Feature/logging (#463)

* Update logger imports

* Simplify logging options

* Use loguru defaults

* Update logger format

* Add multiline formating

* Add multiline formating

* Make date fmt dim

* Fix Multiline formater

* Add verbose tracebacks to logging options

* Update docs

* Avoid logging entire arrays
 Use lazy logging for expensive operation

* Use warning level instead of critical

* Use lazy logging for main results

* Fix rotation size calculation

* Remove unused logger import

* Remove rich import from example

* Remove obsolete test

 Strengthen rotation test

  Refactor tests to avoid private Loguru APIs

* Fix lazy logging

* Update CHANGELOG.md

* Use logging.sucess

* Add sucess level

* Add sucess level

Author: FBumann

CHANGELOG.md

@@ -51,7 +51,7 @@ If upgrading from v2.x, see the [v3.0.0 release notes](https://github.com/flixOp
 
 ## [Unreleased] - ????-??-??
 
-**Summary**: Type system overhaul with comprehensive type hints for better IDE support and code clarity.
+**Summary**: Type system overhaul and migration to loguru for logging
 
 If upgrading from v2.x, see the [v3.0.0 release notes](https://github.com/flixOpt/flixOpt/releases/tag/v3.0.0) and [Migration Guide](https://flixopt.github.io/flixopt/latest/user-guide/migration-guide-v3/).
 
@@ -64,8 +64,13 @@ If upgrading from v2.x, see the [v3.0.0 release notes](https://github.com/flixOp
     - Added `Scalar` type for scalar-only numeric values
     - Added `NumericOrBool` utility type for internal use
     - Type system supports scalars, numpy arrays, pandas Series/DataFrames, and xarray DataArrays
+- Lazy logging evaluation - expensive log operations only execute when log level is active
+- `CONFIG.Logging.verbose_tracebacks` option for detailed debugging with variable values
 
 ### 💥 Breaking Changes
+- **Logging framework**: Migrated to [loguru](https://loguru.readthedocs.io/)
+    - Removed `CONFIG.Logging` parameters: `rich`, `Colors`, `date_format`, `format`, `console_width`, `show_path`, `show_logger_name`
+    - For advanced formatting, use loguru's API directly after `CONFIG.apply()`
 
 ### ♻️ Changed
 - **Code structure**: Removed `commons.py` module and moved all imports directly to `__init__.py` for cleaner code organization (no public API changes)
@@ -83,13 +88,15 @@ If upgrading from v2.x, see the [v3.0.0 release notes](https://github.com/flixOp
 
 ### 📦 Dependencies
 - Updated `mkdocs-material` to v9.6.23
+- Replaced `rich >= 13.0.0` with `loguru >= 0.7.0` for logging
 
 ### 📝 Docs
 - Enhanced documentation in `flixopt/types.py` with comprehensive examples and dimension explanation table
 - Clarified Effect type docstrings - Effect types are dicts, but single numeric values work through union types
 - Added clarifying comments in `effects.py` explaining parameter handling and transformation
 - Improved OnOffParameters attribute documentation
-
+- Updated getting-started guide with loguru examples
+- Updated `config.py` docstrings for loguru integration
 
 ### 👷 Development
 - Added test for FlowSystem resampling

docs/getting-started.md

@@ -22,6 +22,24 @@ For all features including interactive network visualizations and time series ag
 pip install "flixopt[full]"
 ```
 
+## Logging
+
+FlixOpt uses [loguru](https://loguru.readthedocs.io/) for logging. Logging is silent by default but can be easily configured. For beginners, use our internal convenience methods. Experts can use loguru directly.
+
+```python
+from flixopt import CONFIG
+
+# Enable console logging
+CONFIG.Logging.console = True
+CONFIG.Logging.level = 'INFO'
+CONFIG.apply()
+
+# Or use a preset configuration for exploring
+CONFIG.exploring()
+```
+
+For more details on logging configuration, see the [`CONFIG.Logging`][flixopt.config.CONFIG.Logging] documentation.
+
 ## Basic Workflow
 
 Working with FlixOpt follows a general pattern:

examples/02_Complex/complex_example.py

@@ -4,7 +4,6 @@
 
 import numpy as np
 import pandas as pd
-from rich.pretty import pprint  # Used for pretty printing
 
 import flixopt as fx
 
@@ -188,7 +187,7 @@
     flow_system.add_elements(Costs, CO2, PE, Gaskessel, Waermelast, Gasbezug, Stromverkauf, speicher)
     flow_system.add_elements(bhkw_2) if use_chp_with_piecewise_conversion else flow_system.add_elements(bhkw)
 
-    pprint(flow_system)  # Get a string representation of the FlowSystem
+    print(flow_system)  # Get a string representation of the FlowSystem
     try:
         flow_system.start_network_app()  # Start the network app
     except ImportError as e:

examples/05_Two-stage-optimization/two_stage_optimization.py

@@ -7,17 +7,15 @@
 While the final optimum might differ from the global optimum, the solving will be much faster.
 """
 
-import logging
 import pathlib
 import timeit
 
 import pandas as pd
 import xarray as xr
+from loguru import logger
 
 import flixopt as fx
 
-logger = logging.getLogger('flixopt')
-
 if __name__ == '__main__':
     fx.CONFIG.exploring()
 

flixopt/aggregation.py

@@ -6,12 +6,12 @@
 from __future__ import annotations
 
 import copy
-import logging
 import pathlib
 import timeit
 from typing import TYPE_CHECKING
 
 import numpy as np
+from loguru import logger
 
 try:
     import tsam.timeseriesaggregation as tsam
@@ -37,8 +37,6 @@
     from .elements import Component
     from .flow_system import FlowSystem
 
-logger = logging.getLogger('flixopt')
-
 
 class Aggregation:
     """
@@ -106,7 +104,7 @@ def cluster(self) -> None:
         self.aggregated_data = self.tsam.predictOriginalData()
 
         self.clustering_duration_seconds = timeit.default_timer() - start_time  # Zeit messen:
-        logger.info(self.describe_clusters())
+        logger.opt(lazy=True).info('{result}', result=lambda: self.describe_clusters())
 
     def describe_clusters(self) -> str:
         description = {}

flixopt/calculation.py

@@ -10,7 +10,6 @@
 
 from __future__ import annotations
 
-import logging
 import math
 import pathlib
 import sys
@@ -20,6 +19,7 @@
 from typing import TYPE_CHECKING, Annotated, Any
 
 import numpy as np
+from loguru import logger
 from tqdm import tqdm
 
 from . import io as fx_io
@@ -39,8 +39,6 @@
     from .solvers import _Solver
     from .structure import FlowSystemModel
 
-logger = logging.getLogger('flixopt')
-
 
 class Calculation:
     """
@@ -238,7 +236,7 @@ def solve(
             **solver.options,
         )
         self.durations['solving'] = round(timeit.default_timer() - t_start, 2)
-        logger.info(f'Model solved with {solver.name} in {self.durations["solving"]:.2f} seconds.')
+        logger.success(f'Model solved with {solver.name} in {self.durations["solving"]:.2f} seconds.')
         logger.info(f'Model status after solve: {self.model.status}')
 
         if self.model.status == 'warning':
@@ -255,12 +253,10 @@ def solve(
         # Log the formatted output
         should_log = log_main_results if log_main_results is not None else CONFIG.Solving.log_main_results
         if should_log:
-            logger.info(
-                f'{" Main Results ":#^80}\n'
-                + fx_io.format_yaml_string(
-                    self.main_results,
-                    compact_numeric_lists=True,
-                )
+            logger.opt(lazy=True).info(
+                '{result}',
+                result=lambda: f'{" Main Results ":#^80}\n'
+                + fx_io.format_yaml_string(self.main_results, compact_numeric_lists=True),
             )
 
         self.results = CalculationResults.from_calculation(self)
@@ -673,7 +669,7 @@ def do_modeling_and_solve(
             for key, value in calc.durations.items():
                 self.durations[key] += value
 
-        logger.info(f'Model solved with {solver.name} in {self.durations["solving"]:.2f} seconds.')
+        logger.success(f'Model solved with {solver.name} in {self.durations["solving"]:.2f} seconds.')
 
         self.results = SegmentedCalculationResults.from_calculation(self)
 

flixopt/color_processing.py

@@ -6,15 +6,12 @@
 
 from __future__ import annotations
 
-import logging
-
 import matplotlib.colors as mcolors
 import matplotlib.pyplot as plt
 import plotly.express as px
+from loguru import logger
 from plotly.exceptions import PlotlyError
 
-logger = logging.getLogger('flixopt')
-
 
 def _rgb_string_to_hex(color: str) -> str:
     """Convert Plotly RGB/RGBA string format to hex.

flixopt/components.py

@@ -4,12 +4,12 @@
 
 from __future__ import annotations
 
-import logging
 import warnings
 from typing import TYPE_CHECKING, Literal
 
 import numpy as np
 import xarray as xr
+from loguru import logger
 
 from . import io as fx_io
 from .core import PlausibilityError
@@ -25,8 +25,6 @@
     from .flow_system import FlowSystem
     from .types import Numeric_PS, Numeric_TPS
 
-logger = logging.getLogger('flixopt')
-
 
 @register_class_for_io
 class LinearConverter(Component):