merge: testing → main (reconcile 2-week divergence)

decnet/config.py

@@ -48,23 +48,67 @@ class Rfc5424Formatter(logging.Formatter):
         msg      = record.getMessage()
         if record.exc_info:
             msg += "\n" + self.formatException(record.exc_info)
+        app = getattr(record, "decnet_component", self._app)
         return (
-            f"<{prival}>1 {ts} {self._hostname} {self._app}"
+            f"<{prival}>1 {ts} {self._hostname} {app}"
             f" {os.getpid()} {record.name} - {msg}"
         )
 
 
 def _configure_logging(dev: bool) -> None:
-    """Install the RFC 5424 handler on the root logger (idempotent)."""
+    """Install RFC 5424 handlers on the root logger (idempotent).
+
+    Always adds a StreamHandler (stderr).  Also adds a RotatingFileHandler
+    writing to DECNET_SYSTEM_LOGS (default: decnet.system.log in $PWD) so
+    all microservice daemons — which redirect stderr to /dev/null — still
+    produce readable logs.  File handler is skipped under pytest.
+    """
+    from decnet.logging.inode_aware_handler import InodeAwareRotatingFileHandler
+
     root = logging.getLogger()
-    # Avoid adding duplicate handlers on re-import (e.g. during testing)
+    # Guard: if our StreamHandler is already installed, all handlers are set.
     if any(isinstance(h, logging.StreamHandler) and isinstance(h.formatter, Rfc5424Formatter)
            for h in root.handlers):
         return
-    handler = logging.StreamHandler()
-    handler.setFormatter(Rfc5424Formatter())
+
+    fmt = Rfc5424Formatter()
     root.setLevel(logging.DEBUG if dev else logging.INFO)
-    root.addHandler(handler)
+
+    stream_handler = logging.StreamHandler()
+    stream_handler.setFormatter(fmt)
+    root.addHandler(stream_handler)
+
+    # Skip the file handler during pytest runs to avoid polluting the test cwd.
+    _in_pytest = any(k.startswith("PYTEST") for k in os.environ)
+    if not _in_pytest:
+        _log_path = os.environ.get("DECNET_SYSTEM_LOGS", "decnet.system.log")
+        # Never let file-handler attach failure kill the process. The
+        # stream handler above is already installed, so losing the file
+        # handler just means 'tail syslog / journalctl instead' — the
+        # daemon itself must keep running. This path trips most
+        # commonly under systemd with ProtectSystem=full + ProtectHome=
+        # read-only when an operator hasn't passed a writable
+        # DECNET_SYSTEM_LOGS yet.
+        try:
+            file_handler = InodeAwareRotatingFileHandler(
+                _log_path,
+                mode="a",
+                maxBytes=10 * 1024 * 1024,  # 10 MB
+                backupCount=5,
+                encoding="utf-8",
+            )
+            file_handler.setFormatter(fmt)
+            root.addHandler(file_handler)
+            # Drop root ownership when invoked via sudo so non-root follow-up
+            # commands (e.g. `decnet api` after `sudo decnet deploy`) can append.
+            from decnet.privdrop import chown_to_invoking_user
+            chown_to_invoking_user(_log_path)
+        except OSError as exc:
+            logging.getLogger(__name__).warning(
+                "could not open %s (%s); continuing with stderr-only logging. "
+                "Set DECNET_SYSTEM_LOGS to a writable path to silence this.",
+                _log_path, exc,
+            )
 
 
 _dev = os.environ.get("DECNET_DEVELOPER", "").lower() == "true"