Add opt-in logging via add_sink, silence library logger by default

src/sqlmem/__init__.py

@@ -1,4 +1,37 @@
+from typing import Any
+
+from loguru import logger
+
+from .config import DEBUG
 from .engine import CachingEngine
 from .exceptions import ReadOnlyError, UnsupportedQueryError
 
-__all__ = ["CachingEngine", "ReadOnlyError", "UnsupportedQueryError"]
+_DEFAULT_FORMAT = (
+    "<green>{time:YYYY-MM-DD HH:mm:ss}</green> | "
+    "<level>{level: <8}</level> | "
+    "<cyan>{name}</cyan>:<cyan>{line}</cyan> - "
+    "<level>{message}</level>"
+)
+
+
+def add_sink(sink: Any, *, level: str | None = None, **kwargs: Any) -> None:
+    """Route sqlmem log records to *sink*.
+
+    Accepts any sink supported by loguru (file path, stream, callable, …).
+    *level* defaults to ``DEBUG`` when ``SQLMEM_DEBUG=true``, otherwise ``INFO``.
+    Extra keyword arguments are forwarded to :func:`loguru.logger.add`.
+
+    Example::
+
+        import sys
+        from sqlmem import add_sink
+        add_sink(sys.stderr)
+        add_sink("sqlmem.log", rotation="10 MB")
+    """
+    logger.enable("sqlmem")
+    kwargs.setdefault("format", _DEFAULT_FORMAT)
+    kwargs.setdefault("colorize", True)
+    logger.add(sink, level=level or ("DEBUG" if DEBUG else "INFO"), filter="sqlmem", **kwargs)
+
+
+__all__ = ["CachingEngine", "ReadOnlyError", "UnsupportedQueryError", "add_sink"]

src/sqlmem/config.py

@@ -10,10 +10,5 @@ DEBUG = os.getenv("SQLMEM_DEBUG", "false").lower() == "true"
 CACHE_DB_PATH = Path(os.getenv("SQLMEM_CACHE_DB", "cache.db"))
 BACKUP_INTERVAL_SECONDS = int(os.getenv("SQLMEM_BACKUP_INTERVAL", "3600"))
 
-logger.remove()
-logger.add(
-    sink=lambda msg: print(msg, end=""),
-    level="DEBUG" if DEBUG else "INFO",
-    format="<green>{time:YYYY-MM-DD HH:mm:ss}</green> | <level>{level: <8}</level> | <cyan>{name}</cyan>:<cyan>{line}</cyan> - <level>{message}</level>",
-    colorize=True,
-)
+# Silent by default — callers opt in via add_sink().
+logger.disable("sqlmem")