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| <h1>Source code for apache_beam.io.kafka</h1><div class="highlight"><pre> |
| <span></span><span class="c1">#</span> |
| <span class="c1"># Licensed to the Apache Software Foundation (ASF) under one or more</span> |
| <span class="c1"># contributor license agreements. See the NOTICE file distributed with</span> |
| <span class="c1"># this work for additional information regarding copyright ownership.</span> |
| <span class="c1"># The ASF licenses this file to You under the Apache License, Version 2.0</span> |
| <span class="c1"># (the "License"); you may not use this file except in compliance with</span> |
| <span class="c1"># the License. You may obtain a copy of the License at</span> |
| <span class="c1">#</span> |
| <span class="c1"># http://www.apache.org/licenses/LICENSE-2.0</span> |
| <span class="c1">#</span> |
| <span class="c1"># Unless required by applicable law or agreed to in writing, software</span> |
| <span class="c1"># distributed under the License is distributed on an "AS IS" BASIS,</span> |
| <span class="c1"># WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span> |
| <span class="c1"># See the License for the specific language governing permissions and</span> |
| <span class="c1"># limitations under the License.</span> |
| <span class="c1">#</span> |
| |
| <span class="sd">"""Unbounded source and sink transforms for</span> |
| <span class="sd"> `Kafka <href="http://kafka.apache.org/>`_.</span> |
| |
| <span class="sd"> These transforms are currently supported by Beam portable runners (for</span> |
| <span class="sd"> example, portable Flink and Spark) as well as Dataflow runner.</span> |
| |
| <span class="sd"> **Setup**</span> |
| |
| <span class="sd"> Transforms provided in this module are cross-language transforms</span> |
| <span class="sd"> implemented in the Beam Java SDK. During the pipeline construction, Python SDK</span> |
| <span class="sd"> will connect to a Java expansion service to expand these transforms.</span> |
| <span class="sd"> To facilitate this, a small amount of setup is needed before using these</span> |
| <span class="sd"> transforms in a Beam Python pipeline.</span> |
| |
| <span class="sd"> There are several ways to setup cross-language Kafka transforms.</span> |
| |
| <span class="sd"> * Option 1: use the default expansion service</span> |
| <span class="sd"> * Option 2: specify a custom expansion service</span> |
| |
| <span class="sd"> See below for details regarding each of these options.</span> |
| |
| <span class="sd"> *Option 1: Use the default expansion service*</span> |
| |
| <span class="sd"> This is the recommended and easiest setup option for using Python Kafka</span> |
| <span class="sd"> transforms. This option is only available for Beam 2.22.0 and later.</span> |
| |
| <span class="sd"> This option requires following pre-requisites before running the Beam</span> |
| <span class="sd"> pipeline.</span> |
| |
| <span class="sd"> * Install Java runtime in the computer from where the pipeline is constructed</span> |
| <span class="sd"> and make sure that 'java' command is available.</span> |
| |
| <span class="sd"> In this option, Python SDK will either download (for released Beam version) or</span> |
| <span class="sd"> build (when running from a Beam Git clone) an expansion service jar and use</span> |
| <span class="sd"> that to expand transforms. Currently Kafka transforms use the</span> |
| <span class="sd"> 'beam-sdks-java-io-expansion-service' jar for this purpose.</span> |
| |
| <span class="sd"> *Option 2: specify a custom expansion service*</span> |
| |
| <span class="sd"> In this option, you startup your own expansion service and provide that as</span> |
| <span class="sd"> a parameter when using the transforms provided in this module.</span> |
| |
| <span class="sd"> This option requires following pre-requisites before running the Beam</span> |
| <span class="sd"> pipeline.</span> |
| |
| <span class="sd"> * Startup your own expansion service.</span> |
| <span class="sd"> * Update your pipeline to provide the expansion service address when</span> |
| <span class="sd"> initiating Kafka transforms provided in this module.</span> |
| |
| <span class="sd"> Flink Users can use the built-in Expansion Service of the Flink Runner's</span> |
| <span class="sd"> Job Server. If you start Flink's Job Server, the expansion service will be</span> |
| <span class="sd"> started on port 8097. For a different address, please set the</span> |
| <span class="sd"> expansion_service parameter.</span> |
| |
| <span class="sd"> **More information**</span> |
| |
| <span class="sd"> For more information regarding cross-language transforms see:</span> |
| <span class="sd"> - https://beam.apache.org/roadmap/portability/</span> |
| |
| <span class="sd"> For more information specific to Flink runner see:</span> |
| <span class="sd"> - https://beam.apache.org/documentation/runners/flink/</span> |
| <span class="sd">"""</span> |
| |
| <span class="c1"># pytype: skip-file</span> |
| |
| <span class="kn">import</span> <span class="nn">typing</span> |
| |
| <span class="kn">from</span> <span class="nn">apache_beam.transforms.external</span> <span class="kn">import</span> <span class="n">BeamJarExpansionService</span> |
| <span class="kn">from</span> <span class="nn">apache_beam.transforms.external</span> <span class="kn">import</span> <span class="n">ExternalTransform</span> |
| <span class="kn">from</span> <span class="nn">apache_beam.transforms.external</span> <span class="kn">import</span> <span class="n">NamedTupleBasedPayloadBuilder</span> |
| |
| <span class="n">ReadFromKafkaSchema</span> <span class="o">=</span> <span class="n">typing</span><span class="o">.</span><span class="n">NamedTuple</span><span class="p">(</span> |
| <span class="s1">'ReadFromKafkaSchema'</span><span class="p">,</span> |
| <span class="p">[(</span><span class="s1">'consumer_config'</span><span class="p">,</span> <span class="n">typing</span><span class="o">.</span><span class="n">Mapping</span><span class="p">[</span><span class="nb">str</span><span class="p">,</span> <span class="nb">str</span><span class="p">]),</span> |
| <span class="p">(</span><span class="s1">'topics'</span><span class="p">,</span> <span class="n">typing</span><span class="o">.</span><span class="n">List</span><span class="p">[</span><span class="nb">str</span><span class="p">]),</span> <span class="p">(</span><span class="s1">'key_deserializer'</span><span class="p">,</span> <span class="nb">str</span><span class="p">),</span> |
| <span class="p">(</span><span class="s1">'value_deserializer'</span><span class="p">,</span> <span class="nb">str</span><span class="p">),</span> <span class="p">(</span><span class="s1">'start_read_time'</span><span class="p">,</span> <span class="n">typing</span><span class="o">.</span><span class="n">Optional</span><span class="p">[</span><span class="nb">int</span><span class="p">]),</span> |
| <span class="p">(</span><span class="s1">'max_num_records'</span><span class="p">,</span> <span class="n">typing</span><span class="o">.</span><span class="n">Optional</span><span class="p">[</span><span class="nb">int</span><span class="p">]),</span> |
| <span class="p">(</span><span class="s1">'max_read_time'</span><span class="p">,</span> <span class="n">typing</span><span class="o">.</span><span class="n">Optional</span><span class="p">[</span><span class="nb">int</span><span class="p">]),</span> |
| <span class="p">(</span><span class="s1">'commit_offset_in_finalize'</span><span class="p">,</span> <span class="nb">bool</span><span class="p">),</span> <span class="p">(</span><span class="s1">'timestamp_policy'</span><span class="p">,</span> <span class="nb">str</span><span class="p">)])</span> |
| |
| |
| <div class="viewcode-block" id="default_io_expansion_service"><a class="viewcode-back" href="../../../apache_beam.io.kafka.html#apache_beam.io.kafka.default_io_expansion_service">[docs]</a><span class="k">def</span> <span class="nf">default_io_expansion_service</span><span class="p">(</span><span class="n">append_args</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span> |
| <span class="k">return</span> <span class="n">BeamJarExpansionService</span><span class="p">(</span> |
| <span class="s1">'sdks:java:io:expansion-service:shadowJar'</span><span class="p">,</span> <span class="n">append_args</span><span class="o">=</span><span class="n">append_args</span><span class="p">)</span></div> |
| |
| |
| <div class="viewcode-block" id="ReadFromKafka"><a class="viewcode-back" href="../../../apache_beam.io.kafka.html#apache_beam.io.kafka.ReadFromKafka">[docs]</a><span class="k">class</span> <span class="nc">ReadFromKafka</span><span class="p">(</span><span class="n">ExternalTransform</span><span class="p">):</span> |
| <span class="w"> </span><span class="sd">"""</span> |
| <span class="sd"> An external PTransform which reads from Kafka and returns a KV pair for</span> |
| <span class="sd"> each item in the specified Kafka topics. If no Kafka Deserializer for</span> |
| <span class="sd"> key/value is provided, then the data will be returned as a raw byte array.</span> |
| |
| <span class="sd"> Experimental; no backwards compatibility guarantees.</span> |
| <span class="sd"> """</span> |
| |
| <span class="c1"># Returns the key/value data as raw byte arrays</span> |
| <span class="n">byte_array_deserializer</span> <span class="o">=</span> <span class="p">(</span> |
| <span class="s1">'org.apache.kafka.common.serialization.ByteArrayDeserializer'</span><span class="p">)</span> |
| |
| <span class="n">processing_time_policy</span> <span class="o">=</span> <span class="s1">'ProcessingTime'</span> |
| <span class="n">create_time_policy</span> <span class="o">=</span> <span class="s1">'CreateTime'</span> |
| <span class="n">log_append_time</span> <span class="o">=</span> <span class="s1">'LogAppendTime'</span> |
| |
| <span class="n">URN_WITH_METADATA</span> <span class="o">=</span> <span class="p">(</span> |
| <span class="s1">'beam:transform:org.apache.beam:kafka_read_with_metadata:v1'</span><span class="p">)</span> |
| <span class="n">URN_WITHOUT_METADATA</span> <span class="o">=</span> <span class="p">(</span> |
| <span class="s1">'beam:transform:org.apache.beam:kafka_read_without_metadata:v1'</span><span class="p">)</span> |
| |
| <span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span> |
| <span class="bp">self</span><span class="p">,</span> |
| <span class="n">consumer_config</span><span class="p">,</span> |
| <span class="n">topics</span><span class="p">,</span> |
| <span class="n">key_deserializer</span><span class="o">=</span><span class="n">byte_array_deserializer</span><span class="p">,</span> |
| <span class="n">value_deserializer</span><span class="o">=</span><span class="n">byte_array_deserializer</span><span class="p">,</span> |
| <span class="n">start_read_time</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> |
| <span class="n">max_num_records</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> |
| <span class="n">max_read_time</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> |
| <span class="n">commit_offset_in_finalize</span><span class="o">=</span><span class="kc">False</span><span class="p">,</span> |
| <span class="n">timestamp_policy</span><span class="o">=</span><span class="n">processing_time_policy</span><span class="p">,</span> |
| <span class="n">with_metadata</span><span class="o">=</span><span class="kc">False</span><span class="p">,</span> |
| <span class="n">expansion_service</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> |
| <span class="p">):</span> |
| <span class="w"> </span><span class="sd">"""</span> |
| <span class="sd"> Initializes a read operation from Kafka.</span> |
| |
| <span class="sd"> :param consumer_config: A dictionary containing the consumer configuration.</span> |
| <span class="sd"> :param topics: A list of topic strings.</span> |
| <span class="sd"> :param key_deserializer: A fully-qualified Java class name of a Kafka</span> |
| <span class="sd"> Deserializer for the topic's key, e.g.</span> |
| <span class="sd"> 'org.apache.kafka.common.serialization.LongDeserializer'.</span> |
| <span class="sd"> Default: 'org.apache.kafka.common.serialization.ByteArrayDeserializer'.</span> |
| <span class="sd"> :param value_deserializer: A fully-qualified Java class name of a Kafka</span> |
| <span class="sd"> Deserializer for the topic's value, e.g.</span> |
| <span class="sd"> 'org.apache.kafka.common.serialization.LongDeserializer'.</span> |
| <span class="sd"> Default: 'org.apache.kafka.common.serialization.ByteArrayDeserializer'.</span> |
| <span class="sd"> :param start_read_time: Use timestamp to set up start offset in milliseconds</span> |
| <span class="sd"> epoch.</span> |
| <span class="sd"> :param max_num_records: Maximum amount of records to be read. Mainly used</span> |
| <span class="sd"> for tests and demo applications.</span> |
| <span class="sd"> :param max_read_time: Maximum amount of time in seconds the transform</span> |
| <span class="sd"> executes. Mainly used for tests and demo applications.</span> |
| <span class="sd"> :param commit_offset_in_finalize: Whether to commit offsets when finalizing.</span> |
| <span class="sd"> :param timestamp_policy: The built-in timestamp policy which is used for</span> |
| <span class="sd"> extracting timestamp from KafkaRecord.</span> |
| <span class="sd"> :param with_metadata: whether the returned PCollection should contain</span> |
| <span class="sd"> Kafka related metadata or not. If False (default), elements of the</span> |
| <span class="sd"> returned PCollection will be of type 'bytes' if True, elements of the</span> |
| <span class="sd"> returned PCollection will be of the type 'Row'. Note that, currently</span> |
| <span class="sd"> this only works when using default key and value deserializers where</span> |
| <span class="sd"> Java Kafka Reader reads keys and values as 'byte[]'.</span> |
| <span class="sd"> :param expansion_service: The address (host:port) of the ExpansionService.</span> |
| <span class="sd"> """</span> |
| <span class="k">if</span> <span class="n">timestamp_policy</span> <span class="ow">not</span> <span class="ow">in</span> <span class="p">[</span><span class="n">ReadFromKafka</span><span class="o">.</span><span class="n">processing_time_policy</span><span class="p">,</span> |
| <span class="n">ReadFromKafka</span><span class="o">.</span><span class="n">create_time_policy</span><span class="p">,</span> |
| <span class="n">ReadFromKafka</span><span class="o">.</span><span class="n">log_append_time</span><span class="p">]:</span> |
| <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span> |
| <span class="s1">'timestamp_policy should be one of '</span> |
| <span class="s1">'[ProcessingTime, CreateTime, LogAppendTime]'</span><span class="p">)</span> |
| |
| <span class="nb">super</span><span class="p">()</span><span class="o">.</span><span class="fm">__init__</span><span class="p">(</span> |
| <span class="bp">self</span><span class="o">.</span><span class="n">URN_WITH_METADATA</span> <span class="k">if</span> <span class="n">with_metadata</span> <span class="k">else</span> <span class="bp">self</span><span class="o">.</span><span class="n">URN_WITHOUT_METADATA</span><span class="p">,</span> |
| <span class="n">NamedTupleBasedPayloadBuilder</span><span class="p">(</span> |
| <span class="n">ReadFromKafkaSchema</span><span class="p">(</span> |
| <span class="n">consumer_config</span><span class="o">=</span><span class="n">consumer_config</span><span class="p">,</span> |
| <span class="n">topics</span><span class="o">=</span><span class="n">topics</span><span class="p">,</span> |
| <span class="n">key_deserializer</span><span class="o">=</span><span class="n">key_deserializer</span><span class="p">,</span> |
| <span class="n">value_deserializer</span><span class="o">=</span><span class="n">value_deserializer</span><span class="p">,</span> |
| <span class="n">max_num_records</span><span class="o">=</span><span class="n">max_num_records</span><span class="p">,</span> |
| <span class="n">max_read_time</span><span class="o">=</span><span class="n">max_read_time</span><span class="p">,</span> |
| <span class="n">start_read_time</span><span class="o">=</span><span class="n">start_read_time</span><span class="p">,</span> |
| <span class="n">commit_offset_in_finalize</span><span class="o">=</span><span class="n">commit_offset_in_finalize</span><span class="p">,</span> |
| <span class="n">timestamp_policy</span><span class="o">=</span><span class="n">timestamp_policy</span><span class="p">)),</span> |
| <span class="n">expansion_service</span> <span class="ow">or</span> <span class="n">default_io_expansion_service</span><span class="p">())</span></div> |
| |
| |
| <span class="n">WriteToKafkaSchema</span> <span class="o">=</span> <span class="n">typing</span><span class="o">.</span><span class="n">NamedTuple</span><span class="p">(</span> |
| <span class="s1">'WriteToKafkaSchema'</span><span class="p">,</span> |
| <span class="p">[</span> |
| <span class="p">(</span><span class="s1">'producer_config'</span><span class="p">,</span> <span class="n">typing</span><span class="o">.</span><span class="n">Mapping</span><span class="p">[</span><span class="nb">str</span><span class="p">,</span> <span class="nb">str</span><span class="p">]),</span> |
| <span class="p">(</span><span class="s1">'topic'</span><span class="p">,</span> <span class="nb">str</span><span class="p">),</span> |
| <span class="p">(</span><span class="s1">'key_serializer'</span><span class="p">,</span> <span class="nb">str</span><span class="p">),</span> |
| <span class="p">(</span><span class="s1">'value_serializer'</span><span class="p">,</span> <span class="nb">str</span><span class="p">),</span> |
| <span class="p">])</span> |
| |
| |
| <div class="viewcode-block" id="WriteToKafka"><a class="viewcode-back" href="../../../apache_beam.io.kafka.html#apache_beam.io.kafka.WriteToKafka">[docs]</a><span class="k">class</span> <span class="nc">WriteToKafka</span><span class="p">(</span><span class="n">ExternalTransform</span><span class="p">):</span> |
| <span class="w"> </span><span class="sd">"""</span> |
| <span class="sd"> An external PTransform which writes KV data to a specified Kafka topic.</span> |
| <span class="sd"> If no Kafka Serializer for key/value is provided, then key/value are</span> |
| <span class="sd"> assumed to be byte arrays.</span> |
| |
| <span class="sd"> Experimental; no backwards compatibility guarantees.</span> |
| <span class="sd"> """</span> |
| |
| <span class="c1"># Default serializer which passes raw bytes to Kafka</span> |
| <span class="n">byte_array_serializer</span> <span class="o">=</span> <span class="p">(</span> |
| <span class="s1">'org.apache.kafka.common.serialization.ByteArraySerializer'</span><span class="p">)</span> |
| |
| <span class="n">URN</span> <span class="o">=</span> <span class="s1">'beam:transform:org.apache.beam:kafka_write:v1'</span> |
| |
| <span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span> |
| <span class="bp">self</span><span class="p">,</span> |
| <span class="n">producer_config</span><span class="p">,</span> |
| <span class="n">topic</span><span class="p">,</span> |
| <span class="n">key_serializer</span><span class="o">=</span><span class="n">byte_array_serializer</span><span class="p">,</span> |
| <span class="n">value_serializer</span><span class="o">=</span><span class="n">byte_array_serializer</span><span class="p">,</span> |
| <span class="n">expansion_service</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span> |
| <span class="w"> </span><span class="sd">"""</span> |
| <span class="sd"> Initializes a write operation to Kafka.</span> |
| |
| <span class="sd"> :param producer_config: A dictionary containing the producer configuration.</span> |
| <span class="sd"> :param topic: A Kafka topic name.</span> |
| <span class="sd"> :param key_deserializer: A fully-qualified Java class name of a Kafka</span> |
| <span class="sd"> Serializer for the topic's key, e.g.</span> |
| <span class="sd"> 'org.apache.kafka.common.serialization.LongSerializer'.</span> |
| <span class="sd"> Default: 'org.apache.kafka.common.serialization.ByteArraySerializer'.</span> |
| <span class="sd"> :param value_deserializer: A fully-qualified Java class name of a Kafka</span> |
| <span class="sd"> Serializer for the topic's value, e.g.</span> |
| <span class="sd"> 'org.apache.kafka.common.serialization.LongSerializer'.</span> |
| <span class="sd"> Default: 'org.apache.kafka.common.serialization.ByteArraySerializer'.</span> |
| <span class="sd"> :param expansion_service: The address (host:port) of the ExpansionService.</span> |
| <span class="sd"> """</span> |
| <span class="nb">super</span><span class="p">()</span><span class="o">.</span><span class="fm">__init__</span><span class="p">(</span> |
| <span class="bp">self</span><span class="o">.</span><span class="n">URN</span><span class="p">,</span> |
| <span class="n">NamedTupleBasedPayloadBuilder</span><span class="p">(</span> |
| <span class="n">WriteToKafkaSchema</span><span class="p">(</span> |
| <span class="n">producer_config</span><span class="o">=</span><span class="n">producer_config</span><span class="p">,</span> |
| <span class="n">topic</span><span class="o">=</span><span class="n">topic</span><span class="p">,</span> |
| <span class="n">key_serializer</span><span class="o">=</span><span class="n">key_serializer</span><span class="p">,</span> |
| <span class="n">value_serializer</span><span class="o">=</span><span class="n">value_serializer</span><span class="p">,</span> |
| <span class="p">)),</span> |
| <span class="n">expansion_service</span> <span class="ow">or</span> <span class="n">default_io_expansion_service</span><span class="p">())</span></div> |
| </pre></div> |
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