Merge remote-tracking branch 'ivan/feature/3134_redirect-output-to-logger' into develop

2 files changed, 181 insertions, 0 deletions

diff --git a/src/leap/util/streamtologger.py b/src/leap/util/streamtologger.py
new file mode 100644
index 00000000..25a06718
--- /dev/null
+++ b/src/leap/util/streamtologger.py
@@ -0,0 +1,59 @@
+# -*- coding: utf-8 -*-
+# streamtologger.py
+# Copyright (C) 2013 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+Stream object that redirects writes to a logger instance.
+"""
+import logging
+
+
+class StreamToLogger(object):
+    """
+    Fake file-like stream object that redirects writes to a logger instance.
+
+    Credits to:
+    http://www.electricmonk.nl/log/2011/08/14/\
+        redirect-stdout-and-stderr-to-a-logger-in-python/
+    """
+    def __init__(self, logger, log_level=logging.INFO):
+        """
+        Constructor, defines the logger and level to use to log messages.
+
+        :param logger: logger object to log messages.
+        :type logger: logging.Handler
+        :param log_level: the level to use to log messages through the logger.
+        :type log_level: int
+                        look at logging-levels in 'logging' docs.
+        """
+        self._logger = logger
+        self._log_level = log_level
+
+    def write(self, data):
+        """
+        Simulates the 'write' method in a file object.
+        It writes the data receibed in buf to the logger 'self._logger'.
+
+        :param data: data to write to the 'file'
+        :type data: str
+        """
+        for line in data.rstrip().splitlines():
+            self._logger.log(self._log_level, line.rstrip())
+
+    def flush(self):
+        """
+        Dummy method. Needed to replace the twisted.log output.
+        """
+        pass
diff --git a/src/leap/util/tests/test_streamtologger.py b/src/leap/util/tests/test_streamtologger.py
new file mode 100644
index 00000000..4c98e562
--- /dev/null
+++ b/src/leap/util/tests/test_streamtologger.py
@@ -0,0 +1,122 @@
+# -*- coding: utf-8 -*-
+# test_streamtologger.py
+# Copyright (C) 2013 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+tests for streamtologger
+"""
+
+try:
+    import unittest2 as unittest
+except ImportError:
+    import unittest
+
+import logging
+import sys
+
+from leap.util.streamtologger import StreamToLogger
+from leap.common.testing.basetest import BaseLeapTest
+
+
+class SimpleLogHandler(logging.Handler):
+    """
+    The simplest log handler that allows to check if the log was
+    delivered to the handler correctly.
+    """
+    def __init__(self):
+        logging.Handler.__init__(self)
+        self._last_log = ""
+        self._last_log_level = ""
+
+    def emit(self, record):
+        self._last_log = record.getMessage()
+        self._last_log_level = record.levelno
+
+    def get_last_log(self):
+        """
+        Returns the last logged message by this handler.
+
+        :return: the last logged message.
+        :rtype: str
+        """
+        return self._last_log
+
+    def get_last_log_level(self):
+        """
+        Returns the level of the last logged message by this handler.
+
+        :return: the last logged level.
+        :rtype: str
+        """
+        return self._last_log_level
+
+
+class StreamToLoggerTest(BaseLeapTest):
+    """
+    StreamToLogger's tests.
+
+    NOTE: we may need to find a way to test the use case that an exception
+    is raised. I couldn't catch the output of an exception because the
+    test failed if some exception is raised.
+    """
+    def setUp(self):
+        # Create the logger
+        level = logging.DEBUG
+        self.logger = logging.getLogger(name='test')
+        self.logger.setLevel(level)
+
+        # Simple log handler
+        self.handler = SimpleLogHandler()
+        self.logger.addHandler(self.handler)
+
+        # Preserve original values
+        self._sys_stdout = sys.stdout
+        self._sys_stderr = sys.stderr
+
+        # Create the handler
+        sys.stdout = StreamToLogger(self.logger, logging.DEBUG)
+        sys.stderr = StreamToLogger(self.logger, logging.ERROR)
+
+    def tearDown(self):
+        # Restore original values
+        sys.stdout = self._sys_stdout
+        sys.stderr = self._sys_stderr
+
+    def test_logger_starts_empty(self):
+        self.assertEqual(self.handler.get_last_log(), '')
+
+    def test_standard_output(self):
+        message = 'Test string'
+        print message
+
+        log = self.handler.get_last_log()
+        log_level = self.handler.get_last_log_level()
+
+        self.assertEqual(log, message)
+        self.assertEqual(log_level, logging.DEBUG)
+
+    def test_standard_error(self):
+        message = 'Test string'
+        sys.stderr.write(message)
+
+        log_level = self.handler.get_last_log_level()
+        log = self.handler.get_last_log()
+
+        self.assertEqual(log, message)
+        self.assertEqual(log_level, logging.ERROR)
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)