Fix problems with rel paths in logging files (ecmwf#742)

* Fixed relative path handling for logging files.

* Adding default argument to _load_private_conf()

Author: clessig

src/weathergen/utils/logger.py

@@ -13,6 +13,8 @@
 import sys
 from functools import cache
 
+from weathergen.utils.config import _load_private_conf
+
 
 class ColoredRelPathFormatter(logging.Formatter):
     COLOR_CODES = {
@@ -53,6 +55,10 @@ def init_logger_per_stream(logger, stream_handle, output_streams):
             # path + file are specified as string or already path object
             assert type(ostr) is str or type(ostr) is pathlib.Path
             ofile = pathlib.Path(ostr)
+            # make sure the path is independent of path where job is launched
+            if not ofile.is_absolute():
+                work_dir = pathlib.Path(_load_private_conf().get("path_shared_working_dir"))
+                ofile = work_dir / ofile
             # make sure the parent directory exists
             pathlib.Path(ofile.parent).mkdir(parents=True, exist_ok=True)
             handler = logging.FileHandler(ofile)