Logger Generator Skill

This skill guides the creation of robust, "out-of-the-box" logging utilities for any software project. It ensures that generated logging modules meet production standards for observability, reliability, and ease of use, regardless of the target programming language.

When to Use This Skill

Use this skill when:

• •Setting up a new project (Python, Node.js, Go, Rust, etc.) and need a reliable logger.
• •Replacing simple print or console.log statements with a proper logging system.
• •The user asks for a "logging module", "log util", or "logger setup".
• •You need to standardize log collection across different services in a polyglot repository.

Core Requirements Checklist

Any logger generated using this skill MUST satisfy the following criteria unless explicitly overridden:

1. •Stand-alone Module: Must be a single, portable file (e.g., logger.py, logger.ts, logger.go).
2. •Dual Channel Output:
   • •Console: With COLOR coding for log levels (Human readable).
   • •File: Plain text, structured, standard encoding (Machine readable).
3. •Complete Log Levels: DEBUG, INFO, WARN/WARNING, ERROR, FATAL/CRITICAL.
4. •Standardized Format:
   • •Timestamp (ISO-like or YYYY-MM-DD HH:MM:SS.mmm).
   • •Log Level (Aligned).
   • •Source Location (File + Line Number).
   • •Component/Module Name.
   • •Message.
5. •Log Rotation:
   • •Automatic rotation (Time-based/Daily or Size-based).
   • •Automatic cleanup (Retention policy, e.g., keep last 30 days).
6. •Configuration:
   • •Support default "Zero Config" (Global Singleton).
   • •Support custom instances (Configurable paths, levels).
   • •Support UTF-8/Unicode characters specifically.
7. •Robustness:
   • •Thread-safe / Async-safe where applicable.
   • •No external dependencies if possible (prefer Standard Lib). If external libs are needed (e.g., Node.js), minimize them.
8. •Traceability:
   • •Error logs must support printing Stack Traces / Tracebacks.

Language-Specific Implementation Guides

Python

• •Library: logging (Standard Lib).
• •Rotation: logging.handlers.TimedRotatingFileHandler.
• •Colors: ANSI escape codes in a custom logging.Formatter.
• •Pattern: Singleton instance with getLogger().

TypeScript / Node.js

• •Library: Prefer winston for robust features, or a custom wrapper around fs + console for zero-dependency needs.
• •Rotation: winston-daily-rotate-file (if using winston).
• •Colors: chalk or simple ANSI codes.
• •Pattern: Export a Logger class and a default logger instance.

Go (Golang)

• •Library: log/slog (Standard Lib > 1.21) or zap (High perf).
• •Rotation: Go stdlib does not rotate. Use gopkg.in/natefinch/lumberjack.v2 for file rotation.
• •Pattern: MultiWriter for splitting output to os.Stdout and file.

Example Output Format

2024-03-20 10:15:30.123 | INFO     | main.py:45       | auth_service | Server started on port 8080
2024-03-20 10:15:32.456 | ERROR    | db.py:102        | db_pool      | Connection failed (Retrying...)

Generation Protocol

1. •Identify Language: Confirm the target language (Python, TS, Go, etc.).
2. •Select Strategy: Choose between "Standard Library Only" (preferred for simple scripts) or "Industry Standard Package" (preferred for large apps).
3. •Generate Code: Write the module implementing the [Core Requirements Checklist].
4. •Verify: Ensure usage examples cover:
   • •Basic usage (Global logger).
   • •Configuration (Custom file paths).
   • •Exception handling (Try-Catch logging).