from #129

Author: jafranc

geos-utils/src/geos/utils/Logger.py

@@ -2,16 +2,96 @@
 # SPDX-FileCopyrightText: Copyright 2023-2024 TotalEnergies.
 # SPDX-FileContributor: Martin Lemay
 import logging
-from typing import Any, Union
+from typing import Any, Union, Generator
 from typing_extensions import Self
 
+import os
+import re
+import tempfile
+from contextlib import contextmanager
+
 __doc__ = """
 Logger module manages logging tools.
 
 Code was modified from <https://stackoverflow.com/questions/384076/how-can-i-color-python-logging-output>
+
+It also include adaptor strategy to make vtkLogger behave as a logging's logger.
+Indeed, C++ adapted class is based on private Callback assignement which is not compatible
+with logging python's logic.
+
+usage:
+    #near logger definition
+    from vtkmodules.vtkCommonCore import vtkLogger
+
+    vtkLogger.SetStderrVerbosity(vtkLogger.VERBOSITY_TRACE)
+    logger.addFilter(RegexExceptionFilter())
+
+    ...
+
+    #near VTK calls
+     with VTKCaptureLog() as captured_log:
+        vtkcalls..
+        captured_log.seek(0) # be kind let's just rewind
+        captured = captured_log.read().decode()
+
+    logger.error(captured.strip())
+
 """
 
 
+class RegexExceptionFilter( logging.Filter ):
+    """Class to regexp VTK messages rethrown into logger by VTKCaptureLog."""
+
+    pattern: str = r"ERR"  #pattern captured that will raise a vtkError
+
+    def __init__( self ) -> None:
+        """Init filter with class based pattern as this is patch to logging logic."""
+        super().__init__()
+        self.regex = re.compile( self.pattern )
+
+    def filter( self, record: logging.LogRecord ) -> bool:
+        """Filter VTK Error from stdErr.
+
+        Args:
+            record(loggging.LogRecord) : record that logger will provide as evaluated
+
+        Raises:
+            VTKError(geos.utils.Error) if a pattern symbol is caught in the stderr.
+        """
+        message = record.getMessage()
+        if self.regex.search( message ):
+            raise TypeError( f"Log message matched forbidden pattern: {message}" )
+        return True  # Allow other messages to pass
+
+
+@contextmanager
+def VTKCaptureLog() -> Generator[ Any, Any, Any ]:
+    """Hard way of adapting C-like vtkLogger to logging class by throwing in stderr and reading back from it.
+
+    Returns:
+        Generator: buffering os stderr.
+
+    """
+    #equiv to pyvista's
+    # from pyvista.utilities import VtkErrorCatcher
+    # with VtkErrorCatcher() as err:
+    #     append_filter.Update()
+    #     print(err)
+    # original_stderr_fd = sys.stderr.fileno()
+    original_stderr_fd = 2
+    saved_stderr_fd = os.dup( original_stderr_fd )
+
+    # Create a temporary file to capture stderr
+    with tempfile.TemporaryFile( mode='w+b' ) as tmp:
+        os.dup2( tmp.fileno(), original_stderr_fd )
+        try:
+            yield tmp
+        finally:
+            # Restore original stderr
+            os.dup2( saved_stderr_fd, original_stderr_fd )
+            os.close( saved_stderr_fd )
+
+
 class CountWarningHandler( logging.Handler ):
     """Create an handler to count the warnings logged."""