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POProgress monitoring using Django model is not syncronized (One writer and multiple readers)
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copied!<p>I am implementing a progress monitoring function using Django. However, I cannot get the updated value in the front end.</p> <p>A Django management command is executed by <code>popen</code> to keep updating the progress of a <code>webscan</code>. Scan is a Django model and <code>progress_info</code> is an attribute of the model which is saved in database. The code is as follows:</p> <pre><code> d = 10 while (d) : time.sleep(10) try: isBusy = server.call("framework.busy?") logging.debug(isBusy) if isBusy.strip() == 'true': progress = webscan.progress webscan.progress_info = progress webscan.save() logging.debug("%s"%progress) else: d = 0 except Exception as e: logging.debug("In an exception when calling busy. Exception: %s and Type %s"%(e, type(e))) d -= 1 </code></pre> <p>In the front-end, I make an ajax call to get the value of <code>progress_info</code>. The handler simply get the value of <code>webscan.progress_info</code>and returns it to the front-end. The code is as follows:</p> <pre><code>@property def get_progress(self): return self.progress_info </code></pre> <p>Using the GUI of the DB, I can see that the value of progress_info is kept updated. However, the ajax call keeps returning <code>0</code> to the front-end until the command finishes (0 is the initial value of <code>progress_info</code>).</p> <p>I guess it is because of the locking mechanism of DB or Django but do not fully understand why. Could anyone help me with it? Thanks a lot~</p>

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