Install Celery on CentOS6

1. insall epel (ref-link)

2. install erlang
#yum install erlang

3. install rabbitmq
  a. download rabbitmq rpm (link)
  b. install:
    #rpm -Uvh rabbitmq-xxxx.rpm
  c. let rabbitmq daemon auto-start on boot up:
    #chkconfig rabbitmq-server on
  d. start rabbitmq server:
    #service rabbitmq-server start

4. install Celery
#easy_install Celery

5. install django-celery
#easy_install django-celery

6. setting up django-celery on project (link)

using mod_wsgi deploy django project

1. install httpd-devel, python-devel
# yum install htppd-devel, python-devel

2. install mod_wsgi
  a. Download mod_wsgi source code. modwsgi
  b. untar & using ./configure; make; make install

3. edit /etc/httpd/conf/httpd.conf
LoadModule wsgi_module modules/mod_wsgi.so
WSGIScriptAlias /mysite /usr/local/www/mysite/apache/django.wsgi

4. Create django project
#cd /usr/local/www
#django-admin.py startproject mysite

5. create apache folder
# cd /usr/loca/www/mysite
# mkdir apache

6. Create django.wsgi file in apache folder, the content is:

import os
import sys
path = '/usr/local/www'
if path not in sys.path:
    sys.path.append(path)

os.environ['DJANGO_SETTINGS_MODULE'] = 'mysite.settings'

import django.core.handlers.wsgi
application = django.core.handlers.wsgi.WSGIHandler()

7. restart httpd

8. open brower and open link: http://localhost/mysite

Reference:
http://code.google.com/p/modwsgi/wiki/QuickInstallationGuide
http://code.google.com/p/modwsgi/wiki/QuickConfigurationGuide
https://docs.djangoproject.com/en/1.3/howto/deployment/modwsgi/

python with statement

python 2.5支援with statement,用法像這樣,以open file為例:

printf("xxxx");
with open("x.txt") as f:
  data = f.read()
  do something with data

  因為file object已經有了__enter__()和__exit__()這兩個method,利用with statement就能自動達到像是try-except-finally的程式流程

  若自定class implement __enter__(self)和__exit__(self, type, value, traceback)也能利用with statement來簡化

參考資料:
http://effbot.org/zone/python-with-statement.htm
http://effbot.org/pyref/with.htm

解決yum update perl conflict問題

若yum update perl發生
conflicts with file from package perl.x.x.x
用rpm -e移除perl.i386 (若妳的CentOS是x64)
rpm -e perl.i386
在執行yum update perl應該就不會發生conflicts了

參考資料:
http://slash4.de/tutorials/CentOS_5.4_perl_update_problem

vsftpd ipv6 setup

讓vsftpd service 可用ipv6 address連線 (環境: CentOS 5.X)

1. 編輯 /etc/vsftpd/vsftpd.conf
listen=NO #關掉ipv4-only sockets
listen_ipv6=YES #打開ipv4 ipv6相容的模式

2. restart vsftpd
# service vsftpd restart

linux bash getopt

getopt 是 shell 裡抓參數的好工具
例: getopt abc:d: 容許參數 -a -b -c -d, -c and -d 後面要接參數

#!/bin/sh
set - `getopt abc:d: $*`
while true; do
  case $1 in
    -a) echo option -a
      shift ;; 
    -b) echo option -b
      shift ;; 
    -c) echo option -c=$2
      shift 2 ;; 
    -d) echo option -d=$2
      shift 2 ;; 
    --) shift
      break ;; 
    *) echo "error!"
      exit 1 ;; 
  esac
done

執行結果 
# ./go -a
option a
# ./go -c jack
option -c=jack
# ./go -b -c jack
option -b
option -c=jack
# ./go -b -c test -d
getopt: option requires an argument -- d
option -b
option -c=test
(使用後面要加參數的 option 會提示)
# ./go -b -c test -f
getopt: invalid option -- f
option -b
option -c=test
(使用未支援的參數會提示)

 http://pank.org/blog/2004/05/getopt-example.html

python join

把string的list join成一個string

tmp = ["a", "b", "c", "d"]
" ".join(tmp)
a b c d

http://stackoverflow.com/questions/3627270/python-how-exactly-can-you-take-a-string-split-it-reverse-it-and-join-it-back