live-logging: Colorize levelname

_pytest/logging.py

@@ -2,6 +2,7 @@
 
 import logging
 from contextlib import closing, contextmanager
+import re
 import six
 
 import pytest
@@ -12,6 +13,60 @@
 DEFAULT_LOG_DATE_FORMAT = '%H:%M:%S'
 
 
+class ColoredLevelFormatter(logging.Formatter):
+    """
+    Colorize the %(levelname)..s part of the log format passed to __init__.
+    """
+
+    LOGLEVEL_COLOROPTS = {
+        logging.CRITICAL: {'red'},
+        logging.ERROR: {'red', 'bold'},
+        logging.WARNING: {'yellow'},
+        logging.WARN: {'yellow'},
+        logging.INFO: {'green'},
+        logging.DEBUG: {'purple'},
+        logging.NOTSET: set(),
+    }
+    LEVELNAME_FMT_REGEX = re.compile(r'%\(levelname\)([+-]?\d*s)')
+
+    def __init__(self, *args, **kwargs):
+        super(ColoredLevelFormatter, self).__init__(
+            *args, **kwargs)
+        if six.PY2:
+            self._original_fmt = self._fmt
+        else:
+            self._original_fmt = self._style._fmt
+        self._level_to_fmt_mapping = {}
+
+        levelname_fmt_match = self.LEVELNAME_FMT_REGEX.search(self._fmt)
+        if not levelname_fmt_match:
+            return
+        levelname_fmt = levelname_fmt_match.group()
+
+        tw = py.io.TerminalWriter()
+
+        for level, color_opts in self.LOGLEVEL_COLOROPTS.items():
+            formatted_levelname = levelname_fmt % {
+                'levelname': logging.getLevelName(level)}
+
+            # add ANSI escape sequences around the formatted levelname
+            color_kwargs = {name: True for name in color_opts}
+            colorized_formatted_levelname = tw.markup(
+                formatted_levelname, **color_kwargs)
+            self._level_to_fmt_mapping[level] = self.LEVELNAME_FMT_REGEX.sub(
+                colorized_formatted_levelname,
+                self._fmt)
+
+    def format(self, record):
+        fmt = self._level_to_fmt_mapping.get(
+            record.levelno, self._original_fmt)
+        if six.PY2:
+            self._fmt = fmt
+        else:
+            self._style._fmt = fmt
+        return super(ColoredLevelFormatter, self).format(record)
+
+
 def get_option_ini(config, *names):
     for name in names:
         ret = config.getoption(name)  # 'default' arg won't work as expected
@@ -376,7 +431,10 @@ def _setup_cli_logging(self):
             log_cli_handler = _LiveLoggingStreamHandler(terminal_reporter, capture_manager)
             log_cli_format = get_option_ini(self._config, 'log_cli_format', 'log_format')
             log_cli_date_format = get_option_ini(self._config, 'log_cli_date_format', 'log_date_format')
-            log_cli_formatter = logging.Formatter(log_cli_format, datefmt=log_cli_date_format)
+            if ColoredLevelFormatter.LEVELNAME_FMT_REGEX.search(log_cli_format):
+                log_cli_formatter = ColoredLevelFormatter(log_cli_format, datefmt=log_cli_date_format)
+            else:
+                log_cli_formatter = logging.Formatter(log_cli_format, datefmt=log_cli_date_format)
             log_cli_level = get_actual_log_level(self._config, 'log_cli_level', 'log_level')
             self.log_cli_handler = log_cli_handler
             self.live_logs_context = catching_logs(log_cli_handler, formatter=log_cli_formatter, level=log_cli_level)

changelog/3142.feature

@@ -0,0 +1 @@
+Colorize the levelname column in the live-log output.

testing/logging/test_formatter.py

@@ -0,0 +1,32 @@
+import logging
+import os
+
+import six
+
+from py.io import TerminalWriter
+import pytest
+from _pytest.logging import ColoredLevelFormatter
+
+
+def test_coloredlogformatter():
+    # TODO remove usage of mock module in this test
+    pytest.importorskip("mock")
+    import mock
+
+    logfmt = '%(filename)-25s %(lineno)4d %(levelname)-8s %(message)s'
+
+    tw = TerminalWriter()
+    tw.hasmarkup = True  # otherwise tw.markup does not add any escape
+                         # sequences
+
+    record = logging.LogRecord(
+        name='dummy', level=logging.INFO, pathname='dummypath', lineno=10,
+        msg='Test Message', args=(), exc_info=False)
+
+    with mock.patch('py.io.TerminalWriter') as mock_tw:
+        mock_tw.return_value = tw
+        formatter = ColoredLevelFormatter(logfmt)
+
+        output = formatter.format(record)
+        assert output == ('dummypath                   10 '
+                          '\x1b[32mINFO    \x1b[0m Test Message')