colorize error log messages

If running in terminal, make the levelnames colored. This makes
the output much easier to read.

3 files changed, 71 insertions, 8 deletions

diff --git a/config/lmi.conf b/config/lmi.conf
index 50d0160..349976b 100644
--- a/config/lmi.conf
+++ b/config/lmi.conf
@@ -46,7 +46,7 @@
 # Format string used, when logging to a console. For details visit:
 # http://docs.python.org/2/library/logging.html#logrecord-attributes
 # This applies to levels more severe than INFO.
-#ConsoleFormat = %(levelname)-8s: %(message)s
+#ConsoleFormat = %(cseq)s%(levelname)-8s:%(creset)s %(message)s
 
 # Format string used, when logging to a console. This applies to all messages
 # with severity level up to INFO.
diff --git a/lmi/scripts/_metacommand/util.py b/lmi/scripts/_metacommand/util.py
index aabf588..96317df 100644
--- a/lmi/scripts/_metacommand/util.py
+++ b/lmi/scripts/_metacommand/util.py
@@ -34,6 +34,7 @@ Meta-command utility module.
 import logging
 import logging.config
 import pkg_resources
+import platform
 import re
 import sys
 import urlparse
@@ -134,7 +135,8 @@ def setup_logging(app_config, stderr=sys.stderr):
         del cfg['handlers']['console']
         cfg['root']['handlers'].remove('console')
 
-    lmi_logging.setup_logger()
+    use_colors = platform.system() != 'Windows' and stderr.isatty()
+    lmi_logging.setup_logger(use_colors = use_colors)
     logging.config.dictConfig(cfg)
 
 def get_version(egg_name=PYTHON_EGG_NAME):
diff --git a/lmi/scripts/common/lmi_logging.py b/lmi/scripts/common/lmi_logging.py
index fb9c4f0..5402363 100644
--- a/lmi/scripts/common/lmi_logging.py
+++ b/lmi/scripts/common/lmi_logging.py
@@ -29,24 +29,79 @@
 #
 import logging
 
+TERM_COLOR_NAMES = (
+        'black',
+        'red',
+        'green',
+        'yellow',
+        'blue',
+        'magenta',
+        'cyan',
+        'white',
+        )
+
+# Following are terminal color codes of normal mode.
+CN_BLACK   = 0
+CN_RED     = 1
+CN_GREEN   = 2
+CN_YELLOW  = 3
+CN_BLUE    = 4
+CN_MAGENTA = 5
+CN_CYAN    = 6
+CN_WHITE   = 7
+# Following are terminal color codes of bright mode.
+CB_BLACK   = 8
+CB_RED     = 9
+CB_GREEN   = 10
+CB_YELLOW  = 11
+CB_BLUE    = 12
+CB_MAGENTA = 13
+CB_CYAN    = 14
+CB_WHITE   = 15
+
 #: Default format string to use in stderr handlers.
-DEFAULT_FORMAT_STRING = "%(levelname_)-8s: %(message)s"
+DEFAULT_FORMAT_STRING = "%(cseq)s%(levelname_)-8s:%(creset)s %(message)s"
+
+WARNING_COLOR  = CB_YELLOW
+ERROR_COLOR    = CB_RED
+CRITICAL_COLOR = CB_MAGENTA
+
+LOG_LEVEL_2_COLOR = {
+        logging.WARNING : WARNING_COLOR,
+        logging.ERROR   : ERROR_COLOR,
+        logging.CRITICAL: CRITICAL_COLOR
+}
 
 class LogRecord(logging.LogRecord):
 
-    def __init__(self, name, *args, **kwargs):
-        logging.LogRecord.__init__(self, name, *args, **kwargs)
-        self.levelname_ = self.levelname
+    def __init__(self, name, level, *args, **kwargs):
+        use_colors = kwargs.pop('use_colors', True)
+        logging.LogRecord.__init__(self, name, level, *args, **kwargs)
+        self.levelname_ = self.levelname.lower()
+        if use_colors and level >= logging.WARNING:
+            if level >= logging.CRITICAL:
+                color = LOG_LEVEL_2_COLOR[logging.CRITICAL]
+            elif level >= logging.ERROR:
+                color = LOG_LEVEL_2_COLOR[logging.ERROR]
+            else:
+                color = LOG_LEVEL_2_COLOR[logging.WARNING]
+            self.cseq = get_color_sequence(color)
+            self.creset = "\x1b[39m"
+        else:
+            self.cseq = self.creset = ''
 
 class ScriptsLogger(logging.getLoggerClass()):
 
+    USE_COLORS = True
+
     def makeRecord(self, name, level, fn, lno, msg, args, exc_info, func=None,
             extra=None):
         """
         Overriden method that just changes the *LogRecord* class to our
         predefined.
         """
-        rv = LogRecord(name, level, fn, lno, msg, args, exc_info, func)
+        rv = LogRecord(name, level, fn, lno, msg, args, exc_info, func,
+                use_colors=self.USE_COLORS)
         if extra is not None:
             for key in extra:
                 if (key in ["message", "asctime"]) or (key in rv.__dict__):
@@ -132,5 +187,11 @@ def get_logger(module_name):
         return logging.getLogger(module_name)
     return _logger
 
-def setup_logger():
+def get_color_sequence(color_code):
+    if color_code <= 7:
+        return "\x1b[%dm" % (30 + color_code)
+    return "\x1b[38;5;%dm" % color_code
+
+def setup_logger(use_colors=True):
+    ScriptsLogger.USE_COLORS = use_colors
     logging.setLoggerClass(ScriptsLogger)