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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"># "License"); 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"># "AS IS" 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="../../../../code.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">"""</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 'hosts'</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"> 'ssl_options' : {</span> |
| <span class="sd"> 'ca_certs' : 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 LB policy:</span> |
| <span class="sd"> - DCAwareRoundRobinPolicy</span> |
| <span class="sd"> {</span> |
| <span class="sd"> 'load_balancing_policy': 'DCAwareRoundRobinPolicy',</span> |
| <span class="sd"> 'load_balancing_policy_args': {</span> |
| <span class="sd"> 'local_dc': LOCAL_DC_NAME, // optional</span> |
| <span class="sd"> 'used_hosts_per_remote_dc': 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"> 'load_balancing_policy': 'WhiteListRoundRobinPolicy',</span> |
| <span class="sd"> 'load_balancing_policy_args': {</span> |
| <span class="sd"> 'hosts': ['HOST1', 'HOST2', 'HOST3']</span> |
| <span class="sd"> }</span> |
| <span class="sd"> }</span> |
| <span class="sd"> - TokenAwarePolicy</span> |
| <span class="sd"> {</span> |
| <span class="sd"> 'load_balancing_policy': 'TokenAwarePolicy',</span> |
| <span class="sd"> 'load_balancing_policy_args': {</span> |
| <span class="sd"> 'child_load_balancing_policy': CHILD_POLICY_NAME, // optional</span> |
| <span class="sd"> 'child_load_balancing_policy_args': { ... } // 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"> """</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">'cassandra_default'</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">'contact_points'</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">','</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">'port'</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">'auth_provider'</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">'load_balancing_policy'</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">'load_balancing_policy_args'</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">'load_balancing_policy'</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">'cql_version'</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">'cql_version'</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">'ssl_options'</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">'ssl_options'</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="../../../../code.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">"""</span> |
| <span class="sd"> Returns a cassandra Session object</span> |
| <span class="sd"> """</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> |
| |
| <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 class="viewcode-block" id="CassandraHook.shutdown_cluster"><a class="viewcode-back" href="../../../../code.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">"""</span> |
| <span class="sd"> Closes all sessions and connections associated with this Cluster.</span> |
| <span class="sd"> """</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> |
| <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">'RoundRobinPolicy'</span><span class="p">:</span> <span class="n">RoundRobinPolicy</span><span class="p">,</span> |
| <span class="s1">'DCAwareRoundRobinPolicy'</span><span class="p">:</span> <span class="n">DCAwareRoundRobinPolicy</span><span class="p">,</span> |
| <span class="s1">'WhiteListRoundRobinPolicy'</span><span class="p">:</span> <span class="n">WhiteListRoundRobinPolicy</span><span class="p">,</span> |
| <span class="s1">'TokenAwarePolicy'</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">'RoundRobinPolicy'</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">'DCAwareRoundRobinPolicy'</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">'local_dc'</span><span class="p">,</span> <span class="s1">''</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">'used_hosts_per_remote_dc'</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">'WhiteListRoundRobinPolicy'</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">'hosts'</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">'Hosts must be specified for WhiteListRoundRobinPolicy'</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">'TokenAwarePolicy'</span><span class="p">:</span> |
| <span class="n">allowed_child_policies</span> <span class="o">=</span> <span class="p">(</span><span class="s1">'RoundRobinPolicy'</span><span class="p">,</span> |
| <span class="s1">'DCAwareRoundRobinPolicy'</span><span class="p">,</span> |
| <span class="s1">'WhiteListRoundRobinPolicy'</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">'child_load_balancing_policy'</span><span class="p">,</span> |
| <span class="s1">'RoundRobinPolicy'</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">'child_load_balancing_policy_args'</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 class="viewcode-block" id="CassandraHook.table_exists"><a class="viewcode-back" href="../../../../code.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">"""</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: string</span> |
| <span class="sd"> """</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">'.'</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">'.'</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="../../../../code.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">"""</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: string</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"> """</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">'.'</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">'.'</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">" AND "</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="s2">"</span><span class="si">{}</span><span class="s2">=%(</span><span class="si">{}</span><span class="s2">)s"</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">"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">"</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> |
| </pre></div> |
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