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@@ -191,7 +191,9 b' html_additional_pages = {' | |||||
191 | htmlhelp_basename = 'ipythondoc' |
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191 | htmlhelp_basename = 'ipythondoc' | |
192 |
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192 | |||
193 | intersphinx_mapping = {'python': ('http://docs.python.org/2/', None), |
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193 | intersphinx_mapping = {'python': ('http://docs.python.org/2/', None), | |
194 |
'rpy2': ('http://rpy.sourceforge.net/rpy2/doc-2.4/html/', None) |
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194 | 'rpy2': ('http://rpy.sourceforge.net/rpy2/doc-2.4/html/', None), | |
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195 | 'traitlets': ('http://traitlets.readthedocs.org/en/latest/', None), | |||
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196 | } | |||
195 |
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197 | |||
196 | # Options for LaTeX output |
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198 | # Options for LaTeX output | |
197 | # ------------------------ |
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199 | # ------------------------ |
@@ -37,7 +37,7 b' no error.' | |||||
37 |
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37 | |||
38 | To add to a collection which may have already been defined elsewhere, |
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38 | To add to a collection which may have already been defined elsewhere, | |
39 | you can use methods like those found on lists, dicts and sets: append, |
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39 | you can use methods like those found on lists, dicts and sets: append, | |
40 |
extend, :meth:`~traitlets.config. |
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40 | extend, :meth:`~traitlets.config.LazyConfigValue.prepend` (like | |
41 | extend, but at the front), add and update (which works both for dicts |
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41 | extend, but at the front), add and update (which works both for dicts | |
42 | and sets):: |
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42 | and sets):: | |
43 |
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43 |
@@ -4,296 +4,9 b'' | |||||
4 | Overview of the IPython configuration system |
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4 | Overview of the IPython configuration system | |
5 | ============================================ |
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5 | ============================================ | |
6 |
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6 | |||
7 | This section describes the IPython configuration system. |
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7 | This section describes the IPython configuration system. This is based on | |
8 |
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8 | :mod:`traitlets.config`; see that documentation for more information | ||
9 | The main concepts |
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9 | about the overall architecture. | |
10 | ================= |
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11 |
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12 | There are a number of abstractions that the IPython configuration system uses. |
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13 | Each of these abstractions is represented by a Python class. |
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14 |
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15 | Configuration object: :class:`~traitlets.config.loader.Config` |
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16 | A configuration object is a simple dictionary-like class that holds |
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17 | configuration attributes and sub-configuration objects. These classes |
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18 | support dotted attribute style access (``cfg.Foo.bar``) in addition to the |
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19 | regular dictionary style access (``cfg['Foo']['bar']``). |
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20 | The Config object is a wrapper around a simple dictionary with some convenience methods, |
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21 | such as merging and automatic section creation. |
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22 |
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23 | Application: :class:`~traitlets.config.application.Application` |
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24 | An application is a process that does a specific job. The most obvious |
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25 | application is the :command:`ipython` command line program. Each |
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26 | application reads *one or more* configuration files and a single set of |
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27 | command line options |
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28 | and then produces a master configuration object for the application. This |
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29 | configuration object is then passed to the configurable objects that the |
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30 | application creates. These configurable objects implement the actual logic |
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31 | of the application and know how to configure themselves given the |
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32 | configuration object. |
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33 |
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34 | Applications always have a `log` attribute that is a configured Logger. |
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35 | This allows centralized logging configuration per-application. |
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36 |
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37 | Configurable: :class:`~traitlets.config.configurable.Configurable` |
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38 | A configurable is a regular Python class that serves as a base class for |
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39 | all main classes in an application. The |
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40 | :class:`~traitlets.config.configurable.Configurable` base class is |
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41 | lightweight and only does one things. |
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42 |
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43 | This :class:`~traitlets.config.configurable.Configurable` is a subclass |
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44 | of :class:`~traitlets.HasTraits` that knows how to configure |
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45 | itself. Class level traits with the metadata ``config=True`` become |
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46 | values that can be configured from the command line and configuration |
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47 | files. |
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48 |
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49 | Developers create :class:`~traitlets.config.configurable.Configurable` |
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50 | subclasses that implement all of the logic in the application. Each of |
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51 | these subclasses has its own configuration information that controls how |
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52 | instances are created. |
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53 |
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54 | Singletons: :class:`~traitlets.config.configurable.SingletonConfigurable` |
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55 | Any object for which there is a single canonical instance. These are |
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56 | just like Configurables, except they have a class method |
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57 | :meth:`~traitlets.config.configurable.SingletonConfigurable.instance`, |
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58 | that returns the current active instance (or creates one if it |
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59 | does not exist). Examples of singletons include |
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60 | :class:`~traitlets.config.application.Application`s and |
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61 | :class:`~IPython.core.interactiveshell.InteractiveShell`. This lets |
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62 | objects easily connect to the current running Application without passing |
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63 | objects around everywhere. For instance, to get the current running |
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64 | Application instance, simply do: ``app = Application.instance()``. |
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65 |
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66 |
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67 | .. note:: |
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68 |
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69 | Singletons are not strictly enforced - you can have many instances |
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70 | of a given singleton class, but the :meth:`instance` method will always |
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71 | return the same one. |
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72 |
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73 | Having described these main concepts, we can now state the main idea in our |
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74 | configuration system: *"configuration" allows the default values of class |
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75 | attributes to be controlled on a class by class basis*. Thus all instances of |
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76 | a given class are configured in the same way. Furthermore, if two instances |
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77 | need to be configured differently, they need to be instances of two different |
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78 | classes. While this model may seem a bit restrictive, we have found that it |
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79 | expresses most things that need to be configured extremely well. However, it |
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80 | is possible to create two instances of the same class that have different |
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81 | trait values. This is done by overriding the configuration. |
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82 |
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83 | Now, we show what our configuration objects and files look like. |
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84 |
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85 | Configuration objects and files |
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86 | =============================== |
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87 |
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88 | A configuration object is little more than a wrapper around a dictionary. |
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89 | A configuration *file* is simply a mechanism for producing that object. |
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90 | The main IPython configuration file is a plain Python script, |
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91 | which can perform extensive logic to populate the config object. |
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92 | IPython 2.0 introduces a JSON configuration file, |
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93 | which is just a direct JSON serialization of the config dictionary, |
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94 | which is easily processed by external software. |
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95 |
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96 | When both Python and JSON configuration file are present, both will be loaded, |
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97 | with JSON configuration having higher priority. |
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98 |
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99 | Python configuration Files |
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100 | -------------------------- |
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101 |
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102 | A Python configuration file is a pure Python file that populates a configuration object. |
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103 | This configuration object is a :class:`~traitlets.config.loader.Config` instance. |
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104 | While in a configuration file, to get a reference to this object, simply call the :func:`get_config` |
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105 | function, which is available in the global namespace of the script. |
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106 |
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107 | Here is an example of a super simple configuration file that does nothing:: |
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108 |
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109 | c = get_config() |
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110 |
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111 | Once you get a reference to the configuration object, you simply set |
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112 | attributes on it. All you have to know is: |
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113 |
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114 | * The name of the class to configure. |
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115 | * The name of the attribute. |
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116 | * The type of each attribute. |
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117 |
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118 | The answers to these questions are provided by the various |
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119 | :class:`~traitlets.config.configurable.Configurable` subclasses that an |
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120 | application uses. Let's look at how this would work for a simple configurable |
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121 | subclass:: |
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122 |
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123 | # Sample configurable: |
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124 | from traitlets.config.configurable import Configurable |
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125 | from traitlets import Int, Float, Unicode, Bool |
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126 |
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127 | class MyClass(Configurable): |
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128 | name = Unicode(u'defaultname', config=True) |
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129 | ranking = Int(0, config=True) |
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130 | value = Float(99.0) |
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131 | # The rest of the class implementation would go here.. |
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132 |
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133 | In this example, we see that :class:`MyClass` has three attributes, two |
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134 | of which (``name``, ``ranking``) can be configured. All of the attributes |
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135 | are given types and default values. If a :class:`MyClass` is instantiated, |
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136 | but not configured, these default values will be used. But let's see how |
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137 | to configure this class in a configuration file:: |
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138 |
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139 | # Sample config file |
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140 | c = get_config() |
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141 |
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142 | c.MyClass.name = 'coolname' |
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143 | c.MyClass.ranking = 10 |
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144 |
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145 | After this configuration file is loaded, the values set in it will override |
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146 | the class defaults anytime a :class:`MyClass` is created. Furthermore, |
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147 | these attributes will be type checked and validated anytime they are set. |
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148 | This type checking is handled by the :mod:`traitlets` module, |
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149 | which provides the :class:`Unicode`, :class:`Int` and :class:`Float` types. |
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150 | In addition to these traitlets, the :mod:`traitlets` provides |
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151 | traitlets for a number of other types. |
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152 |
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153 | .. note:: |
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154 |
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155 | Underneath the hood, the :class:`Configurable` base class is a subclass of |
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156 | :class:`traitlets.HasTraits`. The |
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157 | :mod:`traitlets` module is a lightweight version of |
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158 | :mod:`enthought.traits`. Our implementation is a pure Python subset |
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159 | (mostly API compatible) of :mod:`enthought.traits` that does not have any |
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160 | of the automatic GUI generation capabilities. Our plan is to achieve 100% |
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161 | API compatibility to enable the actual :mod:`enthought.traits` to |
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162 | eventually be used instead. Currently, we cannot use |
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163 | :mod:`enthought.traits` as we are committed to the core of IPython being |
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164 | pure Python. |
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165 |
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166 | It should be very clear at this point what the naming convention is for |
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167 | configuration attributes:: |
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168 |
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169 | c.ClassName.attribute_name = attribute_value |
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170 |
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171 | Here, ``ClassName`` is the name of the class whose configuration attribute you |
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172 | want to set, ``attribute_name`` is the name of the attribute you want to set |
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173 | and ``attribute_value`` the the value you want it to have. The ``ClassName`` |
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174 | attribute of ``c`` is not the actual class, but instead is another |
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175 | :class:`~traitlets.config.loader.Config` instance. |
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176 |
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177 | .. note:: |
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178 |
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179 | The careful reader may wonder how the ``ClassName`` (``MyClass`` in |
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180 | the above example) attribute of the configuration object ``c`` gets |
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181 | created. These attributes are created on the fly by the |
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182 | :class:`~traitlets.config.loader.Config` instance, using a simple naming |
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183 | convention. Any attribute of a :class:`~traitlets.config.loader.Config` |
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184 | instance whose name begins with an uppercase character is assumed to be a |
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185 | sub-configuration and a new empty :class:`~traitlets.config.loader.Config` |
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186 | instance is dynamically created for that attribute. This allows deeply |
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187 | hierarchical information created easily (``c.Foo.Bar.value``) on the fly. |
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188 |
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189 | JSON configuration Files |
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190 | ------------------------ |
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191 |
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192 | A JSON configuration file is simply a file that contains a |
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193 | :class:`~traitlets.config.loader.Config` dictionary serialized to JSON. |
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194 | A JSON configuration file has the same base name as a Python configuration file, |
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195 | but with a .json extension. |
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196 |
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197 | Configuration described in previous section could be written as follows in a |
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198 | JSON configuration file: |
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199 |
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200 | .. sourcecode:: json |
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201 |
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202 | { |
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203 | "version": "1.0", |
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204 | "MyClass": { |
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205 | "name": "coolname", |
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206 | "ranking": 10 |
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207 | } |
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208 | } |
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209 |
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210 | JSON configuration files can be more easily generated or processed by programs |
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211 | or other languages. |
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212 |
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213 |
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214 | Configuration files inheritance |
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215 | =============================== |
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216 |
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217 | .. note:: |
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218 |
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219 | This section only apply to Python configuration files. |
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220 |
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221 | Let's say you want to have different configuration files for various purposes. |
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222 | Our configuration system makes it easy for one configuration file to inherit |
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223 | the information in another configuration file. The :func:`load_subconfig` |
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224 | command can be used in a configuration file for this purpose. Here is a simple |
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225 | example that loads all of the values from the file :file:`base_config.py`:: |
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226 |
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227 | # base_config.py |
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228 | c = get_config() |
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229 | c.MyClass.name = 'coolname' |
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230 | c.MyClass.ranking = 100 |
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231 |
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232 | into the configuration file :file:`main_config.py`:: |
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233 |
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234 | # main_config.py |
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235 | c = get_config() |
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236 |
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237 | # Load everything from base_config.py |
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238 | load_subconfig('base_config.py') |
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239 |
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240 | # Now override one of the values |
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241 | c.MyClass.name = 'bettername' |
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242 |
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243 | In a situation like this the :func:`load_subconfig` makes sure that the |
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244 | search path for sub-configuration files is inherited from that of the parent. |
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245 | Thus, you can typically put the two in the same directory and everything will |
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246 | just work. |
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247 |
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248 | You can also load configuration files by profile, for instance: |
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249 |
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250 | .. sourcecode:: python |
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251 |
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252 | load_subconfig('ipython_config.py', profile='default') |
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253 |
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254 | to inherit your default configuration as a starting point. |
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255 |
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256 |
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257 | Class based configuration inheritance |
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258 | ===================================== |
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259 |
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260 | There is another aspect of configuration where inheritance comes into play. |
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261 | Sometimes, your classes will have an inheritance hierarchy that you want |
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262 | to be reflected in the configuration system. Here is a simple example:: |
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263 |
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264 | from traitlets.config.configurable import Configurable |
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265 | from traitlets import Int, Float, Unicode, Bool |
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266 |
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267 | class Foo(Configurable): |
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268 | name = Unicode(u'fooname', config=True) |
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269 | value = Float(100.0, config=True) |
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270 |
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271 | class Bar(Foo): |
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272 | name = Unicode(u'barname', config=True) |
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273 | othervalue = Int(0, config=True) |
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274 |
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275 | Now, we can create a configuration file to configure instances of :class:`Foo` |
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276 | and :class:`Bar`:: |
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277 |
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278 | # config file |
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279 | c = get_config() |
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280 |
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281 | c.Foo.name = u'bestname' |
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282 | c.Bar.othervalue = 10 |
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283 |
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284 | This class hierarchy and configuration file accomplishes the following: |
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285 |
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286 | * The default value for :attr:`Foo.name` and :attr:`Bar.name` will be |
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287 | 'bestname'. Because :class:`Bar` is a :class:`Foo` subclass it also |
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288 | picks up the configuration information for :class:`Foo`. |
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289 | * The default value for :attr:`Foo.value` and :attr:`Bar.value` will be |
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290 | ``100.0``, which is the value specified as the class default. |
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291 | * The default value for :attr:`Bar.othervalue` will be 10 as set in the |
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292 | configuration file. Because :class:`Foo` is the parent of :class:`Bar` |
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293 | it doesn't know anything about the :attr:`othervalue` attribute. |
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294 |
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295 |
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296 | .. _ipython_dir: |
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297 |
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10 | |||
298 | Configuration file location |
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11 | Configuration file location | |
299 | =========================== |
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12 | =========================== | |
@@ -305,7 +18,7 b' following algorithm:' | |||||
305 |
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18 | |||
306 | * If the ``ipython-dir`` command line flag is given, its value is used. |
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19 | * If the ``ipython-dir`` command line flag is given, its value is used. | |
307 |
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20 | |||
308 |
* If not, the value returned by :func:`IPython. |
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21 | * If not, the value returned by :func:`IPython.paths.get_ipython_dir` | |
309 | is used. This function will first look at the :envvar:`IPYTHONDIR` |
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22 | is used. This function will first look at the :envvar:`IPYTHONDIR` | |
310 | environment variable and then default to :file:`~/.ipython`. |
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23 | environment variable and then default to :file:`~/.ipython`. | |
311 | Historical support for the :envvar:`IPYTHON_DIR` environment variable will |
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24 | Historical support for the :envvar:`IPYTHON_DIR` environment variable will | |
@@ -400,6 +113,14 b' you create profiles with the name of one of our shipped profiles, these config' | |||||
400 | files will be copied over instead of starting with the automatically generated |
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113 | files will be copied over instead of starting with the automatically generated | |
401 | config files. |
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114 | config files. | |
402 |
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115 | |||
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116 | IPython extends the config loader for Python files so that you can inherit | |||
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117 | config from another profile. To do this, use a line like this in your Python | |||
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118 | config file: | |||
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119 | ||||
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120 | .. sourcecode:: python | |||
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121 | ||||
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122 | load_subconfig('ipython_config.py', profile='default') | |||
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123 | ||||
403 | Security Files |
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124 | Security Files | |
404 | -------------- |
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125 | -------------- | |
405 |
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126 | |||
@@ -425,142 +146,3 b' constructed, and before any other code or scripts you have specified. If you' | |||||
425 | have multiple files in the startup directory, they will be run in |
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146 | have multiple files in the startup directory, they will be run in | |
426 | lexicographical order, so you can control the ordering by adding a '00-' |
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147 | lexicographical order, so you can control the ordering by adding a '00-' | |
427 | prefix. |
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148 | prefix. | |
428 |
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429 |
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430 | .. _commandline: |
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431 |
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432 | Command-line arguments |
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433 | ====================== |
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434 |
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435 | IPython exposes *all* configurable options on the command-line. The command-line |
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436 | arguments are generated from the Configurable traits of the classes associated |
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437 | with a given Application. Configuring IPython from the command-line may look |
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438 | very similar to an IPython config file |
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439 |
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440 | IPython applications use a parser called |
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441 | :class:`~traitlets.config.loader.KeyValueLoader` to load values into a Config |
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442 | object. Values are assigned in much the same way as in a config file: |
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443 |
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444 | .. code-block:: bash |
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445 |
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446 | $ ipython --InteractiveShell.use_readline=False --BaseIPythonApplication.profile='myprofile' |
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447 |
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448 | Is the same as adding: |
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449 |
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450 | .. sourcecode:: python |
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451 |
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452 | c.InteractiveShell.use_readline=False |
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453 | c.BaseIPythonApplication.profile='myprofile' |
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454 |
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455 | to your config file. Key/Value arguments *always* take a value, separated by '=' |
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456 | and no spaces. |
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457 |
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458 | Common Arguments |
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459 | ---------------- |
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460 |
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461 | Since the strictness and verbosity of the KVLoader above are not ideal for everyday |
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462 | use, common arguments can be specified as flags_ or aliases_. |
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463 |
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464 | Flags and Aliases are handled by :mod:`argparse` instead, allowing for more flexible |
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465 | parsing. In general, flags and aliases are prefixed by ``--``, except for those |
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466 | that are single characters, in which case they can be specified with a single ``-``, e.g.: |
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467 |
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468 | .. code-block:: bash |
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469 |
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470 | $ ipython -i -c "import numpy; x=numpy.linspace(0,1)" --profile testing --colors=lightbg |
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471 |
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472 | Aliases |
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473 | ******* |
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474 |
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||||
475 | For convenience, applications have a mapping of commonly used traits, so you don't have |
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476 | to specify the whole class name: |
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477 |
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478 | .. code-block:: bash |
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479 |
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480 | $ ipython --profile myprofile |
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481 | # and |
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482 | $ ipython --profile='myprofile' |
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483 | # are equivalent to |
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484 | $ ipython --BaseIPythonApplication.profile='myprofile' |
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485 |
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486 | Flags |
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487 | ***** |
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488 |
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489 | Applications can also be passed **flags**. Flags are options that take no |
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490 | arguments. They are simply wrappers for |
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491 | setting one or more configurables with predefined values, often True/False. |
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492 |
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493 | For instance: |
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494 |
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||||
495 | .. code-block:: bash |
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496 |
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497 | $ ipcontroller --debug |
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498 | # is equivalent to |
|
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499 | $ ipcontroller --Application.log_level=DEBUG |
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500 | # and |
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501 | $ ipython --matplotlib |
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502 | # is equivalent to |
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503 | $ ipython --matplotlib auto |
|
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504 | # or |
|
|||
505 | $ ipython --no-banner |
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506 | # is equivalent to |
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507 | $ ipython --TerminalIPythonApp.display_banner=False |
|
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508 |
|
||||
509 | Subcommands |
|
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510 | ----------- |
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511 |
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512 |
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513 | Some IPython applications have **subcommands**. Subcommands are modeled after |
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514 | :command:`git`, and are called with the form :command:`command subcommand |
|
|||
515 | [...args]`. Currently, the QtConsole is a subcommand of terminal IPython: |
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516 |
|
||||
517 | .. code-block:: bash |
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518 |
|
||||
519 | $ ipython qtconsole --profile myprofile |
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520 |
|
||||
521 | and :command:`ipcluster` is simply a wrapper for its various subcommands (start, |
|
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522 | stop, engines). |
|
|||
523 |
|
||||
524 | .. code-block:: bash |
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|||
525 |
|
||||
526 | $ ipcluster start --profile=myprofile -n 4 |
|
|||
527 |
|
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528 |
|
||||
529 | To see a list of the available aliases, flags, and subcommands for an IPython application, simply pass ``-h`` or ``--help``. And to see the full list of configurable options (*very* long), pass ``--help-all``. |
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530 |
|
||||
531 |
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||||
532 | Design requirements |
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|||
533 | =================== |
|
|||
534 |
|
||||
535 | Here are the main requirements we wanted our configuration system to have: |
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|||
536 |
|
||||
537 | * Support for hierarchical configuration information. |
|
|||
538 |
|
||||
539 | * Full integration with command line option parsers. Often, you want to read |
|
|||
540 | a configuration file, but then override some of the values with command line |
|
|||
541 | options. Our configuration system automates this process and allows each |
|
|||
542 | command line option to be linked to a particular attribute in the |
|
|||
543 | configuration hierarchy that it will override. |
|
|||
544 |
|
||||
545 | * Configuration files that are themselves valid Python code. This accomplishes |
|
|||
546 | many things. First, it becomes possible to put logic in your configuration |
|
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547 | files that sets attributes based on your operating system, network setup, |
|
|||
548 | Python version, etc. Second, Python has a super simple syntax for accessing |
|
|||
549 | hierarchical data structures, namely regular attribute access |
|
|||
550 | (``Foo.Bar.Bam.name``). Third, using Python makes it easy for users to |
|
|||
551 | import configuration attributes from one configuration file to another. |
|
|||
552 | Fourth, even though Python is dynamically typed, it does have types that can |
|
|||
553 | be checked at runtime. Thus, a ``1`` in a config file is the integer '1', |
|
|||
554 | while a ``'1'`` is a string. |
|
|||
555 |
|
||||
556 | * A fully automated method for getting the configuration information to the |
|
|||
557 | classes that need it at runtime. Writing code that walks a configuration |
|
|||
558 | hierarchy to extract a particular attribute is painful. When you have |
|
|||
559 | complex configuration information with hundreds of attributes, this makes |
|
|||
560 | you want to cry. |
|
|||
561 |
|
||||
562 | * Type checking and validation that doesn't require the entire configuration |
|
|||
563 | hierarchy to be specified statically before runtime. Python is a very |
|
|||
564 | dynamic language and you don't always know everything that needs to be |
|
|||
565 | configured when a program starts. |
|
|||
566 |
|
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