Merge pull request realpython#296 from tommy3001/master

Kenneth Reitz · Kenneth Reitz · commit a59c581d3679 · 2013-07-30T11:43:15.000-07:00
Psutil system resources library added to scenarios/admin
diff --git a/docs/scenarios/admin.rst b/docs/scenarios/admin.rst
@@ -120,6 +120,60 @@ State files can be written using YAML, the Jinja2 template system or pure python
 
     `Salt Documentation <http://docs.saltstack.org/en/latest/index.html>`_
 
+
+Psutil
+------
+`Psutil <https://code.google.com/p/psutil/>`_ is an interface to different system information (e.g. CPU, memory, disks, network, users and processes).
+
+Here is an example to be aware of some server overload. In case of some failed test (net, CPU) it send an email.
+
+.. code-block:: python
+
+    # Functions to get system values:
+    from psutil import cpu_percent, net_io_counters
+    # Functions to take a break:
+    from time import sleep
+    # Package for email services:
+    import smtplib
+    import string
+    MAX_NET_USAGE = 400000
+    MAX_ATTACKS = 4
+    attack = 0
+    counter = 0
+    while attack <= MAX_ATTACKS:
+        sleep(4)
+        counter = counter + 1
+        # Check the cpu usage
+        if cpu_percent(interval = 1) > 70:
+            attack = attack + 1
+        # Check the net usage
+        neti1 = net_io_counters()[1]
+        neto1 = net_io_counters()[0]
+        sleep(1)
+        neti2 = net_io_counters()[1]
+        neto2 = net_io_counters()[0]
+        # Calculate the bytes per second
+        net = ((neti2+neto2) - (neti1+neto1))/2
+        if net > MAX_NET_USAGE:
+            attack = attack + 1
+        if counter > 25:
+            attack = 0
+            counter = 0
+    # Write a very important email if attack is higher then 4
+    TO = "you@your_email.com"
+    FROM = "webmaster@your_domain.com"
+    SUBJECT = "Your domain is out of system resources!"
+    text = "Go and fix your server!"
+    BODY = string.join(("From: %s" %FROM,"To: %s" %TO,"Subject: %s" %SUBJECT, "",text), "\r\n")
+    server = smtplib.SMTP('127.0.0.1')
+    server.sendmail(FROM, [TO], BODY)
+    server.quit()
+
+
+A full terminal application like a widely extended top which is based on psutil and with the ability of a client-server
+monitoring is `glance <https://github.com/nicolargo/glances/>`_.
+
+
 Chef
 ----
 
diff --git a/docs/scenarios/imaging.rst b/docs/scenarios/imaging.rst
@@ -9,66 +9,20 @@ Python Imaging Library
 ----------------------
 
 The `Python Imaging Library <http://www.pythonware.com/products/pil/>`_, or PIL
-for short, is *the* library for image manipulation in Python.
+for short, is *the* library for image manipulation in Python. Unfortunately, its
+development has stagnated, with its last release in 2009.
 
-It works with Python 1.5.2 and above, including 2.5, 2.6 and 2.7. Unfortunately,
-it doesn't work with 3.0+ yet.
+Lucky for you, there's an actively-developed fork of PIL called `Pillow <http://python-imaging.github.io/>`_ -
+it's easier to install, runs on all operating systems, and supports Python 3.
 
 Installation
 ~~~~~~~~~~~~
 
-PIL has a reputation of not being very straightforward to install. Listed below
-are installation notes on various systems.
+Before installing Pillow, you'll have to install Pillow's prerequisites. Find
+the instructions for your platform `here <https://pypi.python.org/pypi/Pillow/2.1.0#platform-specific-instructions>`_.
 
-Also, there's a fork named `Pillow <http://pypi.python.org/pypi/Pillow>`_ which is easier
-to install. It has good setup instructions for all platforms.
-
-Installing on Linux
-~~~~~~~~~~~~~~~~~~~
-
-Arch Linux
-``````````
-
-PIL is maintained in the official community repository, and installed with the system installer as:
-
-.. code-block:: bash
-
-    $ sudo pacman -S python2-imaging
-
-Ubuntu 12.10
-````````````
-
-Can be installed on the command line as:
-
-.. code-block:: bash
-
-    $ sudo apt-get install python-imaging
-
-
-Installing on Mac OS X
-~~~~~~~~~~~~~~~~~~~~~~
-
-PIP doesn't know about the Mac OS X Freetype paths. To rectify that:
-
-.. code-block:: bash
-
-    $ ln -s /usr/X11/include/freetype2 /usr/local/include/
-    $ ln -s /usr/X11/include/ft2build.h /usr/local/include/
-    $ ln -s /usr/X11/lib/libfreetype.6.dylib /usr/local/lib/
-    $ ln -s /usr/X11/lib/libfreetype.6.dylib /usr/local/lib/libfreetype.dylib
-
-then:
+After that, it's straightforward:
 
 .. code-block:: bash
 
-    $ brew install libjpeg
-    $ pip install PIL
-
-
-Installing on Windows
-~~~~~~~~~~~~~~~~~~~~~
-
-.. todo::
-    Notes on installing on Windows machines
-
-
+    $ pip install Pillow
diff --git a/docs/scenarios/web.rst b/docs/scenarios/web.rst
@@ -319,7 +319,7 @@ to use.
     import tornado.ioloop
     import tornado.web
 
-    # Load tamplate file templates/site.html
+    # Load template file templates/site.html
     TEMPLATE_FILE = "site.html"
     templateLoader = FileSystemLoader( searchpath="templates/" )
     templateEnv = Environment( loader=templateLoader )
