log message with DEBUG.")
}