一不小心又是大概有一年多时间没有用过Django了。最近经常有之前部门的同事来讨论Django和Python Web开发，大概是他们用asp做的客服系统终于要换架构了。今天国庆提前放假，用了一个下午的时间重温一下。Django的Template还是相对弱一些，居然无法在template里调用model的方法。这样auth模块里判断用户登录的is_authticated()方法就不能在template里调，如此非得在view判断（Django是MTV模型，它的view即MVC里的controller），那如果是用generic_view，这个似乎就无解了？？
贴个图。体验一下Firefox3.5开始支持的@font-face，Webkit核心和Opera浏览器都支持这个功能。不过我Ubuntu上的Midori貌似遇到Mootools就直接崩溃，看来要等到gnome2.28里epiphany了。
忘了提了，域名是我yy的，之所以有这样的效果是修改了hosts
半年没碰那个首页了，最近看到commandlinefu提供了jsonp接口，顺手把commandlinefu加了进来：
Classicning7.clifu();
这个程序是去年此时还在用JavaScript工作的时候写的，隔了一年再看，很难不感慨啊。话说，大家要是发现一些好玩的，好用的JSONP服务可以分享一下。
以下是今天的闲言碎语。
洗完澡回来补一枪，上周买了一本这个，周五在火车上看了前面一两章，感觉还不错，尤其是压力测试方面解决了我最近的一些疑问。同时我也感觉到写这么一本书确实要有一大瓶水和可观的时间和精力，这个还是很难的。熟悉俺的人都知道出本误人子弟的书是俺长久以来的梦想，不过看了这位28本书的作者的状况，我这个梦想离照进现实还是有距离的。
After I post my command to commandlinefu.com, there is an alternative command followed:
(echo “set terminal png;plot ‘-’ u 1:2 t ‘cpu’ w linespoints;”; sudo vmstat 2 10 | awk ‘NR > 2 {print NR, $13}’) | gnuplot > plot.png
This one is appreciated for using pipes and redirection. It works on Ubuntu Jaunty, on which, gnuplot doesn’t provide a -e option. The author also showed an link to an open source project ‘vmplot’ on freshmeat. Vmplot is written in python, which combines parameters with scripts and end up with an os.system call. Grab the source from here. (Why use python instead on a simple bash command? because it’s difficult to draw a multiplot without temp file or variables, you cannot read ‘-’ twice.)
There are several people vote me down for my command! It must be primers whose use ubuntu and knows the world via Synaptic only, because they failed to run the command on their dated machine (*_*)
Gnuplot is considered to be one of the most famous plotting tools on both linux and windows. With Gnuplot, generation of charts becomes agile and easy. Gnuplot supports sorts of terminals range from gui, image to printer. To enable png terminal support, we will build gnuplot with following steps. (However, on most linux distributions you don’t have to do these manually, install gnuplot with package manager is doubtlessly the best choice for most cases.)
Well, for a naked machine, it won’t be too long to type commands in gnuplot.
linpng provides functionality to write png images.
Grab source form libpng’s website:
wget http://downloads.sourceforge.net/project/libpng/00-libpng-stable/1.2.39/libpng-1.2.39.tar.gz?use_mirror=ncu
Uncompress the package:
tar xfz libpng-1.2.39.tar.gz
cd to result directory and build it:
cd libpng-1.2.39
./configure
make
make install
gd provides api for programmer to draw images like Graphics2d in java. Gnuplot uses gd to draw charts on images.
Grab source from gd’s website:
wget http://www.libgd.org/releases/gd-2.0.35.tar.gz
Uncompress it:
tar xfz gd-2.0.35.tar.gz
build it:
cd gd-2.0.35
./configure
make
make install
Grab source from sourceforge:
wget http://downloads.sourceforge.net/project/gnuplot/gnuplot/4.2.6/gnuplot-4.2.6.tar.gz?use_mirror=ncu
Uncompress and compile:
tar xfz gnuplot-4.2.6.tar.gz
cd gnuplot
./configure
make
make install
if “‘@LIBICONV@’ not found” encountered during make, just edit src/Makefile to replace -l@LIBICONV@ to -liconv, and make again.
Try to start gnuplot simply with:
gnuplot
Now you may be stopped by error message like libiconv.so.2 not found, then you have to copy it from somewhere(such as /usr/local/lib) to /usr/lib, the it will work.
As the installation completed, we start to use it.
vmstat is a great utility shows you the status of your process queue, memory, swap, io rates, interrupts and cpu usage. With command-line arguments, we can dump these data in a fixed interval and fixed count:
vmstat 5 10
awk is a well-known editor to analyze and extract text from input, we can filter specified fields with awk like this:
vmstat 5 10 | awk ‘NR > 2 {print NR-2, $13}’
The header was ignored by the conditional expression NR>2 which NR stands for Number-of-Row
The output is just enough for gnuplot, now use pipe to connect them together:
vmstat 5 10 | awk ‘NR > 2 {print NR, $13}’ | gnuplot -e “set terminal png; set output ‘v.png’; plot ‘-’ u 1:2 t ‘cpu’ w linespoints;”
To gather more information at one time, a more complex command is needed:
vmstat 10 360 | awk ‘NR > 2 {print NR, $4, $9, $10, $13}’ > vmstat.dat ; gnuplot -e “set terminal png;set output ‘vmstat.png’;set grid; set multiplot;set size 0.5, 0.5;set origin 0, 0;plot ‘vmstat.dat’ u 1:2 t ‘freemem’ w linespoints;set size 0.5, 0.5;set origin 0.5, 0;plot ‘vmstat.dat’ u 1:3 t ‘bi’ w linespoints;set size 0.5, 0.5;set origin 0, 0.5;plot ‘vmstat.dat’ u 1:4 t ‘bo’ w linespoints;set size 0.5, 0.5;set origin 0.5, 0.5;plot ‘vmstat.dat’ u 1:5 t ‘cpu’ w linespoints;unset multiplot;”
Unfortunately, gnuplot in Ubuntu jaunty is at version of 4.2.4, which doesn’t support -e option. So you cannot send gnuplot commands directly in command-line. The solution is split it to several steps:
vmstat 10 360 | awk ‘NR > 2 {print NR, $4, $9, $10, $13}’ > vmstat.dat
gnuplot
>set terminal png;
>set output ‘vmstat.png’;
>set grid;
>set multiplot;
>set size 0.5, 0.5;
>set origin 0, 0;
>plot ‘vmstat.dat’ u 1:2 t ‘freemem’ w linespoints;
>set size 0.5, 0.5;
>set origin 0.5, 0;
>plot ‘vmstat.dat’ u 1:3 t ‘bi’ w linespoints;
>set size 0.5, 0.5;
>set origin 0, 0.5;plot ‘vmstat.dat’ u 1:4 t ‘bo’ w linespoints;
>set size 0.5, 0.5;
>set origin 0.5, 0.5;
>plot ‘vmstat.dat’ u 1:5 t ‘cpu’ w linespoints;
>unset multiplot;
This picture is a stat result of performance test this afternoon
For more detailed tutorials, check the article on ibm dw:
http://www.ibm.com/developerworks/library/l-gnuplot/