Added init_logging

neat/common.py

@@ -18,11 +18,15 @@
 from contracts import contract
 from neat.contracts_extra import *
 
+import os
 import time
 
 from neat.config import *
 from neat.db_utils import *
 
+import logging
+log = logging.getLogger(__name__)
+
 
 @contract
 def start(init_state, execute, config, time_interval, iterations):
@@ -130,3 +134,46 @@ def frange(start, end, step):
     while start <= end:
         yield start
         start += step
+
+
+@contract
+def init_logging(log_directory, log_file, log_level):
+    """ Initialize the logging system.
+
+    :param log_directory: The directory to store log files.
+     :type log_directory: str
+
+    :param log_file: The file name to store log messages.
+     :type log_file: str
+
+    :param log_level: The level of emitted log messages.
+     :type log_level: int
+
+    :return: Whether the logging system has been initialized.
+     :rtype: bool
+    """
+    if log_level == 0:
+        logging.disable(logging.CRITICAL)
+        return True
+
+    if not os.access(log_file, os.F_OK):
+        if not os.access(log_directory, os.F_OK):
+            os.makedirs(log_directory)
+        elif not os.access(log_directory, os.W_OK):
+            raise IOError(
+                'Cannot write to the log directory: ' + log_directory)
+    elif not os.access(log_file, os.W_OK):
+        raise IOError('Cannot write to the log file: ' + log_file)
+
+    if log_level == 3:
+        level = logging.DEBUG
+    elif log_level == 2:
+        level = logging.INFO
+    else:
+        level = logging.WARNING
+
+    logging.basicConfig(
+        format='%(asctime)s %(levelname)-8s %(name)s %(message)s',
+        filename=os.path.join(log_directory, log_file),
+        level=level)
+    return True

tests/test_common.py

@@ -16,6 +16,8 @@ from mocktest import *
 from pyqcy import *
 
 import os
+import shutil
+import logging
 import libvirt
 
 import neat.common as common
@@ -73,3 +75,44 @@ class Common(TestCase):
                          [0.0, 0.5, 1.0])
         self.assertEqual([round(x, 1) for x in common.frange(0, 1.0, 0.2)],
                          [0.0, 0.2, 0.4, 0.6, 0.8, 1.0])
+
+    def test_init_logging(self):
+        log_dir = os.path.join(
+            os.path.dirname(__file__), 'resources', 'log')
+        log_file = 'test.log'
+        log_path = os.path.join(log_dir, log_file)
+
+        with MockTransaction:
+            expect(logging).disable(logging.CRITICAL).once()
+            expect(logging).basicConfig.never()
+            assert common.init_logging(log_dir, log_file, 0)
+
+        with MockTransaction:
+            shutil.rmtree(log_dir, True)
+            expect(logging).disable.never()
+            expect(logging).basicConfig(
+                format='%(asctime)s %(levelname)-8s %(name)s %(message)s',
+                filename=log_path,
+                level=logging.WARNING)
+            assert common.init_logging(log_dir, log_file, 1)
+            assert os.access(log_dir, os.W_OK)
+
+        with MockTransaction:
+            expect(logging).disable.never()
+            expect(logging).basicConfig(
+                format='%(asctime)s %(levelname)-8s %(name)s %(message)s',
+                filename=log_path,
+                level=logging.INFO)
+            assert common.init_logging(log_dir, log_file, 2)
+            assert os.access(log_dir, os.W_OK)
+
+        with MockTransaction:
+            expect(logging).disable.never()
+            expect(logging).basicConfig(
+                format='%(asctime)s %(levelname)-8s %(name)s %(message)s',
+                filename=log_path,
+                level=logging.DEBUG)
+            assert common.init_logging(log_dir, log_file, 3)
+            assert os.access(log_dir, os.W_OK)
+
+        shutil.rmtree(log_dir, True)