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  <div class="section" id="module-celery.task.strategy">
<h1>Common Task Strategies - celery.task.strategy<a class="headerlink" href="#module-celery.task.strategy" title="Permalink to this headline">¶</a></h1>
<dl class="function">
<dt id="celery.task.strategy.even_time_distribution">
<tt class="descclassname">celery.task.strategy.</tt><tt class="descname">even_time_distribution</tt><big>(</big><em>task</em>, <em>size</em>, <em>time_window</em>, <em>iterable</em>, <em>**apply_kwargs</em><big>)</big><a class="headerlink" href="#celery.task.strategy.even_time_distribution" title="Permalink to this definition">¶</a></dt>
<dd><p>With an iterator yielding task args, kwargs tuples, evenly distribute
the processing of its tasks throughout the time window available.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple">
<li><em>task</em> &#8211; The kind of task (a <a title="celery.task.base.Task" class="reference external" href="celery.task.base.html#celery.task.base.Task"><tt class="xref docutils literal"><span class="pre">celery.task.base.Task</span></tt></a>.)</li>
<li><em>size</em> &#8211; Total number of elements the iterator gives.</li>
<li><em>time_window</em> &#8211; Total time available, in minutes.</li>
<li><em>iterable</em> &#8211; Iterable yielding task args, kwargs tuples.</li>
<li><em>**apply_kwargs</em> &#8211; Additional keyword arguments to be passed on to
<a title="celery.execute.apply_async" class="reference external" href="celery.execute.html#celery.execute.apply_async"><tt class="xref docutils literal"><span class="pre">celery.execute.apply_async()</span></tt></a>.</li>
</ul>
</td>
</tr>
</tbody>
</table>
<p>Example</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">&gt;&gt;&gt; </span><span class="k">class</span> <span class="nc">RefreshAllFeeds</span><span class="p">(</span><span class="n">Task</span><span class="p">):</span>
<span class="gp">...</span>
<span class="gp">... </span>    <span class="k">def</span> <span class="nf">run</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
<span class="gp">... </span>        <span class="n">feeds</span> <span class="o">=</span> <span class="n">Feed</span><span class="o">.</span><span class="n">objects</span><span class="o">.</span><span class="n">all</span><span class="p">()</span>
<span class="gp">... </span>        <span class="n">total</span> <span class="o">=</span> <span class="n">feeds</span><span class="o">.</span><span class="n">count</span><span class="p">()</span>
<span class="gp">...</span>
<span class="gp">... </span>        <span class="n">time_window</span> <span class="o">=</span> <span class="n">REFRESH_FEEDS_EVERY_INTERVAL_MINUTES</span>
<span class="gp">...</span>
<span class="gp">... </span>        <span class="k">def</span> <span class="nf">iter_feed_task_args</span><span class="p">(</span><span class="n">iterable</span><span class="p">):</span>
<span class="gp">... </span>            <span class="k">for</span> <span class="n">feed</span> <span class="ow">in</span> <span class="n">iterable</span><span class="p">:</span>
<span class="gp">... </span>                <span class="k">yield</span> <span class="p">([</span><span class="n">feed</span><span class="o">.</span><span class="n">feed_url</span><span class="p">],</span> <span class="p">{})</span> <span class="c"># args, kwargs tuple</span>
<span class="gp">...</span>
<span class="gp">... </span>        <span class="n">it</span> <span class="o">=</span> <span class="n">iter_feed_task_args</span><span class="p">(</span><span class="n">feeds</span><span class="o">.</span><span class="n">iterator</span><span class="p">())</span>
<span class="gp">...</span>
<span class="gp">... </span>        <span class="n">even_time_distribution</span><span class="p">(</span><span class="n">RefreshFeedTask</span><span class="p">,</span> <span class="n">total</span><span class="p">,</span>
<span class="gp">... </span>                               <span class="n">time_window</span><span class="p">,</span> <span class="n">it</span><span class="p">)</span>
</pre></div>
</div>
</dd></dl>

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