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<h1>Source code for airflow.utils.helpers</h1><div class="highlight"><pre>
<span></span><span class="c1"># -*- coding: utf-8 -*-</span>
<span class="c1">#</span>
<span class="c1"># Licensed to the Apache Software Foundation (ASF) under one</span>
<span class="c1"># or more contributor license agreements. See the NOTICE file</span>
<span class="c1"># distributed with this work for additional information</span>
<span class="c1"># regarding copyright ownership. The ASF licenses this file</span>
<span class="c1"># to you under the Apache License, Version 2.0 (the</span>
<span class="c1"># &quot;License&quot;); you may not use this file except in compliance</span>
<span class="c1"># with 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,</span>
<span class="c1"># software distributed under the License is distributed on an</span>
<span class="c1"># &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY</span>
<span class="c1"># KIND, either express or implied. See the License for the</span>
<span class="c1"># specific language governing permissions and limitations</span>
<span class="c1"># under the License.</span>
<span class="c1">#</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">division</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">from</span> <span class="nn">__future__</span> <span class="k">import</span> <span class="n">unicode_literals</span>
<span class="kn">import</span> <span class="nn">errno</span>
<span class="kn">import</span> <span class="nn">imp</span>
<span class="kn">import</span> <span class="nn">sys</span>
<span class="kn">import</span> <span class="nn">warnings</span>
<span class="kn">import</span> <span class="nn">psutil</span>
<span class="kn">from</span> <span class="nn">builtins</span> <span class="k">import</span> <span class="nb">input</span>
<span class="kn">from</span> <span class="nn">past.builtins</span> <span class="k">import</span> <span class="n">basestring</span>
<span class="kn">from</span> <span class="nn">datetime</span> <span class="k">import</span> <span class="n">datetime</span>
<span class="kn">from</span> <span class="nn">functools</span> <span class="k">import</span> <span class="n">reduce</span>
<span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">re</span>
<span class="kn">import</span> <span class="nn">signal</span>
<span class="kn">from</span> <span class="nn">jinja2</span> <span class="k">import</span> <span class="n">Template</span>
<span class="kn">from</span> <span class="nn">airflow</span> <span class="k">import</span> <span class="n">configuration</span>
<span class="kn">from</span> <span class="nn">airflow.exceptions</span> <span class="k">import</span> <span class="n">AirflowException</span>
<span class="c1"># When killing processes, time to wait after issuing a SIGTERM before issuing a</span>
<span class="c1"># SIGKILL.</span>
<span class="n">DEFAULT_TIME_TO_WAIT_AFTER_SIGTERM</span> <span class="o">=</span> <span class="n">configuration</span><span class="o">.</span><span class="n">conf</span><span class="o">.</span><span class="n">getint</span><span class="p">(</span>
<span class="s1">&#39;core&#39;</span><span class="p">,</span> <span class="s1">&#39;KILLED_TASK_CLEANUP_TIME&#39;</span>
<span class="p">)</span>
<div class="viewcode-block" id="validate_key"><a class="viewcode-back" href="../../../_api/airflow/models/index.html#airflow.models.validate_key">[docs]</a><span class="k">def</span> <span class="nf">validate_key</span><span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">max_length</span><span class="o">=</span><span class="mi">250</span><span class="p">):</span>
<span class="k">if</span> <span class="ow">not</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">basestring</span><span class="p">):</span>
<span class="k">raise</span> <span class="ne">TypeError</span><span class="p">(</span><span class="s2">&quot;The key has to be a string&quot;</span><span class="p">)</span>
<span class="k">elif</span> <span class="nb">len</span><span class="p">(</span><span class="n">k</span><span class="p">)</span> <span class="o">&gt;</span> <span class="n">max_length</span><span class="p">:</span>
<span class="k">raise</span> <span class="n">AirflowException</span><span class="p">(</span>
<span class="s2">&quot;The key has to be less than </span><span class="si">{0}</span><span class="s2"> characters&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">max_length</span><span class="p">))</span>
<span class="k">elif</span> <span class="ow">not</span> <span class="n">re</span><span class="o">.</span><span class="n">match</span><span class="p">(</span><span class="sa">r</span><span class="s1">&#39;^[A-Za-z0-9_\-\.]+$&#39;</span><span class="p">,</span> <span class="n">k</span><span class="p">):</span>
<span class="k">raise</span> <span class="n">AirflowException</span><span class="p">(</span>
<span class="s2">&quot;The key (</span><span class="si">{k}</span><span class="s2">) has to be made of alphanumeric characters, dashes, &quot;</span>
<span class="s2">&quot;dots and underscores exclusively&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="o">**</span><span class="nb">locals</span><span class="p">()))</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">return</span> <span class="kc">True</span></div>
<span class="k">def</span> <span class="nf">alchemy_to_dict</span><span class="p">(</span><span class="n">obj</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Transforms a SQLAlchemy model instance into a dictionary</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">obj</span><span class="p">:</span>
<span class="k">return</span> <span class="kc">None</span>
<span class="n">d</span> <span class="o">=</span> <span class="p">{}</span>
<span class="k">for</span> <span class="n">c</span> <span class="ow">in</span> <span class="n">obj</span><span class="o">.</span><span class="n">__table__</span><span class="o">.</span><span class="n">columns</span><span class="p">:</span>
<span class="n">value</span> <span class="o">=</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">obj</span><span class="p">,</span> <span class="n">c</span><span class="o">.</span><span class="n">name</span><span class="p">)</span>
<span class="k">if</span> <span class="nb">type</span><span class="p">(</span><span class="n">value</span><span class="p">)</span> <span class="o">==</span> <span class="n">datetime</span><span class="p">:</span>
<span class="n">value</span> <span class="o">=</span> <span class="n">value</span><span class="o">.</span><span class="n">isoformat</span><span class="p">()</span>
<span class="n">d</span><span class="p">[</span><span class="n">c</span><span class="o">.</span><span class="n">name</span><span class="p">]</span> <span class="o">=</span> <span class="n">value</span>
<span class="k">return</span> <span class="n">d</span>
<span class="k">def</span> <span class="nf">ask_yesno</span><span class="p">(</span><span class="n">question</span><span class="p">):</span>
<span class="n">yes</span> <span class="o">=</span> <span class="nb">set</span><span class="p">([</span><span class="s1">&#39;yes&#39;</span><span class="p">,</span> <span class="s1">&#39;y&#39;</span><span class="p">])</span>
<span class="n">no</span> <span class="o">=</span> <span class="nb">set</span><span class="p">([</span><span class="s1">&#39;no&#39;</span><span class="p">,</span> <span class="s1">&#39;n&#39;</span><span class="p">])</span>
<span class="n">done</span> <span class="o">=</span> <span class="kc">False</span>
<span class="nb">print</span><span class="p">(</span><span class="n">question</span><span class="p">)</span>
<span class="k">while</span> <span class="ow">not</span> <span class="n">done</span><span class="p">:</span>
<span class="n">choice</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span>
<span class="k">if</span> <span class="n">choice</span> <span class="ow">in</span> <span class="n">yes</span><span class="p">:</span>
<span class="k">return</span> <span class="kc">True</span>
<span class="k">elif</span> <span class="n">choice</span> <span class="ow">in</span> <span class="n">no</span><span class="p">:</span>
<span class="k">return</span> <span class="kc">False</span>
<span class="k">else</span><span class="p">:</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">&quot;Please respond by yes or no.&quot;</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">is_in</span><span class="p">(</span><span class="n">obj</span><span class="p">,</span> <span class="n">l</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Checks whether an object is one of the item in the list.</span>
<span class="sd"> This is different from ``in`` because ``in`` uses __cmp__ when</span>
<span class="sd"> present. Here we change based on the object itself</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">for</span> <span class="n">item</span> <span class="ow">in</span> <span class="n">l</span><span class="p">:</span>
<span class="k">if</span> <span class="n">item</span> <span class="ow">is</span> <span class="n">obj</span><span class="p">:</span>
<span class="k">return</span> <span class="kc">True</span>
<span class="k">return</span> <span class="kc">False</span>
<div class="viewcode-block" id="is_container"><a class="viewcode-back" href="../../../_api/airflow/models/index.html#airflow.models.is_container">[docs]</a><span class="k">def</span> <span class="nf">is_container</span><span class="p">(</span><span class="n">obj</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Test if an object is a container (iterable) but not a string</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">return</span> <span class="nb">hasattr</span><span class="p">(</span><span class="n">obj</span><span class="p">,</span> <span class="s1">&#39;__iter__&#39;</span><span class="p">)</span> <span class="ow">and</span> <span class="ow">not</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">obj</span><span class="p">,</span> <span class="n">basestring</span><span class="p">)</span></div>
<div class="viewcode-block" id="as_tuple"><a class="viewcode-back" href="../../../_api/airflow/models/index.html#airflow.models.as_tuple">[docs]</a><span class="k">def</span> <span class="nf">as_tuple</span><span class="p">(</span><span class="n">obj</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> If obj is a container, returns obj as a tuple.</span>
<span class="sd"> Otherwise, returns a tuple containing obj.</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">if</span> <span class="n">is_container</span><span class="p">(</span><span class="n">obj</span><span class="p">):</span>
<span class="k">return</span> <span class="nb">tuple</span><span class="p">(</span><span class="n">obj</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">return</span> <span class="nb">tuple</span><span class="p">([</span><span class="n">obj</span><span class="p">])</span></div>
<span class="k">def</span> <span class="nf">chunks</span><span class="p">(</span><span class="n">items</span><span class="p">,</span> <span class="n">chunk_size</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Yield successive chunks of a given size from a list of items</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">if</span> <span class="n">chunk_size</span> <span class="o">&lt;=</span> <span class="mi">0</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s1">&#39;Chunk size must be a positive integer&#39;</span><span class="p">)</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="nb">len</span><span class="p">(</span><span class="n">items</span><span class="p">),</span> <span class="n">chunk_size</span><span class="p">):</span>
<span class="k">yield</span> <span class="n">items</span><span class="p">[</span><span class="n">i</span><span class="p">:</span><span class="n">i</span> <span class="o">+</span> <span class="n">chunk_size</span><span class="p">]</span>
<span class="k">def</span> <span class="nf">reduce_in_chunks</span><span class="p">(</span><span class="n">fn</span><span class="p">,</span> <span class="n">iterable</span><span class="p">,</span> <span class="n">initializer</span><span class="p">,</span> <span class="n">chunk_size</span><span class="o">=</span><span class="mi">0</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Reduce the given list of items by splitting it into chunks</span>
<span class="sd"> of the given size and passing each chunk through the reducer</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">iterable</span><span class="p">)</span> <span class="o">==</span> <span class="mi">0</span><span class="p">:</span>
<span class="k">return</span> <span class="n">initializer</span>
<span class="k">if</span> <span class="n">chunk_size</span> <span class="o">==</span> <span class="mi">0</span><span class="p">:</span>
<span class="n">chunk_size</span> <span class="o">=</span> <span class="nb">len</span><span class="p">(</span><span class="n">iterable</span><span class="p">)</span>
<span class="k">return</span> <span class="n">reduce</span><span class="p">(</span><span class="n">fn</span><span class="p">,</span> <span class="n">chunks</span><span class="p">(</span><span class="n">iterable</span><span class="p">,</span> <span class="n">chunk_size</span><span class="p">),</span> <span class="n">initializer</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">as_flattened_list</span><span class="p">(</span><span class="n">iterable</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Return an iterable with one level flattened</span>
<span class="sd"> &gt;&gt;&gt; as_flattened_list(((&#39;blue&#39;, &#39;red&#39;), (&#39;green&#39;, &#39;yellow&#39;, &#39;pink&#39;)))</span>
<span class="sd"> [&#39;blue&#39;, &#39;red&#39;, &#39;green&#39;, &#39;yellow&#39;, &#39;pink&#39;]</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">return</span> <span class="p">[</span><span class="n">e</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="n">iterable</span> <span class="k">for</span> <span class="n">e</span> <span class="ow">in</span> <span class="n">i</span><span class="p">]</span>
<span class="k">def</span> <span class="nf">chain</span><span class="p">(</span><span class="o">*</span><span class="n">tasks</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Given a number of tasks, builds a dependency chain.</span>
<span class="sd"> chain(task_1, task_2, task_3, task_4)</span>
<span class="sd"> is equivalent to</span>
<span class="sd"> task_1.set_downstream(task_2)</span>
<span class="sd"> task_2.set_downstream(task_3)</span>
<span class="sd"> task_3.set_downstream(task_4)</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">for</span> <span class="n">up_task</span><span class="p">,</span> <span class="n">down_task</span> <span class="ow">in</span> <span class="nb">zip</span><span class="p">(</span><span class="n">tasks</span><span class="p">[:</span><span class="o">-</span><span class="mi">1</span><span class="p">],</span> <span class="n">tasks</span><span class="p">[</span><span class="mi">1</span><span class="p">:]):</span>
<span class="n">up_task</span><span class="o">.</span><span class="n">set_downstream</span><span class="p">(</span><span class="n">down_task</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">cross_downstream</span><span class="p">(</span><span class="n">from_tasks</span><span class="p">,</span> <span class="n">to_tasks</span><span class="p">):</span>
<span class="sa">r</span><span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Set downstream dependencies for all tasks in from_tasks to all tasks in to_tasks.</span>
<span class="sd"> E.g.: cross_downstream(from_tasks=[t1, t2, t3], to_tasks=[t4, t5, t6])</span>
<span class="sd"> Is equivalent to:</span>
<span class="sd"> t1 --&gt; t4</span>
<span class="sd"> \ /</span>
<span class="sd"> t2 -X&gt; t5</span>
<span class="sd"> / \</span>
<span class="sd"> t3 --&gt; t6</span>
<span class="sd"> t1.set_downstream(t4)</span>
<span class="sd"> t1.set_downstream(t5)</span>
<span class="sd"> t1.set_downstream(t6)</span>
<span class="sd"> t2.set_downstream(t4)</span>
<span class="sd"> t2.set_downstream(t5)</span>
<span class="sd"> t2.set_downstream(t6)</span>
<span class="sd"> t3.set_downstream(t4)</span>
<span class="sd"> t3.set_downstream(t5)</span>
<span class="sd"> t3.set_downstream(t6)</span>
<span class="sd"> :param from_tasks: List of tasks to start from.</span>
<span class="sd"> :type from_tasks: List[airflow.models.BaseOperator]</span>
<span class="sd"> :param to_tasks: List of tasks to set as downstream dependencies.</span>
<span class="sd"> :type to_tasks: List[airflow.models.BaseOperator]</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">for</span> <span class="n">task</span> <span class="ow">in</span> <span class="n">from_tasks</span><span class="p">:</span>
<span class="n">task</span><span class="o">.</span><span class="n">set_downstream</span><span class="p">(</span><span class="n">to_tasks</span><span class="p">)</span>
<div class="viewcode-block" id="pprinttable"><a class="viewcode-back" href="../../../_api/airflow/models/index.html#airflow.models.pprinttable">[docs]</a><span class="k">def</span> <span class="nf">pprinttable</span><span class="p">(</span><span class="n">rows</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;Returns a pretty ascii table from tuples</span>
<span class="sd"> If namedtuple are used, the table will have headers</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">rows</span><span class="p">:</span>
<span class="k">return</span>
<span class="k">if</span> <span class="nb">hasattr</span><span class="p">(</span><span class="n">rows</span><span class="p">[</span><span class="mi">0</span><span class="p">],</span> <span class="s1">&#39;_fields&#39;</span><span class="p">):</span> <span class="c1"># if namedtuple</span>
<span class="n">headers</span> <span class="o">=</span> <span class="n">rows</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">_fields</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">headers</span> <span class="o">=</span> <span class="p">[</span><span class="s2">&quot;col</span><span class="si">{}</span><span class="s2">&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">i</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">rows</span><span class="p">[</span><span class="mi">0</span><span class="p">]))]</span>
<span class="n">lens</span> <span class="o">=</span> <span class="p">[</span><span class="nb">len</span><span class="p">(</span><span class="n">s</span><span class="p">)</span> <span class="k">for</span> <span class="n">s</span> <span class="ow">in</span> <span class="n">headers</span><span class="p">]</span>
<span class="k">for</span> <span class="n">row</span> <span class="ow">in</span> <span class="n">rows</span><span class="p">:</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">rows</span><span class="p">[</span><span class="mi">0</span><span class="p">])):</span>
<span class="n">slenght</span> <span class="o">=</span> <span class="nb">len</span><span class="p">(</span><span class="s2">&quot;</span><span class="si">{}</span><span class="s2">&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">row</span><span class="p">[</span><span class="n">i</span><span class="p">]))</span>
<span class="k">if</span> <span class="n">slenght</span> <span class="o">&gt;</span> <span class="n">lens</span><span class="p">[</span><span class="n">i</span><span class="p">]:</span>
<span class="n">lens</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o">=</span> <span class="n">slenght</span>
<span class="n">formats</span> <span class="o">=</span> <span class="p">[]</span>
<span class="n">hformats</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">rows</span><span class="p">[</span><span class="mi">0</span><span class="p">])):</span>
<span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">rows</span><span class="p">[</span><span class="mi">0</span><span class="p">][</span><span class="n">i</span><span class="p">],</span> <span class="nb">int</span><span class="p">):</span>
<span class="n">formats</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="s2">&quot;</span><span class="si">%%%d</span><span class="s2">d&quot;</span> <span class="o">%</span> <span class="n">lens</span><span class="p">[</span><span class="n">i</span><span class="p">])</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">formats</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="s2">&quot;</span><span class="si">%%</span><span class="s2">-</span><span class="si">%d</span><span class="s2">s&quot;</span> <span class="o">%</span> <span class="n">lens</span><span class="p">[</span><span class="n">i</span><span class="p">])</span>
<span class="n">hformats</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="s2">&quot;</span><span class="si">%%</span><span class="s2">-</span><span class="si">%d</span><span class="s2">s&quot;</span> <span class="o">%</span> <span class="n">lens</span><span class="p">[</span><span class="n">i</span><span class="p">])</span>
<span class="n">pattern</span> <span class="o">=</span> <span class="s2">&quot; | &quot;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">formats</span><span class="p">)</span>
<span class="n">hpattern</span> <span class="o">=</span> <span class="s2">&quot; | &quot;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">hformats</span><span class="p">)</span>
<span class="n">separator</span> <span class="o">=</span> <span class="s2">&quot;-+-&quot;</span><span class="o">.</span><span class="n">join</span><span class="p">([</span><span class="s1">&#39;-&#39;</span> <span class="o">*</span> <span class="n">n</span> <span class="k">for</span> <span class="n">n</span> <span class="ow">in</span> <span class="n">lens</span><span class="p">])</span>
<span class="n">s</span> <span class="o">=</span> <span class="s2">&quot;&quot;</span>
<span class="n">s</span> <span class="o">+=</span> <span class="n">separator</span> <span class="o">+</span> <span class="s1">&#39;</span><span class="se">\n</span><span class="s1">&#39;</span>
<span class="n">s</span> <span class="o">+=</span> <span class="p">(</span><span class="n">hpattern</span> <span class="o">%</span> <span class="nb">tuple</span><span class="p">(</span><span class="n">headers</span><span class="p">))</span> <span class="o">+</span> <span class="s1">&#39;</span><span class="se">\n</span><span class="s1">&#39;</span>
<span class="n">s</span> <span class="o">+=</span> <span class="n">separator</span> <span class="o">+</span> <span class="s1">&#39;</span><span class="se">\n</span><span class="s1">&#39;</span>
<span class="k">def</span> <span class="nf">f</span><span class="p">(</span><span class="n">t</span><span class="p">):</span>
<span class="k">return</span> <span class="s2">&quot;</span><span class="si">{}</span><span class="s2">&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">t</span><span class="p">)</span> <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">t</span><span class="p">,</span> <span class="n">basestring</span><span class="p">)</span> <span class="k">else</span> <span class="n">t</span>
<span class="k">for</span> <span class="n">line</span> <span class="ow">in</span> <span class="n">rows</span><span class="p">:</span>
<span class="n">s</span> <span class="o">+=</span> <span class="n">pattern</span> <span class="o">%</span> <span class="nb">tuple</span><span class="p">(</span><span class="n">f</span><span class="p">(</span><span class="n">t</span><span class="p">)</span> <span class="k">for</span> <span class="n">t</span> <span class="ow">in</span> <span class="n">line</span><span class="p">)</span> <span class="o">+</span> <span class="s1">&#39;</span><span class="se">\n</span><span class="s1">&#39;</span>
<span class="n">s</span> <span class="o">+=</span> <span class="n">separator</span> <span class="o">+</span> <span class="s1">&#39;</span><span class="se">\n</span><span class="s1">&#39;</span>
<span class="k">return</span> <span class="n">s</span></div>
<span class="k">def</span> <span class="nf">reap_process_group</span><span class="p">(</span><span class="n">pid</span><span class="p">,</span> <span class="n">log</span><span class="p">,</span> <span class="n">sig</span><span class="o">=</span><span class="n">signal</span><span class="o">.</span><span class="n">SIGTERM</span><span class="p">,</span>
<span class="n">timeout</span><span class="o">=</span><span class="n">DEFAULT_TIME_TO_WAIT_AFTER_SIGTERM</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Tries really hard to terminate all children (including grandchildren). Will send</span>
<span class="sd"> sig (SIGTERM) to the process group of pid. If any process is alive after timeout</span>
<span class="sd"> a SIGKILL will be send.</span>
<span class="sd"> :param log: log handler</span>
<span class="sd"> :param pid: pid to kill</span>
<span class="sd"> :param sig: signal type</span>
<span class="sd"> :param timeout: how much time a process has to terminate</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">def</span> <span class="nf">on_terminate</span><span class="p">(</span><span class="n">p</span><span class="p">):</span>
<span class="n">log</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s2">&quot;Process </span><span class="si">%s</span><span class="s2"> (</span><span class="si">%s</span><span class="s2">) terminated with exit code </span><span class="si">%s</span><span class="s2">&quot;</span><span class="p">,</span> <span class="n">p</span><span class="p">,</span> <span class="n">p</span><span class="o">.</span><span class="n">pid</span><span class="p">,</span> <span class="n">p</span><span class="o">.</span><span class="n">returncode</span><span class="p">)</span>
<span class="k">if</span> <span class="n">pid</span> <span class="o">==</span> <span class="n">os</span><span class="o">.</span><span class="n">getpid</span><span class="p">():</span>
<span class="k">raise</span> <span class="ne">RuntimeError</span><span class="p">(</span><span class="s2">&quot;I refuse to kill myself&quot;</span><span class="p">)</span>
<span class="n">parent</span> <span class="o">=</span> <span class="n">psutil</span><span class="o">.</span><span class="n">Process</span><span class="p">(</span><span class="n">pid</span><span class="p">)</span>
<span class="n">children</span> <span class="o">=</span> <span class="n">parent</span><span class="o">.</span><span class="n">children</span><span class="p">(</span><span class="n">recursive</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="n">children</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">parent</span><span class="p">)</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">pg</span> <span class="o">=</span> <span class="n">os</span><span class="o">.</span><span class="n">getpgid</span><span class="p">(</span><span class="n">pid</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">OSError</span> <span class="k">as</span> <span class="n">err</span><span class="p">:</span>
<span class="c1"># Skip if not such process - we experience a race and it just terminated</span>
<span class="k">if</span> <span class="n">err</span><span class="o">.</span><span class="n">errno</span> <span class="o">==</span> <span class="n">errno</span><span class="o">.</span><span class="n">ESRCH</span><span class="p">:</span>
<span class="k">return</span>
<span class="k">raise</span>
<span class="n">log</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s2">&quot;Sending </span><span class="si">%s</span><span class="s2"> to GPID </span><span class="si">%s</span><span class="s2">&quot;</span><span class="p">,</span> <span class="n">sig</span><span class="p">,</span> <span class="n">pg</span><span class="p">)</span>
<span class="n">os</span><span class="o">.</span><span class="n">killpg</span><span class="p">(</span><span class="n">os</span><span class="o">.</span><span class="n">getpgid</span><span class="p">(</span><span class="n">pid</span><span class="p">),</span> <span class="n">sig</span><span class="p">)</span>
<span class="n">gone</span><span class="p">,</span> <span class="n">alive</span> <span class="o">=</span> <span class="n">psutil</span><span class="o">.</span><span class="n">wait_procs</span><span class="p">(</span><span class="n">children</span><span class="p">,</span> <span class="n">timeout</span><span class="o">=</span><span class="n">timeout</span><span class="p">,</span> <span class="n">callback</span><span class="o">=</span><span class="n">on_terminate</span><span class="p">)</span>
<span class="k">if</span> <span class="n">alive</span><span class="p">:</span>
<span class="k">for</span> <span class="n">p</span> <span class="ow">in</span> <span class="n">alive</span><span class="p">:</span>
<span class="n">log</span><span class="o">.</span><span class="n">warn</span><span class="p">(</span><span class="s2">&quot;process </span><span class="si">%s</span><span class="s2"> (</span><span class="si">%s</span><span class="s2">) did not respond to SIGTERM. Trying SIGKILL&quot;</span><span class="p">,</span> <span class="n">p</span><span class="p">,</span> <span class="n">pid</span><span class="p">)</span>
<span class="n">os</span><span class="o">.</span><span class="n">killpg</span><span class="p">(</span><span class="n">os</span><span class="o">.</span><span class="n">getpgid</span><span class="p">(</span><span class="n">pid</span><span class="p">),</span> <span class="n">signal</span><span class="o">.</span><span class="n">SIGKILL</span><span class="p">)</span>
<span class="n">gone</span><span class="p">,</span> <span class="n">alive</span> <span class="o">=</span> <span class="n">psutil</span><span class="o">.</span><span class="n">wait_procs</span><span class="p">(</span><span class="n">alive</span><span class="p">,</span> <span class="n">timeout</span><span class="o">=</span><span class="n">timeout</span><span class="p">,</span> <span class="n">callback</span><span class="o">=</span><span class="n">on_terminate</span><span class="p">)</span>
<span class="k">if</span> <span class="n">alive</span><span class="p">:</span>
<span class="k">for</span> <span class="n">p</span> <span class="ow">in</span> <span class="n">alive</span><span class="p">:</span>
<span class="n">log</span><span class="o">.</span><span class="n">error</span><span class="p">(</span><span class="s2">&quot;Process </span><span class="si">%s</span><span class="s2"> (</span><span class="si">%s</span><span class="s2">) could not be killed. Giving up.&quot;</span><span class="p">,</span> <span class="n">p</span><span class="p">,</span> <span class="n">p</span><span class="o">.</span><span class="n">pid</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">parse_template_string</span><span class="p">(</span><span class="n">template_string</span><span class="p">):</span>
<span class="k">if</span> <span class="s2">&quot;{{&quot;</span> <span class="ow">in</span> <span class="n">template_string</span><span class="p">:</span> <span class="c1"># jinja mode</span>
<span class="k">return</span> <span class="kc">None</span><span class="p">,</span> <span class="n">Template</span><span class="p">(</span><span class="n">template_string</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">return</span> <span class="n">template_string</span><span class="p">,</span> <span class="kc">None</span>
<span class="k">class</span> <span class="nc">AirflowImporter</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Importer that dynamically loads a class and module from its parent. This</span>
<span class="sd"> allows Airflow to support ``from airflow.operators import BashOperator``</span>
<span class="sd"> even though BashOperator is actually in</span>
<span class="sd"> ``airflow.operators.bash_operator``.</span>
<span class="sd"> The importer also takes over for the parent_module by wrapping it. This is</span>
<span class="sd"> required to support attribute-based usage:</span>
<span class="sd"> .. code:: python</span>
<span class="sd"> from airflow import operators</span>
<span class="sd"> operators.BashOperator(...)</span>
<span class="sd"> &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">parent_module</span><span class="p">,</span> <span class="n">module_attributes</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> :param parent_module: The string package name of the parent module. For</span>
<span class="sd"> example, &#39;airflow.operators&#39;</span>
<span class="sd"> :type parent_module: str</span>
<span class="sd"> :param module_attributes: The file to class mappings for all importable</span>
<span class="sd"> classes.</span>
<span class="sd"> :type module_attributes: str</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_parent_module</span> <span class="o">=</span> <span class="n">parent_module</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_attribute_modules</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_build_attribute_modules</span><span class="p">(</span><span class="n">module_attributes</span><span class="p">)</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_loaded_modules</span> <span class="o">=</span> <span class="p">{}</span>
<span class="c1"># Wrap the module so we can take over __getattr__.</span>
<span class="n">sys</span><span class="o">.</span><span class="n">modules</span><span class="p">[</span><span class="n">parent_module</span><span class="o">.</span><span class="vm">__name__</span><span class="p">]</span> <span class="o">=</span> <span class="bp">self</span>
<span class="nd">@staticmethod</span>
<span class="k">def</span> <span class="nf">_build_attribute_modules</span><span class="p">(</span><span class="n">module_attributes</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Flips and flattens the module_attributes dictionary from:</span>
<span class="sd"> module =&gt; [Attribute, ...]</span>
<span class="sd"> To:</span>
<span class="sd"> Attribute =&gt; module</span>
<span class="sd"> This is useful so that we can find the module to use, given an</span>
<span class="sd"> attribute.</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="n">attribute_modules</span> <span class="o">=</span> <span class="p">{}</span>
<span class="k">for</span> <span class="n">module</span><span class="p">,</span> <span class="n">attributes</span> <span class="ow">in</span> <span class="nb">list</span><span class="p">(</span><span class="n">module_attributes</span><span class="o">.</span><span class="n">items</span><span class="p">()):</span>
<span class="k">for</span> <span class="n">attribute</span> <span class="ow">in</span> <span class="n">attributes</span><span class="p">:</span>
<span class="n">attribute_modules</span><span class="p">[</span><span class="n">attribute</span><span class="p">]</span> <span class="o">=</span> <span class="n">module</span>
<span class="k">return</span> <span class="n">attribute_modules</span>
<span class="k">def</span> <span class="nf">_load_attribute</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">attribute</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Load the class attribute if it hasn&#39;t been loaded yet, and return it.</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="n">module</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_attribute_modules</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">attribute</span><span class="p">,</span> <span class="kc">False</span><span class="p">)</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">module</span><span class="p">:</span>
<span class="c1"># This shouldn&#39;t happen. The check happens in find_modules, too.</span>
<span class="k">raise</span> <span class="ne">ImportError</span><span class="p">(</span><span class="n">attribute</span><span class="p">)</span>
<span class="k">elif</span> <span class="n">module</span> <span class="ow">not</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_loaded_modules</span><span class="p">:</span>
<span class="c1"># Note that it&#39;s very important to only load a given modules once.</span>
<span class="c1"># If they are loaded more than once, the memory reference to the</span>
<span class="c1"># class objects changes, and Python thinks that an object of type</span>
<span class="c1"># Foo that was declared before Foo&#39;s module was reloaded is no</span>
<span class="c1"># longer the same type as Foo after it&#39;s reloaded.</span>
<span class="n">path</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">realpath</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_parent_module</span><span class="o">.</span><span class="vm">__file__</span><span class="p">)</span>
<span class="n">folder</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">dirname</span><span class="p">(</span><span class="n">path</span><span class="p">)</span>
<span class="n">f</span><span class="p">,</span> <span class="n">filename</span><span class="p">,</span> <span class="n">description</span> <span class="o">=</span> <span class="n">imp</span><span class="o">.</span><span class="n">find_module</span><span class="p">(</span><span class="n">module</span><span class="p">,</span> <span class="p">[</span><span class="n">folder</span><span class="p">])</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_loaded_modules</span><span class="p">[</span><span class="n">module</span><span class="p">]</span> <span class="o">=</span> <span class="n">imp</span><span class="o">.</span><span class="n">load_module</span><span class="p">(</span><span class="n">module</span><span class="p">,</span> <span class="n">f</span><span class="p">,</span> <span class="n">filename</span><span class="p">,</span> <span class="n">description</span><span class="p">)</span>
<span class="c1"># This functionality is deprecated, and AirflowImporter should be</span>
<span class="c1"># removed in 2.0.</span>
<span class="n">warnings</span><span class="o">.</span><span class="n">warn</span><span class="p">(</span>
<span class="s2">&quot;Importing &#39;</span><span class="si">{i}</span><span class="s2">&#39; directly from &#39;</span><span class="si">{m}</span><span class="s2">&#39; has been &quot;</span>
<span class="s2">&quot;deprecated. Please import from &quot;</span>
<span class="s2">&quot;&#39;</span><span class="si">{m}</span><span class="s2">.[operator_module]&#39; instead. Support for direct &quot;</span>
<span class="s2">&quot;imports will be dropped entirely in Airflow 2.0.&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span>
<span class="n">i</span><span class="o">=</span><span class="n">attribute</span><span class="p">,</span> <span class="n">m</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">_parent_module</span><span class="o">.</span><span class="vm">__name__</span><span class="p">),</span>
<span class="ne">DeprecationWarning</span><span class="p">)</span>
<span class="n">loaded_module</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_loaded_modules</span><span class="p">[</span><span class="n">module</span><span class="p">]</span>
<span class="k">return</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">loaded_module</span><span class="p">,</span> <span class="n">attribute</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">__getattr__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">attribute</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Get an attribute from the wrapped module. If the attribute doesn&#39;t</span>
<span class="sd"> exist, try and import it as a class from a submodule.</span>
<span class="sd"> This is a Python trick that allows the class to pretend it&#39;s a module,</span>
<span class="sd"> so that attribute-based usage works:</span>
<span class="sd"> from airflow import operators</span>
<span class="sd"> operators.BashOperator(...)</span>
<span class="sd"> It also allows normal from imports to work:</span>
<span class="sd"> from airflow.operators.bash_operator import BashOperator</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">if</span> <span class="nb">hasattr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_parent_module</span><span class="p">,</span> <span class="n">attribute</span><span class="p">):</span>
<span class="c1"># Always default to the parent module if the attribute exists.</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">_parent_module</span><span class="p">,</span> <span class="n">attribute</span><span class="p">)</span>
<span class="k">elif</span> <span class="n">attribute</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_attribute_modules</span><span class="p">:</span>
<span class="c1"># Try and import the attribute if it&#39;s got a module defined.</span>
<span class="n">loaded_attribute</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_load_attribute</span><span class="p">(</span><span class="n">attribute</span><span class="p">)</span>
<span class="nb">setattr</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">attribute</span><span class="p">,</span> <span class="n">loaded_attribute</span><span class="p">)</span>
<span class="k">return</span> <span class="n">loaded_attribute</span>
<span class="k">raise</span> <span class="ne">AttributeError</span>
<span class="k">def</span> <span class="nf">render_log_filename</span><span class="p">(</span><span class="n">ti</span><span class="p">,</span> <span class="n">try_number</span><span class="p">,</span> <span class="n">filename_template</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Given task instance, try_number, filename_template, return the rendered log filename</span>
<span class="sd"> :param ti: task instance</span>
<span class="sd"> :param try_number: try_number of the task</span>
<span class="sd"> :param filename_template: filename template, which can be jinja template or python string template</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="n">filename_template</span><span class="p">,</span> <span class="n">filename_jinja_template</span> <span class="o">=</span> <span class="n">parse_template_string</span><span class="p">(</span><span class="n">filename_template</span><span class="p">)</span>
<span class="k">if</span> <span class="n">filename_jinja_template</span><span class="p">:</span>
<span class="n">jinja_context</span> <span class="o">=</span> <span class="n">ti</span><span class="o">.</span><span class="n">get_template_context</span><span class="p">()</span>
<span class="n">jinja_context</span><span class="p">[</span><span class="s1">&#39;try_number&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="n">try_number</span>
<span class="k">return</span> <span class="n">filename_jinja_template</span><span class="o">.</span><span class="n">render</span><span class="p">(</span><span class="o">**</span><span class="n">jinja_context</span><span class="p">)</span>
<span class="k">return</span> <span class="n">filename_template</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">dag_id</span><span class="o">=</span><span class="n">ti</span><span class="o">.</span><span class="n">dag_id</span><span class="p">,</span>
<span class="n">task_id</span><span class="o">=</span><span class="n">ti</span><span class="o">.</span><span class="n">task_id</span><span class="p">,</span>
<span class="n">execution_date</span><span class="o">=</span><span class="n">ti</span><span class="o">.</span><span class="n">execution_date</span><span class="o">.</span><span class="n">isoformat</span><span class="p">(),</span>
<span class="n">try_number</span><span class="o">=</span><span class="n">try_number</span><span class="p">)</span>
</pre></div>
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