Initial Commit

app/owuitools/logging_setup.py

@@ -0,0 +1,44 @@
+"""Logging that goes to a file as well as to stdout.
+
+WHY BOTH
+
+stdout is what `docker compose logs` reads and what Docker's own log
+driver captures, so it has to stay. The file is so that every component
+in this stack has ONE findable place - ./logs, bind-mounted at /logs -
+rather than leaving somebody to work out which compose invocation shows
+the thing they are looking for.
+
+Falling back to stdout alone is deliberate. A container run without the
+mount, or with the directory not writable, should keep working and say
+why once; refusing to start because a log file could not be opened would
+be the tail wagging the dog.
+"""
+
+from __future__ import annotations
+
+import logging
+import os
+import sys
+
+FORMAT = "%(asctime)s %(levelname)-7s %(name)s | %(message)s"
+
+
+def configure(component: str, level: str = "INFO") -> logging.Logger:
+    """stdout always; ./logs/<component>.log when the directory is there."""
+    handlers: list[logging.Handler] = [logging.StreamHandler(sys.stdout)]
+    problem = ""
+    log_dir = os.environ.get("OWUITOOLS_LOG_DIR", "/logs")
+    if log_dir:
+        try:
+            os.makedirs(log_dir, exist_ok=True)
+            handlers.append(logging.FileHandler(
+                os.path.join(log_dir, f"{component}.log"), encoding="utf-8"))
+        except OSError as exc:
+            problem = f"{log_dir} is not writable ({exc}); logging to stdout only"
+
+    logging.basicConfig(level=getattr(logging, level.upper(), logging.INFO),
+                        format=FORMAT, handlers=handlers, force=True)
+    logger = logging.getLogger(component)
+    if problem:
+        logger.warning(problem)
+    return logger