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Django Q2
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<li class="toctree-l3"><a class="reference internal" href="#django_q.async_chain"><code class="docutils literal notranslate"><span class="pre">async_chain()</span></code></a></li>
<li class="toctree-l3"><a class="reference internal" href="#django_q.Chain"><code class="docutils literal notranslate"><span class="pre">Chain</span></code></a><ul>
<li class="toctree-l4"><a class="reference internal" href="#django_q.Chain.append"><code class="docutils literal notranslate"><span class="pre">Chain.append()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#django_q.Chain.run"><code class="docutils literal notranslate"><span class="pre">Chain.run()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#django_q.Chain.result"><code class="docutils literal notranslate"><span class="pre">Chain.result()</span></code></a></li>
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<li class="toctree-l4"><a class="reference internal" href="#django_q.Chain.current"><code class="docutils literal notranslate"><span class="pre">Chain.current()</span></code></a></li>
<li class="toctree-l4"><a class="reference internal" href="#django_q.Chain.length"><code class="docutils literal notranslate"><span class="pre">Chain.length()</span></code></a></li>
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<section id="chains">
<h1>Chains<a class="headerlink" href="#chains" title="Link to this heading"></a></h1>
<p>Sometimes you want to run tasks sequentially. For that you can use the <a class="reference internal" href="#django_q.async_chain" title="django_q.async_chain"><code class="xref py py-func docutils literal notranslate"><span class="pre">async_chain()</span></code></a> function:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="c1"># async a chain of tasks</span>
<span class="kn">from</span> <span class="nn">django_q.tasks</span> <span class="kn">import</span> <span class="n">async_chain</span><span class="p">,</span> <span class="n">result_group</span>
<span class="c1"># the chain must be in the format</span>
<span class="c1"># [(func,(args),{kwargs}),(func,(args),{kwargs}),..]</span>
<span class="n">group_id</span> <span class="o">=</span> <span class="n">async_chain</span><span class="p">([(</span><span class="s1">'math.copysign'</span><span class="p">,</span> <span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="o">-</span><span class="mi">1</span><span class="p">)),</span>
<span class="p">(</span><span class="s1">'math.floor'</span><span class="p">,</span> <span class="p">(</span><span class="mi">1</span><span class="p">,))])</span>
<span class="c1"># get group result</span>
<span class="n">result_group</span><span class="p">(</span><span class="n">group_id</span><span class="p">,</span> <span class="n">count</span><span class="o">=</span><span class="mi">2</span><span class="p">)</span>
</pre></div>
</div>
<p>A slightly more convenient way is to use a <a class="reference internal" href="#django_q.Chain" title="django_q.Chain"><code class="xref py py-class docutils literal notranslate"><span class="pre">Chain</span></code></a> instance:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="c1"># Chain async</span>
<span class="kn">from</span> <span class="nn">django_q.tasks</span> <span class="kn">import</span> <span class="n">Chain</span>
<span class="c1"># create a chain that uses the cache backend</span>
<span class="n">chain</span> <span class="o">=</span> <span class="n">Chain</span><span class="p">(</span><span class="n">cached</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="c1"># add some tasks</span>
<span class="n">chain</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="s1">'math.copysign'</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="o">-</span><span class="mi">1</span><span class="p">)</span>
<span class="n">chain</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="s1">'math.floor'</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
<span class="c1"># run it</span>
<span class="n">chain</span><span class="o">.</span><span class="n">run</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="n">chain</span><span class="o">.</span><span class="n">result</span><span class="p">())</span>
</pre></div>
</div>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="p">[</span><span class="o">-</span><span class="mf">1.0</span><span class="p">,</span> <span class="mi">1</span><span class="p">]</span>
</pre></div>
</div>
<section id="reference">
<h2>Reference<a class="headerlink" href="#reference" title="Link to this heading"></a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="django_q.async_chain">
<span class="sig-name descname"><span class="pre">async_chain</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">chain</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">group</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">cached</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">Conf.CACHED</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">sync</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">Conf.SYNC</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">broker</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#django_q.async_chain" title="Link to this definition"></a></dt>
<dd><p>Async a chain of tasks. See also the <a class="reference internal" href="#django_q.Chain" title="django_q.Chain"><code class="xref py py-class docutils literal notranslate"><span class="pre">Chain</span></code></a> class.</p>
<dl class="field-list simple">
<dt class="field-odd">Parameters<span class="colon">:</span></dt>
<dd class="field-odd"><ul class="simple">
<li><p><strong>chain</strong> (<em>list</em>) – a list of tasks in the format [(func,(args),{kwargs}), (func,(args),{kwargs})]</p></li>
<li><p><strong>group</strong> (<em>str</em>) – an optional group name.</p></li>
<li><p><strong>cached</strong> (<em>bool</em>) – run this against the cache backend</p></li>
<li><p><strong>sync</strong> (<em>bool</em>) – execute this inline instead of asynchronous</p></li>
</ul>
</dd>
</dl>
</dd></dl>
<dl class="py class">
<dt class="sig sig-object py" id="django_q.Chain">
<em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-name descname"><span class="pre">Chain</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">chain</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">group</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">cached</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">Conf.CACHED</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">sync</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">Conf.SYNC</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#django_q.Chain" title="Link to this definition"></a></dt>
<dd><p>A sequential chain of tasks. Acts as a convenient wrapper for <a class="reference internal" href="#django_q.async_chain" title="django_q.async_chain"><code class="xref py py-func docutils literal notranslate"><span class="pre">async_chain()</span></code></a>
You can pass the task chain at construction or you can append individual tasks before running them.</p>
<blockquote>
<div><dl class="field-list simple">
<dt class="field-odd">param list chain<span class="colon">:</span></dt>
<dd class="field-odd"><p>a list of task in the format [(func,(args),{kwargs}), (func,(args),{kwargs})]</p>
</dd>
<dt class="field-even">param str group<span class="colon">:</span></dt>
<dd class="field-even"><p>an optional group name.</p>
</dd>
<dt class="field-odd">param bool cached<span class="colon">:</span></dt>
<dd class="field-odd"><p>run this against the cache backend</p>
</dd>
<dt class="field-even">param bool sync<span class="colon">:</span></dt>
<dd class="field-even"><p>execute this inline instead of asynchronous</p>
</dd>
</dl>
</div></blockquote>
<dl class="py method">
<dt class="sig sig-object py" id="django_q.Chain.append">
<span class="sig-name descname"><span class="pre">append</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">func</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">*</span></span><span class="n"><span class="pre">args</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">**</span></span><span class="n"><span class="pre">kwargs</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#django_q.Chain.append" title="Link to this definition"></a></dt>
<dd></dd></dl>
<p>Append a task to the chain. Takes the same arguments as <a class="reference internal" href="tasks.html#django_q.async_task" title="django_q.async_task"><code class="xref py py-func docutils literal notranslate"><span class="pre">async_task()</span></code></a></p>
<blockquote>
<div><dl class="field-list simple">
<dt class="field-odd">return<span class="colon">:</span></dt>
<dd class="field-odd"><p>the current number of tasks in the chain</p>
</dd>
<dt class="field-even">rtype<span class="colon">:</span></dt>
<dd class="field-even"><p>int</p>
</dd>
</dl>
</div></blockquote>
<dl class="py method">
<dt class="sig sig-object py" id="django_q.Chain.run">
<span class="sig-name descname"><span class="pre">run</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#django_q.Chain.run" title="Link to this definition"></a></dt>
<dd></dd></dl>
<p>Start queueing the chain to the worker cluster.</p>
<blockquote>
<div><dl class="field-list simple">
<dt class="field-odd">return<span class="colon">:</span></dt>
<dd class="field-odd"><p>the chains group id</p>
</dd>
</dl>
</div></blockquote>
<dl class="py method">
<dt class="sig sig-object py" id="django_q.Chain.result">
<span class="sig-name descname"><span class="pre">result</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">wait</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#django_q.Chain.result" title="Link to this definition"></a></dt>
<dd></dd></dl>
<p>return the full list of results from the chain when it finishes. Blocks until timeout or result.</p>
<blockquote>
<div><dl class="field-list simple">
<dt class="field-odd">param int wait<span class="colon">:</span></dt>
<dd class="field-odd"><p>how many milliseconds to wait for a result</p>
</dd>
<dt class="field-even">return<span class="colon">:</span></dt>
<dd class="field-even"><p>an unsorted list of results</p>
</dd>
</dl>
</div></blockquote>
<dl class="py method">
<dt class="sig sig-object py" id="django_q.Chain.fetch">
<span class="sig-name descname"><span class="pre">fetch</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">failures</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">True</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">wait</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#django_q.Chain.fetch" title="Link to this definition"></a></dt>
<dd></dd></dl>
<p>get the task result objects from the chain when it finishes. Blocks until timeout or result.</p>
<blockquote>
<div><dl class="field-list simple">
<dt class="field-odd">param failures<span class="colon">:</span></dt>
<dd class="field-odd"><p>include failed tasks</p>
</dd>
<dt class="field-even">param int wait<span class="colon">:</span></dt>
<dd class="field-even"><p>how many milliseconds to wait for a result</p>
</dd>
<dt class="field-odd">return<span class="colon">:</span></dt>
<dd class="field-odd"><p>an unsorted list of task objects</p>
</dd>
</dl>
</div></blockquote>
<dl class="py method">
<dt class="sig sig-object py" id="django_q.Chain.current">
<span class="sig-name descname"><span class="pre">current</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#django_q.Chain.current" title="Link to this definition"></a></dt>
<dd></dd></dl>
<p>get the index of the currently executing chain element</p>
<blockquote>
<div><dl class="field-list simple">
<dt class="field-odd">return int<span class="colon">:</span></dt>
<dd class="field-odd"><p>current chain index</p>
</dd>
</dl>
</div></blockquote>
<dl class="py method">
<dt class="sig sig-object py" id="django_q.Chain.length">
<span class="sig-name descname"><span class="pre">length</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#django_q.Chain.length" title="Link to this definition"></a></dt>
<dd></dd></dl>
<p>get the length of the chain</p>
<blockquote>
<div><dl class="field-list simple">
<dt class="field-odd">return int<span class="colon">:</span></dt>
<dd class="field-odd"><p>length of the chain</p>
</dd>
</dl>
</div></blockquote>
</dd></dl>
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