✨ Add log to file.

src/muse/__init__.py

@@ -34,6 +34,49 @@ def _create_logger(color: bool = True):
     return logger
 
 
+def add_file_logger() -> None:
+    """Adds a file logger to the main logger.
+
+    The file logger is split into two files: one for INFO and DEBUG messages, and one
+    for WARNING messages and above to avoid cluttering the main log file and highlight
+    potential issues.
+    """
+    import logging
+    from pathlib import Path
+
+    from .defaults import DEFAULT_OUTPUT_DIRECTORY
+
+    formatter = logging.Formatter(
+        "%(asctime)s - %(name)s - %(levelname)s - %(message)s"
+    )
+
+    DEFAULT_OUTPUT_DIRECTORY.mkdir(parents=True, exist_ok=True)
+
+    # Sets the warning log, for warnings and above
+    warning_file = Path(DEFAULT_OUTPUT_DIRECTORY) / "muse_warning.log"
+    if warning_file.exists():
+        warning_file.unlink()
+
+    warning_file_handler = logging.FileHandler(warning_file)
+    warning_file_handler.setLevel(logging.WARNING)
+    warning_file_handler.setFormatter(formatter)
+    warning_file_handler.filters = [lambda record: record.levelno > logging.INFO]
+
+    logging.getLogger("muse").addHandler(warning_file_handler)
+
+    # Sets the info log, for debug and info only
+    info_file = Path(DEFAULT_OUTPUT_DIRECTORY) / "muse_info.log"
+    if info_file.exists():
+        info_file.unlink()
+
+    info_file_handler = logging.FileHandler(info_file)
+    info_file_handler.setLevel(logging.DEBUG)
+    info_file_handler.setFormatter(formatter)
+    info_file_handler.filters = [lambda record: record.levelno <= logging.INFO]
+
+    logging.getLogger("muse").addHandler(info_file_handler)
+
+
 logger = _create_logger(os.environ.get("MUSE_COLOR_LOG") != "False")
 """ Main logger """
 

src/muse/__main__.py

@@ -38,7 +38,7 @@ def muse_main(settings, model, copy):
     from logging import getLogger
     from pathlib import Path
 
-    from muse import examples
+    from muse import add_file_logger, examples
     from muse.mca import MCA
     from muse.readers.toml import read_settings
 
@@ -53,6 +53,7 @@ def muse_main(settings, model, copy):
     else:
         settings = read_settings(settings)
         getLogger("muse").setLevel(settings.log_level)
+        add_file_logger()
         MCA.factory(settings).run()
 
 

src/muse/examples.py

@@ -51,10 +51,21 @@ def available_examples() -> list[str]:
     return [d.stem for d in example_data_dir().iterdir() if d.is_dir()]
 
 
-def model(name: str = "default") -> MCA:
-    """Fully constructs a given example model."""
+def model(name: str = "default", test: bool = False) -> MCA:
+    """Fully constructs a given example model.
+
+    File logging is added if ``test`` is False.
+
+    Args:
+        name: Name of the model to load.
+        test: If True, the logging to file is not added.
+
+    Returns:
+        The MCA model.
+    """
     from tempfile import TemporaryDirectory
 
+    from muse import add_file_logger
     from muse.readers.toml import read_settings
 
     # we could modify the settings directly, but instead we use the copy_model function.
@@ -63,6 +74,8 @@ def model(name: str = "default") -> MCA:
         path = copy_model(name, tmpdir)
         settings = read_settings(path / "settings.toml")
         getLogger("muse").setLevel(settings.log_level)
+        if not test:
+            add_file_logger()
         return MCA.factory(settings)
 
 

tests/test_aggregoutput.py

@@ -9,7 +9,7 @@ def test_aggregate_sector():
     """
     from pandas import DataFrame, concat
 
-    mca = examples.model("multiple_agents")
+    mca = examples.model("multiple_agents", test=True)
     year = [2020, 2025]
     sector_list = [sector for sector in mca.sectors if "preset" not in sector.name]
     agent_list = [list(a.agents) for a in sector_list]
@@ -43,7 +43,7 @@ def test_aggregate_sectors():
 
     from muse.outputs.mca import _aggregate_sectors
 
-    mca = examples.model("multiple_agents")
+    mca = examples.model("multiple_agents", test=True)
     year = [2020, 2025, 2030]
     sector_list = [sector for sector in mca.sectors if "preset" not in sector.name]
     agent_list = [list(a.agents) for a in sector_list]
@@ -83,7 +83,7 @@ def test_aggregate_sector_manyregions():
 
     from muse.outputs.mca import _aggregate_sectors
 
-    mca = examples.model("multiple_agents")
+    mca = examples.model("multiple_agents", test=True)
     residential = next(sector for sector in mca.sectors if sector.name == "residential")
     agents = list(residential.agents)
     agents[0].assets["region"] = "BELARUS"

tests/test_subsector.py

@@ -34,7 +34,7 @@ def test_subsector_investing_aggregation():
     sector_list = ["residential", "power", "gas"]
 
     for model in model_list:
-        mca = examples.model(model)
+        mca = examples.model(model, test=True)
         for sname in sector_list:
             agents = list(examples.sector(sname, model).agents)
             sector = next(sector for sector in mca.sectors if sector.name == sname)