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@@ -1,493 +1,464 b'' | |||
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1 | 1 | # -*- coding: utf-8 -*- |
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2 | 2 | """Manage background (threaded) jobs conveniently from an interactive shell. |
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3 | 3 | |
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4 | 4 | This module provides a BackgroundJobManager class. This is the main class |
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5 | 5 | meant for public usage, it implements an object which can create and manage |
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6 | 6 | new background jobs. |
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7 | 7 | |
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8 | 8 | It also provides the actual job classes managed by these BackgroundJobManager |
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9 | 9 | objects, see their docstrings below. |
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10 | 10 | |
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11 | 11 | |
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12 | 12 | This system was inspired by discussions with B. Granger and the |
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13 | 13 | BackgroundCommand class described in the book Python Scripting for |
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14 | 14 | Computational Science, by H. P. Langtangen: |
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15 | 15 | |
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16 | 16 | http://folk.uio.no/hpl/scripting |
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17 | 17 | |
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18 | 18 | (although ultimately no code from this text was used, as IPython's system is a |
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19 | 19 | separate implementation). |
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20 | ||
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21 | An example notebook is provided in our documentation illustrating interactive | |
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22 | use of the system. | |
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20 | 23 | """ |
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21 | 24 | |
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22 | 25 | #***************************************************************************** |
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23 | 26 | # Copyright (C) 2005-2006 Fernando Perez <fperez@colorado.edu> |
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24 | 27 | # |
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25 | 28 | # Distributed under the terms of the BSD License. The full license is in |
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26 | 29 | # the file COPYING, distributed as part of this software. |
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27 | 30 | #***************************************************************************** |
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28 | 31 | |
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29 | 32 | # Code begins |
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30 | 33 | import sys |
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31 | 34 | import threading |
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32 | 35 | |
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33 | 36 | from IPython.core.ultratb import AutoFormattedTB |
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34 | 37 | from IPython.utils.warn import warn, error |
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35 | 38 | |
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36 | class BackgroundJobManager: | |
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39 | ||
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40 | class BackgroundJobManager(object): | |
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37 | 41 | """Class to manage a pool of backgrounded threaded jobs. |
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38 | 42 | |
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39 | 43 | Below, we assume that 'jobs' is a BackgroundJobManager instance. |
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40 | 44 | |
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41 | 45 | Usage summary (see the method docstrings for details): |
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42 | 46 | |
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43 | 47 | jobs.new(...) -> start a new job |
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44 | 48 | |
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45 | 49 | jobs() or jobs.status() -> print status summary of all jobs |
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46 | 50 | |
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47 | 51 | jobs[N] -> returns job number N. |
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48 | 52 | |
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49 | 53 | foo = jobs[N].result -> assign to variable foo the result of job N |
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50 | 54 | |
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51 | 55 | jobs[N].traceback() -> print the traceback of dead job N |
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52 | 56 | |
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53 | 57 | jobs.remove(N) -> remove (finished) job N |
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54 | 58 | |
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55 |
jobs.flush |
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59 | jobs.flush() -> remove all finished jobs | |
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56 | 60 | |
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57 | 61 | As a convenience feature, BackgroundJobManager instances provide the |
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58 | 62 | utility result and traceback methods which retrieve the corresponding |
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59 | 63 | information from the jobs list: |
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60 | 64 | |
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61 | 65 | jobs.result(N) <--> jobs[N].result |
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62 | 66 | jobs.traceback(N) <--> jobs[N].traceback() |
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63 | 67 | |
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64 | 68 | While this appears minor, it allows you to use tab completion |
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65 | 69 | interactively on the job manager instance. |
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66 | ||
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67 | In interactive mode, IPython provides the magic fuction %bg for quick | |
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68 | creation of backgrounded expression-based jobs. Type bg? for details.""" | |
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70 | """ | |
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69 | 71 | |
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70 | 72 | def __init__(self): |
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71 | 73 | # Lists for job management |
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72 |
self. |
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73 |
self. |
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74 |
self. |
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74 | self.running = [] | |
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75 | self.completed = [] | |
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76 | self.dead = [] | |
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75 | 77 | # A dict of all jobs, so users can easily access any of them |
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76 |
self. |
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78 | self.all = {} | |
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77 | 79 | # For reporting |
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78 | 80 | self._comp_report = [] |
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79 | 81 | self._dead_report = [] |
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80 | 82 | # Store status codes locally for fast lookups |
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81 | 83 | self._s_created = BackgroundJobBase.stat_created_c |
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82 | 84 | self._s_running = BackgroundJobBase.stat_running_c |
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83 | 85 | self._s_completed = BackgroundJobBase.stat_completed_c |
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84 | 86 | self._s_dead = BackgroundJobBase.stat_dead_c |
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85 | 87 | |
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86 | 88 | def new(self,func_or_exp,*args,**kwargs): |
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87 | 89 | """Add a new background job and start it in a separate thread. |
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88 | 90 | |
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89 | 91 | There are two types of jobs which can be created: |
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90 | 92 | |
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91 | 93 | 1. Jobs based on expressions which can be passed to an eval() call. |
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92 | 94 | The expression must be given as a string. For example: |
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93 | 95 | |
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94 | 96 | job_manager.new('myfunc(x,y,z=1)'[,glob[,loc]]) |
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95 | 97 | |
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96 | 98 | The given expression is passed to eval(), along with the optional |
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97 | 99 | global/local dicts provided. If no dicts are given, they are |
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98 | 100 | extracted automatically from the caller's frame. |
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99 | 101 | |
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100 | 102 | A Python statement is NOT a valid eval() expression. Basically, you |
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101 | 103 | can only use as an eval() argument something which can go on the right |
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102 | 104 | of an '=' sign and be assigned to a variable. |
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103 | 105 | |
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104 | 106 | For example,"print 'hello'" is not valid, but '2+3' is. |
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105 | 107 | |
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106 | 108 | 2. Jobs given a function object, optionally passing additional |
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107 | 109 | positional arguments: |
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108 | 110 | |
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109 | 111 | job_manager.new(myfunc,x,y) |
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110 | 112 | |
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111 | 113 | The function is called with the given arguments. |
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112 | 114 | |
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113 | 115 | If you need to pass keyword arguments to your function, you must |
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114 | 116 | supply them as a dict named kw: |
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115 | 117 | |
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116 | 118 | job_manager.new(myfunc,x,y,kw=dict(z=1)) |
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117 | 119 | |
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118 | 120 | The reason for this assymmetry is that the new() method needs to |
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119 | 121 | maintain access to its own keywords, and this prevents name collisions |
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120 | 122 | between arguments to new() and arguments to your own functions. |
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121 | 123 | |
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122 | 124 | In both cases, the result is stored in the job.result field of the |
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123 | 125 | background job object. |
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124 | 126 | |
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125 | 127 | |
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126 | 128 | Notes and caveats: |
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127 | 129 | |
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128 | 130 | 1. All threads running share the same standard output. Thus, if your |
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129 | 131 | background jobs generate output, it will come out on top of whatever |
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130 | 132 | you are currently writing. For this reason, background jobs are best |
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131 | 133 | used with silent functions which simply return their output. |
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132 | 134 | |
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133 | 135 | 2. Threads also all work within the same global namespace, and this |
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134 | 136 | system does not lock interactive variables. So if you send job to the |
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135 | 137 | background which operates on a mutable object for a long time, and |
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136 | 138 | start modifying that same mutable object interactively (or in another |
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137 | 139 | backgrounded job), all sorts of bizarre behaviour will occur. |
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138 | 140 | |
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139 | 141 | 3. If a background job is spending a lot of time inside a C extension |
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140 | 142 | module which does not release the Python Global Interpreter Lock |
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141 | 143 | (GIL), this will block the IPython prompt. This is simply because the |
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142 | 144 | Python interpreter can only switch between threads at Python |
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143 | 145 | bytecodes. While the execution is inside C code, the interpreter must |
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144 | 146 | simply wait unless the extension module releases the GIL. |
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145 | 147 | |
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146 | 148 | 4. There is no way, due to limitations in the Python threads library, |
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147 | 149 | to kill a thread once it has started.""" |
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148 | 150 | |
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149 | 151 | if callable(func_or_exp): |
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150 | 152 | kw = kwargs.get('kw',{}) |
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151 | 153 | job = BackgroundJobFunc(func_or_exp,*args,**kw) |
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152 | elif isinstance(func_or_exp,basestring): | |
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154 | elif isinstance(func_or_exp, basestring): | |
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153 | 155 | if not args: |
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154 | 156 | frame = sys._getframe(1) |
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155 | 157 | glob, loc = frame.f_globals, frame.f_locals |
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156 | 158 | elif len(args)==1: |
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157 | 159 | glob = loc = args[0] |
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158 | 160 | elif len(args)==2: |
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159 | 161 | glob,loc = args |
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160 | 162 | else: |
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161 |
raise ValueError |
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162 | 'Expression jobs take at most 2 args (globals,locals)' | |
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163 | job = BackgroundJobExpr(func_or_exp,glob,loc) | |
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164 | else: | |
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165 | raise | |
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166 | jkeys = self.jobs_all.keys() | |
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167 | if jkeys: | |
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168 | job.num = max(jkeys)+1 | |
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163 | raise ValueError( | |
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164 | 'Expression jobs take at most 2 args (globals,locals)') | |
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165 | job = BackgroundJobExpr(func_or_exp, glob, loc) | |
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169 | 166 | else: |
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170 | job.num = 0 | |
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171 | self.jobs_run.append(job) | |
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172 | self.jobs_all[job.num] = job | |
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167 | raise TypeError('invalid args for new job') | |
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168 | ||
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169 | job.num = len(self.all)+1 if self.all else 0 | |
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170 | self.running.append(job) | |
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171 | self.all[job.num] = job | |
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173 | 172 | print 'Starting job # %s in a separate thread.' % job.num |
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174 | 173 | job.start() |
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175 | 174 | return job |
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176 | 175 | |
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177 | def __getitem__(self,key): | |
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178 | return self.jobs_all[key] | |
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176 | def __getitem__(self, job_key): | |
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177 | num = job_key if isinstance(job_key, int) else job_key.num | |
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178 | return self.all[num] | |
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179 | 179 | |
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180 | 180 | def __call__(self): |
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181 | 181 | """An alias to self.status(), |
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182 | 182 | |
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183 | 183 | This allows you to simply call a job manager instance much like the |
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184 | Unix jobs shell command.""" | |
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184 | Unix `jobs` shell command.""" | |
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185 | 185 | |
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186 | 186 | return self.status() |
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187 | 187 | |
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188 | 188 | def _update_status(self): |
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189 | 189 | """Update the status of the job lists. |
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190 | 190 | |
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191 | 191 | This method moves finished jobs to one of two lists: |
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192 |
- self. |
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193 |
- self. |
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192 | - self.completed: jobs which completed successfully | |
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193 | - self.dead: jobs which finished but died. | |
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194 | 194 | |
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195 | 195 | It also copies those jobs to corresponding _report lists. These lists |
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196 | 196 | are used to report jobs completed/dead since the last update, and are |
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197 | 197 | then cleared by the reporting function after each call.""" |
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198 | 198 | |
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199 | 199 | run,comp,dead = self._s_running,self._s_completed,self._s_dead |
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200 |
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201 |
for num in range(len( |
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202 |
job = |
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200 | running = self.running | |
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201 | for num in range(len(running)): | |
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202 | job = running[num] | |
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203 | 203 | stat = job.stat_code |
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204 | 204 | if stat == run: |
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205 | 205 | continue |
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206 | 206 | elif stat == comp: |
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207 |
self. |
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207 | self.completed.append(job) | |
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208 | 208 | self._comp_report.append(job) |
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209 |
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209 | running[num] = False | |
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210 | 210 | elif stat == dead: |
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211 |
self. |
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211 | self.dead.append(job) | |
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212 | 212 | self._dead_report.append(job) |
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213 |
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214 |
self. |
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213 | running[num] = False | |
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214 | self.running = filter(None,self.running) | |
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215 | 215 | |
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216 | 216 | def _group_report(self,group,name): |
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217 | 217 | """Report summary for a given job group. |
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218 | 218 | |
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219 | 219 | Return True if the group had any elements.""" |
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220 | 220 | |
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221 | 221 | if group: |
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222 | 222 | print '%s jobs:' % name |
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223 | 223 | for job in group: |
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224 | 224 | print '%s : %s' % (job.num,job) |
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225 | 225 | |
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226 | 226 | return True |
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227 | 227 | |
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228 | 228 | def _group_flush(self,group,name): |
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229 | 229 | """Flush a given job group |
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230 | 230 | |
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231 | 231 | Return True if the group had any elements.""" |
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232 | 232 | |
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233 | 233 | njobs = len(group) |
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234 | 234 | if njobs: |
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235 | 235 | plural = {1:''}.setdefault(njobs,'s') |
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236 | 236 | print 'Flushing %s %s job%s.' % (njobs,name,plural) |
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237 | 237 | group[:] = [] |
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238 | 238 | return True |
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239 | 239 | |
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240 | 240 | def _status_new(self): |
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241 | 241 | """Print the status of newly finished jobs. |
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242 | 242 | |
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243 | 243 | Return True if any new jobs are reported. |
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244 | 244 | |
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245 | 245 | This call resets its own state every time, so it only reports jobs |
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246 | 246 | which have finished since the last time it was called.""" |
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247 | 247 | |
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248 | 248 | self._update_status() |
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249 | new_comp = self._group_report(self._comp_report,'Completed') | |
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249 | new_comp = self._group_report(self._comp_report, 'Completed') | |
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250 | 250 | new_dead = self._group_report(self._dead_report, |
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251 | 251 | 'Dead, call jobs.traceback() for details') |
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252 | 252 | self._comp_report[:] = [] |
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253 | 253 | self._dead_report[:] = [] |
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254 | 254 | return new_comp or new_dead |
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255 | 255 | |
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256 | 256 | def status(self,verbose=0): |
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257 | 257 | """Print a status of all jobs currently being managed.""" |
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258 | 258 | |
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259 | 259 | self._update_status() |
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260 |
self._group_report(self. |
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261 |
self._group_report(self. |
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262 |
self._group_report(self. |
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260 | self._group_report(self.running,'Running') | |
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261 | self._group_report(self.completed,'Completed') | |
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262 | self._group_report(self.dead,'Dead') | |
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263 | 263 | # Also flush the report queues |
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264 | 264 | self._comp_report[:] = [] |
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265 | 265 | self._dead_report[:] = [] |
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266 | 266 | |
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267 | 267 | def remove(self,num): |
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268 | 268 | """Remove a finished (completed or dead) job.""" |
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269 | 269 | |
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270 | 270 | try: |
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271 |
job = self. |
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271 | job = self.all[num] | |
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272 | 272 | except KeyError: |
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273 | 273 | error('Job #%s not found' % num) |
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274 | 274 | else: |
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275 | 275 | stat_code = job.stat_code |
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276 | 276 | if stat_code == self._s_running: |
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277 | 277 | error('Job #%s is still running, it can not be removed.' % num) |
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278 | 278 | return |
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279 | 279 | elif stat_code == self._s_completed: |
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280 |
self. |
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280 | self.completed.remove(job) | |
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281 | 281 | elif stat_code == self._s_dead: |
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282 |
self. |
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282 | self.dead.remove(job) | |
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283 | 283 | |
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284 |
def flush |
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285 |
"""Flush all |
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284 | def flush(self): | |
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285 | """Flush all finished jobs (completed and dead) from lists. | |
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286 | 286 | |
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287 | 287 | Running jobs are never flushed. |
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288 | 288 | |
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289 | 289 | It first calls _status_new(), to update info. If any jobs have |
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290 | 290 | completed since the last _status_new() call, the flush operation |
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291 | 291 | aborts.""" |
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292 | 292 | |
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293 | 293 | if self._status_new(): |
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294 | 294 | error('New jobs completed since last '\ |
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295 | 295 | '_status_new(), aborting flush.') |
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296 | 296 | return |
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297 | 297 | |
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298 | 298 | # Remove the finished jobs from the master dict |
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299 |
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300 |
for job in self. |
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301 |
del( |
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299 | all = self.all | |
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300 | for job in self.completed+self.dead: | |
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301 | del(all[job.num]) | |
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302 | 302 | |
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303 | 303 | # Now flush these lists completely |
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304 |
fl_comp = self._group_flush(self. |
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305 |
fl_dead = self._group_flush(self. |
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304 | fl_comp = self._group_flush(self.completed, 'Completed') | |
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305 | fl_dead = self._group_flush(self.dead, 'Dead') | |
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306 | 306 | if not (fl_comp or fl_dead): |
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307 | 307 | print 'No jobs to flush.' |
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308 | 308 | |
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309 | 309 | def result(self,num): |
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310 | 310 | """result(N) -> return the result of job N.""" |
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311 | 311 | try: |
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312 |
return self. |
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312 | return self.all[num].result | |
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313 | 313 | except KeyError: |
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314 | 314 | error('Job #%s not found' % num) |
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315 | 315 | |
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316 |
def traceback(self, |
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316 | def _traceback(self, job): | |
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317 | num = job if isinstance(job, int) else job.num | |
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317 | 318 | try: |
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318 |
self. |
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319 | self.all[num].traceback() | |
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319 | 320 | except KeyError: |
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320 | 321 | error('Job #%s not found' % num) |
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321 | 322 | |
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323 | def traceback(self, job=None): | |
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324 | if job is None: | |
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325 | self._update_status() | |
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326 | for deadjob in self.dead: | |
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327 | print "Traceback for: %r" % deadjob | |
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328 | self._traceback(deadjob) | |
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329 | ||
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330 | else: | |
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331 | self._traceback(job) | |
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332 | ||
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322 | 333 | |
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323 | 334 | class BackgroundJobBase(threading.Thread): |
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324 | 335 | """Base class to build BackgroundJob classes. |
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325 | 336 | |
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326 | 337 | The derived classes must implement: |
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327 | 338 | |
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328 | 339 | - Their own __init__, since the one here raises NotImplementedError. The |
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329 | 340 | derived constructor must call self._init() at the end, to provide common |
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330 | 341 | initialization. |
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331 | 342 | |
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332 | 343 | - A strform attribute used in calls to __str__. |
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333 | 344 | |
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334 | 345 | - A call() method, which will make the actual execution call and must |
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335 | 346 | return a value to be held in the 'result' field of the job object.""" |
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336 | 347 | |
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337 | 348 | # Class constants for status, in string and as numerical codes (when |
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338 | 349 | # updating jobs lists, we don't want to do string comparisons). This will |
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339 | 350 | # be done at every user prompt, so it has to be as fast as possible |
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340 | 351 | stat_created = 'Created'; stat_created_c = 0 |
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341 | 352 | stat_running = 'Running'; stat_running_c = 1 |
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342 | 353 | stat_completed = 'Completed'; stat_completed_c = 2 |
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343 | 354 | stat_dead = 'Dead (Exception), call jobs.traceback() for details' |
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344 | 355 | stat_dead_c = -1 |
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345 | 356 | |
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346 | 357 | def __init__(self): |
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347 | 358 | raise NotImplementedError, \ |
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348 | 359 | "This class can not be instantiated directly." |
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349 | 360 | |
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350 | 361 | def _init(self): |
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351 | 362 | """Common initialization for all BackgroundJob objects""" |
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352 | 363 | |
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353 | 364 | for attr in ['call','strform']: |
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354 | 365 | assert hasattr(self,attr), "Missing attribute <%s>" % attr |
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355 | 366 | |
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356 | 367 | # The num tag can be set by an external job manager |
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357 | 368 | self.num = None |
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358 | 369 | |
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359 | 370 | self.status = BackgroundJobBase.stat_created |
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360 | 371 | self.stat_code = BackgroundJobBase.stat_created_c |
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361 | 372 | self.finished = False |
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362 | 373 | self.result = '<BackgroundJob has not completed>' |
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374 | ||
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363 | 375 | # reuse the ipython traceback handler if we can get to it, otherwise |
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364 | 376 | # make a new one |
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365 | 377 | try: |
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366 | 378 | make_tb = get_ipython().InteractiveTB.text |
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367 | 379 | except: |
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368 | 380 | make_tb = AutoFormattedTB(mode = 'Context', |
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369 | 381 | color_scheme='NoColor', |
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370 | 382 | tb_offset = 1).text |
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383 | # Note that the actual API for text() requires the three args to be | |
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384 | # passed in, so we wrap it in a simple lambda. | |
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371 | 385 | self._make_tb = lambda : make_tb(None, None, None) |
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386 | ||
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372 | 387 | # Hold a formatted traceback if one is generated. |
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373 | 388 | self._tb = None |
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374 | 389 | |
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375 | 390 | threading.Thread.__init__(self) |
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376 | 391 | |
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377 | 392 | def __str__(self): |
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378 | 393 | return self.strform |
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379 | 394 | |
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380 | 395 | def __repr__(self): |
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381 | return '<BackgroundJob: %s>' % self.strform | |
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396 | return '<BackgroundJob #%d: %s>' % (self.num, self.strform) | |
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382 | 397 | |
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383 | 398 | def traceback(self): |
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384 | 399 | print self._tb |
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385 | 400 | |
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386 | 401 | def run(self): |
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387 | 402 | try: |
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388 | 403 | self.status = BackgroundJobBase.stat_running |
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389 | 404 | self.stat_code = BackgroundJobBase.stat_running_c |
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390 | 405 | self.result = self.call() |
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391 | 406 | except: |
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392 | 407 | self.status = BackgroundJobBase.stat_dead |
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393 | 408 | self.stat_code = BackgroundJobBase.stat_dead_c |
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394 | 409 | self.finished = None |
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395 | 410 | self.result = ('<BackgroundJob died, call jobs.traceback() for details>') |
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396 | 411 | self._tb = self._make_tb() |
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397 | 412 | else: |
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398 | 413 | self.status = BackgroundJobBase.stat_completed |
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399 | 414 | self.stat_code = BackgroundJobBase.stat_completed_c |
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400 | 415 | self.finished = True |
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401 | 416 | |
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417 | ||
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402 | 418 | class BackgroundJobExpr(BackgroundJobBase): |
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403 | 419 | """Evaluate an expression as a background job (uses a separate thread).""" |
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404 | 420 | |
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405 | def __init__(self,expression,glob=None,loc=None): | |
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421 | def __init__(self, expression, glob=None, loc=None): | |
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406 | 422 | """Create a new job from a string which can be fed to eval(). |
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407 | 423 | |
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408 | 424 | global/locals dicts can be provided, which will be passed to the eval |
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409 | 425 | call.""" |
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410 | 426 | |
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411 | 427 | # fail immediately if the given expression can't be compiled |
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412 | 428 | self.code = compile(expression,'<BackgroundJob compilation>','eval') |
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413 | 429 | |
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414 |
if glob is None |
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415 | glob = {} | |
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416 | if loc is None: | |
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417 | loc = {} | |
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418 | ||
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430 | glob = {} if glob is None else glob | |
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431 | loc = {} if loc is None else loc | |
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419 | 432 | self.expression = self.strform = expression |
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420 | 433 | self.glob = glob |
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421 | 434 | self.loc = loc |
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422 | 435 | self._init() |
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423 | 436 | |
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424 | 437 | def call(self): |
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425 | 438 | return eval(self.code,self.glob,self.loc) |
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426 | 439 | |
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440 | ||
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427 | 441 | class BackgroundJobFunc(BackgroundJobBase): |
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428 | 442 | """Run a function call as a background job (uses a separate thread).""" |
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429 | 443 | |
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430 | def __init__(self,func,*args,**kwargs): | |
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444 | def __init__(self, func, *args, **kwargs): | |
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431 | 445 | """Create a new job from a callable object. |
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432 | 446 | |
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433 | 447 | Any positional arguments and keyword args given to this constructor |
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434 | 448 | after the initial callable are passed directly to it.""" |
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435 | 449 | |
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436 | assert callable(func),'first argument must be callable' | |
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437 | ||
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438 | if args is None: | |
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439 | args = [] | |
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440 | if kwargs is None: | |
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441 | kwargs = {} | |
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450 | if not callable(func): | |
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451 | raise TypeError( | |
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452 | 'first argument to BackgroundJobFunc must be callable') | |
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442 | 453 | |
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443 | 454 | self.func = func |
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444 | 455 | self.args = args |
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445 | 456 | self.kwargs = kwargs |
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446 | 457 | # The string form will only include the function passed, because |
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447 | 458 | # generating string representations of the arguments is a potentially |
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448 | 459 | # _very_ expensive operation (e.g. with large arrays). |
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449 | 460 | self.strform = str(func) |
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450 | 461 | self._init() |
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451 | 462 | |
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452 | 463 | def call(self): |
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453 | return self.func(*self.args,**self.kwargs) | |
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454 | ||
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455 | ||
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456 | if __name__=='__main__': | |
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457 | ||
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458 | import sys | |
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459 | import time | |
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460 | ||
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461 | def sleepfunc(interval=2,*a,**kw): | |
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462 | args = dict(interval=interval, | |
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463 | args=a, | |
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464 | kwargs=kw) | |
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465 | time.sleep(interval) | |
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466 | return args | |
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467 | ||
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468 | def diefunc(interval=2,*a,**kw): | |
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469 | time.sleep(interval) | |
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470 | die | |
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471 | ||
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472 | def printfunc(interval=1,reps=5): | |
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473 | for n in range(reps): | |
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474 | time.sleep(interval) | |
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475 | print 'In the background...', n | |
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476 | sys.stdout.flush() | |
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477 | ||
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478 | jobs = BackgroundJobManager() | |
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479 | # first job will have # 0 | |
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480 | jobs.new(sleepfunc,4) | |
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481 | jobs.new(sleepfunc,kw={'reps':2}) | |
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482 | # This makes a job which will die | |
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483 | jobs.new(diefunc,1) | |
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484 | jobs.new('printfunc(1,3)') | |
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485 | ||
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486 | # after a while, you can get the traceback of a dead job. Run the line | |
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487 | # below again interactively until it prints a traceback (check the status | |
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488 | # of the job): | |
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489 | print jobs[1].status | |
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490 | jobs[1].traceback() | |
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491 | ||
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492 | # Run this line again until the printed result changes | |
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493 | print "The result of job #0 is:",jobs[0].result | |
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464 | return self.func(*self.args, **self.kwargs) |
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