1 | |
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2 | ################################################################################ |
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3 | #This software was developed by the University of Tennessee as part of the |
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4 | #Distributed Data Analysis of Neutron Scattering Experiments (DANSE) |
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5 | #project funded by the US National Science Foundation. |
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6 | # |
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7 | #See the license text in license.txt |
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8 | # |
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9 | #copyright 2010, University of Tennessee |
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10 | ################################################################################ |
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11 | |
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12 | |
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13 | import sys |
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14 | import time |
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15 | import subprocess |
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16 | import os |
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17 | import getopt |
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18 | from threading import Thread |
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19 | |
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20 | ## Maximum number of seconds to wait for an answer from the server |
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21 | MAX_WAIT_TIME = 20 |
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22 | ## Local storage file name |
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23 | VERSION_FILE = '.current_version' |
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24 | |
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25 | class VersionChecker(object): |
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26 | """ |
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27 | Class of objects used to obtain the current version of an application |
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28 | from the deployment server. |
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29 | A sub process is started to read the URL associated with the version number. |
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30 | The version number is written on file locally before the reading process |
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31 | ends, then read when the version number is requested. |
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32 | |
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33 | The reading of the URL is put in a separate process so that it doesn't |
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34 | affect the performance of the application and can be managed and stopped at any time. |
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35 | """ |
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36 | ## Process used to obtain the current application version from the server |
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37 | _process = None |
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38 | ## Start time of the process of obtaining a version number |
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39 | _t_0 = None |
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40 | |
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41 | def __init__(self, version_url): |
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42 | """ |
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43 | Start the sub-process used to read the version URL |
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44 | """ |
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45 | self._process = subprocess.Popen([sys.executable, __file__, |
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46 | '-g', '-u%s' % version_url]) |
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47 | self._t_0 = time.time() |
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48 | |
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49 | def is_complete(self): |
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50 | """ |
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51 | Method used to poll the reading process. The process will be killed |
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52 | if the wait time is longer than a predefined maximum. |
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53 | This method should always be called before get_version() to ensure |
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54 | accuracy of the version number that is returned. |
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55 | """ |
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56 | if(time.time() - self._t_0 < MAX_WAIT_TIME): |
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57 | if self._process.poll() is not None: |
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58 | return True |
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59 | return False |
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60 | else: |
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61 | self._process.kill() |
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62 | return True |
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63 | |
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64 | def get_version(self): |
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65 | """ |
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66 | Returns the last version number that was read from the server. |
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67 | """ |
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68 | try: |
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69 | f = open(VERSION_FILE, 'r') |
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70 | return f.read() |
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71 | except: |
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72 | return '0.0.0' |
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73 | |
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74 | class VersionThread(Thread): |
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75 | """ |
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76 | Thread used to start the process of reading the current version of an |
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77 | application from the deployment server. |
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78 | |
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79 | The VersionChecker is user in a Thread to allow the main application |
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80 | to continue dealing with UI requests from the user. The main application |
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81 | provides a call-back method for when the version number is obtained. |
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82 | """ |
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83 | def __init__ (self, url, call_back=None, baggage=None): |
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84 | Thread.__init__(self) |
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85 | self._url = url |
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86 | self._call_back = call_back |
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87 | self._baggage = baggage |
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88 | |
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89 | def run(self): |
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90 | """ |
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91 | Execute the process of reading the current application version number. |
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92 | """ |
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93 | checker = VersionChecker(self._url) |
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94 | while(not checker.is_complete()): |
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95 | time.sleep(1) |
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96 | self._call_back(checker.get_version(), self._baggage) |
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97 | |
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98 | def write_version(version, filename=VERSION_FILE): |
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99 | """ |
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100 | Store the version number |
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101 | This could be put into a DB if the application has one. |
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102 | """ |
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103 | f = open(filename, 'w') |
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104 | f.write(version) |
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105 | f.close() |
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106 | |
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107 | def _get_version_from_server(url): |
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108 | """ |
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109 | Method executed in the independent process used to read the |
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110 | current version number from the server. |
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111 | |
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112 | :param url: URL to read the version number from |
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113 | |
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114 | """ |
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115 | import urllib |
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116 | import re |
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117 | try: |
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118 | h = urllib.urlopen(url) |
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119 | for line in h.readlines(): |
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120 | version = line.strip() |
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121 | if len(re.findall('\d+\.\d+\.\d+$', version)) > 0: |
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122 | write_version(version) |
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123 | return |
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124 | write_version('0.0.0') |
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125 | except: |
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126 | write_version('0.0.0') |
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127 | |
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128 | if __name__ == "__main__": |
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129 | _get_version = False |
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130 | _url = 'http://danse.chem.utk.edu/prview_version.php' |
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131 | |
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132 | opts, args = getopt.getopt(sys.argv[1:], "gu:", ["get", "url="]) |
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133 | for opt, arg in opts: |
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134 | if opt in ("-u", "--url"): |
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135 | _url = arg |
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136 | elif opt in ("-g", "--get"): |
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137 | _get_version = True |
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138 | |
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139 | if _get_version: |
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140 | # Get the version number from the URL. |
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141 | _get_version_from_server(_url) |
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142 | else: |
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143 | # Test execution of the reading process |
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144 | def _process(version, baggage=None): |
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145 | print "Received:", version |
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146 | checker = VersionThread(_url, _process) |
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147 | checker.start() |
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148 | |
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