GoLogger

A flexible, feature-rich logging package for Go applications built on top of zerolog. This logger provides structured logging with multiple output formats, log levels, and convenient helper functions.

Features

• Multiple logging modes (Debug, Pretty, Info, Production, Test, JSON)
• Structured logging with JSON output
• Pretty printing with colors for development
• Configurable log levels (Debug, Info, Warn, Error, Fatal, Disabled)
• Component-based logging
• Trace ID support for request tracking
• Thread-safe operations
• Customizable time formats
• Caller information (optional)
• Color output (can be disabled)
• Log rotation with compression
• File-based logging with size limits
• Level-based log splitting
• Global fields support
• Automatic old log cleanup

Installation

go get github.com/theblitlabs/gologger

Quick Start

Console Logging

package main

import (
    "github.com/theblitlabs/gologger"
)

func main() {
    // Initialize with pretty printing for development
    gologger.InitWithMode(gologger.LogModePretty)

    // Log some messages
    gologger.Info("main", "Application started")

    // Log with additional fields
    gologger.Info("main", "User logged in", map[string]interface{}{
        "user_id": "123",
        "ip": "192.168.1.1",
    })

    // Log an error
    err := someOperation()
    if err != nil {
        gologger.Error("main", err, "Operation failed")
    }
}

File-Based Logging

package main

import (
    "github.com/theblitlabs/gologger"
)

func main() {
    // Initialize logging to a file with default settings:
    // - 100MB max file size
    // - 7 days retention
    // - 5 backup files
    // - Compression enabled
    err := gologger.InitWithFile("/var/log/myapp/app.log")
    if err != nil {
        panic(err)
    }

    // Log as usual
    gologger.Info("main", "Application started")
}

Advanced Configuration

File Output with Rotation

config := gologger.Config{
    Level:         gologger.LogLevelInfo,
    Pretty:        false,
    TimeFormat:    time.RFC3339,
    CallerEnabled: true,
    Output: &gologger.OutputConfig{
        File:       "/var/log/myapp/app.log",
        MaxSize:    100,    // 100MB
        MaxAge:     7 * 24 * time.Hour,  // 7 days
        MaxBackups: 5,      // Keep 5 old files
        Compress:   true,   // Compress old files
        SplitLevel: true,   // Split logs by level
    },
    Fields: map[string]interface{}{
        "app_name": "myapp",
        "version":  "1.0.0",
    },
}
gologger.Init(config)

Level-Based Logging

When SplitLevel is enabled, logs will be written to separate files based on their level:

• /var/log/myapp/app.log (all logs)
• /var/log/myapp/app.error.log (error and fatal only)
• /var/log/myapp/app.info.log (info and above)
• /var/log/myapp/app.debug.log (debug and above)

Global Fields

Add fields to all log entries:

config := gologger.Config{
    // ... other config ...
    Fields: map[string]interface{}{
        "environment": "production",
        "service":     "auth-api",
    },
}

Component-Based Logging

logger := gologger.WithComponent("auth")
logger.Info().Str("user", "john").Msg("User authenticated")

Field Management

// Add multiple fields
logger := gologger.WithFields(map[string]interface{}{
    "request_id": "123",
    "user_id":    "456",
})

// Add a single field
logger := gologger.WithField("transaction_id", "789")

Fatal Logging

if err := criticalOperation(); err != nil {
    gologger.Fatal("main", err, "Critical error occurred", map[string]interface{}{
        "operation": "system_init",
    })
    // Program will exit after this
}

Configuration

You can customize the logger using the Config struct:

config := gologger.Config{
    Level:         gologger.LogLevelDebug,
    Pretty:        true,
    TimeFormat:    time.RFC3339,
    CallerEnabled: true,
    NoColor:      false,
}
gologger.Init(config)

Predefined Modes

• LogModeDebug: Debug level with pretty printing
• LogModePretty: Info level with pretty printing
• LogModeInfo: Standard info level logging
• LogModeProd: Production mode (no colors, nano timestamps)
• LogModeTest: Test mode (error level only)

Component-Based Logging

logger := gologger.WithComponent("auth")
logger.Info().Str("user", "john").Msg("User authenticated")

Trace ID Support

logger := gologger.WithTraceID("request-123")
logger.Info().Msg("Processing request")

License

MIT License

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.