R/W error with the glances.log file (issue #474)

NEWS

@@ -5,6 +5,8 @@ Glances Version 2.x
 Version 2.3
 ===========
 
+Enhancements and news features:
+
     * Add actions on alerts (issue #132). It is now possible to run action (command line) by triggers. Action could containq {Mustache} {{tag}} (Mustache) with stat value.
     * Add InfluxDB export module (--export-influxdb) (issue #455)
     * Add Statsd export module (--export-statsd) (issue #465)
@@ -13,6 +15,10 @@ Version 2.3
     * Add the RAID plugin (issue #447)
     * Add the Docker plugin (issue #440)
 
+Bugs corrected:
+
+    *  R/W error with the glances.log file (issue #474) 
+
 Version 2.2.1
 =============
 

docs/glances-doc.rst

@@ -332,6 +332,8 @@ By default, the log file is under:
 :Linux, \*BSD and OS X: ``/tmp/glances.log``
 :Windows: ``%APPDATA%\Local\temp\glances.log``
 
+If glances.log is not writable, a new file will be created and returned to the user console.
+
 Anatomy Of The Application
 ==========================
 

glances/core/glances_logging.py

@@ -71,14 +71,27 @@ LOGGING_CFG = {
 }
 
 
+def tempfile_name():
+    """Return the tempfile name (full path)"""
+    ret = os.path.join(tempfile.gettempdir(), 'glances.log')
+    if os.access(ret, os.F_OK) and not os.access(ret, os.W_OK):
+        print("Warning: can't write logs to file {} (permission denied)".format(ret))
+        ret = tempfile.mkstemp(prefix='glances', suffix='.tmp', text=True)
+        print("Create a new log file: {}".format(ret[1]))
+    return ret[1]
+
+
 def glances_logger():
+    """Build and return the logger"""
+    temp_path = tempfile_name()
     _logger = logging.getLogger()
     try:
+        LOGGING_CFG['handlers']['file']['filename'] = temp_path
         logging.config.dictConfig(LOGGING_CFG)
     except AttributeError:
         # dictConfig is only available for Python 2.7 or higher
         # Minimal configuration for Python 2.6
-        logging.basicConfig(filename=os.path.join(tempfile.gettempdir(), 'glances.log'),
+        logging.basicConfig(filename=temp_path,
                             level=logging.DEBUG,
                             format='%(asctime)s -- %(levelname)s -- %(message)s')
     return _logger