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   <h1>Source code for apache_beam.transforms.external</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;Defines Transform whose expansion is implemented elsewhere.</span>

 <span class="sd">No backward compatibility guarantees. Everything in this module is experimental.</span>
 <span class="sd">&quot;&quot;&quot;</span>
 <span class="kn">from</span> <span class="nn">__future__</span> <span class="k">import</span> <span class="n">absolute_import</span>
 <span class="kn">from</span> <span class="nn">__future__</span> <span class="k">import</span> <span class="n">print_function</span>

 <span class="kn">import</span> <span class="nn">contextlib</span>
 <span class="kn">import</span> <span class="nn">copy</span>
 <span class="kn">import</span> <span class="nn">threading</span>

 <span class="kn">from</span> <span class="nn">apache_beam</span> <span class="k">import</span> <span class="n">pvalue</span>
 <span class="kn">from</span> <span class="nn">apache_beam.portability</span> <span class="k">import</span> <span class="n">common_urns</span>
 <span class="kn">from</span> <span class="nn">apache_beam.portability.api</span> <span class="k">import</span> <span class="n">beam_expansion_api_pb2</span>
 <span class="kn">from</span> <span class="nn">apache_beam.portability.api</span> <span class="k">import</span> <span class="n">beam_runner_api_pb2</span>
 <span class="kn">from</span> <span class="nn">apache_beam.runners</span> <span class="k">import</span> <span class="n">pipeline_context</span>
 <span class="kn">from</span> <span class="nn">apache_beam.transforms</span> <span class="k">import</span> <span class="n">ptransform</span>

 <span class="c1"># Protect against environments where grpc is not available.</span>
 <span class="c1"># pylint: disable=wrong-import-order, wrong-import-position, ungrouped-imports</span>
 <span class="k">try</span><span class="p">:</span>
   <span class="kn">import</span> <span class="nn">grpc</span>
   <span class="kn">from</span> <span class="nn">apache_beam.portability.api</span> <span class="k">import</span> <span class="n">beam_expansion_api_pb2_grpc</span>
 <span class="k">except</span> <span class="ne">ImportError</span><span class="p">:</span>
   <span class="n">grpc</span> <span class="o">=</span> <span class="kc">None</span>
 <span class="c1"># pylint: enable=wrong-import-order, wrong-import-position, ungrouped-imports</span>


 <div class="viewcode-block" id="ExternalTransform"><a class="viewcode-back" href="../../../apache_beam.transforms.external.html#apache_beam.transforms.external.ExternalTransform">[docs]</a><span class="k">class</span> <span class="nc">ExternalTransform</span><span class="p">(</span><span class="n">ptransform</span><span class="o">.</span><span class="n">PTransform</span><span class="p">):</span>
   <span class="sd">&quot;&quot;&quot;</span>
 <span class="sd">    External provides a cross-language transform via expansion services in</span>
 <span class="sd">    foreign SDKs.</span>

 <span class="sd">    Experimental; no backwards compatibility guarantees.</span>
 <span class="sd">  &quot;&quot;&quot;</span>
   <span class="n">_namespace_counter</span> <span class="o">=</span> <span class="mi">0</span>
   <span class="n">_namespace</span> <span class="o">=</span> <span class="n">threading</span><span class="o">.</span><span class="n">local</span><span class="p">()</span>

   <span class="n">_EXPANDED_TRANSFORM_UNIQUE_NAME</span> <span class="o">=</span> <span class="s1">&#39;root&#39;</span>
   <span class="n">_IMPULSE_PREFIX</span> <span class="o">=</span> <span class="s1">&#39;impulse&#39;</span>

   <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">urn</span><span class="p">,</span> <span class="n">payload</span><span class="p">,</span> <span class="n">endpoint</span><span class="p">):</span>
     <span class="k">if</span> <span class="n">grpc</span> <span class="ow">is</span> <span class="kc">None</span> <span class="ow">and</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">endpoint</span><span class="p">,</span> <span class="nb">str</span><span class="p">):</span>
       <span class="k">raise</span> <span class="ne">NotImplementedError</span><span class="p">(</span><span class="s1">&#39;Grpc required for external transforms.&#39;</span><span class="p">)</span>
     <span class="c1"># TODO: Start an endpoint given an environment?</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_urn</span> <span class="o">=</span> <span class="n">urn</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_payload</span> <span class="o">=</span> <span class="n">payload</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_endpoint</span> <span class="o">=</span> <span class="n">endpoint</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_namespace</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_fresh_namespace</span><span class="p">()</span>

 <div class="viewcode-block" id="ExternalTransform.default_label"><a class="viewcode-back" href="../../../apache_beam.transforms.external.html#apache_beam.transforms.external.ExternalTransform.default_label">[docs]</a>  <span class="k">def</span> <span class="nf">default_label</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
     <span class="k">return</span> <span class="s1">&#39;</span><span class="si">%s</span><span class="s1">(</span><span class="si">%s</span><span class="s1">)&#39;</span> <span class="o">%</span> <span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="vm">__class__</span><span class="o">.</span><span class="vm">__name__</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">_urn</span><span class="p">)</span></div>

 <div class="viewcode-block" id="ExternalTransform.get_local_namespace"><a class="viewcode-back" href="../../../apache_beam.transforms.external.html#apache_beam.transforms.external.ExternalTransform.get_local_namespace">[docs]</a>  <span class="nd">@classmethod</span>
   <span class="k">def</span> <span class="nf">get_local_namespace</span><span class="p">(</span><span class="bp">cls</span><span class="p">):</span>
     <span class="k">return</span> <span class="nb">getattr</span><span class="p">(</span><span class="bp">cls</span><span class="o">.</span><span class="n">_namespace</span><span class="p">,</span> <span class="s1">&#39;value&#39;</span><span class="p">,</span> <span class="s1">&#39;external&#39;</span><span class="p">)</span></div>

 <div class="viewcode-block" id="ExternalTransform.outer_namespace"><a class="viewcode-back" href="../../../apache_beam.transforms.external.html#apache_beam.transforms.external.ExternalTransform.outer_namespace">[docs]</a>  <span class="nd">@classmethod</span>
   <span class="nd">@contextlib</span><span class="o">.</span><span class="n">contextmanager</span>
   <span class="k">def</span> <span class="nf">outer_namespace</span><span class="p">(</span><span class="bp">cls</span><span class="p">,</span> <span class="n">namespace</span><span class="p">):</span>
     <span class="n">prev</span> <span class="o">=</span> <span class="bp">cls</span><span class="o">.</span><span class="n">get_local_namespace</span><span class="p">()</span>
     <span class="bp">cls</span><span class="o">.</span><span class="n">_namespace</span><span class="o">.</span><span class="n">value</span> <span class="o">=</span> <span class="n">namespace</span>
     <span class="k">yield</span>
     <span class="bp">cls</span><span class="o">.</span><span class="n">_namespace</span><span class="o">.</span><span class="n">value</span> <span class="o">=</span> <span class="n">prev</span></div>

   <span class="nd">@classmethod</span>
   <span class="k">def</span> <span class="nf">_fresh_namespace</span><span class="p">(</span><span class="bp">cls</span><span class="p">):</span>
     <span class="n">ExternalTransform</span><span class="o">.</span><span class="n">_namespace_counter</span> <span class="o">+=</span> <span class="mi">1</span>
     <span class="k">return</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="p">(</span><span class="bp">cls</span><span class="o">.</span><span class="n">get_local_namespace</span><span class="p">(),</span> <span class="bp">cls</span><span class="o">.</span><span class="n">_namespace_counter</span><span class="p">)</span>

 <div class="viewcode-block" id="ExternalTransform.expand"><a class="viewcode-back" href="../../../apache_beam.transforms.external.html#apache_beam.transforms.external.ExternalTransform.expand">[docs]</a>  <span class="k">def</span> <span class="nf">expand</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">pvalueish</span><span class="p">):</span>
     <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">pvalueish</span><span class="p">,</span> <span class="n">pvalue</span><span class="o">.</span><span class="n">PBegin</span><span class="p">):</span>
       <span class="bp">self</span><span class="o">.</span><span class="n">_inputs</span> <span class="o">=</span> <span class="p">{}</span>
     <span class="k">elif</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">pvalueish</span><span class="p">,</span> <span class="p">(</span><span class="nb">list</span><span class="p">,</span> <span class="nb">tuple</span><span class="p">)):</span>
       <span class="bp">self</span><span class="o">.</span><span class="n">_inputs</span> <span class="o">=</span> <span class="p">{</span><span class="nb">str</span><span class="p">(</span><span class="n">ix</span><span class="p">):</span> <span class="n">pvalue</span> <span class="k">for</span> <span class="n">ix</span><span class="p">,</span> <span class="n">pvalue</span> <span class="ow">in</span> <span class="nb">enumerate</span><span class="p">(</span><span class="n">pvalueish</span><span class="p">)}</span>
     <span class="k">elif</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">pvalueish</span><span class="p">,</span> <span class="nb">dict</span><span class="p">):</span>
       <span class="bp">self</span><span class="o">.</span><span class="n">_inputs</span> <span class="o">=</span> <span class="n">pvalueish</span>
     <span class="k">else</span><span class="p">:</span>
       <span class="bp">self</span><span class="o">.</span><span class="n">_inputs</span> <span class="o">=</span> <span class="p">{</span><span class="s1">&#39;input&#39;</span><span class="p">:</span> <span class="n">pvalueish</span><span class="p">}</span>
     <span class="n">pipeline</span> <span class="o">=</span> <span class="p">(</span>
         <span class="nb">next</span><span class="p">(</span><span class="nb">iter</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_inputs</span><span class="o">.</span><span class="n">values</span><span class="p">()))</span><span class="o">.</span><span class="n">pipeline</span>
         <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">_inputs</span>
         <span class="k">else</span> <span class="n">pvalueish</span><span class="o">.</span><span class="n">pipeline</span><span class="p">)</span>
     <span class="n">context</span> <span class="o">=</span> <span class="n">pipeline_context</span><span class="o">.</span><span class="n">PipelineContext</span><span class="p">()</span>
     <span class="n">transform_proto</span> <span class="o">=</span> <span class="n">beam_runner_api_pb2</span><span class="o">.</span><span class="n">PTransform</span><span class="p">(</span>
         <span class="n">unique_name</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">_EXPANDED_TRANSFORM_UNIQUE_NAME</span><span class="p">,</span>
         <span class="n">spec</span><span class="o">=</span><span class="n">beam_runner_api_pb2</span><span class="o">.</span><span class="n">FunctionSpec</span><span class="p">(</span>
             <span class="n">urn</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">_urn</span><span class="p">,</span> <span class="n">payload</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">_payload</span><span class="p">))</span>
     <span class="k">for</span> <span class="n">tag</span><span class="p">,</span> <span class="n">pcoll</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_inputs</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
       <span class="n">transform_proto</span><span class="o">.</span><span class="n">inputs</span><span class="p">[</span><span class="n">tag</span><span class="p">]</span> <span class="o">=</span> <span class="n">context</span><span class="o">.</span><span class="n">pcollections</span><span class="o">.</span><span class="n">get_id</span><span class="p">(</span><span class="n">pcoll</span><span class="p">)</span>
       <span class="c1"># Conversion to/from proto assumes producers.</span>
       <span class="c1"># TODO: Possibly loosen this.</span>
       <span class="n">context</span><span class="o">.</span><span class="n">transforms</span><span class="o">.</span><span class="n">put_proto</span><span class="p">(</span>
           <span class="s1">&#39;</span><span class="si">%s</span><span class="s1">_</span><span class="si">%s</span><span class="s1">&#39;</span> <span class="o">%</span> <span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_IMPULSE_PREFIX</span><span class="p">,</span> <span class="n">tag</span><span class="p">),</span>
           <span class="n">beam_runner_api_pb2</span><span class="o">.</span><span class="n">PTransform</span><span class="p">(</span>
               <span class="n">unique_name</span><span class="o">=</span><span class="s1">&#39;</span><span class="si">%s</span><span class="s1">_</span><span class="si">%s</span><span class="s1">&#39;</span> <span class="o">%</span> <span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_IMPULSE_PREFIX</span><span class="p">,</span> <span class="n">tag</span><span class="p">),</span>
               <span class="n">spec</span><span class="o">=</span><span class="n">beam_runner_api_pb2</span><span class="o">.</span><span class="n">FunctionSpec</span><span class="p">(</span>
                   <span class="n">urn</span><span class="o">=</span><span class="n">common_urns</span><span class="o">.</span><span class="n">primitives</span><span class="o">.</span><span class="n">IMPULSE</span><span class="o">.</span><span class="n">urn</span><span class="p">),</span>
               <span class="n">outputs</span><span class="o">=</span><span class="p">{</span><span class="s1">&#39;out&#39;</span><span class="p">:</span> <span class="n">transform_proto</span><span class="o">.</span><span class="n">inputs</span><span class="p">[</span><span class="n">tag</span><span class="p">]}))</span>
     <span class="n">components</span> <span class="o">=</span> <span class="n">context</span><span class="o">.</span><span class="n">to_runner_api</span><span class="p">()</span>
     <span class="n">request</span> <span class="o">=</span> <span class="n">beam_expansion_api_pb2</span><span class="o">.</span><span class="n">ExpansionRequest</span><span class="p">(</span>
         <span class="n">components</span><span class="o">=</span><span class="n">components</span><span class="p">,</span>
         <span class="n">namespace</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">_namespace</span><span class="p">,</span>
         <span class="n">transform</span><span class="o">=</span><span class="n">transform_proto</span><span class="p">)</span>

     <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_endpoint</span><span class="p">,</span> <span class="nb">str</span><span class="p">):</span>
       <span class="k">with</span> <span class="n">grpc</span><span class="o">.</span><span class="n">insecure_channel</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_endpoint</span><span class="p">)</span> <span class="k">as</span> <span class="n">channel</span><span class="p">:</span>
         <span class="n">response</span> <span class="o">=</span> <span class="n">beam_expansion_api_pb2_grpc</span><span class="o">.</span><span class="n">ExpansionServiceStub</span><span class="p">(</span>
             <span class="n">channel</span><span class="p">)</span><span class="o">.</span><span class="n">Expand</span><span class="p">(</span><span class="n">request</span><span class="p">)</span>
     <span class="k">else</span><span class="p">:</span>
       <span class="n">response</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_endpoint</span><span class="o">.</span><span class="n">Expand</span><span class="p">(</span><span class="n">request</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span>

     <span class="k">if</span> <span class="n">response</span><span class="o">.</span><span class="n">error</span><span class="p">:</span>
       <span class="k">raise</span> <span class="ne">RuntimeError</span><span class="p">(</span><span class="n">response</span><span class="o">.</span><span class="n">error</span><span class="p">)</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_expanded_components</span> <span class="o">=</span> <span class="n">response</span><span class="o">.</span><span class="n">components</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_expanded_transform</span> <span class="o">=</span> <span class="n">response</span><span class="o">.</span><span class="n">transform</span>
     <span class="n">result_context</span> <span class="o">=</span> <span class="n">pipeline_context</span><span class="o">.</span><span class="n">PipelineContext</span><span class="p">(</span><span class="n">response</span><span class="o">.</span><span class="n">components</span><span class="p">)</span>

     <span class="k">def</span> <span class="nf">fix_output</span><span class="p">(</span><span class="n">pcoll</span><span class="p">,</span> <span class="n">tag</span><span class="p">):</span>
       <span class="n">pcoll</span><span class="o">.</span><span class="n">pipeline</span> <span class="o">=</span> <span class="n">pipeline</span>
       <span class="n">pcoll</span><span class="o">.</span><span class="n">tag</span> <span class="o">=</span> <span class="n">tag</span>
       <span class="k">return</span> <span class="n">pcoll</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_outputs</span> <span class="o">=</span> <span class="p">{</span>
         <span class="n">tag</span><span class="p">:</span> <span class="n">fix_output</span><span class="p">(</span><span class="n">result_context</span><span class="o">.</span><span class="n">pcollections</span><span class="o">.</span><span class="n">get_by_id</span><span class="p">(</span><span class="n">pcoll_id</span><span class="p">),</span> <span class="n">tag</span><span class="p">)</span>
         <span class="k">for</span> <span class="n">tag</span><span class="p">,</span> <span class="n">pcoll_id</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_expanded_transform</span><span class="o">.</span><span class="n">outputs</span><span class="o">.</span><span class="n">items</span><span class="p">()</span>
     <span class="p">}</span>

     <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">_output_to_pvalueish</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_outputs</span><span class="p">)</span></div>

   <span class="k">def</span> <span class="nf">_output_to_pvalueish</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">output_dict</span><span class="p">):</span>
     <span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">output_dict</span><span class="p">)</span> <span class="o">==</span> <span class="mi">1</span><span class="p">:</span>
       <span class="k">return</span> <span class="nb">next</span><span class="p">(</span><span class="nb">iter</span><span class="p">(</span><span class="n">output_dict</span><span class="o">.</span><span class="n">values</span><span class="p">()))</span>
     <span class="k">else</span><span class="p">:</span>
       <span class="k">return</span> <span class="n">output_dict</span>

 <div class="viewcode-block" id="ExternalTransform.to_runner_api_transform"><a class="viewcode-back" href="../../../apache_beam.transforms.external.html#apache_beam.transforms.external.ExternalTransform.to_runner_api_transform">[docs]</a>  <span class="k">def</span> <span class="nf">to_runner_api_transform</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">context</span><span class="p">,</span> <span class="n">full_label</span><span class="p">):</span>
     <span class="n">pcoll_renames</span> <span class="o">=</span> <span class="p">{}</span>
     <span class="n">renamed_tag_seen</span> <span class="o">=</span> <span class="kc">False</span>
     <span class="k">for</span> <span class="n">tag</span><span class="p">,</span> <span class="n">pcoll</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_inputs</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
       <span class="k">if</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">_expanded_transform</span><span class="o">.</span><span class="n">inputs</span><span class="p">:</span>
         <span class="k">if</span> <span class="n">renamed_tag_seen</span><span class="p">:</span>
           <span class="k">raise</span> <span class="ne">RuntimeError</span><span class="p">(</span>
               <span class="s1">&#39;Ambiguity due to non-preserved tags: </span><span class="si">%s</span><span class="s1"> vs </span><span class="si">%s</span><span class="s1">&#39;</span> <span class="o">%</span> <span class="p">(</span>
                   <span class="nb">sorted</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_expanded_transform</span><span class="o">.</span><span class="n">inputs</span><span class="o">.</span><span class="n">keys</span><span class="p">()),</span>
                   <span class="nb">sorted</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_inputs</span><span class="o">.</span><span class="n">keys</span><span class="p">())))</span>
         <span class="k">else</span><span class="p">:</span>
           <span class="n">renamed_tag_seen</span> <span class="o">=</span> <span class="kc">True</span>
           <span class="n">tag</span><span class="p">,</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_expanded_transform</span><span class="o">.</span><span class="n">inputs</span><span class="o">.</span><span class="n">keys</span><span class="p">()</span>
       <span class="n">pcoll_renames</span><span class="p">[</span><span class="bp">self</span><span class="o">.</span><span class="n">_expanded_transform</span><span class="o">.</span><span class="n">inputs</span><span class="p">[</span><span class="n">tag</span><span class="p">]]</span> <span class="o">=</span> <span class="p">(</span>
           <span class="n">context</span><span class="o">.</span><span class="n">pcollections</span><span class="o">.</span><span class="n">get_id</span><span class="p">(</span><span class="n">pcoll</span><span class="p">))</span>
     <span class="k">for</span> <span class="n">tag</span><span class="p">,</span> <span class="n">pcoll</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_outputs</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
       <span class="n">pcoll_renames</span><span class="p">[</span><span class="bp">self</span><span class="o">.</span><span class="n">_expanded_transform</span><span class="o">.</span><span class="n">outputs</span><span class="p">[</span><span class="n">tag</span><span class="p">]]</span> <span class="o">=</span> <span class="p">(</span>
           <span class="n">context</span><span class="o">.</span><span class="n">pcollections</span><span class="o">.</span><span class="n">get_id</span><span class="p">(</span><span class="n">pcoll</span><span class="p">))</span>

     <span class="k">def</span> <span class="nf">_equivalent</span><span class="p">(</span><span class="n">coder1</span><span class="p">,</span> <span class="n">coder2</span><span class="p">):</span>
       <span class="k">return</span> <span class="n">coder1</span> <span class="o">==</span> <span class="n">coder2</span> <span class="ow">or</span> <span class="n">_normalize</span><span class="p">(</span><span class="n">coder1</span><span class="p">)</span> <span class="o">==</span> <span class="n">_normalize</span><span class="p">(</span><span class="n">coder2</span><span class="p">)</span>

     <span class="k">def</span> <span class="nf">_normalize</span><span class="p">(</span><span class="n">coder_proto</span><span class="p">):</span>
       <span class="n">normalized</span> <span class="o">=</span> <span class="n">copy</span><span class="o">.</span><span class="n">copy</span><span class="p">(</span><span class="n">coder_proto</span><span class="p">)</span>
       <span class="n">normalized</span><span class="o">.</span><span class="n">spec</span><span class="o">.</span><span class="n">environment_id</span> <span class="o">=</span> <span class="s1">&#39;&#39;</span>
       <span class="c1"># TODO(robertwb): Normalize components as well.</span>
       <span class="k">return</span> <span class="n">normalized</span>

     <span class="k">for</span> <span class="nb">id</span><span class="p">,</span> <span class="n">proto</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_expanded_components</span><span class="o">.</span><span class="n">coders</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
       <span class="k">if</span> <span class="nb">id</span><span class="o">.</span><span class="n">startswith</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_namespace</span><span class="p">):</span>
         <span class="n">context</span><span class="o">.</span><span class="n">coders</span><span class="o">.</span><span class="n">put_proto</span><span class="p">(</span><span class="nb">id</span><span class="p">,</span> <span class="n">proto</span><span class="p">)</span>
       <span class="k">elif</span> <span class="nb">id</span> <span class="ow">in</span> <span class="n">context</span><span class="o">.</span><span class="n">coders</span><span class="p">:</span>
         <span class="k">if</span> <span class="ow">not</span> <span class="n">_equivalent</span><span class="p">(</span><span class="n">context</span><span class="o">.</span><span class="n">coders</span><span class="o">.</span><span class="n">_id_to_proto</span><span class="p">[</span><span class="nb">id</span><span class="p">],</span> <span class="n">proto</span><span class="p">):</span>
           <span class="k">raise</span> <span class="ne">RuntimeError</span><span class="p">(</span><span class="s1">&#39;Re-used coder id: </span><span class="si">%s</span><span class="se">\n</span><span class="si">%s</span><span class="se">\n</span><span class="si">%s</span><span class="s1">&#39;</span> <span class="o">%</span> <span class="p">(</span>
               <span class="nb">id</span><span class="p">,</span> <span class="n">context</span><span class="o">.</span><span class="n">coders</span><span class="o">.</span><span class="n">_id_to_proto</span><span class="p">[</span><span class="nb">id</span><span class="p">],</span> <span class="n">proto</span><span class="p">))</span>
       <span class="k">else</span><span class="p">:</span>
         <span class="n">context</span><span class="o">.</span><span class="n">coders</span><span class="o">.</span><span class="n">put_proto</span><span class="p">(</span><span class="nb">id</span><span class="p">,</span> <span class="n">proto</span><span class="p">)</span>
     <span class="k">for</span> <span class="nb">id</span><span class="p">,</span> <span class="n">proto</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_expanded_components</span><span class="o">.</span><span class="n">windowing_strategies</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
       <span class="k">if</span> <span class="nb">id</span><span class="o">.</span><span class="n">startswith</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_namespace</span><span class="p">):</span>
         <span class="n">context</span><span class="o">.</span><span class="n">windowing_strategies</span><span class="o">.</span><span class="n">put_proto</span><span class="p">(</span><span class="nb">id</span><span class="p">,</span> <span class="n">proto</span><span class="p">)</span>
     <span class="k">for</span> <span class="nb">id</span><span class="p">,</span> <span class="n">proto</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_expanded_components</span><span class="o">.</span><span class="n">environments</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
       <span class="k">if</span> <span class="nb">id</span><span class="o">.</span><span class="n">startswith</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_namespace</span><span class="p">):</span>
         <span class="n">context</span><span class="o">.</span><span class="n">environments</span><span class="o">.</span><span class="n">put_proto</span><span class="p">(</span><span class="nb">id</span><span class="p">,</span> <span class="n">proto</span><span class="p">)</span>
     <span class="k">for</span> <span class="nb">id</span><span class="p">,</span> <span class="n">proto</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_expanded_components</span><span class="o">.</span><span class="n">pcollections</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
       <span class="nb">id</span> <span class="o">=</span> <span class="n">pcoll_renames</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="nb">id</span><span class="p">,</span> <span class="nb">id</span><span class="p">)</span>
       <span class="k">if</span> <span class="nb">id</span> <span class="ow">not</span> <span class="ow">in</span> <span class="n">context</span><span class="o">.</span><span class="n">pcollections</span><span class="o">.</span><span class="n">_id_to_obj</span><span class="o">.</span><span class="n">keys</span><span class="p">():</span>
         <span class="n">context</span><span class="o">.</span><span class="n">pcollections</span><span class="o">.</span><span class="n">put_proto</span><span class="p">(</span><span class="nb">id</span><span class="p">,</span> <span class="n">proto</span><span class="p">)</span>

     <span class="k">for</span> <span class="nb">id</span><span class="p">,</span> <span class="n">proto</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_expanded_components</span><span class="o">.</span><span class="n">transforms</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
       <span class="k">if</span> <span class="nb">id</span><span class="o">.</span><span class="n">startswith</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_IMPULSE_PREFIX</span><span class="p">):</span>
         <span class="c1"># Our fake inputs.</span>
         <span class="k">continue</span>
       <span class="k">assert</span> <span class="nb">id</span><span class="o">.</span><span class="n">startswith</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_namespace</span><span class="p">),</span> <span class="p">(</span><span class="nb">id</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">_namespace</span><span class="p">)</span>
       <span class="n">new_proto</span> <span class="o">=</span> <span class="n">beam_runner_api_pb2</span><span class="o">.</span><span class="n">PTransform</span><span class="p">(</span>
           <span class="n">unique_name</span><span class="o">=</span><span class="n">full_label</span> <span class="o">+</span> <span class="n">proto</span><span class="o">.</span><span class="n">unique_name</span><span class="p">[</span>
               <span class="nb">len</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_EXPANDED_TRANSFORM_UNIQUE_NAME</span><span class="p">):],</span>
           <span class="n">spec</span><span class="o">=</span><span class="n">proto</span><span class="o">.</span><span class="n">spec</span><span class="p">,</span>
           <span class="n">subtransforms</span><span class="o">=</span><span class="n">proto</span><span class="o">.</span><span class="n">subtransforms</span><span class="p">,</span>
           <span class="n">inputs</span><span class="o">=</span><span class="p">{</span><span class="n">tag</span><span class="p">:</span> <span class="n">pcoll_renames</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">pcoll</span><span class="p">,</span> <span class="n">pcoll</span><span class="p">)</span>
                   <span class="k">for</span> <span class="n">tag</span><span class="p">,</span> <span class="n">pcoll</span> <span class="ow">in</span> <span class="n">proto</span><span class="o">.</span><span class="n">inputs</span><span class="o">.</span><span class="n">items</span><span class="p">()},</span>
           <span class="n">outputs</span><span class="o">=</span><span class="p">{</span><span class="n">tag</span><span class="p">:</span> <span class="n">pcoll_renames</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">pcoll</span><span class="p">,</span> <span class="n">pcoll</span><span class="p">)</span>
                    <span class="k">for</span> <span class="n">tag</span><span class="p">,</span> <span class="n">pcoll</span> <span class="ow">in</span> <span class="n">proto</span><span class="o">.</span><span class="n">outputs</span><span class="o">.</span><span class="n">items</span><span class="p">()})</span>
       <span class="n">context</span><span class="o">.</span><span class="n">transforms</span><span class="o">.</span><span class="n">put_proto</span><span class="p">(</span><span class="nb">id</span><span class="p">,</span> <span class="n">new_proto</span><span class="p">)</span>

     <span class="k">return</span> <span class="n">beam_runner_api_pb2</span><span class="o">.</span><span class="n">PTransform</span><span class="p">(</span>
         <span class="n">unique_name</span><span class="o">=</span><span class="n">full_label</span><span class="p">,</span>
         <span class="n">spec</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">_expanded_transform</span><span class="o">.</span><span class="n">spec</span><span class="p">,</span>
         <span class="n">subtransforms</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">_expanded_transform</span><span class="o">.</span><span class="n">subtransforms</span><span class="p">,</span>
         <span class="n">inputs</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">_expanded_transform</span><span class="o">.</span><span class="n">inputs</span><span class="p">,</span>
         <span class="n">outputs</span><span class="o">=</span><span class="p">{</span>
             <span class="n">tag</span><span class="p">:</span> <span class="n">pcoll_renames</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">pcoll</span><span class="p">,</span> <span class="n">pcoll</span><span class="p">)</span>
             <span class="k">for</span> <span class="n">tag</span><span class="p">,</span> <span class="n">pcoll</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_expanded_transform</span><span class="o">.</span><span class="n">outputs</span><span class="o">.</span><span class="n">items</span><span class="p">()})</span></div></div>


 <div class="viewcode-block" id="memoize"><a class="viewcode-back" href="../../../apache_beam.transforms.external.html#apache_beam.transforms.external.memoize">[docs]</a><span class="k">def</span> <span class="nf">memoize</span><span class="p">(</span><span class="n">func</span><span class="p">):</span>
   <span class="n">cache</span> <span class="o">=</span> <span class="p">{}</span>

   <span class="k">def</span> <span class="nf">wrapper</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">):</span>
     <span class="k">if</span> <span class="n">args</span> <span class="ow">not</span> <span class="ow">in</span> <span class="n">cache</span><span class="p">:</span>
       <span class="n">cache</span><span class="p">[</span><span class="n">args</span><span class="p">]</span> <span class="o">=</span> <span class="n">func</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">)</span>
     <span class="k">return</span> <span class="n">cache</span><span class="p">[</span><span class="n">args</span><span class="p">]</span>
   <span class="k">return</span> <span class="n">wrapper</span></div>
 </pre></div>

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