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利用 Vagrant 開發 g0v.tw 專案

2013-06-01T19:07:00+08:00

前言

因為每次 g0v.tw 黑客松時，鄉民都化太多時間在設定專案開發環境，所以後來有個發想，看能不能用 Vagrant簡化這些步驟。

什麼是 Vagrant

Vagrant 是 VirtualBox,這類虛擬機器的自動化程式，ihower 在OSDC.TW 演講的投影片 - A brief introduction to Vagrant – 原來 VirtualBox 可以這樣玩已介紹得很完整，如果沒聽過Vagrant可以先看完投影片再繼續。

使用流程

這邊以在linux或mac下開發 hack.g0v.tw 為例, Windows 的使用者可以看這篇

下載專案源碼跟 g0v專用Vagrant Box.

事先先把 VirtualBox 跟 Vagrant 裝好，再打開Sehll執行下面的指令即可.

$ vagrant box add g0v https://dl.dropboxusercontent.com/u/4339854/g0v/g0v-ubuntu-precise64.box
$ git clone git@github.com:g0v/hack.g0v.tw.git

準備開始開發，啟動VM

$ cd hack.g0v.tw
$ vagrant up

這樣 hack.g0v.tw 的工作環境就準備好了，打開瀏覽器連到localhost:6978就可以看到hack.g0v.tw的網頁。(web server 在vm執行)。

工作完畢，關掉VM

$ vagrant suspend

如何製作 Base Box

Ubuntu 官方有提供 Cloud Image的 Vagrant Box, 所以若沒什麼太特別的需求，可以這個做為Base, 再自己寫一個 Vagrantfile 重新 package 一個新的Box.

$ vagrant add cloud-precise64
http://cloud-images.ubuntu.com/precise/current/precise-server-cloudimg-vagrant-amd64-disk1.box

產生Vagrantfile

$ vagrant init

修改一些設定，決定VM啟動後要做什麼事

$ vi Vagrantfile

啟動VM

$ vagrant up

將當前VM重新打包

$ vagrant package --output g0v-ubuntu-precise64.box

幹掉目前啟動的VM

$ vagrant destroy

如何撰寫給專案用的 Vagrantfile

執行vagrant init 會得到一個Vagrantfile的樣板, Vagrant 支援 shell, chef, puppet 做自動化佈署，但如果專案不是太複雜，用 shell 就差不多了。

像 hack.g0v.tw 要做的只是開機後，切到專案原碼目錄去跑安裝程式。Vagrantfile of hack.g0v.tw

# a known issue that symbolic link can not be created in virtualbox
#  shared fold
# we have to workround npm modules installaltion.
  $script = <<SCRIPT
  cp -arf /vagrant /tmp
  cd /tmp/vagrant
  npm i
  cp -r node_modules /vagrant
  cd /vagrant
  npm run start
  SCRIPT

註: 因為在Shared Fold裡面不能建立symbolic link，所以 npm module安裝可能會失敗，目前我的解法是先把Shared Fold 複製到某個地方，裝完後再把裝好的函式庫放回去。

Binding and Assignment

2013-02-09T14:46:00+08:00

所謂的 Functional Language 的變數不可改其實是不精確的。實際上它只是將變數分的更嚴謹，可修改，與不可修改。

先來說說什麼是 Binding. Binding 指的是將一個符號綁定在一個值，綁定後就不可修改，這個符號稱之為變數。以自然語言來理解的話，其實就是代名詞。

favonia: 一個變數沒有指到一個值。一個變數可以被一個值取代，但不會儲存什麼內容在裡面。

所以說下面這個例子，必須理解為3.14的另一個稱呼叫做 PI, 而不是 PI 這個容器的值是 3.14。而 1 + PI 這個式子的另一個稱呼是 result, 而不是 1 + PI 運算後，將值放到 result 這個容器裡。不管是PI，還是 result 都只是個代稱，而不是容器。

PI = 3.14
result = 1.0 + PI

接下來搭配 SML 來解釋什麼是 Assignment。下面這段 code 是說 PI 是 3.14的binding, result 是 1 + PI 的binding。程式執行時(runtime) 會把 PI 這個變數代換成3.14。

val PI = 3.14
val result = 1.0 + PI

那如果需要可修改的變數怎麼辦，SML 可以讓變數綁在值的的指標上, ref 3.14 指的是 3.14 這個值得指標指標。而因為指標指定的值是可以變的，所以現在 PI 可以當成是可以修改的。 PI := 4 只是讓 PI 的值(也就是指標) 從 3.14 指到 4，並不會產生新的binding。

val PI = ref 3.14 # binding
val result = 1.0 + PI # binding
val PI := 4 # assign

因此，在所有的 imperative language 裡，不管是Python, Ruby, C, Java, 變數其實都是被綁在指標上，這樣變數指到的值才能被修改。

所以說，變數只是個值的代稱，如果值是指標，那麼就可以修改指標要指到哪個值，反之則不行。但不管怎麼說，變數都不應該被當成是一個容器。

台南SA10月份 - Be Pythonic

2012-10-24T21:26:00+08:00

好幾年答應CYJ在SA講一場，結果到了他退伍後我都沒講過一次 XD 這次透過CYJ，而有機會在台南SA分享, 簡報呢，一樣是依照慣例在演講前晚開始趕工, 結果大綱跟之前宣傳的完全不一樣。

為什麼會這樣呢? 我想主要是之前列的大綱還是太過highlevel, 所以我很難將他轉成簡報, 後來我在網路上找到一份CC license 的投影片，便以之為基底製作.

由於沒講過3小時的Talk, 所以很怕講不到三小時，因此投影片弄到快100張，結果當天講到2/3，且第二段的decorator幾乎是用帶過去的。

後來Jserv 跟我分享了一下演講的技巧，其實我簡報可以不用這麼多，只需要列出當天要講的大綱，之後在臨場發揮就可以了。

anyway, 附上投影片，這次的主題是 Be Pythonic, 主要是說明寫python時，怎樣會比較像在寫python，而不是其他語言。

PyCon.JP 2012

2012-10-24T20:50:00+08:00

今年一樣又投了(PyCon.JP 2012)1，跟往年不一樣這次比較偏重Python本身的特性，而非介紹自己的專案這類應用性質比較高的主題。

這次去的台灣人不少，大概有11個人吧，包括我在內則有3個人有給Talk。地點則跟去年一樣，還是在品川大，議程跟參加人數都較往年多，甚至多了一軌專門給英文演講。

還滿喜歡這種邊演講邊旅行的生活，但是好累啊 XD

最後附上投影片, 主要是說明Python 的 Type 跟 Object

coscup 2012 簡報檔釋出

2012-08-22T19:25:00+08:00

因為看錯時間把30分鐘要講得東西在20分鐘內說完，所以前20分鐘很多東西都快速帶過, 後10分鐘都在補講。節奏被打亂得亂七八糟。然後，下台後馬上就被 Thinker 說我塞太多東西在30分鐘內了。

用來說明概念的素材

Create a new instance of an object

Python

(coscup2012_new_instance.py) download

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright (C) 2012  Hsin-Yi Chen

# Author(s): Hsin-Yi Chen <ossug.hychen@gmail.com>

# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.

# To define a class object
class MyClass(object):

  def __init__(self, instance_attr):
      self.attr = instance_attr;   

# MyClass's constructor
print MyClass.__init__

# MyClass's Class is type
print type(MyClass)

# To create a new instance of 
# MyClass 
obj = MyClass.__new__(MyClass)

# To initial the new instance 
MyClass.__init__(obj, 'Attr bound on the instance')

# The result is Attr bound on the instance
print obj.attr

# The base class of MyClass is <type 'object'>
print MyClass.__base__


obj = MyClass('hi')
print obj.attr

JavaScript

(coscup2012_new_instance.js) download

/*                                                                                                                                                                                             
# Copyright (C) 2012  Hsin-Yi Chen

# Author(s): Hsin-Yi Chen <ossug.hychen@gmail.com>

# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
*/

// To define a function object as a Class
function MyClass(instance_attr){
  this.attr = instance_attr;
}

// To bind this to new instance and then execute MyClass
// function.
obj = new MyClass('Attr Bound on the instance');

// The output is Attr Bound on the instance
console.log(obj.attr);

// create a new instance of MyClass prototype
// run MyClass to initial obj
obj2 = Object.create(MyClass);

// The output is No!!!
MyClass.call(obj2, 'No!!!');

// The output is Attr Bound on the instance
console.log(obj2.attr);

// MyClass's constructor is [Function: MyClass]
console.log(MyClass.constructor);

// MyClass's prototype is Object
console.log(typeof(MyClass));

// The prototype of function object is {}, so
// the prototype of MyClass and instances of MyClass
// is also {}
console.log(MyClass.prototype);
console.log(obj.__proto__);

Base Object

Python

(coscup2012_base_obj.py) download

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright (C) 2012  Hsin-Yi Chen

# Author(s): Hsin-Yi Chen <ossug.hychen@gmail.com>

# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
class NewBase(object):
  pass

class MyClass(object):
  pass

obj = MyClass()

# Use NewBase class to instead of object class, 
# but __base__ is readonly 
MyClass.__base__ = NewBase

obj2 = MyClass()

JavaScript

(coscup2012_base_obj.js) download

/*                                                                                                                                                                                         # Copyright (C) 2012  Hsin-Yi Chen

# Author(s): Hsin-Yi Chen <ossug.hychen@gmail.com>

# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
*/
function MyClass(){
}

obj = new MyClass();

// undefined
console.log(obj.name);

// change prototype to another object 
MyClass.prototype = {'name':'hello'}

obj2 = new MyClass();

// The result is still undefiend
console.log(obj.name);

// But this attribute of new instance is redirect to new prototype
console.log(obj2.name);

Trace Object Creation

JavaScript

(coscup2012_traceObj.js) download

/* 
# Copyright (C) 2012  Hsin-Yi Chen

# Author(s): Hsin-Yi Chen <ossug.hychen@gmail.com>

# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
*/

// Add logger function to functions of prototype
function logged(proto){
  for(prop in proto){
      var fn = proto[prop];
      proto[prop] = function(){
          console.log('-> Enter ' + prop);
          show_args(arguments);
          var ret = fn(arguments[0]);
          console.log('   Return: ' + ret);
          console.log('-> Exit ' + prop);
          return ret;
      };
  }
  return proto;
}

function show_args(args){
  for(var i=0; i<args.length;i++){
      console.log('      args:' + args[i]);
  }
}

function tail(list){
  var ret = new Array();
  for(var i=1;i<list.length;i++){
      ret[i-1] = list[i];
  }
  return ret;
}

// create traceable object based on a object
function new_traced_obj(base_obj){
  myargs = tail(arguments);
  console.log(base_obj.name);
  // create new function object
  var traced_obj = function(){
      console.log('-> Enter constructor');
      show_args(myargs);
      // execute base object constructor
      // on new instance of traced object.
      console.log('     -> Enter ' + base_obj.name);
      base_obj.call(this, myargs[0]);
      console.log('     -> Exit  ' + base_obj.name);
      console.log('<- Exit constructor');
  };
  // set new object's prototype is the base object 
  // prototype
  traced_obj.prototype = logged(base_obj.prototype);
  console.log('-> Enter - create new instance');
  // create new instance of sub object
  var new_inst = new traced_obj();
  console.log('<- Exit  - create new instance');
  return new_inst;
};

// To define a MyClass Function
function MyClass(name){
  this.name = name;
}

// Add add5 function to MyClass's prototype
MyClass.prototype.add5 = function(num){return num+5;};

// Main
instance = new_traced_obj(MyClass, 'M');
console.log('instance.name:'+instance.name);
console.log('=============================');
console.log('instance.add5(3,4): '+instance.add5(3,4));

My slide 'What can meta class do for you' in PyCon Taiwan 2012

2012-06-12T16:55:00+08:00

I had a chance to sharing my study notes of meta class in PyCon Taiwan 2012. It is a 30 minuts talk. The topic is roughly to introduce 5 examples to show meta class is useful and also to gave a conculution that why we use/don’t use it.

the slide is here:

What can meta class do for you? @PyCon Taiwan 2012

View more presentations from HsinYi Chen

Example Codes

Singleton

(metaclass_Singleton.py) download

#!/usr/bin/env python
# vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4
# -*- encoding=utf8 -*-
#
# Author 2012 Hsin-Yi Chen
class Singleton(type):
    def __init__(cls,name,bases,dic):
        super(Singleton,cls).__init__(name,bases,dic)
        cls.instance=None

    def __call__(cls, *args, **kwargs):
            print "please use get_instance function to get the instance"

    def get_instance(cls,*args,**kw):
        if cls.instance is None:
            cls.instance=super(Singleton,cls).__call__(*args,**kw)
        return cls.instance

class _db(object):
    """
    >>> obj=_db()
    please use get_instance function to get the instance
    >>> obj is None
    True
    >>> obj1 = _db.get_instance()
    connecting to 0
    >>> obj2 = _db.get_instance()
    >>> id(obj1) == id(obj2)
    True
    """
    __metaclass__ = Singleton
    session_max = 0

    def __init__(self):
        print 'connecting to {0}'.format(self.session_max)

class MySQL(_db):
    """
    >>> obj1 = MySQL.get_instance()
    connecting to 1000
    >>> obj2 = MySQL.get_instance()
    >>> id(obj1) == id(obj2)
    True
    """
    session_max = 1000

import doctest
doctest.testmod()

Countable

(metaclass_countable.py) download

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright (C) 2012  Hsin-Yi Chen

# Author(s): Hsin-Yi Chen <ossug.hychen@gmail.com>

# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.

# Goal: Class knows the count of its instances.

# metaclass
class Countable(type):

    def __new__(mbs, name, bases, dct):
        cls = type.__new__(mbs, name, bases, dct)
        cls.count = 0
        return cls

    def __call__(cls, *args, **kwargs):
        cls.count += 1
        type.__call__(cls, *args, **kwargs)


# class
class Book(object):
    __metaclass__ = Countable

    def __init__(self, title):
        self.title = title

# run
print 'I have {} books'.format(Book.count)
a=Book('A1')
b=Book('A2')
c=Book('A3')
d=Book('A4')
print 'I have {} books'.format(Book.count)

Class Verification

(metaclass_verification.py) download

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright (C) 2012  Hsin-Yi Chen

# Author(s): Hsin-Yi Chen <ossug.hychen@gmail.com>

# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
def check(cls, inf):
    for attrname in inf.__dict__:
        if attrname.startswith('__'):
            continue
        if not attrname in cls.__dict__.keys():
            msg = 'ERROR: Can not find {} in {}'.format(attrname,
                                                cls.__name__)
            msg = msg.format(cls.__name__, inf.__name__, attrname)
            print msg

class JokeRequirement(object):
    HaHaPoint = None

class HasInterface(type):
    def __new__(mbs, name, bases, dct):
        interface = dct['__implemented__']
        cls = type.__new__(mbs, name, bases, dct)
        check(cls, interface)
        return cls

class JokeRequirement(object):
    HaHaPoint = None

class JokeInPTT(object):
    __metaclass__ = HasInterface
    __implemented__ = JokeRequirement

Delegation

(metaclass_delegation.py) download

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright (C) 2012  Hsin-Yi Chen

# Author(s): Hsin-Yi Chen <ossug.hychen@gmail.com>

# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
class Delegated(type):

    def __new__(mbs, name, bases, dct):
        cls = type.__new__(mbs, name, bases, dct)
        def myget(self, k):
                return getattr(self.context, k)
        def myset(self, k, v):
            if not hasattr(self, 'context'):
                self.__dict__['context'] = v
            if k != 'context':
                setattr(self.context, k, v)
        cls.__getattr__ = myget
        cls.__setattr__ = myset
        return cls

class Wrapper(object):
    __metaclass__ = Delegated
    def __init__(self, context):
        self.context = context

    def dump(self):
        print 'the data is ' + repr(self.data)

class Result(object):
    def __init__(self, **kwargs):
        self.__dict__.update(kwargs)

result = Result(title='man ages', data=[1,2,3,4,5])
wrap_result = Wrapper(result)
wrap_result.dump()
wrap_result.title = 'girl args'
print result.title

Logged

(metaclass_logged.py) download

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright (C) 2012  Hsin-Yi Chen

# Author(s): Hsin-Yi Chen <ossug.hychen@gmail.com>

# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.

# Goal: Log informations to other places.
def info(msg):
    print 'info:'+msg
def error(msg):
    print 'error:'+msg

import functools

# To create a wrapped function
def log(name, fn):
    @functools.wraps(fn)
    def wrap_fn(*args, **kwargs):
        info('Enter func:{}'.format(name))
        try:
            ret = fn(*args, **kwargs)
        except Exception, e:
            error('Raised exception: {}'.format(e.message))
            raise e
        info('Got return value:{}'.format(ret))
        info('Exit func:{}'.format(name))
        return ret
    return wrap_fn

# Add logger decorator for each attr
def add_logger(name, val):
    return callable(val) and log(name, val) or val

# Metaclass
class Logged(type):

    def __new__(mbs, name, bases, dct):
        # if attr is callable log it.
        dct = {k:add_logger(k, v) for k,v in dct.items()}
        cls = type.__new__(mbs, name, bases, dct)
        return cls

# Class
class Person(object):
    __metaclass__ = Logged

    def get(self):
        return "I am get method"

# Run!
if __name__ == '__main__':
    obj =  Person()
    obj.get()

serialized python function object

2012-03-28T20:24:00+08:00

想法

利用marshal把python bytecode轉成string, 就可以pickled.

把Function轉成Pickled string

import pickle
import marshal
maintask_bytecode = marshal.dumps(maintask_callback.func_code)
output = {
  'maintask_bytecode': maintask_bytecode,
  'maintask_defaults': maintask_defaults,
  'maintask_args': maintask_args}
print pickle.dumps(output)

把Pickled string轉成function

import sys
import types
import marshal
import pickle
## \brief reconstruct function from bytecode
#  \param func_bytecode str marshaled bytecode of func_code
#  \param func_default dict func_defaults
#  \return Function
def reconstruct_function(func_bytecode, func_defaults):
    func_code = marshal.loads(func_bytecode)
    return types.FunctionType(func_code, globals(), func_code.co_name,
                             func_defaults)
string = sys.stdin.read()
received = pickle.loads(string)
callback = reconstruct_function(received['maintask_bytecode'],
      received['maintask_defaults'])
print callback(maintask_args)

fix chromium can not play mp4

2012-03-21T01:03:00+08:00

I found my chromium in Ubuntu 11.10 can not play mp4 video. after I googling, the solution is to install chromium-codecs-ffmpeg-extra to solve these problems.

$ apt-get install chromium-codecs-ffmpeg-extra

how to create a custom launchpad bugs report

2012-03-18T04:23:00+08:00

I already use lp-cli to generate reports about one month and think this may benefit someone has the same requirmentation. so here you are.

This document will show

howto collected bugs data with custom search conditions
combine collected bugs data and report template

comments are welcome.

metaclass in Python (1) - Singleton

2012-03-13T01:43:00+08:00

Singleton 這東西大家想必不陌生，在Python裡實做的方式滿多, 這邊用這個當例子介紹 Metaclass 可以做什麼。

概念上很簡當, 讓Class的建構子不能產生Instance, 然後再提供一個 Classmethod 能夠取得Instance(而且只能有一個), 在Python你可以用id來檢查兩個物件是不是相同的。

原則上Singleton我只會用在不用花腦袋就會覺得這個class建出來的instance這個程式執行時只能有一個。

Singleton 的源碼

class Singleton(type):
    def __init__(cls,name,bases,dic):
        super(Singleton,cls).__init__(name,bases,dic)
        cls.instance=None

    def __call__(cls, *args, **kwargs):
      # 這裡不raise Exception, 是因為doctest比較好寫
            print "please use get_instance function to get the instance"
            # 你也可讓cls()直接傳回instance, 讓class user不用在意他用的class
      # 是不是Singleton, 他只要注意class的主功能即可
            # return cls.get_instance(*args, *kw)

    def get_instance(cls,*args,**kw):
        if cls.instance is None:
            cls.instance=super(Singleton,cls).__call__(*args,**kw)
        return cls.instance

用法

把你想變成Singleton class 的 metaclass 設成 Singleton 就可以了，後悔的話，把那一行註解起來，這個class就不是Singleton。

要注意的地方是這class的Singleton特性是可以被繼承的，但這也是為什麼我喜歡用這種方式的原因，另一個好處是Class的功能跟Design Pattern的耦合度會比較低。缺點就是會遇到metaclass衝突的狀況，但也不是不能解決。

class _db(object):
  __metaclass__ = Singleton

完整的源碼加測試

(metaclass_Singleton.py) download

#!/usr/bin/env python
# vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4
# -*- encoding=utf8 -*-
#
# Author 2012 Hsin-Yi Chen
class Singleton(type):
    def __init__(cls,name,bases,dic):
        super(Singleton,cls).__init__(name,bases,dic)
        cls.instance=None

    def __call__(cls, *args, **kwargs):
            print "please use get_instance function to get the instance"

    def get_instance(cls,*args,**kw):
        if cls.instance is None:
            cls.instance=super(Singleton,cls).__call__(*args,**kw)
        return cls.instance

class _db(object):
    """
    >>> obj=_db()
    please use get_instance function to get the instance
    >>> obj is None
    True
    >>> obj1 = _db.get_instance()
    connecting to 0
    >>> obj2 = _db.get_instance()
    >>> id(obj1) == id(obj2)
    True
    """
    __metaclass__ = Singleton
    session_max = 0

    def __init__(self):
        print 'connecting to {0}'.format(self.session_max)

class MySQL(_db):
    """
    >>> obj1 = MySQL.get_instance()
    connecting to 1000
    >>> obj2 = MySQL.get_instance()
    >>> id(obj1) == id(obj2)
    True
    """
    session_max = 1000

import doctest
doctest.testmod()

Will you attend PyCon TW 2012?

2012-02-25T09:41:00+08:00

從兩三年前開始，就不斷有人在喊”那會有Python Conference 嗎”?

尤其是去年有Ruby Con TW 2011, PHP Conf TW 2011…

終於，前陣子PyCon TW 2012 官方網站公佈啦! 活動預計在2012 年 6月9日(六)及10日(日) 假中研院人文館舉辦, 目前正在統計可能參與人數, 請幫忙填問卷

有興趣提供講題的人，請到這裡
有興趣發表論文的人，請到這裡
有興趣提供贊助的公司，請到這裡

用Python的人應該是不少才對, 大家不要在潛水了!

How-To: change string.template's delimiter in runtime

2012-02-13T15:33:00+08:00

這篇文章提到Template因為用到了Metaclass, 因此改Class或是Instance的delimiter是沒作用的, 因為Template的pattern atrtibute 在 class 建構時, 就已經決定好, 於是你只能建立一個class 來繼承他, 把Template.delimiter Overwrite掉, 這樣 Template().delimter 才是你要的, 可我實在懶得為了改delimiter就去寫一個自定義class, 原文的方式我也覺得有點麻煩, 因為要組出完整的pattern

基本上這很好解, 就runtime時產生一個自定義class就好了 :p

   import string
  def create_tpl(content, **tpl_config):
          if tpl_config:
                  tplcls = type('CustomTemplate', (string.Template,), tpl_config)
          else:
                  tplcls = string.Template
          return tplcls(content)

  tpl = create_tpl('#aa', delimiter='#')
  print tpl.substitute(aa=1)

How-to: 輸出已被redirect 到時, 想要把字串印到Terminal

2012-02-10T12:53:00+08:00

最近在寫lp-cli時, 因為stdout已經用來傳遞pickle data到下一個command, 例子如下

# 找出ossug-hychen' 正在處理幾個bug
$ lp-searchbugs people ossug-hychen --status 'In Progress' | lp-print count

所以如果我想要print 一些資訊到terminal 其實是辦不的, 昨日在H4時與Thinker討論時, 他提出了一個辦法

如果要在輸出已被redirect 到時, 想要把字串印到Terminal，可以把訊息寫到 /dev/tty (等於目前的 control terminal)

        # Use TTY for print information or debugging message
        # Use STDOUT for printing MissionMessage
        self.tty_fd = os.open('/dev/tty', os.O_WRONLY)
          self.bk_stdout = os.dup(sys.stdout.fileno())
        os.close(sys.stdout.fileno())
        os.dup(self.tty_fd)
        self.bk_stdout = os.fdopen(self.bk_stdout, 'w')

但是這方法仍有缺點:

stdout 沒辦法被rederiect,
不能用cron, 因為cron沒有tty

meeting room name

2012-01-18T21:10:00+08:00

台北辦公室擴建完畢後, 內部在詢問會議室的命名意見，命名規則很簡單。要有台灣特色且容易翻譯。於是想當然爾眾人的提案不外乎高山、景點、小吃之類的。

因會議室剛好有午間，有同事提議用台灣五院來命名，而且這樣以後辦公室會有下列有趣的對話….

同事A: 等下在哪開會

同事B: 立法院

當然這個提案，不是很被多數人認可，因為英文名字有點太長…

而我自己的提案是台灣高山湖, 這些湖的共同點就是交通不便，需要親力親為上山後方能領略美景。至於象徵意含嘛… 我沒想這麼多。

五個會議室名稱分別如下

嘉明湖 - 海拔3310/11公尺, 素有天使的眼淚之稱七彩湖 - 海拔2980公尺
松蘿湖 - 海拔1300公尺, 素有「十七歲之湖」及「夢幻之湖」之稱
七彩湖 - 海拔2980公尺
白石池 - 海拔2770公尺
翠池 - 海拔3520公尺 , 台灣最高的高山湖泊

註:我還有另一個提案是用台灣36秘境中的5個來命名, 不過目前比較偏好用高山湖泊命名

lp-cli - just another command line tool of Launchpad

2012-01-08T23:11:00+08:00

The web interface of Launchpad is awesome, but it does not provide a function that you can save your search result, or even create a custom bug display list, I believe managers would like this function, especially they want to track each team member status.

I am just a engineer but also have almost the same requirement, here are 3 questions I need to answer in the end of weekend.

Which bugs I worked this week?
Which bugs I need to work next week?
Which bugs are waiting me to fix?

It is better to have a way to always show bugs I am interesting for different purpose, so I start to write a script by using python-launchpadlib.

by the way, another needs is to find bugs and modify attribute(s) of each bug.

python-launchpad

Launchpad has a very friendly python library, I will not talk this too much, if you want to know the details of it, please check these websites.

lp-cli

lp-cli include several tools which is very small and has only one trivial purpose, that is users can use Unix pipeline to combine small tools to archive a complex task.

All work of process data of Launchpad can be simplified as the following

get data from Launchpad
get sub set of data by some conditions
do something on each entry one or multiple times
do something on the final result such as save as a file or print to console

Use Case 1

Create a text file contains bugs I worked is modified this week.

$ lp-searchbugs people ossug-hychen  | \
  lp-view modified_thisweek | \
  lp-print buglist |  \
  lp-save bugs_modified_thisweek.txt

lp-searchbugs people ossug-hychen – find related bugtask of a user that login name is ossug-hychen
lp-view modified_thisweek – get bugs worked by ossug-hychen before and modified this week
lp-print buglist – then print the result in buglist style
lp-save bugs_worked_this_week.txt – then save the result as a file

the view modified_thisweek means the bug worked by anyone since 7 days before as defined here

---
data_getters:
...
        modified_thisweek:
                status: [Fix Committed,
                         Fix Released,
                         In Progress,
                         Incomplete (with response),
                         Incomplete (without response),
                         Triaged,
                         Invalid,
                         Won't Fix,
                         Confirmed]
                modified_since: $date_before_now
...

so if you want to know which bugs is really worked by yourself, we need another tool to limit the scope of result which is not done yet.

Use Case 2

reassign bugs I fixed in project ABC to another people, some time is QA

$ lp-searchbugs project ABC --status 'Fix Committed' --assignee ossug-hychen  | \
  lp-edit --assignee QA

first command is to get bugs fixed by me in project ABC
second command is to reassign each bugs to a QA guy

Available Commands

lp-searchbugs - type:Fetcher, generate a task of searching bugs in launchpad
lp-view - type:View, add extra args to received task (like lp-searchbugs)
lp-print - type:Task Action, execute received task and print the result
lp-save - type:Action, save STDIN to a file
lp-mybugs - shortcut of lp-searchbugs people $your-lp-login-id

because accessing Launchpad takes a lot of time, so the real data fetching work is only executed in Task Action command in my design.

[update]

Tim Chen told me a cool idea I never think about that you can save STDOUT of lp-searchbugs , lp-mybugs or lp-view to a text file

$ lp-mybugs | lp-view plan_nextweek > bugs_I_need_to_work_next_week.view

next time when you want to get the result, just type

$ lp-print buglist <  bugs_I_need_to_work_next_week.view

this behavior is similar what lp-view does, so now you can create any view you want!

Installation

$ add-apt-repository ppa:ossug-hychen/ppa
$ apt-get update
$ apt-get install lp-cli

Thanks

The idea of lp-cli is inspired by my friend Thinker Li’s image downloading tool

decorator of display deprecated warring in Python

2011-12-18T20:24:00+08:00

用途: 用來警告 function 或 class method 已過時，如果有指定取代的function的話，在runtime時改用取代的function

Python 2.7.2+ (default, Oct  4 2011, 20:03:08)
[GCC 4.6.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from vsgui.api import input_text
>>> input_text
<function ask_text at 0x8e0009c>
>>> input_text('input it')
vsgui/api.py:45: DeprecationWarning: Call to deprecated function input_text.; use ask_text instead
  def input_text(*args, **kwargs):

用法一 - 只宣告function已被depreacted, 不指定取代的function

@depreacted() # <- 這一段表示執行deprecated() 取得wrap function
def old1():   # 當old1()被呼叫時，實際上是先呼叫wrap(old1)以取得old1 function, 再執行old()
  print 1

print 'function is '+old1
old1()

執行結果:

function is <function old1 at 0xb7317f44>
recipe-deprecated-warring.py:45: DeprecationWarning: Call to deprecated function old1.
  def old1():
called old1

因為有使用functools.wraps，所以雖然old1 這個變數實際上已繫結在wrap function, 但print時還是會顯示為old1 function

用法二: 除了警告外，還會在runtime時改執行取代depreacted function的新functoin

@depreacted(new1) # <- 這一段表示執行deprecated(new1) 取得wrap
def old2():       # 當old1()被呼叫時，實際上是呼叫wrap(old1) 取得new_func 再執行 new_func
  print 1   # 而new_func會再執行new1，並把*args, **kwargs全數pass給new1

print 'function is '+old2

執行結果

<function new1 at 0xb7292dbc>
source/downloads/code/recipe-deprecated-warring.py:49: DeprecationWarning: Call to deprecated function old2.; use new1 instead
  def old2():
called new1

注意: 目前還不能對class method 指定 replacement method

源始碼

重用了Python Wiki - Smart deprecation warnings , Active Code Stack - deprecated 的部份源碼

(recipe-deprecated-warring.py) download

# took codes from the following:
#
#- [Python Wiki - Smart deprecation warnings ](http://wiki.python.org/moin/PythonDecoratorLibrary#Smart_deprecation_warnings_.28with_valid_filenames.2C_line_numbers.2C_etc..29)
# - [Active Code Stack - deprecated ](http://code.activestate.com/recipes/391367-deprecated/)

import os
import warnings
import functools

# enable to show warring
warnings.simplefilter('default')

def deprecated(replacement=None):
    """This is a decorator which can be used to mark functions
    as deprecated. It will result in a warning being emitted
    when the function is used.

    ref:
        - recipe-391367-1 on active stack code
        - recipe-577819-1 on active stack code

    @replacement function replacement function
    """
    def wrapper(old_func):
        wrapped_func = replacement and replacement or old_func
        @functools.wraps(wrapped_func)
        def new_func(*args, **kwargs):
            msg = "Call to deprecated function %(funcname)s." % {
                    'funcname': old_func.__name__}
            if replacement:
                msg += "; use {} instead".format(replacement.__name__)
            warnings.warn_explicit(msg,
                category=DeprecationWarning,
                filename=old_func.func_code.co_filename,
                lineno=old_func.func_code.co_firstlineno + 1
            )
            return wrapped_func(*args, **kwargs)
        return new_func
    return wrapper

def new1():
    print 'called new1'

@deprecated()
def old1():
    print 'called old1'

@deprecated(new1)
def old2():
    print 'called old1'

if __name__ == '__main__':
    print old1
    old1()
    print old2
    old2()

運作原理

第一個decorator用來產生第二個decorator wrapper
第二個decorator wrapper 用來產生新的function new_func
執行新的function new_func 會先顯示warrning, 最後再把參數傳給要wrapped_func 最後再傳回wrapped_func執行結果
在runtime 時，因為是閉包的關係, 要執行的 wrapped_func 根據decorator wrapper的replacement參數來決定是用來代換的function, 還是原本的function.

下面是抽象化後的源碼

@deprecated()
def _sum(args):
  pass

def deprecated(replacement=None): # 第一個 decorator
  ....
  def real_decorator(original_func): # 第二個 decorator,
                     # 套用在original function 上, 也就是_sum
      ....
      def func_with_warn(*args, **kwargs): # 產生好新function
          ....
          # 顯示warring字串
          ....
          return original_func(*args, **kwargs) # 回傳_sum的執行解果
      return func_with_warn
  return real_decorator

參考資料

使用 dh_python2 製作 python module debian package

2011-12-17T13:36:00+08:00

Debian 官方目前建議改用使用dh_python2取代py_support及py_central, 以下是自己轉換的紀錄。本筆記只適用打包單純的Python module, 並不適合Python module裡面有包含extension.

debian/control

修改Build-Depends及Build-Depends-Indep，改用python-all取代python-support,python-central

Build-Depends: python-all (>= 2.6.6-3), debhelper (>= 7)

移除所有的XB-Python-Version，改使用X-Python-Version 指定支援的Python版本

X-Python-Version: >= 2.5

debian/rules

若 debhelper >= 7, 加上 –with python2

dh $@ --buildsystem=python_distutils --with python2

若 debhelper <= 7

python-support, 執行 sed -i -e 's/dh_pysupport/dh_python2/' debian/rules
python-central, 執行 sed -i -e 's/dh_pycentral/dh_python2/' debian/rules

移除不再使用的檔案

debian/pyversions
debian/pycompat

參考資料

Octopress 程式碼與網站內容的管理

2011-12-04T16:04:00+08:00

草稿 - 尚未完成的文章，不會顯示在網誌上

Octopress 本身並不如 Wordpress一樣提供草稿功能，我與Octopress 搬家記 (2) – 程式碼與網站內容的管裡的作者一樣，還未完成的文章不想出現在我的Blog上。

程式碼及發表的文章，與 compiled HTML 隔離開來，且草稿先不公開。草稿可以放到 dropbox ，而程式碼加上已發表的文章，可以放到 GitHub 公開出來

幸好這樣的需求可以利用git bracnh來達成，而與原文作者不同的是，我採用Octopress原先的設定，Deploy 到 Github 上。

master branch : 產生初來的Blog HTML，也就是 github pages branch
source branch : Octopress 源碼，文章。一旦 Octopress 更新，只要把 Octopress 的 master merge 進來即可

為此我寫了一個小程式來減少重複的動作: Source (alpha version, 易爆)，~~因為這個程式需要 python-ucltip 0.6 以上，而 Ubuntu 目前的版本是0.5-1，所以Ubuntu 的 user 請自己去pypi上抓 source…~~所以我上傳了新版的python-ucltip同時也包了一個ocotopress-admin debian pacakge 給Ubuntu 11.10用，Ubuntu 11.10的使用者請使用下列指令(不過rvm你還是要自己裝啊!!)

add-apt-repository ppa:ossug-hychen/python-ucltip
add-apt-repository ppa:ossug-hychen/ppa
apt-get update
apt-get install octopress-admin

~~p.s 本來想包個 Debian Pacakge ，但Ubuntu 11.10 的 ruby-rvm 太舊了…~~

建立新的Blog:

$ octopress-admin new myblog
$ cd myblog
$ octopress-admin init

從 github 上抓下 Octopress 原始碼
並且安裝需要的bundle (必須事前設定好RVM環境)
執行rake setup_github_page

升級 Blog:

更新Octopress的源碼，本指令並不會影響到遠端的Blog網站，除非你執行octopress-admin deploy

$ octopress-admin upgrade

將最新的 Octopress 源碼合併的 source branch
安裝需要的bundle。

發佈到線上:

$ octopress-admin deploy

checkout source branch
把source branch push 到github `source branch
跑rake generate來重新 compile 整個站
跑rake deploy 丟到 github master branch 上 (更新github上的Blog)

寫新文章:

每篇草稿都被放在單獨的drafts開頭的branch，所以只有sourcebranch上的文章會被編成html。

$ octopress-admin post 'hello'

開一個草稿 branch ，命名為 drafts/2011-12-04-hello
checkout 到那個 branch ，然後開新文章、寫文章、 commit 他的 markdown 檔。

執行後的git log 長這樣

2011-12-04 Hsin-Yi Chen (hyc~ o [source] enable facebook like
2011-12-04 Hsin-Yi Chen (hyc~ │ o [drafts/2011-12-04-hello] start to write hiello
2011-12-04 Hsin-Yi Chen (hyc~ I─┘ Finished github deploy settings

查詢現在有多少草稿:

顯示目前放在 drafts開頭的branch 的 markdown 檔，同時顯示 draft 編號，供octopress-admin edit, octopress-admin publish 使用。

$ octopress-admin drafts
[1] source/_posts/2011-12-04-hello.markdown (branch: drafts/2011-12-04-hello)

繼續寫文章:

必須先用octopress-admin drafts 得知要編輯的草稿的編號，以下的 1 代表草稿1

$ octopress-admin edit 1

checkout 到草稿的 branch
使用sensible-browser開啟你偏好的Editor修改這個 branch 的 markdown 檔案
你完成編輯後，請記得手動commit，這樣的設計是因為你可能只是暫時中斷編輯，而並不是完成一個段

$ git commit -m 'add new section: why'

執行後的 git log 長這樣

2011-12-04 Hsin-Yi Chen (hyc~ o [source] enable facebook like
2011-12-04 Hsin-Yi Chen (hyc~ │ o [drafts/2011-12-04-hiello] add new section: why
2011-12-04 Hsin-Yi Chen (hyc~ │ o [drafts/2011-12-04-hiello] start to write hiello
2011-12-04 Hsin-Yi Chen (hyc~ I─┘ Finished github deploy settings

定稿:

必須先用octopress-admin drafts 得知要公佈的草稿的編號，以下的 1 代表草稿1

$ octopress-admin publish 1

把該草稿的 branch 給 merge 進 srouce （使用 –no-ff 來產生 merge commit）。
刪除草稿的 branch (一旦定稿即不可回頭)

執行後的 git log 長這樣

2011-12-04 Hsin-Yi Chen (hyc~ M─┐ [source] Merge branch 'drafts/2011-12-04-hello' into source
2011-12-04 Hsin-Yi Chen (hyc~ │ o add new section: why
2011-12-04 Hsin-Yi Chen (hyc~ │ o start to write hello
2011-12-04 Hsin-Yi Chen (hyc~ o │ enable facebook like
2011-12-04 Hsin-Yi Chen (hyc~ o─┘ Finished github deploy settings

預覽 Blog:

原先的規劃是執行rake preview後，用sensible-browser直接開啟local的blog，目前只有rake preview的功能

blog preview

其他的指令

foreach:

對當前目錄下所有的Octopress Blog目錄執行指令, 下面這個指令是deploy所有的blog

$ octopress-admin foreach 'octopress-admin deploy'

結語:

Octopress 本身提供的管理系統非成有限，但也因此有更大的彈性作客製化。目前這套script並沒有提供把草稿備份到Dropbox上的功能，需然要加也是可以….

現在這些已經滿足我的需求了，以後自己有需要再加吧!

如果你嫌octopress-admin指令太長，你可以跟我一樣把 alias 成blog

$ echo alias blog='octopress-admin' >> ~/.bashrc

Jockey and modaliases

2011-12-02T20:20:00+08:00

前言

Jockey 是第三方驅動程式套件管裡程式，使User可以簡單的安裝不被Ubuntu收納的閉源驅動程式由 Martin Piit 於 UDS-N 時提出，在Onereic版本後都可以使用。

它的設計理念如下

使驅動程式的 Package Maintainer 可以利用 modaliases 宣告支援的裝置
Jockey 會檢查 package 的Modaliases Section，判斷這個 package 適不適用這台電腦，使得User 可以輕易找出適合的第三方驅動程式，常見的ATI，Nvidia的顯卡Driver 均是使用這個方式安裝。

那麼什麼是 modaliases 呢?

modaliases 其實就是讓 sysfs 把DMI table 及 Kernel 的硬體資訊 Dump 出來到檔名為 modalias 的檔案上，讓 User Space 的軟體可以讀取

$ cat /sys/devices/pci0000:00/0000:00:1f.1/modalias
      pci:v00008086d000024DBsv0000103Csd0000006Abc01sc01i8A

小寫英文字母代表屬性名稱, 所代表的意義每個裝置不一定一樣, v通常代表vendor ID, d通常代表device ID (通常也只用這個來判斷)

在Arch Linux Wiki上有面文章說明 modaliases 在 Kernel Module的用法，算是滿清楚的，有興趣的人可以連過去閱讀。

製作 Debian Binary Package 需修改的地方

修改 debian/modaliases

寫入這個 pacakge 支援的 modaliases，以下這個範例包含4個MODALIASE Trigger，每一行皆為一個MODALIAS Trigger

alias usb:v0A5Cp21D3d*dc*dsc*dp*ic*isc*ip* bcm bt-bcm43142
alias usb:v0A5Cp21D7d*dc*dsc*dp*ic*isc*ip* bcm bt-bcm43142
alias usb:v0A5Cp21E1d*dc*dsc*dp*ic*isc*ip* bcm bt-bcm43142
alias usb:v0A5Cp21E3d*dc*dsc*dp*ic*isc*ip* bcm bt-bcm43142

MODALIASE Trigger 的語法為

aliases MODALIAS TAG PACKAGE

每一個 Trigger 由三個部份組成，分別是 MODALIASE , TAG , PACKAGE ，其中MODALIASES前面介紹過了，而 PACKAGE 則為要安裝的套件名稱。

這段句子翻成中文就是”若電腦上有符合 MODALIASE 的裝置，就安裝 PACKAGE “, MODALIASE可以為裝置的硬體資料或是DMI Table

修改 debian/control
- 增加一行 XB-Modaliases: ${modaliases}
- 再把 dh_modalises 加進 Build-Depends
修改 debian/rules

在dh後面加--with modaliases

dh $@ --with modaliases"

如何測試包好的套件

要讓Jockey可以判斷你所做的package是不是適合的驅動程式的前提是，你用apt-cache search可以找到你包好的pacakge。

最簡單的方式就是你自己製作一個Local APT Archive，再把它加進apt source, 這方面資訊網路上很多，我就不在重複了。 :p

online courses of Stanford

2011-11-21T11:00:00+08:00

Known from google plus, you can study courses of Stanford on internet.

無為閣

利用 Vagrant 開發 g0v.tw 專案

前言

什麼是 Vagrant

使用流程

下載專案源碼跟 g0v專用Vagrant Box.

準備開始開發，啟動VM

工作完畢，關掉VM

如何製作 Base Box

如何撰寫給專案用的 Vagrantfile

Binding and Assignment

台南SA10月份 - Be Pythonic

PyCon.JP 2012

coscup 2012 簡報檔釋出

用來說明概念的素材

Create a new instance of an object

Python

JavaScript

Base Object

Python

JavaScript

Trace Object Creation

JavaScript

My slide 'What can meta class do for you' in PyCon Taiwan 2012

Example Codes

Singleton

Countable

Class Verification

Delegation

Logged

serialized python function object

想法

fix chromium can not play mp4

how to create a custom launchpad bugs report

metaclass in Python (1) - Singleton

Singleton 的源碼

用法

完整的源碼加測試

Will you attend PyCon TW 2012?

How-To: change string.template's delimiter in runtime

How-to: 輸出已被redirect 到時, 想要把字串印到Terminal

meeting room name

lp-cli - just another command line tool of Launchpad

python-launchpad

lp-cli

Use Case 1

Use Case 2

Available Commands

Installation

Thanks

decorator of display deprecated warring in Python

用法一 - 只宣告function已被depreacted, 不指定取代的function

用法二: 除了警告外，還會在runtime時改執行取代depreacted function的新functoin

源始碼

運作原理

參考資料

使用 dh_python2 製作 python module debian package

debian/control

debian/rules

移除不再使用的檔案

參考資料

Octopress 程式碼與網站內容的管理

建立新的Blog:

升級 Blog:

發佈到線上:

寫新文章:

查詢現在有多少草稿:

繼續寫文章:

定稿:

預覽 Blog:

其他的指令

foreach:

結語:

Jockey and modaliases

前言

製作 Debian Binary Package 需修改的地方

如何測試包好的套件

online courses of Stanford

Computer Science

Entrepreneurship