app/core/logging.py

"""
Structured JSON logging for Workforce Microservice.
"""
import json
import logging
import logging.handlers
import os
import sys
import traceback
from datetime import datetime, timezone
from pathlib import Path
from typing import Any, Dict


SERVICE_NAME = "workforce-ms"
LOG_DIR = Path(os.getenv("LOG_DIR", "logs"))
LOG_MAX_BYTES = int(os.getenv("LOG_MAX_BYTES", 50 * 1024 * 1024))
LOG_BACKUP_COUNT = int(os.getenv("LOG_BACKUP_COUNT", "10"))


class JSONFormatter(logging.Formatter):
    RESERVED = frozenset({
        "args", "created", "exc_info", "exc_text", "filename",
        "funcName", "levelname", "levelno", "lineno", "message",
        "module", "msecs", "msg", "name", "pathname", "process",
        "processName", "relativeCreated", "stack_info", "thread", "threadName",
    })

    def format(self, record: logging.LogRecord) -> str:
        payload: Dict[str, Any] = {
            "timestamp": datetime.fromtimestamp(record.created, tz=timezone.utc).isoformat(),
            "level": record.levelname,
            "logger": record.name,
            "message": record.getMessage(),
            "service": SERVICE_NAME,
            "pid": record.process,
        }
        if record.levelno >= logging.WARNING:
            payload["caller"] = f"{record.pathname}:{record.lineno}"
        for key, val in record.__dict__.items():
            if key not in self.RESERVED and not key.startswith("_"):
                payload[key] = val
        if record.exc_info and record.exc_info[0] is not None:
            exc_type, exc_value, exc_tb = record.exc_info
            payload["exception"] = {
                "type": exc_type.__name__,
                "message": str(exc_value),
                "stacktrace": traceback.format_exception(exc_type, exc_value, exc_tb),
            }
        try:
            return json.dumps(payload, default=str)
        except Exception:
            return json.dumps({"message": str(record.getMessage()), "service": SERVICE_NAME}, default=str)


class ConsoleFormatter(logging.Formatter):
    CYAN = "\x1b[36m"
    YELLOW = "\x1b[33m"
    RED = "\x1b[31m"
    GREY = "\x1b[38;5;240m"
    BOLD_RED = "\x1b[1;31m"
    RESET = "\x1b[0m"
    LEVEL_COLOURS = {
        logging.DEBUG: "\x1b[38;5;240m",
        logging.INFO: "\x1b[36m",
        logging.WARNING: "\x1b[33m",
        logging.ERROR: "\x1b[31m",
        logging.CRITICAL: "\x1b[1;31m",
    }
    FMT = "%(asctime)s %(levelname)-8s %(name)s — %(message)s"

    def format(self, record: logging.LogRecord) -> str:
        colour = self.LEVEL_COLOURS.get(record.levelno, self.RESET)
        formatter = logging.Formatter(
            f"{colour}{self.FMT}{self.RESET}", datefmt="%Y-%m-%d %H:%M:%S"
        )
        return formatter.format(record)


def setup_logging(level: str = "INFO") -> None:
    numeric_level = getattr(logging, level.upper(), logging.INFO)
    root = logging.getLogger()
    root.setLevel(numeric_level)
    root.handlers.clear()

    # Console handler
    ch = logging.StreamHandler(sys.stdout)
    ch.setLevel(numeric_level)
    ch.setFormatter(ConsoleFormatter())
    root.addHandler(ch)

    # File handlers (JSON)
    try:
        LOG_DIR.mkdir(parents=True, exist_ok=True)
        fh = logging.handlers.RotatingFileHandler(
            LOG_DIR / "app.log", maxBytes=LOG_MAX_BYTES, backupCount=LOG_BACKUP_COUNT
        )
        fh.setLevel(numeric_level)
        fh.setFormatter(JSONFormatter())
        root.addHandler(fh)

        eh = logging.handlers.RotatingFileHandler(
            LOG_DIR / "app_errors.log", maxBytes=LOG_MAX_BYTES, backupCount=LOG_BACKUP_COUNT
        )
        eh.setLevel(logging.ERROR)
        eh.setFormatter(JSONFormatter())
        root.addHandler(eh)
    except Exception:
        pass  # Non-critical if log dir can't be created


def get_logger(name: str) -> logging.Logger:
    return logging.getLogger(name)