Add the ability to filter logging messages

qutebrowser/app.py

@@ -29,7 +29,6 @@ earlyinit.check_pyqt_webkit()
 import os
 import sys
 import types
-import logging
 import subprocess
 import faulthandler
 import configparser
@@ -127,7 +126,7 @@ class QuteBrowser(QApplication):
         sys.excepthook = self._exception_hook
 
         self._args = self._parse_args()
-        self._init_log()
+        log.init_log(self._args)
         self._init_misc()
         actute_warning()
         self._init_config()
@@ -166,6 +165,8 @@ class QuteBrowser(QApplication):
         parser = ArgumentParser("usage: %(prog)s [options]")
         parser.add_argument('-l', '--log', dest='loglevel',
                             help="Set loglevel", default='info')
+        parser.add_argument('-f', '--logfilter',
+                            help="Comma-separated list of things to be logged")
         parser.add_argument('-c', '--confdir', help="Set config directory "
                             "(empty for no config storage)")
         parser.add_argument('-d', '--debug', help="Turn on debugging options.",
@@ -231,22 +232,6 @@ class QuteBrowser(QApplication):
                               passthrough=True)
         self.modeman.register('yesno', self._keyparsers['yesno'].handle)
 
-    def _init_log(self):
-        """Initialisation of the logging output.
-
-        Raise:
-            ValueError if there was an invalid loglevel.
-        """
-        loglevel = 'debug' if self._args.debug else self._args.loglevel
-        numeric_level = getattr(logging, loglevel.upper(), None)
-        if not isinstance(numeric_level, int):
-            raise ValueError("Invalid log level: {}".format(loglevel))
-        logging.basicConfig(
-            level=numeric_level,
-            format='%(asctime)s [%(levelname)s] [%(name)s|'
-                   '%(module)s:%(funcName)s:%(lineno)s] %(message)s',
-            datefmt='%Y-%m-%d %H:%M:%S')
-
     def _init_misc(self):
         """Initialize misc things."""
         if self._args.debug:

qutebrowser/utils/log.py

@@ -17,6 +17,7 @@
 
 """Loggers and utilities related to logging."""
 
+import logging
 from logging import getLogger
 
 # The different loggers used.
@@ -35,3 +36,46 @@ init = getLogger('init')
 signals = getLogger('signals')
 hints = getLogger('hints')
 keyboard = getLogger('keyboard')
+
+
+def init_log(args):
+    """Init loggers based on the argparse namespace passed."""
+    logfilter = LogFilter(None if args.logfilter is None
+                          else args.logfilter.split(','))
+    console_handler = logging.StreamHandler()
+    console_handler.addFilter(logfilter)
+    logging.basicConfig(
+        level='DEBUG' if args.debug else args.loglevel.upper(),
+        format='%(asctime)s [%(levelname)s] [%(name)s|'
+               '%(module)s:%(funcName)s:%(lineno)s] %(message)s',
+        datefmt='%Y-%m-%d %H:%M:%S',
+        handlers=[console_handler])
+
+
+class LogFilter(logging.Filter):
+
+    """Filter to filter log records based on the commandline argument.
+
+    The default Filter only supports one name to show - we support a
+    comma-separated list instead.
+
+    Attributes:
+        names: A list of names that should be logged.
+    """
+
+    def __init__(self, names):
+        super().__init__()
+        self.names = names
+
+    def filter(self, record):
+        """Determine if the specified record is to be logged."""
+        if self.names is None:
+            return True
+        for name in self.names:
+            if record.name == name:
+                return True
+            elif not record.name.startswith(name):
+                continue
+            elif record.name[len(name)] == '.':
+                return True
+        return False