Logger Package

Overview

This package provides a powerful and flexible logging wrapper for Go applications, built on top of the zap logging library. It offers enhanced functionality and ease of use compared to the standard logging packages.

Features

• Colored Log Levels: Improve log readability with color-coded log levels (e.g., blue for INFO, red for ERROR).
• Extended Logging Methods: Includes f and w variants for all log levels (e.g., Infof, Infow) for formatted and key-value pair logging.
• Contextual Logging: Ability to add default attributes from context using AddAttributesFromContext(ctx) []LogField.
• Customizable JSON Formatting: Flexible JSON output with custom field ordering and formatting.
• Multiple Log Levels: Supports DEBUG, INFO, WARN, ERROR, FATAL, and CRITICAL log levels.
• File Logging: Option to log to files in addition to standard output.
• Performance Optimized: Utilizes zap for high-performance logging.

Installation

go get github.com/diegoclair/go_utils

Quick Start

import "github.com/diegoclair/go_utils/logger"

func main() {
    params := logger.LogParams{
        AppName:    "MyApp",
        DebugLevel: true,
        LogToFile:  false,
        AddAttributesFromContext: func(ctx context.Context) []logger.LogField {
            return []logger.LogField{
                logger.String("user_id", getUserIDFromContext(ctx)),
            }
        },
    }
    log := logger.New(params)
    log.Info(ctx, "Application started")
    log.Infow(ctx, "User logged in", logger.Int("user_id", 12345))
}

Usage

Creating a Logger

Use logger.New(params) to create a new logger instance. Configure the logger using LogParams:

params := logger.LogParams{
    AppName:    "MyApp",
    DebugLevel: true,
    LogToFile:  false,
    AddAttributesFromContext: func(ctx context.Context) []logger.LogField {
        // Add custom fields from context
    },
}
log := logger.New(params)

Logging Methods

• Basic logging: log.Info(ctx, "message")
• Formatted logging: log.Infof(ctx, "User %s logged in", username)
• Structured logging: log.Infow(ctx, "User action", "action", "login", "username", username)

Log Levels

• Debug: log.Debug, log.Debugf, log.Debugw
• Info: log.Info, log.Infof, log.Infow
• Warn: log.Warn, log.Warnf, log.Warnw
• Error: log.Error, log.Errorf, log.Errorw
• Fatal: log.Fatal, log.Fatalf, log.Fatalw
• Critical: log.Critical, log.Criticalf, log.Criticalw

Custom Formatting

The logger uses a custom JSON formatter that allows for colored output and custom field ordering. You can modify the customJSONFormatter in the package to adjust the formatting to your needs.

Advanced Usage

Contextual Logging

Use the AddAttributesFromContext function to automatically add fields from your context to every log entry:

params.AddAttributesFromContext = func(ctx context.Context) []logger.LogField {
    return []logger.LogField{
        logger.String("request_id", getRequestIDFromContext(ctx)),
        logger.String("user_id", getUserIDFromContext(ctx)),
    }
}