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   <div class="section" id="module-apache_beam.utils.multi_process_shared">
 <span id="apache-beam-utils-multi-process-shared-module"></span><h1>apache_beam.utils.multi_process_shared module<a class="headerlink" href="#module-apache_beam.utils.multi_process_shared" title="Permalink to this headline">¶</a></h1>
 <p>Implements a shared object that spans processes.</p>
 <p>This object will be instanciated once per VM and methods will be invoked
 on it via rpc.</p>
 <dl class="class">
 <dt id="apache_beam.utils.multi_process_shared.MultiProcessShared">
 <em class="property">class </em><code class="descclassname">apache_beam.utils.multi_process_shared.</code><code class="descname">MultiProcessShared</code><span class="sig-paren">(</span><em>constructor: Callable[[], T], tag: Optional[Any] = None, *, path: str = '/usr/local/google/home/jrmccluskey/website_update_dir/python_doc/beam/sdks/python/target/.tox/py38-docs/tmp', always_proxy: Optional[bool] = None</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/utils/multi_process_shared.html#MultiProcessShared"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.utils.multi_process_shared.MultiProcessShared" title="Permalink to this definition">¶</a></dt>
 <dd><p>Bases: <a class="reference external" href="https://docs.python.org/3/library/typing.html#typing.Generic" title="(in Python v3.11)"><code class="xref py py-class docutils literal notranslate"><span class="pre">typing.Generic</span></code></a></p>
 <p>MultiProcessShared is used to share a single object across processes.</p>
 <p>For example, one could have the class:</p>
 <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">MyExpensiveObject</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
   <span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">args</span><span class="p">):</span>
     <span class="p">[</span><span class="n">expensive</span> <span class="n">initialization</span> <span class="ow">and</span> <span class="n">memory</span> <span class="n">allocation</span><span class="p">]</span>

   <span class="k">def</span> <span class="nf">method</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
     <span class="o">...</span>
 </pre></div>
 </div>
 <p>One could share a single instance of this class by wrapping it as:</p>
 <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">shared_ptr</span> <span class="o">=</span> <span class="n">MultiProcessShared</span><span class="p">(</span><span class="k">lambda</span><span class="p">:</span> <span class="n">MyExpensiveObject</span><span class="p">(</span><span class="o">...</span><span class="p">))</span>
 <span class="n">my_expensive_object</span> <span class="o">=</span> <span class="n">shared_ptr</span><span class="o">.</span><span class="n">acquire</span><span class="p">()</span>
 </pre></div>
 </div>
 <p>which could then be invoked as:</p>
 <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">my_expensive_object</span><span class="o">.</span><span class="n">method</span><span class="p">(</span><span class="n">arg</span><span class="p">)</span>
 </pre></div>
 </div>
 <p>This can then be released with:</p>
 <div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">shared_ptr</span><span class="o">.</span><span class="n">release</span><span class="p">(</span><span class="n">my_expensive_object</span><span class="p">)</span>
 </pre></div>
 </div>
 <p>but care should be taken to avoid releasing the object too soon or
 expensive re-initialization may be required, defeating the point of
 using a shared object.</p>
 <table class="docutils field-list" frame="void" rules="none">
 <col class="field-name" />
 <col class="field-body" />
 <tbody valign="top">
 <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple">
 <li><strong>constructor</strong> – function that initialises / constructs the object if not
 present in the cache. This function should take no arguments. It should
 return an initialised object, or raise an exception if the object could
 not be initialised / constructed.</li>
 <li><strong>tag</strong> – an optional indentifier to store with the cached object. If multiple
 MultiProcessShared instances are created with the same tag, they will all
 share the same proxied object.</li>
 <li><strong>path</strong> – a temporary path in which to create the inter-process lock</li>
 <li><strong>always_proxy</strong> – whether to direct all calls through the proxy, rather than
 call the object directly for the process that created it</li>
 </ul>
 </td>
 </tr>
 </tbody>
 </table>
 <dl class="method">
 <dt id="apache_beam.utils.multi_process_shared.MultiProcessShared.acquire">
 <code class="descname">acquire</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/utils/multi_process_shared.html#MultiProcessShared.acquire"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.utils.multi_process_shared.MultiProcessShared.acquire" title="Permalink to this definition">¶</a></dt>
 <dd></dd></dl>

 <dl class="method">
 <dt id="apache_beam.utils.multi_process_shared.MultiProcessShared.release">
 <code class="descname">release</code><span class="sig-paren">(</span><em>obj</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/utils/multi_process_shared.html#MultiProcessShared.release"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.utils.multi_process_shared.MultiProcessShared.release" title="Permalink to this definition">¶</a></dt>
 <dd></dd></dl>

 </dd></dl>

 </div>


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	<div class="section" id="module-apache_beam.utils.multi_process_shared">
	<span id="apache-beam-utils-multi-process-shared-module"></span><h1>apache_beam.utils.multi_process_shared module<a class="headerlink" href="#module-apache_beam.utils.multi_process_shared" title="Permalink to this headline">¶</a></h1>
	<p>Implements a shared object that spans processes.</p>
	<p>This object will be instanciated once per VM and methods will be invoked
	on it via rpc.</p>
	<dl class="class">
	<dt id="apache_beam.utils.multi_process_shared.MultiProcessShared">
	<em class="property">class </em><code class="descclassname">apache_beam.utils.multi_process_shared.</code><code class="descname">MultiProcessShared</code><span class="sig-paren">(</span><em>constructor: Callable[[], T], tag: Optional[Any] = None, *, path: str = '/usr/local/google/home/jrmccluskey/website_update_dir/python_doc/beam/sdks/python/target/.tox/py38-docs/tmp', always_proxy: Optional[bool] = None</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/utils/multi_process_shared.html#MultiProcessShared"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.utils.multi_process_shared.MultiProcessShared" title="Permalink to this definition">¶</a></dt>
	<dd><p>Bases: <a class="reference external" href="https://docs.python.org/3/library/typing.html#typing.Generic" title="(in Python v3.11)"><code class="xref py py-class docutils literal notranslate"><span class="pre">typing.Generic</span></code></a></p>
	<p>MultiProcessShared is used to share a single object across processes.</p>
	<p>For example, one could have the class:</p>
	<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">MyExpensiveObject</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
	<span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">args</span><span class="p">):</span>
	<span class="p">[</span><span class="n">expensive</span> <span class="n">initialization</span> <span class="ow">and</span> <span class="n">memory</span> <span class="n">allocation</span><span class="p">]</span>

	<span class="k">def</span> <span class="nf">method</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">arg</span><span class="p">):</span>
	<span class="o">...</span>
	</pre></div>
	</div>
	<p>One could share a single instance of this class by wrapping it as:</p>
	<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">shared_ptr</span> <span class="o">=</span> <span class="n">MultiProcessShared</span><span class="p">(</span><span class="k">lambda</span><span class="p">:</span> <span class="n">MyExpensiveObject</span><span class="p">(</span><span class="o">...</span><span class="p">))</span>
	<span class="n">my_expensive_object</span> <span class="o">=</span> <span class="n">shared_ptr</span><span class="o">.</span><span class="n">acquire</span><span class="p">()</span>
	</pre></div>
	</div>
	<p>which could then be invoked as:</p>
	<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">my_expensive_object</span><span class="o">.</span><span class="n">method</span><span class="p">(</span><span class="n">arg</span><span class="p">)</span>
	</pre></div>
	</div>
	<p>This can then be released with:</p>
	<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">shared_ptr</span><span class="o">.</span><span class="n">release</span><span class="p">(</span><span class="n">my_expensive_object</span><span class="p">)</span>
	</pre></div>
	</div>
	<p>but care should be taken to avoid releasing the object too soon or
	expensive re-initialization may be required, defeating the point of
	using a shared object.</p>
	<table class="docutils field-list" frame="void" rules="none">
	<col class="field-name" />
	<col class="field-body" />
	<tbody valign="top">
	<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple">
	<li><strong>constructor</strong> – function that initialises / constructs the object if not
	present in the cache. This function should take no arguments. It should
	return an initialised object, or raise an exception if the object could
	not be initialised / constructed.</li>
	<li><strong>tag</strong> – an optional indentifier to store with the cached object. If multiple
	MultiProcessShared instances are created with the same tag, they will all
	share the same proxied object.</li>
	<li><strong>path</strong> – a temporary path in which to create the inter-process lock</li>
	<li><strong>always_proxy</strong> – whether to direct all calls through the proxy, rather than
	call the object directly for the process that created it</li>
	</ul>
	</td>
	</tr>
	</tbody>
	</table>
	<dl class="method">
	<dt id="apache_beam.utils.multi_process_shared.MultiProcessShared.acquire">
	<code class="descname">acquire</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/utils/multi_process_shared.html#MultiProcessShared.acquire"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.utils.multi_process_shared.MultiProcessShared.acquire" title="Permalink to this definition">¶</a></dt>
	<dd></dd></dl>

	<dl class="method">
	<dt id="apache_beam.utils.multi_process_shared.MultiProcessShared.release">
	<code class="descname">release</code><span class="sig-paren">(</span><em>obj</em><span class="sig-paren">)</span><a class="reference internal" href="_modules/apache_beam/utils/multi_process_shared.html#MultiProcessShared.release"><span class="viewcode-link">[source]</span></a><a class="headerlink" href="#apache_beam.utils.multi_process_shared.MultiProcessShared.release" title="Permalink to this definition">¶</a></dt>
	<dd></dd></dl>

	</dd></dl>

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