[Sugar-devel] [PATCH] Add cpu and memory resource indicator to frame

[anishmangal2002]

This patch adds an icon to the frame, whose palette
menu displays the memory and cpu resources. For computing
free memory, the code reads the /proc/meminfo file (thanks
quozl) and for computing cpu usage, the code reads the
/proc/stat file.

The palette menu entries are only updated (in one second
intervals) when the palette menu is visible thus
possibly saving cpu cycles.

Signed-off-by: anishmangal2002 <anishmangal2002 at gmail.com>
---
 extensions/deviceicon/Makefile.am  |    3 +-
 extensions/deviceicon/resources.py |  188 ++++++++++++++++++++++++++++++++++++
 2 files changed, 190 insertions(+), 1 deletions(-)
 create mode 100644 extensions/deviceicon/resources.py

diff --git a/extensions/deviceicon/Makefile.am b/extensions/deviceicon/Makefile.am
index 8a2e765..038c059 100644
--- a/extensions/deviceicon/Makefile.am
+++ b/extensions/deviceicon/Makefile.am
@@ -5,4 +5,5 @@ sugar_PYTHON = 		\
 	battery.py	\
 	network.py	\
 	speaker.py	\
-	volume.py
+	volume.py	\
+	resources.py
diff --git a/extensions/deviceicon/resources.py b/extensions/deviceicon/resources.py
new file mode 100644
index 0000000..7503bef
--- /dev/null
+++ b/extensions/deviceicon/resources.py
@@ -0,0 +1,188 @@
+# Copyright (C) Anish Mangal <anishmangal2002 at gmail.com>
+#
+# 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 St, Fifth Floor, Boston, MA  02110-1301  USA
+
+from gettext import gettext as _
+import logging
+import os
+
+import gobject
+import gtk
+import gconf
+
+from sugar.graphics.tray import TrayIcon
+from sugar.graphics.xocolor import XoColor
+from sugar.graphics.palette import Palette
+from sugar.graphics import style
+
+from jarabe.frame.frameinvoker import FrameWidgetInvoker
+
+class DeviceView(TrayIcon):
+
+    FRAME_POSITION_RELATIVE = 500
+
+    def __init__(self):
+        client = gconf.client_get_default()
+        color = XoColor(client.get_string('/desktop/sugar/user/color'))
+        TrayIcon.__init__(self, icon_name='computer', xo_color=color)
+        self.set_palette_invoker(FrameWidgetInvoker(self))
+
+    def create_palette(self):
+        palette = ResourcePalette(_('System resources'))
+        palette.set_group_id('frame')
+        return palette
+
+class ResourcePalette(Palette):
+
+    def __init__(self, primary_text):
+        Palette.__init__(self, label=primary_text)
+
+        self._popup_cb_id = self.connect('popup', self._popup_cb)
+        self._popdown_cb_id = self.connect('popdown', self._popdown_cb)
+
+        self.vbox = gtk.VBox()
+        self.set_content(self.vbox)
+
+        self._cpu_text = gtk.Label()
+        self.vbox.pack_start(self._cpu_text, padding=style.DEFAULT_PADDING)
+        self._cpu_text.show()
+
+        self._cpu_bar = gtk.ProgressBar()
+        self._cpu_bar.set_size_request(
+            style.zoom(style.GRID_CELL_SIZE * 4), -1)
+        self.vbox.pack_start(self._cpu_bar, padding=style.DEFAULT_PADDING)
+        self._cpu_bar.show()
+
+        self._memory_text = gtk.Label()
+        self.vbox.pack_start(self._memory_text, padding=style.DEFAULT_PADDING)
+        self._memory_text.show()
+
+        self._memory_bar = gtk.ProgressBar()
+        self._memory_bar.set_size_request(
+            style.zoom(style.GRID_CELL_SIZE * 4), -1)
+        self.vbox.pack_start(self._memory_bar, padding=style.DEFAULT_PADDING)
+        self._memory_bar.show()
+
+        self.vbox.show()
+
+        try:
+            self._cpu_times = self._get_cpu_times_list()
+        except Exception:
+            logging.exception('An error ocurred while attempting to '
+                'read /proc/stat')
+            self._remove_callbacks()
+
+    def _get_cpu_times_list(self):
+        """Return various cpu times as read from /proc/stat
+
+        This method returns the following cpu times measured
+        in jiffies (1/100 of a second for x86 systems)
+        as an ordered list of numbers - [user, nice,
+        system, idle, iowait] where,
+
+        user: normal processes executing in user mode
+        nice: niced processes executing in user mode
+        system: processes executing in kernel mode
+        idle: twiddling thumbs
+        iowait: waiting for I/O to complete
+
+        Note: For systems having 2 or more CPU's, the above
+        numbers would be the cumulative sum of these times
+        for all CPU's present in the system.
+
+        """
+        return [int(count)
+           for count in file('/proc/stat').readline().split()[1:6]]
+
+    def _percentage_cpu_available(self):
+        """
+        Return free CPU resources as a percentage
+
+        """
+        _cpu_times_new = self._get_cpu_times_list()
+        _cpu_times_current = [(new - old)
+            for new, old in zip(_cpu_times_new, self._cpu_times)]
+        user, nice, system, idle, iowait = _cpu_times_current
+        cpu_free = (idle + iowait) * 100.0 / sum(_cpu_times_current)
+        self._cpu_times = self._get_cpu_times_list()
+        return cpu_free
+
+    def _percentage_memory_available(self):
+        """
+        Return free memory as a percentage
+
+        """
+        for line in file('/proc/meminfo'):
+            name, value, unit = line.split()[:3]
+            if 'MemTotal:' == name:
+                total = int(value)
+            elif 'MemFree:' == name:
+                free = int(value)
+            elif 'Buffers:' == name:
+                buffers = int(value)
+            elif 'Cached:' == name:
+                cached = int(value)
+            elif 'Active:' == name:
+                break
+        return (free + buffers + cached) * 100.0 / total
+
+    def __timer_cb(self):
+        try:
+            cpu_free = self._percentage_cpu_available()
+            memory_free = self._percentage_memory_available()
+            self._cpu_text.set_label(_('CPU free: %d%%' % cpu_free))
+            self._cpu_bar.set_fraction(cpu_free/100.0)
+            self._memory_text.set_label(_('Memory free: %d%%' % memory_free))
+            self._memory_bar.set_fraction(memory_free/100.0)
+            return True
+        except Exception:
+            logging.exception('An error ocurred while trying to '
+                'retrieve resource usage statistics')
+            self._remove_callbacks()
+            return False
+
+    def _remove_callbacks(self):
+        """
+        Stop computing usage statistics and display and error message
+        since we've hit an exception.
+
+        """
+        self.disconnect(self._popup_cb_id)
+        self.disconnect(self._popdown_cb_id)
+
+        # Use the existing _cpu_text label to display the error. Remove
+        # everything else.
+        self._cpu_text.set_size_request(
+            style.zoom(style.GRID_CELL_SIZE * 4), -1)
+        self._cpu_text.set_line_wrap(True)
+        self._cpu_text.set_text(_('Cannot compute CPU and memory usage '
+            'statistics!'))
+        self.vbox.remove(self._cpu_bar)
+        self.vbox.remove(self._memory_text)
+        self.vbox.remove(self._memory_bar)
+
+    def _popup_cb(self, gobject_ref):
+        self.__timer_cb()
+        self._timer = gobject.timeout_add(2000, self.__timer_cb)
+
+    def _popdown_cb(self, gobject_ref):
+        gobject.source_remove(self._timer)
+
+def setup(tray):
+    if not (os.path.exists('/proc/stat') and os.path.exists('/proc/meminfo')):
+        logging.warning('Either /proc/stat or /proc/meminfo not present. Not '
+            'adding the CPU and memory usage icon to the frame')
+        return
+    tray.add_device(DeviceView())
-- 
1.7.1