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<h1>Source code for airflow.contrib.hooks.cassandra_hook</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="kn">from</span> <span class="nn">cassandra.cluster</span> <span class="k">import</span> <span class="n">Cluster</span>
<span class="kn">from</span> <span class="nn">cassandra.policies</span> <span class="k">import</span> <span class="p">(</span><span class="n">RoundRobinPolicy</span><span class="p">,</span> <span class="n">DCAwareRoundRobinPolicy</span><span class="p">,</span>
<span class="n">TokenAwarePolicy</span><span class="p">,</span> <span class="n">WhiteListRoundRobinPolicy</span><span class="p">)</span>
<span class="kn">from</span> <span class="nn">cassandra.auth</span> <span class="k">import</span> <span class="n">PlainTextAuthProvider</span>
<span class="kn">from</span> <span class="nn">airflow.hooks.base_hook</span> <span class="k">import</span> <span class="n">BaseHook</span>
<span class="kn">from</span> <span class="nn">airflow.utils.log.logging_mixin</span> <span class="k">import</span> <span class="n">LoggingMixin</span>
<div class="viewcode-block" id="CassandraHook"><a class="viewcode-back" href="../../../../_api/airflow/contrib/hooks/cassandra_hook/index.html#airflow.contrib.hooks.cassandra_hook.CassandraHook">[docs]</a><span class="k">class</span> <span class="nc">CassandraHook</span><span class="p">(</span><span class="n">BaseHook</span><span class="p">,</span> <span class="n">LoggingMixin</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Hook used to interact with Cassandra</span>
<span class="sd"> Contact points can be specified as a comma-separated string in the &#39;hosts&#39;</span>
<span class="sd"> field of the connection.</span>
<span class="sd"> Port can be specified in the port field of the connection.</span>
<span class="sd"> If SSL is enabled in Cassandra, pass in a dict in the extra field as kwargs for</span>
<span class="sd"> ``ssl.wrap_socket()``. For example::</span>
<span class="sd"> {</span>
<span class="sd"> &#39;ssl_options&#39; : {</span>
<span class="sd"> &#39;ca_certs&#39; : PATH_TO_CA_CERTS</span>
<span class="sd"> }</span>
<span class="sd"> }</span>
<span class="sd"> Default load balancing policy is RoundRobinPolicy. To specify a different</span>
<span class="sd"> LB policy::</span>
<span class="sd"> - DCAwareRoundRobinPolicy</span>
<span class="sd"> {</span>
<span class="sd"> &#39;load_balancing_policy&#39;: &#39;DCAwareRoundRobinPolicy&#39;,</span>
<span class="sd"> &#39;load_balancing_policy_args&#39;: {</span>
<span class="sd"> &#39;local_dc&#39;: LOCAL_DC_NAME, // optional</span>
<span class="sd"> &#39;used_hosts_per_remote_dc&#39;: SOME_INT_VALUE, // optional</span>
<span class="sd"> }</span>
<span class="sd"> }</span>
<span class="sd"> - WhiteListRoundRobinPolicy</span>
<span class="sd"> {</span>
<span class="sd"> &#39;load_balancing_policy&#39;: &#39;WhiteListRoundRobinPolicy&#39;,</span>
<span class="sd"> &#39;load_balancing_policy_args&#39;: {</span>
<span class="sd"> &#39;hosts&#39;: [&#39;HOST1&#39;, &#39;HOST2&#39;, &#39;HOST3&#39;]</span>
<span class="sd"> }</span>
<span class="sd"> }</span>
<span class="sd"> - TokenAwarePolicy</span>
<span class="sd"> {</span>
<span class="sd"> &#39;load_balancing_policy&#39;: &#39;TokenAwarePolicy&#39;,</span>
<span class="sd"> &#39;load_balancing_policy_args&#39;: {</span>
<span class="sd"> &#39;child_load_balancing_policy&#39;: CHILD_POLICY_NAME, // optional</span>
<span class="sd"> &#39;child_load_balancing_policy_args&#39;: { ... } // optional</span>
<span class="sd"> }</span>
<span class="sd"> }</span>
<span class="sd"> For details of the Cluster config, see cassandra.cluster.</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">cassandra_conn_id</span><span class="o">=</span><span class="s1">&#39;cassandra_default&#39;</span><span class="p">):</span>
<span class="n">conn</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">get_connection</span><span class="p">(</span><span class="n">cassandra_conn_id</span><span class="p">)</span>
<span class="n">conn_config</span> <span class="o">=</span> <span class="p">{}</span>
<span class="k">if</span> <span class="n">conn</span><span class="o">.</span><span class="n">host</span><span class="p">:</span>
<span class="n">conn_config</span><span class="p">[</span><span class="s1">&#39;contact_points&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">host</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="s1">&#39;,&#39;</span><span class="p">)</span>
<span class="k">if</span> <span class="n">conn</span><span class="o">.</span><span class="n">port</span><span class="p">:</span>
<span class="n">conn_config</span><span class="p">[</span><span class="s1">&#39;port&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="n">conn</span><span class="o">.</span><span class="n">port</span><span class="p">)</span>
<span class="k">if</span> <span class="n">conn</span><span class="o">.</span><span class="n">login</span><span class="p">:</span>
<span class="n">conn_config</span><span class="p">[</span><span class="s1">&#39;auth_provider&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="n">PlainTextAuthProvider</span><span class="p">(</span>
<span class="n">username</span><span class="o">=</span><span class="n">conn</span><span class="o">.</span><span class="n">login</span><span class="p">,</span> <span class="n">password</span><span class="o">=</span><span class="n">conn</span><span class="o">.</span><span class="n">password</span><span class="p">)</span>
<span class="n">policy_name</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">extra_dejson</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;load_balancing_policy&#39;</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span>
<span class="n">policy_args</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">extra_dejson</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;load_balancing_policy_args&#39;</span><span class="p">,</span> <span class="p">{})</span>
<span class="n">lb_policy</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">get_lb_policy</span><span class="p">(</span><span class="n">policy_name</span><span class="p">,</span> <span class="n">policy_args</span><span class="p">)</span>
<span class="k">if</span> <span class="n">lb_policy</span><span class="p">:</span>
<span class="n">conn_config</span><span class="p">[</span><span class="s1">&#39;load_balancing_policy&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="n">lb_policy</span>
<span class="n">cql_version</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">extra_dejson</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;cql_version&#39;</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span>
<span class="k">if</span> <span class="n">cql_version</span><span class="p">:</span>
<span class="n">conn_config</span><span class="p">[</span><span class="s1">&#39;cql_version&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="n">cql_version</span>
<span class="n">ssl_options</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">extra_dejson</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;ssl_options&#39;</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span>
<span class="k">if</span> <span class="n">ssl_options</span><span class="p">:</span>
<span class="n">conn_config</span><span class="p">[</span><span class="s1">&#39;ssl_options&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="n">ssl_options</span>
<span class="bp">self</span><span class="o">.</span><span class="n">cluster</span> <span class="o">=</span> <span class="n">Cluster</span><span class="p">(</span><span class="o">**</span><span class="n">conn_config</span><span class="p">)</span>
<span class="bp">self</span><span class="o">.</span><span class="n">keyspace</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">schema</span>
<span class="bp">self</span><span class="o">.</span><span class="n">session</span> <span class="o">=</span> <span class="kc">None</span>
<div class="viewcode-block" id="CassandraHook.get_conn"><a class="viewcode-back" href="../../../../_api/airflow/contrib/hooks/cassandra_hook/index.html#airflow.contrib.hooks.cassandra_hook.CassandraHook.get_conn">[docs]</a> <span class="k">def</span> <span class="nf">get_conn</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Returns a cassandra Session object</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">session</span> <span class="ow">and</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">session</span><span class="o">.</span><span class="n">is_shutdown</span><span class="p">:</span>
<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">session</span>
<span class="bp">self</span><span class="o">.</span><span class="n">session</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">cluster</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">keyspace</span><span class="p">)</span>
<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">session</span></div>
<div class="viewcode-block" id="CassandraHook.get_cluster"><a class="viewcode-back" href="../../../../_api/airflow/contrib/hooks/cassandra_hook/index.html#airflow.contrib.hooks.cassandra_hook.CassandraHook.get_cluster">[docs]</a> <span class="k">def</span> <span class="nf">get_cluster</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">cluster</span></div>
<div class="viewcode-block" id="CassandraHook.shutdown_cluster"><a class="viewcode-back" href="../../../../_api/airflow/contrib/hooks/cassandra_hook/index.html#airflow.contrib.hooks.cassandra_hook.CassandraHook.shutdown_cluster">[docs]</a> <span class="k">def</span> <span class="nf">shutdown_cluster</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Closes all sessions and connections associated with this Cluster.</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">if</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">cluster</span><span class="o">.</span><span class="n">is_shutdown</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">cluster</span><span class="o">.</span><span class="n">shutdown</span><span class="p">()</span></div>
<span class="nd">@staticmethod</span>
<div class="viewcode-block" id="CassandraHook.get_lb_policy"><a class="viewcode-back" href="../../../../_api/airflow/contrib/hooks/cassandra_hook/index.html#airflow.contrib.hooks.cassandra_hook.CassandraHook.get_lb_policy">[docs]</a> <span class="k">def</span> <span class="nf">get_lb_policy</span><span class="p">(</span><span class="n">policy_name</span><span class="p">,</span> <span class="n">policy_args</span><span class="p">):</span>
<span class="n">policies</span> <span class="o">=</span> <span class="p">{</span>
<span class="s1">&#39;RoundRobinPolicy&#39;</span><span class="p">:</span> <span class="n">RoundRobinPolicy</span><span class="p">,</span>
<span class="s1">&#39;DCAwareRoundRobinPolicy&#39;</span><span class="p">:</span> <span class="n">DCAwareRoundRobinPolicy</span><span class="p">,</span>
<span class="s1">&#39;WhiteListRoundRobinPolicy&#39;</span><span class="p">:</span> <span class="n">WhiteListRoundRobinPolicy</span><span class="p">,</span>
<span class="s1">&#39;TokenAwarePolicy&#39;</span><span class="p">:</span> <span class="n">TokenAwarePolicy</span><span class="p">,</span>
<span class="p">}</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">policies</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">policy_name</span><span class="p">)</span> <span class="ow">or</span> <span class="n">policy_name</span> <span class="o">==</span> <span class="s1">&#39;RoundRobinPolicy&#39;</span><span class="p">:</span>
<span class="k">return</span> <span class="n">RoundRobinPolicy</span><span class="p">()</span>
<span class="k">if</span> <span class="n">policy_name</span> <span class="o">==</span> <span class="s1">&#39;DCAwareRoundRobinPolicy&#39;</span><span class="p">:</span>
<span class="n">local_dc</span> <span class="o">=</span> <span class="n">policy_args</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;local_dc&#39;</span><span class="p">,</span> <span class="s1">&#39;&#39;</span><span class="p">)</span>
<span class="n">used_hosts_per_remote_dc</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="n">policy_args</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;used_hosts_per_remote_dc&#39;</span><span class="p">,</span> <span class="mi">0</span><span class="p">))</span>
<span class="k">return</span> <span class="n">DCAwareRoundRobinPolicy</span><span class="p">(</span><span class="n">local_dc</span><span class="p">,</span> <span class="n">used_hosts_per_remote_dc</span><span class="p">)</span>
<span class="k">if</span> <span class="n">policy_name</span> <span class="o">==</span> <span class="s1">&#39;WhiteListRoundRobinPolicy&#39;</span><span class="p">:</span>
<span class="n">hosts</span> <span class="o">=</span> <span class="n">policy_args</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;hosts&#39;</span><span class="p">)</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">hosts</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">Exception</span><span class="p">(</span><span class="s1">&#39;Hosts must be specified for WhiteListRoundRobinPolicy&#39;</span><span class="p">)</span>
<span class="k">return</span> <span class="n">WhiteListRoundRobinPolicy</span><span class="p">(</span><span class="n">hosts</span><span class="p">)</span>
<span class="k">if</span> <span class="n">policy_name</span> <span class="o">==</span> <span class="s1">&#39;TokenAwarePolicy&#39;</span><span class="p">:</span>
<span class="n">allowed_child_policies</span> <span class="o">=</span> <span class="p">(</span><span class="s1">&#39;RoundRobinPolicy&#39;</span><span class="p">,</span>
<span class="s1">&#39;DCAwareRoundRobinPolicy&#39;</span><span class="p">,</span>
<span class="s1">&#39;WhiteListRoundRobinPolicy&#39;</span><span class="p">,)</span>
<span class="n">child_policy_name</span> <span class="o">=</span> <span class="n">policy_args</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;child_load_balancing_policy&#39;</span><span class="p">,</span>
<span class="s1">&#39;RoundRobinPolicy&#39;</span><span class="p">)</span>
<span class="n">child_policy_args</span> <span class="o">=</span> <span class="n">policy_args</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">&#39;child_load_balancing_policy_args&#39;</span><span class="p">,</span> <span class="p">{})</span>
<span class="k">if</span> <span class="n">child_policy_name</span> <span class="ow">not</span> <span class="ow">in</span> <span class="n">allowed_child_policies</span><span class="p">:</span>
<span class="k">return</span> <span class="n">TokenAwarePolicy</span><span class="p">(</span><span class="n">RoundRobinPolicy</span><span class="p">())</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">child_policy</span> <span class="o">=</span> <span class="n">CassandraHook</span><span class="o">.</span><span class="n">get_lb_policy</span><span class="p">(</span><span class="n">child_policy_name</span><span class="p">,</span>
<span class="n">child_policy_args</span><span class="p">)</span>
<span class="k">return</span> <span class="n">TokenAwarePolicy</span><span class="p">(</span><span class="n">child_policy</span><span class="p">)</span></div>
<div class="viewcode-block" id="CassandraHook.table_exists"><a class="viewcode-back" href="../../../../_api/airflow/contrib/hooks/cassandra_hook/index.html#airflow.contrib.hooks.cassandra_hook.CassandraHook.table_exists">[docs]</a> <span class="k">def</span> <span class="nf">table_exists</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">table</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Checks if a table exists in Cassandra</span>
<span class="sd"> :param table: Target Cassandra table.</span>
<span class="sd"> Use dot notation to target a specific keyspace.</span>
<span class="sd"> :type table: str</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="n">keyspace</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">keyspace</span>
<span class="k">if</span> <span class="s1">&#39;.&#39;</span> <span class="ow">in</span> <span class="n">table</span><span class="p">:</span>
<span class="n">keyspace</span><span class="p">,</span> <span class="n">table</span> <span class="o">=</span> <span class="n">table</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="s1">&#39;.&#39;</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
<span class="n">cluster_metadata</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">get_conn</span><span class="p">()</span><span class="o">.</span><span class="n">cluster</span><span class="o">.</span><span class="n">metadata</span>
<span class="k">return</span> <span class="p">(</span><span class="n">keyspace</span> <span class="ow">in</span> <span class="n">cluster_metadata</span><span class="o">.</span><span class="n">keyspaces</span> <span class="ow">and</span>
<span class="n">table</span> <span class="ow">in</span> <span class="n">cluster_metadata</span><span class="o">.</span><span class="n">keyspaces</span><span class="p">[</span><span class="n">keyspace</span><span class="p">]</span><span class="o">.</span><span class="n">tables</span><span class="p">)</span></div>
<div class="viewcode-block" id="CassandraHook.record_exists"><a class="viewcode-back" href="../../../../_api/airflow/contrib/hooks/cassandra_hook/index.html#airflow.contrib.hooks.cassandra_hook.CassandraHook.record_exists">[docs]</a> <span class="k">def</span> <span class="nf">record_exists</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">table</span><span class="p">,</span> <span class="n">keys</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Checks if a record exists in Cassandra</span>
<span class="sd"> :param table: Target Cassandra table.</span>
<span class="sd"> Use dot notation to target a specific keyspace.</span>
<span class="sd"> :type table: str</span>
<span class="sd"> :param keys: The keys and their values to check the existence.</span>
<span class="sd"> :type keys: dict</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="n">keyspace</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">keyspace</span>
<span class="k">if</span> <span class="s1">&#39;.&#39;</span> <span class="ow">in</span> <span class="n">table</span><span class="p">:</span>
<span class="n">keyspace</span><span class="p">,</span> <span class="n">table</span> <span class="o">=</span> <span class="n">table</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="s1">&#39;.&#39;</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
<span class="n">ks</span> <span class="o">=</span> <span class="s2">&quot; AND &quot;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="s2">&quot;</span><span class="si">{}</span><span class="s2">=%(</span><span class="si">{}</span><span class="s2">)s&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">key</span><span class="p">,</span> <span class="n">key</span><span class="p">)</span> <span class="k">for</span> <span class="n">key</span> <span class="ow">in</span> <span class="n">keys</span><span class="o">.</span><span class="n">keys</span><span class="p">())</span>
<span class="n">cql</span> <span class="o">=</span> <span class="s2">&quot;SELECT * FROM </span><span class="si">{keyspace}</span><span class="s2">.</span><span class="si">{table}</span><span class="s2"> WHERE </span><span class="si">{keys}</span><span class="s2">&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span>
<span class="n">keyspace</span><span class="o">=</span><span class="n">keyspace</span><span class="p">,</span> <span class="n">table</span><span class="o">=</span><span class="n">table</span><span class="p">,</span> <span class="n">keys</span><span class="o">=</span><span class="n">ks</span><span class="p">)</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">rs</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">get_conn</span><span class="p">()</span><span class="o">.</span><span class="n">execute</span><span class="p">(</span><span class="n">cql</span><span class="p">,</span> <span class="n">keys</span><span class="p">)</span>
<span class="k">return</span> <span class="n">rs</span><span class="o">.</span><span class="n">one</span><span class="p">()</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span>
<span class="k">except</span> <span class="ne">Exception</span><span class="p">:</span>
<span class="k">return</span> <span class="kc">False</span></div></div>
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