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   <h1>Source code for apache_beam.runners.direct.watermark_manager</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;Manages watermarks of PCollections and AppliedPTransforms.&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">import</span> <span class="nn">threading</span>
 <span class="kn">from</span> <span class="nn">builtins</span> <span class="k">import</span> <span class="nb">object</span>

 <span class="kn">from</span> <span class="nn">apache_beam</span> <span class="k">import</span> <span class="n">pipeline</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.runners.direct.util</span> <span class="k">import</span> <span class="n">TimerFiring</span>
 <span class="kn">from</span> <span class="nn">apache_beam.utils.timestamp</span> <span class="k">import</span> <span class="n">MAX_TIMESTAMP</span>
 <span class="kn">from</span> <span class="nn">apache_beam.utils.timestamp</span> <span class="k">import</span> <span class="n">MIN_TIMESTAMP</span>
 <span class="kn">from</span> <span class="nn">apache_beam.utils.timestamp</span> <span class="k">import</span> <span class="n">TIME_GRANULARITY</span>


 <div class="viewcode-block" id="WatermarkManager"><a class="viewcode-back" href="../../../../apache_beam.runners.direct.watermark_manager.html#apache_beam.runners.direct.watermark_manager.WatermarkManager">[docs]</a><span class="k">class</span> <span class="nc">WatermarkManager</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
   <span class="sd">&quot;&quot;&quot;For internal use only; no backwards-compatibility guarantees.</span>

 <span class="sd">  Tracks and updates watermarks for all AppliedPTransforms.&quot;&quot;&quot;</span>

   <span class="n">WATERMARK_POS_INF</span> <span class="o">=</span> <span class="n">MAX_TIMESTAMP</span>
   <span class="n">WATERMARK_NEG_INF</span> <span class="o">=</span> <span class="n">MIN_TIMESTAMP</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">clock</span><span class="p">,</span> <span class="n">root_transforms</span><span class="p">,</span> <span class="n">value_to_consumers</span><span class="p">,</span>
                <span class="n">transform_keyed_states</span><span class="p">):</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_clock</span> <span class="o">=</span> <span class="n">clock</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_root_transforms</span> <span class="o">=</span> <span class="n">root_transforms</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_value_to_consumers</span> <span class="o">=</span> <span class="n">value_to_consumers</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_transform_keyed_states</span> <span class="o">=</span> <span class="n">transform_keyed_states</span>
     <span class="c1"># AppliedPTransform -&gt; TransformWatermarks</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_transform_to_watermarks</span> <span class="o">=</span> <span class="p">{}</span>

     <span class="k">for</span> <span class="n">root_transform</span> <span class="ow">in</span> <span class="n">root_transforms</span><span class="p">:</span>
       <span class="bp">self</span><span class="o">.</span><span class="n">_transform_to_watermarks</span><span class="p">[</span><span class="n">root_transform</span><span class="p">]</span> <span class="o">=</span> <span class="n">_TransformWatermarks</span><span class="p">(</span>
           <span class="bp">self</span><span class="o">.</span><span class="n">_clock</span><span class="p">,</span> <span class="n">transform_keyed_states</span><span class="p">[</span><span class="n">root_transform</span><span class="p">],</span> <span class="n">root_transform</span><span class="p">)</span>

     <span class="k">for</span> <span class="n">consumers</span> <span class="ow">in</span> <span class="n">value_to_consumers</span><span class="o">.</span><span class="n">values</span><span class="p">():</span>
       <span class="k">for</span> <span class="n">consumer</span> <span class="ow">in</span> <span class="n">consumers</span><span class="p">:</span>
         <span class="bp">self</span><span class="o">.</span><span class="n">_transform_to_watermarks</span><span class="p">[</span><span class="n">consumer</span><span class="p">]</span> <span class="o">=</span> <span class="n">_TransformWatermarks</span><span class="p">(</span>
             <span class="bp">self</span><span class="o">.</span><span class="n">_clock</span><span class="p">,</span> <span class="n">transform_keyed_states</span><span class="p">[</span><span class="n">consumer</span><span class="p">],</span> <span class="n">consumer</span><span class="p">)</span>

     <span class="k">for</span> <span class="n">consumers</span> <span class="ow">in</span> <span class="n">value_to_consumers</span><span class="o">.</span><span class="n">values</span><span class="p">():</span>
       <span class="k">for</span> <span class="n">consumer</span> <span class="ow">in</span> <span class="n">consumers</span><span class="p">:</span>
         <span class="bp">self</span><span class="o">.</span><span class="n">_update_input_transform_watermarks</span><span class="p">(</span><span class="n">consumer</span><span class="p">)</span>

   <span class="k">def</span> <span class="nf">_update_input_transform_watermarks</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">applied_ptransform</span><span class="p">):</span>
     <span class="k">assert</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">applied_ptransform</span><span class="p">,</span> <span class="n">pipeline</span><span class="o">.</span><span class="n">AppliedPTransform</span><span class="p">)</span>
     <span class="n">input_transform_watermarks</span> <span class="o">=</span> <span class="p">[]</span>
     <span class="k">for</span> <span class="n">input_pvalue</span> <span class="ow">in</span> <span class="n">applied_ptransform</span><span class="o">.</span><span class="n">inputs</span><span class="p">:</span>
       <span class="k">assert</span> <span class="n">input_pvalue</span><span class="o">.</span><span class="n">producer</span> <span class="ow">or</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">input_pvalue</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="k">if</span> <span class="n">input_pvalue</span><span class="o">.</span><span class="n">producer</span><span class="p">:</span>
         <span class="n">input_transform_watermarks</span><span class="o">.</span><span class="n">append</span><span class="p">(</span>
             <span class="bp">self</span><span class="o">.</span><span class="n">get_watermarks</span><span class="p">(</span><span class="n">input_pvalue</span><span class="o">.</span><span class="n">producer</span><span class="p">))</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_transform_to_watermarks</span><span class="p">[</span>
         <span class="n">applied_ptransform</span><span class="p">]</span><span class="o">.</span><span class="n">update_input_transform_watermarks</span><span class="p">(</span>
             <span class="n">input_transform_watermarks</span><span class="p">)</span>

 <div class="viewcode-block" id="WatermarkManager.get_watermarks"><a class="viewcode-back" href="../../../../apache_beam.runners.direct.watermark_manager.html#apache_beam.runners.direct.watermark_manager.WatermarkManager.get_watermarks">[docs]</a>  <span class="k">def</span> <span class="nf">get_watermarks</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">applied_ptransform</span><span class="p">):</span>
     <span class="sd">&quot;&quot;&quot;Gets the input and output watermarks for an AppliedPTransform.</span>

 <span class="sd">    If the applied_ptransform has not processed any elements, return a</span>
 <span class="sd">    watermark with minimum value.</span>

 <span class="sd">    Args:</span>
 <span class="sd">      applied_ptransform: AppliedPTransform to get the watermarks for.</span>

 <span class="sd">    Returns:</span>
 <span class="sd">      A snapshot (TransformWatermarks) of the input watermark and output</span>
 <span class="sd">      watermark for the provided transform.</span>
 <span class="sd">    &quot;&quot;&quot;</span>

     <span class="c1"># TODO(altay): Composite transforms should have a composite watermark. Until</span>
     <span class="c1"># then they are represented by their last transform.</span>
     <span class="k">while</span> <span class="n">applied_ptransform</span><span class="o">.</span><span class="n">parts</span><span class="p">:</span>
       <span class="n">applied_ptransform</span> <span class="o">=</span> <span class="n">applied_ptransform</span><span class="o">.</span><span class="n">parts</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="bp">self</span><span class="o">.</span><span class="n">_transform_to_watermarks</span><span class="p">[</span><span class="n">applied_ptransform</span><span class="p">]</span></div>

 <div class="viewcode-block" id="WatermarkManager.update_watermarks"><a class="viewcode-back" href="../../../../apache_beam.runners.direct.watermark_manager.html#apache_beam.runners.direct.watermark_manager.WatermarkManager.update_watermarks">[docs]</a>  <span class="k">def</span> <span class="nf">update_watermarks</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">completed_committed_bundle</span><span class="p">,</span> <span class="n">applied_ptransform</span><span class="p">,</span>
                         <span class="n">completed_timers</span><span class="p">,</span> <span class="n">outputs</span><span class="p">,</span> <span class="n">unprocessed_bundles</span><span class="p">,</span>
                         <span class="n">keyed_earliest_holds</span><span class="p">,</span> <span class="n">side_inputs_container</span><span class="p">):</span>
     <span class="k">assert</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">applied_ptransform</span><span class="p">,</span> <span class="n">pipeline</span><span class="o">.</span><span class="n">AppliedPTransform</span><span class="p">)</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_update_pending</span><span class="p">(</span>
         <span class="n">completed_committed_bundle</span><span class="p">,</span> <span class="n">applied_ptransform</span><span class="p">,</span> <span class="n">completed_timers</span><span class="p">,</span>
         <span class="n">outputs</span><span class="p">,</span> <span class="n">unprocessed_bundles</span><span class="p">)</span>
     <span class="n">tw</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">get_watermarks</span><span class="p">(</span><span class="n">applied_ptransform</span><span class="p">)</span>
     <span class="n">tw</span><span class="o">.</span><span class="n">hold</span><span class="p">(</span><span class="n">keyed_earliest_holds</span><span class="p">)</span>
     <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">_refresh_watermarks</span><span class="p">(</span><span class="n">applied_ptransform</span><span class="p">,</span> <span class="n">side_inputs_container</span><span class="p">)</span></div>

   <span class="k">def</span> <span class="nf">_update_pending</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">input_committed_bundle</span><span class="p">,</span> <span class="n">applied_ptransform</span><span class="p">,</span>
                       <span class="n">completed_timers</span><span class="p">,</span> <span class="n">output_committed_bundles</span><span class="p">,</span>
                       <span class="n">unprocessed_bundles</span><span class="p">):</span>
     <span class="sd">&quot;&quot;&quot;Updated list of pending bundles for the given AppliedPTransform.&quot;&quot;&quot;</span>

     <span class="c1"># Update pending elements. Filter out empty bundles. They do not impact</span>
     <span class="c1"># watermarks and should not trigger downstream execution.</span>
     <span class="k">for</span> <span class="n">output</span> <span class="ow">in</span> <span class="n">output_committed_bundles</span><span class="p">:</span>
       <span class="k">if</span> <span class="n">output</span><span class="o">.</span><span class="n">has_elements</span><span class="p">():</span>
         <span class="k">if</span> <span class="n">output</span><span class="o">.</span><span class="n">pcollection</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_value_to_consumers</span><span class="p">:</span>
           <span class="n">consumers</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_value_to_consumers</span><span class="p">[</span><span class="n">output</span><span class="o">.</span><span class="n">pcollection</span><span class="p">]</span>
           <span class="k">for</span> <span class="n">consumer</span> <span class="ow">in</span> <span class="n">consumers</span><span class="p">:</span>
             <span class="n">consumer_tw</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_transform_to_watermarks</span><span class="p">[</span><span class="n">consumer</span><span class="p">]</span>
             <span class="n">consumer_tw</span><span class="o">.</span><span class="n">add_pending</span><span class="p">(</span><span class="n">output</span><span class="p">)</span>

     <span class="n">completed_tw</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_transform_to_watermarks</span><span class="p">[</span><span class="n">applied_ptransform</span><span class="p">]</span>
     <span class="n">completed_tw</span><span class="o">.</span><span class="n">update_timers</span><span class="p">(</span><span class="n">completed_timers</span><span class="p">)</span>

     <span class="k">for</span> <span class="n">unprocessed_bundle</span> <span class="ow">in</span> <span class="n">unprocessed_bundles</span><span class="p">:</span>
       <span class="n">completed_tw</span><span class="o">.</span><span class="n">add_pending</span><span class="p">(</span><span class="n">unprocessed_bundle</span><span class="p">)</span>

     <span class="k">assert</span> <span class="n">input_committed_bundle</span> <span class="ow">or</span> <span class="n">applied_ptransform</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_root_transforms</span>
     <span class="k">if</span> <span class="n">input_committed_bundle</span> <span class="ow">and</span> <span class="n">input_committed_bundle</span><span class="o">.</span><span class="n">has_elements</span><span class="p">():</span>
       <span class="n">completed_tw</span><span class="o">.</span><span class="n">remove_pending</span><span class="p">(</span><span class="n">input_committed_bundle</span><span class="p">)</span>

   <span class="k">def</span> <span class="nf">_refresh_watermarks</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">applied_ptransform</span><span class="p">,</span> <span class="n">side_inputs_container</span><span class="p">):</span>
     <span class="k">assert</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">applied_ptransform</span><span class="p">,</span> <span class="n">pipeline</span><span class="o">.</span><span class="n">AppliedPTransform</span><span class="p">)</span>
     <span class="n">unblocked_tasks</span> <span class="o">=</span> <span class="p">[]</span>
     <span class="n">tw</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">get_watermarks</span><span class="p">(</span><span class="n">applied_ptransform</span><span class="p">)</span>
     <span class="k">if</span> <span class="n">tw</span><span class="o">.</span><span class="n">refresh</span><span class="p">():</span>
       <span class="k">for</span> <span class="n">pval</span> <span class="ow">in</span> <span class="n">applied_ptransform</span><span class="o">.</span><span class="n">outputs</span><span class="o">.</span><span class="n">values</span><span class="p">():</span>
         <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">pval</span><span class="p">,</span> <span class="n">pvalue</span><span class="o">.</span><span class="n">DoOutputsTuple</span><span class="p">):</span>
           <span class="n">pvals</span> <span class="o">=</span> <span class="p">(</span><span class="n">v</span> <span class="k">for</span> <span class="n">v</span> <span class="ow">in</span> <span class="n">pval</span><span class="p">)</span>
         <span class="k">else</span><span class="p">:</span>
           <span class="n">pvals</span> <span class="o">=</span> <span class="p">(</span><span class="n">pval</span><span class="p">,)</span>
         <span class="k">for</span> <span class="n">v</span> <span class="ow">in</span> <span class="n">pvals</span><span class="p">:</span>
           <span class="k">if</span> <span class="n">v</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_value_to_consumers</span><span class="p">:</span>  <span class="c1"># If there are downstream consumers</span>
             <span class="n">consumers</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_value_to_consumers</span><span class="p">[</span><span class="n">v</span><span class="p">]</span>
             <span class="k">for</span> <span class="n">consumer</span> <span class="ow">in</span> <span class="n">consumers</span><span class="p">:</span>
               <span class="n">unblocked_tasks</span><span class="o">.</span><span class="n">extend</span><span class="p">(</span>
                   <span class="bp">self</span><span class="o">.</span><span class="n">_refresh_watermarks</span><span class="p">(</span><span class="n">consumer</span><span class="p">,</span> <span class="n">side_inputs_container</span><span class="p">))</span>
       <span class="c1"># Notify the side_inputs_container.</span>
       <span class="n">unblocked_tasks</span><span class="o">.</span><span class="n">extend</span><span class="p">(</span>
           <span class="n">side_inputs_container</span>
           <span class="o">.</span><span class="n">update_watermarks_for_transform_and_unblock_tasks</span><span class="p">(</span>
               <span class="n">applied_ptransform</span><span class="p">,</span> <span class="n">tw</span><span class="p">))</span>
     <span class="k">return</span> <span class="n">unblocked_tasks</span>

 <div class="viewcode-block" id="WatermarkManager.extract_all_timers"><a class="viewcode-back" href="../../../../apache_beam.runners.direct.watermark_manager.html#apache_beam.runners.direct.watermark_manager.WatermarkManager.extract_all_timers">[docs]</a>  <span class="k">def</span> <span class="nf">extract_all_timers</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
     <span class="sd">&quot;&quot;&quot;Extracts fired timers for all transforms</span>
 <span class="sd">    and reports if there are any timers set.&quot;&quot;&quot;</span>
     <span class="n">all_timers</span> <span class="o">=</span> <span class="p">[]</span>
     <span class="n">has_realtime_timer</span> <span class="o">=</span> <span class="kc">False</span>
     <span class="k">for</span> <span class="n">applied_ptransform</span><span class="p">,</span> <span class="n">tw</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_transform_to_watermarks</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
       <span class="n">fired_timers</span><span class="p">,</span> <span class="n">had_realtime_timer</span> <span class="o">=</span> <span class="n">tw</span><span class="o">.</span><span class="n">extract_transform_timers</span><span class="p">()</span>
       <span class="k">if</span> <span class="n">fired_timers</span><span class="p">:</span>
         <span class="n">all_timers</span><span class="o">.</span><span class="n">append</span><span class="p">((</span><span class="n">applied_ptransform</span><span class="p">,</span> <span class="n">fired_timers</span><span class="p">))</span>
       <span class="k">if</span> <span class="p">(</span><span class="n">had_realtime_timer</span>
           <span class="ow">and</span> <span class="n">tw</span><span class="o">.</span><span class="n">output_watermark</span> <span class="o">&lt;</span> <span class="n">WatermarkManager</span><span class="o">.</span><span class="n">WATERMARK_POS_INF</span><span class="p">):</span>
         <span class="n">has_realtime_timer</span> <span class="o">=</span> <span class="kc">True</span>
     <span class="k">return</span> <span class="n">all_timers</span><span class="p">,</span> <span class="n">has_realtime_timer</span></div></div>


 <span class="k">class</span> <span class="nc">_TransformWatermarks</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
   <span class="sd">&quot;&quot;&quot;Tracks input and output watermarks for an AppliedPTransform.&quot;&quot;&quot;</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">clock</span><span class="p">,</span> <span class="n">keyed_states</span><span class="p">,</span> <span class="n">transform</span><span class="p">):</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_clock</span> <span class="o">=</span> <span class="n">clock</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_keyed_states</span> <span class="o">=</span> <span class="n">keyed_states</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_input_transform_watermarks</span> <span class="o">=</span> <span class="p">[]</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_input_watermark</span> <span class="o">=</span> <span class="n">WatermarkManager</span><span class="o">.</span><span class="n">WATERMARK_NEG_INF</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_output_watermark</span> <span class="o">=</span> <span class="n">WatermarkManager</span><span class="o">.</span><span class="n">WATERMARK_NEG_INF</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_keyed_earliest_holds</span> <span class="o">=</span> <span class="p">{}</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_pending</span> <span class="o">=</span> <span class="nb">set</span><span class="p">()</span>  <span class="c1"># Scheduled bundles targeted for this transform.</span>
     <span class="bp">self</span><span class="o">.</span><span class="n">_fired_timers</span> <span class="o">=</span> <span class="nb">set</span><span class="p">()</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="bp">self</span><span class="o">.</span><span class="n">_label</span> <span class="o">=</span> <span class="nb">str</span><span class="p">(</span><span class="n">transform</span><span class="p">)</span>

   <span class="k">def</span> <span class="nf">update_input_transform_watermarks</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">input_transform_watermarks</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">_input_transform_watermarks</span> <span class="o">=</span> <span class="n">input_transform_watermarks</span>

   <span class="k">def</span> <span class="nf">update_timers</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">completed_timers</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">for</span> <span class="n">timer_firing</span> <span class="ow">in</span> <span class="n">completed_timers</span><span class="p">:</span>
         <span class="bp">self</span><span class="o">.</span><span class="n">_fired_timers</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="n">timer_firing</span><span class="p">)</span>

   <span class="nd">@property</span>
   <span class="k">def</span> <span class="nf">input_watermark</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">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">_input_watermark</span>

   <span class="nd">@property</span>
   <span class="k">def</span> <span class="nf">output_watermark</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">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">_output_watermark</span>

   <span class="k">def</span> <span class="nf">hold</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">keyed_earliest_holds</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">for</span> <span class="n">key</span><span class="p">,</span> <span class="n">hold_value</span> <span class="ow">in</span> <span class="n">keyed_earliest_holds</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
         <span class="bp">self</span><span class="o">.</span><span class="n">_keyed_earliest_holds</span><span class="p">[</span><span class="n">key</span><span class="p">]</span> <span class="o">=</span> <span class="n">hold_value</span>
         <span class="k">if</span> <span class="p">(</span><span class="n">hold_value</span> <span class="ow">is</span> <span class="kc">None</span> <span class="ow">or</span>
             <span class="n">hold_value</span> <span class="o">==</span> <span class="n">WatermarkManager</span><span class="o">.</span><span class="n">WATERMARK_POS_INF</span><span class="p">):</span>
           <span class="k">del</span> <span class="bp">self</span><span class="o">.</span><span class="n">_keyed_earliest_holds</span><span class="p">[</span><span class="n">key</span><span class="p">]</span>

   <span class="k">def</span> <span class="nf">add_pending</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">pending</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">_pending</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">pending</span><span class="p">)</span>

   <span class="k">def</span> <span class="nf">remove_pending</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">completed</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="c1"># Ignore repeated removes. This will happen if a transform has a repeated</span>
       <span class="c1"># input.</span>
       <span class="k">if</span> <span class="n">completed</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_pending</span><span class="p">:</span>
         <span class="bp">self</span><span class="o">.</span><span class="n">_pending</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="n">completed</span><span class="p">)</span>

   <span class="k">def</span> <span class="nf">refresh</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="n">min_pending_timestamp</span> <span class="o">=</span> <span class="n">WatermarkManager</span><span class="o">.</span><span class="n">WATERMARK_POS_INF</span>
       <span class="n">has_pending_elements</span> <span class="o">=</span> <span class="kc">False</span>
       <span class="k">for</span> <span class="n">input_bundle</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_pending</span><span class="p">:</span>
         <span class="c1"># TODO(ccy): we can have the Bundle class keep track of the minimum</span>
         <span class="c1"># timestamp so we don&#39;t have to do an iteration here.</span>
         <span class="k">for</span> <span class="n">wv</span> <span class="ow">in</span> <span class="n">input_bundle</span><span class="o">.</span><span class="n">get_elements_iterable</span><span class="p">():</span>
           <span class="n">has_pending_elements</span> <span class="o">=</span> <span class="kc">True</span>
           <span class="k">if</span> <span class="n">wv</span><span class="o">.</span><span class="n">timestamp</span> <span class="o">&lt;</span> <span class="n">min_pending_timestamp</span><span class="p">:</span>
             <span class="n">min_pending_timestamp</span> <span class="o">=</span> <span class="n">wv</span><span class="o">.</span><span class="n">timestamp</span>

       <span class="c1"># If there is a pending element with a certain timestamp, we can at most</span>
       <span class="c1"># advance our watermark to the maximum timestamp less than that</span>
       <span class="c1"># timestamp.</span>
       <span class="n">pending_holder</span> <span class="o">=</span> <span class="n">WatermarkManager</span><span class="o">.</span><span class="n">WATERMARK_POS_INF</span>
       <span class="k">if</span> <span class="n">has_pending_elements</span><span class="p">:</span>
         <span class="n">pending_holder</span> <span class="o">=</span> <span class="n">min_pending_timestamp</span> <span class="o">-</span> <span class="n">TIME_GRANULARITY</span>

       <span class="n">input_watermarks</span> <span class="o">=</span> <span class="p">[</span>
           <span class="n">tw</span><span class="o">.</span><span class="n">output_watermark</span> <span class="k">for</span> <span class="n">tw</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_input_transform_watermarks</span><span class="p">]</span>
       <span class="n">input_watermarks</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">WatermarkManager</span><span class="o">.</span><span class="n">WATERMARK_POS_INF</span><span class="p">)</span>
       <span class="n">producer_watermark</span> <span class="o">=</span> <span class="nb">min</span><span class="p">(</span><span class="n">input_watermarks</span><span class="p">)</span>

       <span class="bp">self</span><span class="o">.</span><span class="n">_input_watermark</span> <span class="o">=</span> <span class="nb">max</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_input_watermark</span><span class="p">,</span>
                                   <span class="nb">min</span><span class="p">(</span><span class="n">pending_holder</span><span class="p">,</span> <span class="n">producer_watermark</span><span class="p">))</span>
       <span class="n">earliest_hold</span> <span class="o">=</span> <span class="n">WatermarkManager</span><span class="o">.</span><span class="n">WATERMARK_POS_INF</span>
       <span class="k">for</span> <span class="n">hold</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_keyed_earliest_holds</span><span class="o">.</span><span class="n">values</span><span class="p">():</span>
         <span class="k">if</span> <span class="n">hold</span> <span class="o">&lt;</span> <span class="n">earliest_hold</span><span class="p">:</span>
           <span class="n">earliest_hold</span> <span class="o">=</span> <span class="n">hold</span>
       <span class="n">new_output_watermark</span> <span class="o">=</span> <span class="nb">min</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_input_watermark</span><span class="p">,</span> <span class="n">earliest_hold</span><span class="p">)</span>

       <span class="n">advanced</span> <span class="o">=</span> <span class="n">new_output_watermark</span> <span class="o">&gt;</span> <span class="bp">self</span><span class="o">.</span><span class="n">_output_watermark</span>
       <span class="bp">self</span><span class="o">.</span><span class="n">_output_watermark</span> <span class="o">=</span> <span class="n">new_output_watermark</span>
       <span class="k">return</span> <span class="n">advanced</span>

   <span class="nd">@property</span>
   <span class="k">def</span> <span class="nf">synchronized_processing_output_time</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
     <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">_clock</span><span class="o">.</span><span class="n">time</span><span class="p">()</span>

   <span class="k">def</span> <span class="nf">extract_transform_timers</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
     <span class="sd">&quot;&quot;&quot;Extracts fired timers and reports of any timers set per transform.&quot;&quot;&quot;</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="n">fired_timers</span> <span class="o">=</span> <span class="p">[]</span>
       <span class="n">has_realtime_timer</span> <span class="o">=</span> <span class="kc">False</span>
       <span class="k">for</span> <span class="n">encoded_key</span><span class="p">,</span> <span class="n">state</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_keyed_states</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
         <span class="n">timers</span><span class="p">,</span> <span class="n">had_realtime_timer</span> <span class="o">=</span> <span class="n">state</span><span class="o">.</span><span class="n">get_timers</span><span class="p">(</span>
             <span class="n">watermark</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">_input_watermark</span><span class="p">,</span>
             <span class="n">processing_time</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">_clock</span><span class="o">.</span><span class="n">time</span><span class="p">())</span>
         <span class="k">if</span> <span class="n">had_realtime_timer</span><span class="p">:</span>
           <span class="n">has_realtime_timer</span> <span class="o">=</span> <span class="kc">True</span>
         <span class="k">for</span> <span class="n">expired</span> <span class="ow">in</span> <span class="n">timers</span><span class="p">:</span>
           <span class="n">window</span><span class="p">,</span> <span class="p">(</span><span class="n">name</span><span class="p">,</span> <span class="n">time_domain</span><span class="p">,</span> <span class="n">timestamp</span><span class="p">)</span> <span class="o">=</span> <span class="n">expired</span>
           <span class="n">fired_timers</span><span class="o">.</span><span class="n">append</span><span class="p">(</span>
               <span class="n">TimerFiring</span><span class="p">(</span><span class="n">encoded_key</span><span class="p">,</span> <span class="n">window</span><span class="p">,</span> <span class="n">name</span><span class="p">,</span> <span class="n">time_domain</span><span class="p">,</span> <span class="n">timestamp</span><span class="p">))</span>
       <span class="bp">self</span><span class="o">.</span><span class="n">_fired_timers</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">fired_timers</span><span class="p">)</span>
       <span class="k">return</span> <span class="n">fired_timers</span><span class="p">,</span> <span class="n">has_realtime_timer</span>
 </pre></div>

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