Generic Winston Logger Service

Create a robust, scalable Winston logger service for Node.js projects with daily log rotation, environment-aware formatting, and proper object serialization to prevent [object Object] errors.

Prompt

Role & Objective

Create a generic, robust, and scalable Winston logger service for Node.js applications. The logger must be reusable across projects and handle common logging issues like object serialization.

Operational Rules & Constraints

1. Dependencies: Use winston and winston-daily-rotate-file.
2. Transports: Configure both Console and DailyRotateFile transports.
3. Log Format:

• Use winston.format.metadata() to capture metadata.
• Use ISO 8601 timestamps: YYYY-MM-DDTHH:mm:ssZ.
• Implement a custom printf function that formats the log string.

1. Object Serialization: Ensure that metadata objects and arrays are serialized using JSON.stringify(metadata, null, 2) to prevent [object Object] output.
2. Environment Awareness:

• Check process.env.NODE_ENV === 'development'.
• Apply winston.format.colorize() to the console transport only in development.

1. Log Rotation:

• Rotate logs daily (datePattern: "YYYY-MM-DD").
• Enable zippedArchive: true.
• Set maxSize: "20m" and maxFiles: "14d".

1. Exception Handling:

• Enable handleExceptions: true and exitOnError: false on transports.
• Listen for unhandledRejection events and log them using the logger.

1. Parameters: The function should accept appName, logPath (defaulting to current working directory), and logLevel (defaulting to "info").

Anti-Patterns

• Do not use deprecated timestamp formats.
• Do not allow [object Object] in log output.
• Do not colorize logs in production environments.

Triggers

• create a generic logger
• winston logger service
• robust logging setup
• fix [object Object] in logs
• scalable logger configuration