app/utils/logger.py

"""
Structured logging configuration for VoiceAuth API.

Uses structlog for JSON-formatted logs in production
and human-readable logs in development.
"""

import logging
import sys
from typing import Any

import structlog
from structlog.types import Processor

from app.config import get_settings


def setup_logging() -> None:
    """
    Configure structured logging based on application settings.

    Sets up structlog processors for either JSON or console output
    based on the LOG_FORMAT setting.
    """
    settings = get_settings()

    # Convert string log level to logging constant
    log_level = getattr(logging, settings.LOG_LEVEL.upper(), logging.INFO)

    # Common processors for all output formats
    shared_processors: list[Processor] = [
        structlog.contextvars.merge_contextvars,
        structlog.stdlib.add_log_level,
        structlog.stdlib.add_logger_name,
        structlog.stdlib.PositionalArgumentsFormatter(),
        structlog.processors.TimeStamper(fmt="iso"),
        structlog.processors.StackInfoRenderer(),
        structlog.processors.UnicodeDecoder(),
    ]

    if settings.LOG_FORMAT == "json":
        # JSON format for production
        processors: list[Processor] = shared_processors + [
            structlog.processors.format_exc_info,
            structlog.processors.JSONRenderer(),
        ]
    else:
        # Console format for development
        processors = shared_processors + [
            structlog.dev.ConsoleRenderer(colors=True),
        ]

    # Configure structlog
    structlog.configure(
        processors=processors,
        wrapper_class=structlog.stdlib.BoundLogger,
        context_class=dict,
        logger_factory=structlog.stdlib.LoggerFactory(),
        cache_logger_on_first_use=True,
    )

    # Configure standard library logging
    logging.basicConfig(
        format="%(message)s",
        stream=sys.stdout,
        level=log_level,
    )

    # Set log levels for noisy libraries
    logging.getLogger("uvicorn").setLevel(logging.WARNING)
    logging.getLogger("httpx").setLevel(logging.WARNING)
    logging.getLogger("httpcore").setLevel(logging.WARNING)


def get_logger(name: str | None = None) -> structlog.stdlib.BoundLogger:
    """
    Get a configured logger instance.

    Args:
        name: Optional logger name. If not provided, uses the calling module.

    Returns:
        A configured structlog bound logger.
    """
    return structlog.get_logger(name)


class LoggerMixin:
    """Mixin class that provides a logger property."""

    @property
    def logger(self) -> structlog.stdlib.BoundLogger:
        """Get a logger bound to the class name."""
        return get_logger(self.__class__.__name__)


def log_request(
    method: str,
    path: str,
    status_code: int,
    duration_ms: float,
    **kwargs: Any,
) -> None:
    """
    Log an HTTP request with structured data.

    Args:
        method: HTTP method (GET, POST, etc.)
        path: Request path
        status_code: Response status code
        duration_ms: Request duration in milliseconds
        **kwargs: Additional fields to log
    """
    logger = get_logger("http")
    logger.info(
        "http_request",
        method=method,
        path=path,
        status_code=status_code,
        duration_ms=round(duration_ms, 2),
        **kwargs,
    )