colorize

A powerful log colorization tool built with Chevrotain parser for beautiful and readable log output.

Features

• Smart Log Parsing: Automatically detects and highlights timestamps, log levels, IP addresses, URLs, HTTP methods/status codes, and more
• Multiple Themes: Choose from various color themes (github, monokai, dracula, nord, solarized-dark, tokyo-night, production, test)
• Multiline Support: Intelligently joins multiline log entries like stack traces and JSON objects
• Relative Time: Shows elapsed time between log entries for performance analysis
• Timestamp Deduplication: Removes duplicate timestamps from kubectl logs and similar tools
• Line Buffering: Real-time colorization for streaming logs (tail -f, kubectl logs -f)
• Fast Performance: Built with Bun for blazing fast processing

Installation

Using npm/bunx (Recommended)

# Run directly without installation
npx @kawaz/colorize
# or
bunx @kawaz/colorize

# Install globally
npm install -g @kawaz/colorize
# or
bun add -g @kawaz/colorize

From source

# Clone the repository
git clone https://github.com/kawaz/colorize.git
cd colorize

# Install dependencies
bun install

# Build the project
bun run build

# Run directly
./dist/colorize.js

Usage

Basic Usage

# Pipe logs through colorize
cat logfile.txt | colorize

# Read from file
colorize < logfile.txt

# Real-time log monitoring
tail -f /var/log/app.log | colorize

# With Docker
docker logs -f container_name | colorize

# With kubectl
kubectl logs -f pod_name | colorize

# Run without installation using npx/bunx
cat app.log | npx @kawaz/colorize
tail -f app.log | bunx @kawaz/colorize -t github

Options

colorize [options]

Options:
  -j, --join-multiline       Join multiline log entries (disables line buffering)
  --dedup-timestamps         Remove duplicate timestamps (e.g., kubectl --timestamps)
  -r, --relative-time        Show relative time between log entries
  --line-buffered            Enable line buffering for real-time output (default: ON)
  -c, --force-color          Force color output even when piping
  -t, --theme <name>         Select color theme (use -t without name to list)
  -h, --help                 Show help message

Examples

# Use GitHub theme with relative time
cat app.log | colorize -t github -r

# Join multiline stack traces
cat error.log | colorize -j

# Force colors when piping to less
cat app.log | colorize -c | less -R

# Process kubectl logs with timestamp deduplication
kubectl logs -f --timestamps pod_name | colorize

Environment Variables

You can set default options using environment variables:

# Set default options (includes theme)
export COLORIZE_OPTIONS="-r -t github --dedup-timestamps"

# Command-line arguments override environment settings
# Use --no- prefix to disable options from COLORIZE_OPTIONS
cat log.txt | colorize --no-dedup-timestamps  # Disables dedup even if set in env

# Force color output
export FORCE_COLOR=1

Themes

Available themes:

• production (default): High contrast, optimized for terminals
• github: Clean, GitHub-inspired colors
• github-dark: Dark version of GitHub theme
• monokai: Classic Monokai colors
• dracula: Popular Dracula theme
• nord: Arctic-inspired Nord palette
• solarized-dark: Solarized dark variant
• tokyo-night: Modern Tokyo Night theme
• test: High contrast for testing

List available themes:

colorize --theme

What Gets Colorized?

• Timestamps: ISO 8601, compact formats, with optional relative time
• Log Levels: DEBUG, INFO, WARN, ERROR, FATAL (case-insensitive)
• IP Addresses: IPv4 and IPv6 with proper highlighting
• URLs: HTTP/HTTPS URLs
• HTTP: Methods (GET, POST, etc.) and status codes (200, 404, 500, etc.)
• Source Info: File paths with line numbers ([src/app.ts:42])
• Key-Value Pairs: JSON-like key=value or key:value pairs
• Strings: Quoted strings with escape sequences
• Numbers: Integers and decimals
• Booleans: true/false
• Special Values: null, undefined, NaN, Infinity

Development

# Run in development mode
bun run dev

# Run tests
bun test

# Format code
bun run lint

# Build for production
bun run build

Requirements

• Bun runtime (v1.0 or later)

License

MIT License - see LICENSE file for details

Author

kawaz

Contributing

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