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   <h1>Source code for apache_beam.utils.multi_process_shared</h1><div class="highlight"><pre>
 <span></span><span class="c1">#</span>
 <span class="c1"># Licensed to the Apache Software Foundation (ASF) under one or more</span>
 <span class="c1"># contributor license agreements.  See the NOTICE file distributed with</span>
 <span class="c1"># this work for additional information regarding copyright ownership.</span>
 <span class="c1"># The ASF licenses this file to You under the Apache License, Version 2.0</span>
 <span class="c1"># (the &quot;License&quot;); you may not use this file except in compliance with</span>
 <span class="c1"># the License.  You may obtain a copy of the License at</span>
 <span class="c1">#</span>
 <span class="c1">#    http://www.apache.org/licenses/LICENSE-2.0</span>
 <span class="c1">#</span>
 <span class="c1"># Unless required by applicable law or agreed to in writing, software</span>
 <span class="c1"># distributed under the License is distributed on an &quot;AS IS&quot; BASIS,</span>
 <span class="c1"># WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span>
 <span class="c1"># See the License for the specific language governing permissions and</span>
 <span class="c1"># limitations under the License.</span>
 <span class="c1">#</span>

 <span class="sd">&quot;&quot;&quot;Implements a shared object that spans processes.</span>

 <span class="sd">This object will be instanciated once per VM and methods will be invoked</span>
 <span class="sd">on it via rpc.</span>
 <span class="sd">&quot;&quot;&quot;</span>
 <span class="c1"># pytype: skip-file</span>

 <span class="kn">import</span> <span class="nn">logging</span>
 <span class="kn">import</span> <span class="nn">multiprocessing.managers</span>
 <span class="kn">import</span> <span class="nn">os</span>
 <span class="kn">import</span> <span class="nn">tempfile</span>
 <span class="kn">import</span> <span class="nn">threading</span>
 <span class="kn">import</span> <span class="nn">uuid</span>
 <span class="kn">from</span> <span class="nn">typing</span> <span class="kn">import</span> <span class="n">Any</span>
 <span class="kn">from</span> <span class="nn">typing</span> <span class="kn">import</span> <span class="n">Callable</span>
 <span class="kn">from</span> <span class="nn">typing</span> <span class="kn">import</span> <span class="n">Dict</span>
 <span class="kn">from</span> <span class="nn">typing</span> <span class="kn">import</span> <span class="n">Generic</span>
 <span class="kn">from</span> <span class="nn">typing</span> <span class="kn">import</span> <span class="n">Optional</span>
 <span class="kn">from</span> <span class="nn">typing</span> <span class="kn">import</span> <span class="n">TypeVar</span>

 <span class="kn">import</span> <span class="nn">fasteners</span>

 <span class="n">T</span> <span class="o">=</span> <span class="n">TypeVar</span><span class="p">(</span><span class="s1">&#39;T&#39;</span><span class="p">)</span>


 <span class="k">class</span> <span class="nc">_SingletonProxy</span><span class="p">:</span>
 <span class="w">  </span><span class="sd">&quot;&quot;&quot;Proxies the shared object so we can release it with better errors and no</span>
 <span class="sd">  risk of dangling references in the multiprocessing manager infrastructure.</span>
 <span class="sd">  &quot;&quot;&quot;</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">entry</span><span class="p">):</span>
     <span class="c1"># Guard names so as to not conflict with names of underlying object.</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_SingletonProxy_entry</span> <span class="o">=</span> <span class="n">entry</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_SingletonProxy_valid</span> <span class="o">=</span> <span class="kc">True</span>

   <span class="k">def</span> <span class="nf">_SingletonProxy_release</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
     <span class="k">assert</span> <span class="bp">self</span><span class="o">.</span><span class="n">_SingletonProxy_valid</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_SingletonProxy_valid</span> <span class="o">=</span> <span class="kc">False</span>

   <span class="k">def</span> <span class="fm">__getattr__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">name</span><span class="p">):</span>
     <span class="k">if</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">_SingletonProxy_valid</span><span class="p">:</span>
       <span class="k">raise</span> <span class="ne">RuntimeError</span><span class="p">(</span><span class="s1">&#39;Entry was released.&#39;</span><span class="p">)</span>
     <span class="k">return</span> <span class="nb">getattr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_SingletonProxy_entry</span><span class="o">.</span><span class="n">obj</span><span class="p">,</span> <span class="n">name</span><span class="p">)</span>

   <span class="k">def</span> <span class="fm">__dir__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
     <span class="c1"># Needed for multiprocessing.managers&#39;s proxying.</span>
     <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">_SingletonProxy_entry</span><span class="o">.</span><span class="n">obj</span><span class="o">.</span><span class="fm">__dir__</span><span class="p">()</span>


 <span class="k">class</span> <span class="nc">_SingletonEntry</span><span class="p">:</span>
 <span class="w">  </span><span class="sd">&quot;&quot;&quot;Represents a single, refcounted entry in this process.&quot;&quot;&quot;</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">constructor</span><span class="p">,</span> <span class="n">initialize_eagerly</span><span class="o">=</span><span class="kc">True</span><span class="p">):</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">constructor</span> <span class="o">=</span> <span class="n">constructor</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">refcount</span> <span class="o">=</span> <span class="mi">0</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">lock</span> <span class="o">=</span> <span class="n">threading</span><span class="o">.</span><span class="n">Lock</span><span class="p">()</span>
     <span class="k">if</span> <span class="n">initialize_eagerly</span><span class="p">:</span>
       <span class="bp">self</span><span class="o">.</span><span class="n">obj</span> <span class="o">=</span> <span class="n">constructor</span><span class="p">()</span>
       <span class="bp">self</span><span class="o">.</span><span class="n">initialied</span> <span class="o">=</span> <span class="kc">True</span>
     <span class="k">else</span><span class="p">:</span>
       <span class="bp">self</span><span class="o">.</span><span class="n">initialied</span> <span class="o">=</span> <span class="kc">False</span>

   <span class="k">def</span> <span class="nf">acquire</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
     <span class="k">with</span> <span class="bp">self</span><span class="o">.</span><span class="n">lock</span><span class="p">:</span>
       <span class="k">if</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">initialied</span><span class="p">:</span>
         <span class="bp">self</span><span class="o">.</span><span class="n">obj</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">constructor</span><span class="p">()</span>
         <span class="bp">self</span><span class="o">.</span><span class="n">initialied</span> <span class="o">=</span> <span class="kc">True</span>
       <span class="bp">self</span><span class="o">.</span><span class="n">refcount</span> <span class="o">+=</span> <span class="mi">1</span>
       <span class="k">return</span> <span class="n">_SingletonProxy</span><span class="p">(</span><span class="bp">self</span><span class="p">)</span>

   <span class="k">def</span> <span class="nf">release</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">proxy</span><span class="p">):</span>
     <span class="n">proxy</span><span class="o">.</span><span class="n">_SingletonProxy_release</span><span class="p">()</span>
     <span class="k">with</span> <span class="bp">self</span><span class="o">.</span><span class="n">lock</span><span class="p">:</span>
       <span class="bp">self</span><span class="o">.</span><span class="n">refcount</span> <span class="o">-=</span> <span class="mi">1</span>
       <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">refcount</span> <span class="o">==</span> <span class="mi">0</span><span class="p">:</span>
         <span class="k">del</span> <span class="bp">self</span><span class="o">.</span><span class="n">obj</span>
         <span class="bp">self</span><span class="o">.</span><span class="n">initialied</span> <span class="o">=</span> <span class="kc">False</span>


 <span class="k">class</span> <span class="nc">_SingletonManager</span><span class="p">:</span>
   <span class="n">entries</span><span class="p">:</span> <span class="n">Dict</span><span class="p">[</span><span class="n">Any</span><span class="p">,</span> <span class="n">Any</span><span class="p">]</span> <span class="o">=</span> <span class="p">{}</span>

   <span class="k">def</span> <span class="nf">register_singleton</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">constructor</span><span class="p">,</span> <span class="n">tag</span><span class="p">,</span> <span class="n">initialize_eagerly</span><span class="o">=</span><span class="kc">True</span><span class="p">):</span>
     <span class="k">assert</span> <span class="n">tag</span> <span class="ow">not</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">entries</span><span class="p">,</span> <span class="n">tag</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">entries</span><span class="p">[</span><span class="n">tag</span><span class="p">]</span> <span class="o">=</span> <span class="n">_SingletonEntry</span><span class="p">(</span><span class="n">constructor</span><span class="p">,</span> <span class="n">initialize_eagerly</span><span class="p">)</span>

   <span class="k">def</span> <span class="nf">has_singleton</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">tag</span><span class="p">):</span>
     <span class="k">return</span> <span class="n">tag</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">entries</span>

   <span class="k">def</span> <span class="nf">acquire_singleton</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">tag</span><span class="p">):</span>
     <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">entries</span><span class="p">[</span><span class="n">tag</span><span class="p">]</span><span class="o">.</span><span class="n">acquire</span><span class="p">()</span>

   <span class="k">def</span> <span class="nf">release_singleton</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">tag</span><span class="p">,</span> <span class="n">obj</span><span class="p">):</span>
     <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">entries</span><span class="p">[</span><span class="n">tag</span><span class="p">]</span><span class="o">.</span><span class="n">release</span><span class="p">(</span><span class="n">obj</span><span class="p">)</span>


 <span class="n">_process_level_singleton_manager</span> <span class="o">=</span> <span class="n">_SingletonManager</span><span class="p">()</span>

 <span class="n">_process_local_lock</span> <span class="o">=</span> <span class="n">threading</span><span class="o">.</span><span class="n">Lock</span><span class="p">()</span>


 <span class="k">class</span> <span class="nc">_SingletonRegistrar</span><span class="p">(</span><span class="n">multiprocessing</span><span class="o">.</span><span class="n">managers</span><span class="o">.</span><span class="n">BaseManager</span><span class="p">):</span>
   <span class="k">pass</span>


 <span class="n">_SingletonRegistrar</span><span class="o">.</span><span class="n">register</span><span class="p">(</span>
     <span class="s1">&#39;acquire_singleton&#39;</span><span class="p">,</span>
     <span class="nb">callable</span><span class="o">=</span><span class="n">_process_level_singleton_manager</span><span class="o">.</span><span class="n">acquire_singleton</span><span class="p">)</span>
 <span class="n">_SingletonRegistrar</span><span class="o">.</span><span class="n">register</span><span class="p">(</span>
     <span class="s1">&#39;release_singleton&#39;</span><span class="p">,</span>
     <span class="nb">callable</span><span class="o">=</span><span class="n">_process_level_singleton_manager</span><span class="o">.</span><span class="n">release_singleton</span><span class="p">)</span>


 <div class="viewcode-block" id="MultiProcessShared"><a class="viewcode-back" href="../../../apache_beam.utils.multi_process_shared.html#apache_beam.utils.multi_process_shared.MultiProcessShared">[docs]</a><span class="k">class</span> <span class="nc">MultiProcessShared</span><span class="p">(</span><span class="n">Generic</span><span class="p">[</span><span class="n">T</span><span class="p">]):</span>
 <span class="w">  </span><span class="sd">&quot;&quot;&quot;MultiProcessShared is used to share a single object across processes.</span>

 <span class="sd">  For example, one could have the class::</span>

 <span class="sd">    class MyExpensiveObject(object):</span>
 <span class="sd">      def __init__(self, args):</span>
 <span class="sd">        [expensive initialization and memory allocation]</span>

 <span class="sd">      def method(self, arg):</span>
 <span class="sd">        ...</span>

 <span class="sd">  One could share a single instance of this class by wrapping it as::</span>

 <span class="sd">    shared_ptr = MultiProcessShared(lambda: MyExpensiveObject(...))</span>
 <span class="sd">    my_expensive_object = shared_ptr.acquire()</span>

 <span class="sd">  which could then be invoked as::</span>

 <span class="sd">    my_expensive_object.method(arg)</span>

 <span class="sd">  This can then be released with::</span>

 <span class="sd">    shared_ptr.release(my_expensive_object)</span>

 <span class="sd">  but care should be taken to avoid releasing the object too soon or</span>
 <span class="sd">  expensive re-initialization may be required, defeating the point of</span>
 <span class="sd">  using a shared object.</span>


 <span class="sd">  Args:</span>
 <span class="sd">    constructor: function that initialises / constructs the object if not</span>
 <span class="sd">      present in the cache. This function should take no arguments. It should</span>
 <span class="sd">      return an initialised object, or raise an exception if the object could</span>
 <span class="sd">      not be initialised / constructed.</span>
 <span class="sd">    tag: an optional indentifier to store with the cached object. If multiple</span>
 <span class="sd">      MultiProcessShared instances are created with the same tag, they will all</span>
 <span class="sd">      share the same proxied object.</span>
 <span class="sd">    path: a temporary path in which to create the inter-process lock</span>
 <span class="sd">    always_proxy: whether to direct all calls through the proxy, rather than</span>
 <span class="sd">      call the object directly for the process that created it</span>
 <span class="sd">  &quot;&quot;&quot;</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">constructor</span><span class="p">:</span> <span class="n">Callable</span><span class="p">[[],</span> <span class="n">T</span><span class="p">],</span>
       <span class="n">tag</span><span class="p">:</span> <span class="n">Optional</span><span class="p">[</span><span class="n">Any</span><span class="p">]</span> <span class="o">=</span> <span class="kc">None</span><span class="p">,</span>
       <span class="o">*</span><span class="p">,</span>
       <span class="n">path</span><span class="p">:</span> <span class="nb">str</span> <span class="o">=</span> <span class="n">tempfile</span><span class="o">.</span><span class="n">gettempdir</span><span class="p">(),</span>
       <span class="n">always_proxy</span><span class="p">:</span> <span class="n">Optional</span><span class="p">[</span><span class="nb">bool</span><span class="p">]</span> <span class="o">=</span> <span class="kc">None</span><span class="p">):</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_constructor</span> <span class="o">=</span> <span class="n">constructor</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_tag</span> <span class="o">=</span> <span class="n">tag</span> <span class="ow">or</span> <span class="n">uuid</span><span class="o">.</span><span class="n">uuid4</span><span class="p">()</span><span class="o">.</span><span class="n">hex</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_path</span> <span class="o">=</span> <span class="n">path</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_always_proxy</span> <span class="o">=</span> <span class="kc">False</span> <span class="k">if</span> <span class="n">always_proxy</span> <span class="ow">is</span> <span class="kc">None</span> <span class="k">else</span> <span class="n">always_proxy</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_proxy</span> <span class="o">=</span> <span class="kc">None</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_manager</span> <span class="o">=</span> <span class="kc">None</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_rpc_address</span> <span class="o">=</span> <span class="kc">None</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_cross_process_lock</span> <span class="o">=</span> <span class="n">fasteners</span><span class="o">.</span><span class="n">InterProcessLock</span><span class="p">(</span>
         <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_path</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">_tag</span><span class="p">)</span> <span class="o">+</span> <span class="s1">&#39;.lock&#39;</span><span class="p">)</span>

   <span class="k">def</span> <span class="nf">_get_manager</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
     <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">_manager</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
       <span class="n">address_file</span> <span class="o">=</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_path</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">_tag</span><span class="p">)</span> <span class="o">+</span> <span class="s2">&quot;.address&quot;</span>
       <span class="k">while</span> <span class="bp">self</span><span class="o">.</span><span class="n">_manager</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
         <span class="k">with</span> <span class="n">_process_local_lock</span><span class="p">:</span>
           <span class="k">with</span> <span class="bp">self</span><span class="o">.</span><span class="n">_cross_process_lock</span><span class="p">:</span>
             <span class="k">if</span> <span class="ow">not</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">exists</span><span class="p">(</span><span class="n">address_file</span><span class="p">):</span>
               <span class="bp">self</span><span class="o">.</span><span class="n">_create_server</span><span class="p">(</span><span class="n">address_file</span><span class="p">)</span>

             <span class="k">if</span> <span class="n">_process_level_singleton_manager</span><span class="o">.</span><span class="n">has_singleton</span><span class="p">(</span>
                 <span class="bp">self</span><span class="o">.</span><span class="n">_tag</span><span class="p">)</span> <span class="ow">and</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">_always_proxy</span><span class="p">:</span>
               <span class="bp">self</span><span class="o">.</span><span class="n">_manager</span> <span class="o">=</span> <span class="n">_process_level_singleton_manager</span>
             <span class="k">else</span><span class="p">:</span>
               <span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="n">address_file</span><span class="p">)</span> <span class="k">as</span> <span class="n">fin</span><span class="p">:</span>
                 <span class="n">address</span> <span class="o">=</span> <span class="n">fin</span><span class="o">.</span><span class="n">read</span><span class="p">()</span>
               <span class="n">logging</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s1">&#39;Connecting to remote proxy at </span><span class="si">%s</span><span class="s1">&#39;</span><span class="p">,</span> <span class="n">address</span><span class="p">)</span>
               <span class="n">host</span><span class="p">,</span> <span class="n">port</span> <span class="o">=</span> <span class="n">address</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="s1">&#39;:&#39;</span><span class="p">)</span>
               <span class="n">manager</span> <span class="o">=</span> <span class="n">_SingletonRegistrar</span><span class="p">(</span><span class="n">address</span><span class="o">=</span><span class="p">(</span><span class="n">host</span><span class="p">,</span> <span class="nb">int</span><span class="p">(</span><span class="n">port</span><span class="p">)))</span>
               <span class="k">try</span><span class="p">:</span>
                 <span class="n">manager</span><span class="o">.</span><span class="n">connect</span><span class="p">()</span>
                 <span class="bp">self</span><span class="o">.</span><span class="n">_manager</span> <span class="o">=</span> <span class="n">manager</span>
               <span class="k">except</span> <span class="ne">ConnectionError</span><span class="p">:</span>
                 <span class="c1"># The server is no longer good, assume it died.</span>
                 <span class="n">os</span><span class="o">.</span><span class="n">unlink</span><span class="p">(</span><span class="n">address_file</span><span class="p">)</span>

     <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">_manager</span>

 <div class="viewcode-block" id="MultiProcessShared.acquire"><a class="viewcode-back" href="../../../apache_beam.utils.multi_process_shared.html#apache_beam.utils.multi_process_shared.MultiProcessShared.acquire">[docs]</a>  <span class="k">def</span> <span class="nf">acquire</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
     <span class="c1"># TODO: Allow passing/parameterizing the callable here, in case they are</span>
     <span class="c1"># not available at MultiProcessShared construction time (e.g. from side</span>
     <span class="c1"># inputs)</span>
     <span class="c1"># Caveat: They must always agree, as they will be ignored if the object</span>
     <span class="c1"># is already constructed.</span>
     <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">_get_manager</span><span class="p">()</span><span class="o">.</span><span class="n">acquire_singleton</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_tag</span><span class="p">)</span></div>

 <div class="viewcode-block" id="MultiProcessShared.release"><a class="viewcode-back" href="../../../apache_beam.utils.multi_process_shared.html#apache_beam.utils.multi_process_shared.MultiProcessShared.release">[docs]</a>  <span class="k">def</span> <span class="nf">release</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">obj</span><span class="p">):</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_manager</span><span class="o">.</span><span class="n">release_singleton</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_tag</span><span class="p">,</span> <span class="n">obj</span><span class="p">)</span></div>

   <span class="k">def</span> <span class="nf">_create_server</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">address_file</span><span class="p">):</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_serving_manager</span> <span class="o">=</span> <span class="n">_SingletonRegistrar</span><span class="p">(</span><span class="n">address</span><span class="o">=</span><span class="p">(</span><span class="s1">&#39;localhost&#39;</span><span class="p">,</span> <span class="mi">0</span><span class="p">))</span>
     <span class="c1"># Initialize eagerly to avoid acting as the server if there are issues.</span>
     <span class="c1"># Note, however, that _create_server itself is called lazily.</span>
     <span class="n">_process_level_singleton_manager</span><span class="o">.</span><span class="n">register_singleton</span><span class="p">(</span>
         <span class="bp">self</span><span class="o">.</span><span class="n">_constructor</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">_tag</span><span class="p">,</span> <span class="n">initialize_eagerly</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_server</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_serving_manager</span><span class="o">.</span><span class="n">get_server</span><span class="p">()</span>
     <span class="n">logging</span><span class="o">.</span><span class="n">info</span><span class="p">(</span>
         <span class="s1">&#39;Starting proxy server at </span><span class="si">%s</span><span class="s1"> for shared </span><span class="si">%s</span><span class="s1">&#39;</span><span class="p">,</span>
         <span class="bp">self</span><span class="o">.</span><span class="n">_server</span><span class="o">.</span><span class="n">address</span><span class="p">,</span>
         <span class="bp">self</span><span class="o">.</span><span class="n">_tag</span><span class="p">)</span>
     <span class="k">with</span> <span class="nb">open</span><span class="p">(</span><span class="n">address_file</span> <span class="o">+</span> <span class="s1">&#39;.tmp&#39;</span><span class="p">,</span> <span class="s1">&#39;w&#39;</span><span class="p">)</span> <span class="k">as</span> <span class="n">fout</span><span class="p">:</span>
       <span class="n">fout</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="s1">&#39;</span><span class="si">%s</span><span class="s1">:</span><span class="si">%d</span><span class="s1">&#39;</span> <span class="o">%</span> <span class="bp">self</span><span class="o">.</span><span class="n">_server</span><span class="o">.</span><span class="n">address</span><span class="p">)</span>
     <span class="n">os</span><span class="o">.</span><span class="n">rename</span><span class="p">(</span><span class="n">address_file</span> <span class="o">+</span> <span class="s1">&#39;.tmp&#39;</span><span class="p">,</span> <span class="n">address_file</span><span class="p">)</span>
     <span class="n">t</span> <span class="o">=</span> <span class="n">threading</span><span class="o">.</span><span class="n">Thread</span><span class="p">(</span><span class="n">target</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">_server</span><span class="o">.</span><span class="n">serve_forever</span><span class="p">,</span> <span class="n">daemon</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
     <span class="n">t</span><span class="o">.</span><span class="n">start</span><span class="p">()</span>
     <span class="n">logging</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s1">&#39;Done starting server&#39;</span><span class="p">)</span></div>
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