Feature/loguru cve2

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -29,9 +29,7 @@ body:
       import numpy as np
       import flixopt as fx
 
-      fx.CONFIG.Logging.console = True
-      fx.CONFIG.Logging.level = 'DEBUG'
-      fx.CONFIG.apply()
+      fx.CONFIG.Logging.enable_console('DEBUG')
       flow_system = fx.FlowSystem(pd.date_range('2020-01-01', periods=3, freq='h'))
 
       flow_system.add_elements(

CHANGELOG.md

@@ -72,14 +72,107 @@ If upgrading from v2.x, see the [v3.0.0 release notes](https://github.com/flixOp
 ### 📦 Dependencies
 
 ### 📝 Docs
-- Added missing examples to docs.
 
 ### 👷 Development
 
 ### 🚧 Known Issues
 
 ---
 
+## [4.1.0] - 2025-11-21
+
+**Summary**: Logging migrated from loguru to standard Python logging for stability and security. Simpler API with convenient presets.
+
+!!! info "Migration Required?"
+    **Most users**: No action needed (silent by default). Methods like `CONFIG.exploring()`, `CONFIG.debug()`, etc. continue to work exactly as before.
+    **If you customized logging**: Simple API update (see migration below).
+    **If you used loguru directly**: Breaking change (loguru only in v3.6.0-v4.0.0, ~4 days).
+
+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/).
+
+### ✨ Added
+
+**New logging presets**:
+```python
+CONFIG.production('app.log')    # File-only, no console/plots
+```
+
+**New logging methods**:
+- `CONFIG.Logging.enable_console(level, colored, stream)` - Console output with colors
+- `CONFIG.Logging.enable_file(level, path, max_bytes, backup_count)` - File logging with rotation
+- `CONFIG.Logging.disable()` - Disable all logging
+- `CONFIG.Logging.set_colors(log_colors)` - Customize colors
+
+**Enhanced formatting**:
+- Multi-line messages with box borders (┌─, │, └─)
+- Exception tracebacks with proper indentation
+- Timestamps: `2025-11-21 14:30:45.123`
+
+### 💥 Breaking Changes
+
+**Logging migration** (edge cases only):
+
+| Old (v3.6.0-v4.0.0) | New (v4.1.0+) |
+|---------------------|---------------|
+| `CONFIG.Logging.level = 'INFO'`<br>`CONFIG.Logging.console = True`<br>`CONFIG.apply()` | `CONFIG.Logging.enable_console('INFO')`<br>or `CONFIG.exploring()` |
+| `CONFIG.Logging.file = 'app.log'` | `CONFIG.Logging.enable_file('INFO', 'app.log')` |
+| `logger.opt(lazy=True)` | Built-in (automatic) |
+
+**Migration**:
+```python
+# Before (v3.6.0-v4.0.0)
+CONFIG.Logging.level = 'INFO'
+CONFIG.Logging.console = True
+CONFIG.apply()
+
+# After (v4.1.0+)
+CONFIG.Logging.enable_console('INFO')  # or CONFIG.exploring()
+```
+
+### ♻️ Changed
+
+- Replaced loguru with Python `logging` + optional `colorlog` for colors
+- Configuration immediate (no `CONFIG.apply()` needed)
+- Log format: `[dimmed timestamp] [colored level] │ message`
+- Logs to `stdout` by default (configurable)
+- SUCCESS level preserved (green, level 25)
+- Performance: Expensive operations guarded with `logger.isEnabledFor()` checks
+
+### 🗑️ Deprecated
+
+- `change_logging_level(level)` → Use `CONFIG.Logging.enable_console(level)`. Removal in v5.0.0.
+
+### 🔥 Removed
+
+**CONFIG methods/attributes**:
+- `CONFIG.apply()` → Use helper methods directly
+- `CONFIG.Logging.level`, `.console`, `.file` → Use `enable_console()`/`enable_file()`
+- `CONFIG.Logging.verbose_tracebacks`, `.rich`, `.Colors`, `.date_format`, `.format`, `.console_width`, `.show_path`, `.show_logger_name` → Use standard logging
+- loguru features (`logger.opt()`, etc.)
+
+### 🐛 Fixed
+
+- `TypeError` in `check_bounds()` with loguru-style formatting
+- Exception tracebacks not appearing in custom formatters
+- Inconsistent formatting between console and file logs
+
+### 🔒 Security
+
+- Removed loguru dependency for reduced supply chain risk
+
+### 📦 Dependencies
+
+- **Removed:** `loguru >= 0.7.0`
+- **Added:** `colorlog >= 6.8.0, < 7` (optional)
+
+### 📝 Docs
+
+- Preset comparison table in `CONFIG.Logging` docstring
+- Color customization examples
+- Migration guide with before/after code
+
+---
+
 Until here -->
 
 ## [4.0.0] - 2025-11-19

docs/getting-started.md

@@ -24,20 +24,25 @@ 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.
+FlixOpt uses Python's standard logging module with optional colored output via [colorlog](https://github.com/borntyping/python-colorlog). Logging is silent by default but can be easily configured.
 
 ```python
 from flixopt import CONFIG
 
-# Enable console logging
-CONFIG.Logging.console = True
-CONFIG.Logging.level = 'INFO'
-CONFIG.apply()
+# Enable colored console logging
+CONFIG.Logging.enable_console('INFO')
 
 # Or use a preset configuration for exploring
 CONFIG.exploring()
 ```
 
+For advanced logging configuration, you can use Python's standard logging module directly:
+
+```python
+import logging
+logging.basicConfig(level=logging.DEBUG)
+```
+
 For more details on logging configuration, see the [`CONFIG.Logging`][flixopt.config.CONFIG.Logging] documentation.
 
 ## Basic Workflow

docs/user-guide/migration-guide-v3.md

@@ -89,12 +89,12 @@ Terminology changed and sharing system inverted: effects now "pull" shares.
 
 ### Other Changes
 
-| Category | Old (v2.x) | New (v3.0.0) |
-|----------|------------|--------------|
-| System model class | `SystemModel` | `FlowSystemModel` |
-| Element submodel | `Model` | `Submodel` |
-| Logging default | Enabled | Disabled |
-| Enable logging | (default) | `fx.CONFIG.Logging.console = True; fx.CONFIG.apply()` |
+| Category               | Old (v2.x) | New (v3.0.0+) |
+|------------------------|------------|---------------|
+| System model class     | `SystemModel` | `FlowSystemModel` |
+| Element submodel       | `Model` | `Submodel` |
+| Logging default        | Enabled | Disabled (silent) |
+| Enable console logging | (default) | `fx.CONFIG.Logging.enable_console('INFO')` or `fx.CONFIG.exploring()` |
 
 ---
 

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

@@ -7,15 +7,17 @@
 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/__init__.py

@@ -2,6 +2,7 @@
 This module bundles all common functionality of flixopt and sets up the logging
 """
 
+import logging
 import warnings
 from importlib.metadata import PackageNotFoundError, version
 
@@ -60,6 +61,11 @@
     'solvers',
 ]
 
+# Initialize logger with default configuration (silent: WARNING level, NullHandler)
+logger = logging.getLogger('flixopt')
+logger.setLevel(logging.WARNING)
+logger.addHandler(logging.NullHandler())
+
 # === Runtime warning suppression for third-party libraries ===
 # These warnings are from dependencies and cannot be fixed by end users.
 # They are suppressed at runtime to provide a cleaner user experience.

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
@@ -37,6 +37,8 @@
     from .elements import Component
     from .flow_system import FlowSystem
 
+logger = logging.getLogger('flixopt')
+
 
 class Aggregation:
     """
@@ -104,7 +106,8 @@ def cluster(self) -> None:
         self.aggregated_data = self.tsam.predictOriginalData()
 
         self.clustering_duration_seconds = timeit.default_timer() - start_time  # Zeit messen:
-        logger.opt(lazy=True).info('{result}', result=lambda: self.describe_clusters())
+        if logger.isEnabledFor(logging.INFO):
+            logger.info(self.describe_clusters())
 
     def describe_clusters(self) -> str:
         description = {}

flixopt/calculation.py

@@ -10,6 +10,7 @@
 
 from __future__ import annotations
 
+import logging
 import math
 import pathlib
 import sys
@@ -19,7 +20,6 @@
 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
@@ -39,6 +39,8 @@
     from .solvers import _Solver
     from .structure import FlowSystemModel
 
+logger = logging.getLogger('flixopt')
+
 
 class Calculation:
     """
@@ -255,11 +257,9 @@ 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.opt(lazy=True).info(
-                '{result}',
-                result=lambda: f'{" Main Results ":#^80}\n'
-                + fx_io.format_yaml_string(self.main_results, compact_numeric_lists=True),
+        if should_log and logger.isEnabledFor(logging.INFO):
+            logger.info(
+                f'{" Main Results ":#^80}\n' + fx_io.format_yaml_string(self.main_results, compact_numeric_lists=True)
             )
 
         self.results = CalculationResults.from_calculation(self)

flixopt/color_processing.py

@@ -6,12 +6,15 @@
 
 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

@@ -4,27 +4,30 @@
 
 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 .config import DEPRECATION_REMOVAL_VERSION
 from .core import PlausibilityError
 from .elements import Component, ComponentModel, Flow
 from .features import InvestmentModel, PiecewiseModel
 from .interface import InvestParameters, OnOffParameters, PiecewiseConversion
 from .modeling import BoundingPatterns
-from .structure import DEPRECATION_REMOVAL_VERSION, FlowSystemModel, register_class_for_io
+from .structure import FlowSystemModel, register_class_for_io
 
 if TYPE_CHECKING:
     import linopy
 
     from .flow_system import FlowSystem
     from .types import Numeric_PS, Numeric_TPS
 
+logger = logging.getLogger('flixopt')
+
 
 @register_class_for_io
 class LinearConverter(Component):