util.config: add context manager to set logging level (#160)

Author: chahank

climada/util/__init__.py

@@ -18,6 +18,7 @@
 
 init util
 """
+import logging
 from pint import UnitRegistry
 
 from .config import *
@@ -26,3 +27,37 @@
 from .save import *
 
 ureg = UnitRegistry()
+
+class log_level:
+    """Context manager that sets all loggers with names starting with
+    name_prefix (default is "") to a given specified level.
+
+    Examples
+    --------
+    Set ALL loggers temporarily to the level 'WARNING'
+    >>> with log_level(level='WARNING'):
+    >>>     ...
+
+    Set all the climada loggers temporarily to the level 'ERROR'
+    >>> with log_level(level='ERROR', name_prefix='climada'):
+    >>>     ...
+
+    """
+
+    def __init__(self, level, name_prefix=""):
+        self.level = level
+        self.loggers = {
+            name: (logger, logger.level)
+            for name, logger in logging.root.manager.loggerDict.items()
+            if isinstance(logger, logging.Logger) and name.startswith(name_prefix)
+            }
+        if name_prefix == "":
+            self.loggers[""] = (logging.getLogger(), logging.getLogger().level)
+
+    def __enter__(self):
+        for logger, _ in self.loggers.values():
+            logger.setLevel(self.level)
+
+    def __exit__(self, exception_type, exception, traceback):
+        for logger, previous_level in self.loggers.values():
+            logger.setLevel(previous_level)

climada/util/test/test__init__.py

@@ -0,0 +1,47 @@
+"""
+This file is part of CLIMADA.
+
+Copyright (C) 2017 ETH Zurich, CLIMADA contributors listed in AUTHORS.
+
+CLIMADA is free software: you can redistribute it and/or modify it under the
+terms of the GNU Lesser General Public License as published by the Free
+Software Foundation, version 3.
+
+CLIMADA is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with CLIMADA. If not, see <https://www.gnu.org/licenses/>.
+
+---
+
+Test config module.
+"""
+import unittest
+import logging
+
+from climada.util import log_level
+
+class TestUtilInit(unittest.TestCase):
+    """Test util __init__ methods"""
+
+    def test_log_level_pass(self):
+        """Test log level context manager passes"""
+        #Check loggers are set to level
+        with self.assertLogs('climada', level='INFO') as cm:
+             with log_level('WARNING'):
+                logging.getLogger('climada').info('info')
+                logging.getLogger('climada').error('error')
+                self.assertEqual(cm.output, ['ERROR:climada:error'])
+        #Check if only climada loggers level change
+        with self.assertLogs('matplotlib', level='DEBUG') as cm:
+            with log_level('ERROR', name_prefix='climada'):
+                logging.getLogger('climada').info('info')
+            logging.getLogger('matplotlib').debug('debug')
+            self.assertEqual(cm.output, ['DEBUG:matplotlib:debug'])
+
+# Execute Tests
+if __name__ == "__main__":
+    TESTS = unittest.TestLoader().loadTestsFromTestCase(TestUtilInit)
+    unittest.TextTestRunner(verbosity=2).run(TESTS)