Add the 'Log Client' tab

The 'Log Client' tab shows information from Pythons logging framework.
Log records that previously would only show up in your console or
terminal window is now made available inside of the client.

This is acomplished by adding making LogClientTab class subclass the
logging.StreamHandler class and implementing the emit method.

src/cfclient/ui/tabs/LogClientTab.py

@@ -0,0 +1,90 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+#     ||          ____  _ __
+#  +------+      / __ )(_) /_______________ _____  ___
+#  | 0xBC |     / __  / / __/ ___/ ___/ __ `/_  / / _ \
+#  +------+    / /_/ / / /_/ /__/ /  / /_/ / / /_/  __/
+#   ||  ||    /_____/_/\__/\___/_/   \__,_/ /___/\___/
+#
+#  Copyright (C) 2011-2021 Bitcraze AB
+#
+#  Crazyflie Nano Quadcopter Client
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License
+#  as published by the Free Software Foundation; either version 2
+#  of the License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+
+#  You should have received a copy of the GNU General Public License along with
+#  this program; if not, write to the Free Software Foundation, Inc.,
+#  51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+"""
+Shows information from the Python logging framework
+"""
+
+import logging
+
+from PyQt5 import uic
+from PyQt5.QtCore import pyqtSignal
+
+import cfclient
+from cfclient.ui.tab import Tab
+
+__author__ = 'Bitcraze AB'
+__all__ = ['LogClientTab']
+
+logger = logging.getLogger(__name__)
+
+log_client_tab_class = uic.loadUiType(cfclient.module_path +
+                                      "/ui/tabs/logClientTab.ui")[0]
+
+
+class LogClientTab(Tab, log_client_tab_class, logging.StreamHandler):
+    """
+    A tab for showing client logging information, such
+    as USB Gamepad connections or scan feedback.
+    """
+    _update = pyqtSignal(str)
+
+    def __init__(self, tabWidget, helper, *args):
+        super(LogClientTab, self).__init__(*args)
+        logging.StreamHandler.__init__(self)
+        self.setupUi(self)
+
+        self.tabName = "Log Client"
+        self.menuName = "Log Client"
+
+        self.tabWidget = tabWidget
+
+        self._update.connect(self.printText)
+        self._clearButton.clicked.connect(self.clear)
+        #
+        # We inherit from logging.StreamHandler and ourself to the root logger.
+        # This means that our implementation of emit() will be called when a
+        # new LogRecord is available on the stream.
+        #
+        cflogger = logging.getLogger(None)
+        cflogger.addHandler(self)
+
+    def emit(self, record):
+        fmt = '%(levelname)s:%(name)s:%(message)s'
+        formatter = logging.Formatter(fmt)
+        #
+        # Calling .emit() on the _update signal will make the callback
+        # we registered in __init__ run.
+        #
+        self._update.emit(formatter.format(record))
+
+    def printText(self, text):
+        logger.debug("[%s]", text)
+        self.syslog.insertPlainText(text + '\n')
+
+    def clear(self):
+        self.syslog.clear()

src/cfclient/ui/tabs/__init__.py

@@ -40,6 +40,7 @@
 from .PlotTab import PlotTab
 from .locopositioning_tab import LocoPositioningTab
 from .QualisysTab import QualisysTab
+from .LogClientTab import LogClientTab
 
 __author__ = 'Bitcraze AB'
 __all__ = []
@@ -56,4 +57,5 @@
     PlotTab,
     LocoPositioningTab,
     QualisysTab,
+    LogClientTab,
 ]

src/cfclient/ui/tabs/logClientTab.ui

@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>Form</class>
+ <widget class="QWidget" name="Form">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>693</width>
+    <height>463</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Form</string>
+  </property>
+  <layout class="QHBoxLayout" name="horizontalLayout">
+   <item>
+    <layout class="QHBoxLayout" name="horizontalLayout_2">
+     <item>
+      <widget class="QTextEdit" name="syslog"/>
+     </item>
+     <item>
+      <layout class="QVBoxLayout" name="verticalLayout">
+       <item>
+        <widget class="QPushButton" name="_clearButton">
+         <property name="text">
+          <string>Clear</string>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <spacer name="verticalSpacer">
+         <property name="orientation">
+          <enum>Qt::Vertical</enum>
+         </property>
+         <property name="sizeHint" stdset="0">
+          <size>
+           <width>20</width>
+           <height>40</height>
+          </size>
+         </property>
+        </spacer>
+       </item>
+      </layout>
+     </item>
+    </layout>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>