Allow reload of 'debug' option

Ie9e9a895da1a3fc62580c1febb7cd9f965bbc0f5 adds a 'mutate' flag to
options. This is the first patch to use this functionality. It marks the
'debug' option as mutable and registers '_mutate_hook' to be called
when mutate_config_files runs.

Option 'verbose' is deprecated for removal so I see no need to mark it
mutable even though it's closely related.

Change-Id: I1e7a69de169cc85f4c09954b2f46ce2da7106d90
Depends-On: Ied006631a6edbeeffae485d28eff700b13a626c1
Depends-On: I9bb2ff39dc1ed0a63bd7e7635704b34c53d32d79

oslo_log/_options.py

@@ -34,6 +34,7 @@ common_cli_opts = [
     cfg.BoolOpt('debug',
                 short='d',
                 default=False,
+                mutable=True,
                 help='If set to true, the logging level will be set to '
                      'DEBUG instead of the default INFO level.'),
     cfg.BoolOpt('verbose',

oslo_log/log.py

@@ -219,6 +219,15 @@ def _load_log_config(log_config_append):
         raise LogConfigError(log_config_append, six.text_type(exc))
 
 
+def _mutate_hook(conf, fresh):
+    """Reconfigures oslo.log according to the mutated options."""
+
+    # verbose is deprecated, so I didn't make it mutable, so there's no need to
+    # test for it here.
+    if (None, 'debug') in fresh:
+        _refresh_root_level(conf.debug, conf.verbose)
+
+
 def register_options(conf):
     """Register the command line and configuration options used by oslo.log."""
 
@@ -234,6 +243,8 @@ def register_options(conf):
     conf.register_opts(_options.log_opts)
     formatters._store_global_conf(conf)
 
+    conf.register_mutate_hook(_mutate_hook)
+
 
 def setup(conf, product_name, version='unknown'):
     """Setup logging for the current application."""
@@ -301,6 +312,27 @@ def _find_facility(facility):
     return getattr(syslog, facility)
 
 
+def _refresh_root_level(debug, verbose):
+    """Set the level of the root logger.
+
+    If 'debug' is True, the level will be DEBUG. Otherwise we look at 'verbose'
+    - if that is True, the level will be INFO. If neither are set, the level
+    will be WARNING.
+
+    Note the 'verbose' option is deprecated.
+
+    :param debug
+    :param verbose
+    """
+    log_root = getLogger(None).logger
+    if debug:
+        log_root.setLevel(logging.DEBUG)
+    elif verbose:
+        log_root.setLevel(logging.INFO)
+    else:
+        log_root.setLevel(logging.WARNING)
+
+
 def _setup_logging_from_conf(conf, project, version):
     log_root = getLogger(None).logger
 
@@ -349,13 +381,7 @@ def _setup_logging_from_conf(conf, project, version):
                                                          version=version,
                                                          datefmt=datefmt,
                                                          config=conf))
-
-    if conf.debug:
-        log_root.setLevel(logging.DEBUG)
-    elif conf.verbose:
-        log_root.setLevel(logging.INFO)
-    else:
-        log_root.setLevel(logging.WARNING)
+    _refresh_root_level(conf.debug, conf.verbose)
 
     for pair in conf.default_log_levels:
         mod, _sep, level_name = pair.partition('=')

oslo_log/tests/unit/test_log.py

@@ -19,6 +19,7 @@ import datetime
 import logging
 import os
 import platform
+import shutil
 import sys
 try:
     import syslog
@@ -857,6 +858,32 @@ class FastWatchedFileHandlerTestCase(BaseTestCase):
         self.assertTrue(os.path.exists(log_path))
 
 
+class ConfigTestCase(test_base.BaseTestCase):
+    def test_mutate(self):
+        conf = cfg.CONF
+        old_config = ("[DEFAULT]\n"
+                      "debug = false\n")
+        new_config = ("[DEFAULT]\n"
+                      "debug = true\n")
+        paths = self.create_tempfiles([('old', old_config),
+                                       ('new', new_config)])
+        log.register_options(conf)
+        conf(['--config-file', paths[0]])
+        log_root = log.getLogger(None).logger
+
+        log._setup_logging_from_conf(conf, 'test', 'test')
+        self.assertEqual(conf.debug, False)
+        self.assertEqual(conf.verbose, True)
+        self.assertEqual(log.INFO, log_root.getEffectiveLevel())
+
+        shutil.copy(paths[1], paths[0])
+        conf.mutate_config_files()
+
+        self.assertEqual(conf.debug, True)
+        self.assertEqual(conf.verbose, True)
+        self.assertEqual(log.DEBUG, log_root.getEffectiveLevel())
+
+
 class LogConfigOptsTestCase(BaseTestCase):
 
     def setUp(self):