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Apache Software Foundation (ASF) under one or more + contributor license agreements. See the NOTICE file distributed with + this work for additional information regarding copyright ownership. + The ASF licenses this file to You under the Apache License, Version 2.0 + (the "License"); you may not use this file except in compliance with + the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +--> + +<p>In this tutorial, we will create our first Samza application - <code>WordCount</code>. This application will consume messages from a Kafka stream, tokenize them into individual words and count the frequency of each word. Let us download the entire project from <a href="https://github.com/apache/samza-hello-samza/blob/latest/quickstart/wordcount.tar.gz";>here</a>.</p> + +<h3 id="setting-up-a-java-project">Setting up a Java Project</h3> + +<p>Observe the project structure as follows:</p> + +<figure class="highlight"><pre><code class="language-bash" data-lang="bash"><span></span>wordcount +<span class="p">|</span>-- build.gradle +<span class="p">|</span>-- gradle.properties +<span class="p">|</span>-- scripts +<span class="p">|</span>-- src + <span class="p">|</span>-- main + <span class="p">|</span>-- config + <span class="p">|</span>-- java + <span class="p">|</span>-- samzaapp + <span class="p">|</span>-- WordCount.java</code></pre></figure> + +<p>You can build the project anytime by running:</p> + +<figure class="highlight"><pre><code class="language-bash" data-lang="bash"><span></span>> <span class="nb">cd</span> wordcount +> gradle wrapper --gradle-version <span class="m">4</span>.9 +> ./gradlew build</code></pre></figure> + +<h3 id="create-a-samza-streamapplication">Create a Samza StreamApplication</h3> + +<p>Now letâs write some code! An application written using Samza’s <a href="/learn/documentation/latest/api/high-level-api.html">high-level API</a> implements the <a href="/learn/documentation/latest/api/javadocs/org/apache/samza/application/StreamApplication.html">StreamApplication</a> interface:</p> + +<figure class="highlight"><pre><code class="language-java" data-lang="java"><span></span><span class="kn">package</span> <span class="nn">samzaapp</span><span class="o">;</span> + +<span class="kn">import</span> <span class="nn">org.apache.samza.application.StreamApplication</span><span class="o">;</span> +<span class="kn">import</span> <span class="nn">org.apache.samza.application.descriptors.StreamApplicationDescriptor</span><span class="o">;</span> + +<span class="kd">public</span> <span class="kd">class</span> <span class="nc">WordCount</span> <span class="kd">implements</span> <span class="n">StreamApplication</span> <span class="o">{</span> + <span class="nd">@Override</span> + <span class="kd">public</span> <span class="kt">void</span> <span class="nf">describe</span><span class="o">(</span><span class="n">StreamApplicationDescriptor</span> <span class="n">streamApplicationDescriptor</span><span class="o">)</span> <span class="o">{</span> + <span class="o">}</span> +<span class="o">}</span></code></pre></figure> + +<p>The interface provides a single method named <code>describe()</code>, which allows us to define our inputs, the processing logic and outputs for our application. </p> + +<h3 id="describe-your-inputs-and-outputs">Describe your inputs and outputs</h3> + +<p>To interact with Kafka, we will first create a <code>KafkaSystemDescriptor</code> by providing the coordinates of the Kafka cluster. For each Kafka topic our application reads from, we create a <code>KafkaInputDescriptor</code> with the name of the topic and a serializer. Likewise, for each output topic, we instantiate a corresponding <code>KafkaOutputDescriptor</code>. </p> + +<figure class="highlight"><pre><code class="language-java" data-lang="java"><span></span><span class="kd">public</span> <span class="kd">class</span> <span class="nc">WordCount</span> <span class="kd">implements</span> <span class="n">StreamApplication</span> <span class="o">{</span> + <span class="kd">private</span> <span class="kd">static</span> <span class="kd">final</span> <span class="n">String</span> <span class="n">KAFKA_SYSTEM_NAME</span> <span class="o">=</span> <span class="s">"kafka"</span><span class="o">;</span> + <span class="kd">private</span> <span class="kd">static</span> <span class="kd">final</span> <span class="n">List</span><span class="o"><</span><span class="n">String</span><span class="o">></span> <span class="n">KAFKA_CONSUMER_ZK_CONNECT</span> <span class="o">=</span> <span class="n">ImmutableList</span><span class="o">.</span><span class="na">of</span><span class="o">(</span><span class="s">"localhost:2181"</span><span class="o">);</span> + <span class="kd">private</span> <span class="kd">static</span> <span class="kd">final</span> <span class="n">List</span><span class="o"><</span><span class="n">String</span><span class="o">></span> <span class="n">KAFKA_PRODUCER_BOOTSTRAP_SERVERS</span> <span class="o">=</span> <span class="n">ImmutableList</span><span class="o">.</span><span class="na">of</span><span class="o">(</span><span class="s">"localhost:9092"</span><span class="o">);</span> + <span class="kd">private</span> <span class="kd">static</span> <span class="kd">final</span> <span class="n">Map</span><span class="o"><</span><span class="n">String</span><span class="o">,</span> <span class="n">String</span><span class="o">></span> <span class="n">KAFKA_DEFAULT_STREAM_CONFIGS</span> <span class="o">=</span> <span class="n">ImmutableMap</span><span class="o">.</span><span class="na">of</span><span class="o">(</span><span class="s">"replication.factor"</span><span class="o">,</span> <span class="s">"1"</span><span class="o">);</span> + + <span class="kd">private</span> <span class="kd">static</span> <span class="kd">final</span> <span class="n">String</span> <span class="n">INPUT_STREAM_ID</span> <span class="o">=</span> <span class="s">"sample-text"</span><span class="o">;</span> + <span class="kd">private</span> <span class="kd">static</span> <span class="kd">final</span> <span class="n">String</span> <span class="n">OUTPUT_STREAM_ID</span> <span class="o">=</span> <span class="s">"word-count-output"</span><span class="o">;</span> + + <span class="nd">@Override</span> + <span class="kd">public</span> <span class="kt">void</span> <span class="nf">describe</span><span class="o">(</span><span class="n">StreamApplicationDescriptor</span> <span class="n">streamApplicationDescriptor</span><span class="o">)</span> <span class="o">{</span> + <span class="c1">// Create a KafkaSystemDescriptor providing properties of the cluster</span> + <span class="n">KafkaSystemDescriptor</span> <span class="n">kafkaSystemDescriptor</span> <span class="o">=</span> <span class="k">new</span> <span class="n">KafkaSystemDescriptor</span><span class="o">(</span><span class="n">KAFKA_SYSTEM_NAME</span><span class="o">)</span> + <span class="o">.</span><span class="na">withConsumerZkConnect</span><span class="o">(</span><span class="n">KAFKA_CONSUMER_ZK_CONNECT</span><span class="o">)</span> + <span class="o">.</span><span class="na">withProducerBootstrapServers</span><span class="o">(</span><span class="n">KAFKA_PRODUCER_BOOTSTRAP_SERVERS</span><span class="o">)</span> + <span class="o">.</span><span class="na">withDefaultStreamConfigs</span><span class="o">(</span><span class="n">KAFKA_DEFAULT_STREAM_CONFIGS</span><span class="o">);</span> + + <span class="c1">// For each input or output stream, create a KafkaInput/Output descriptor</span> + <span class="n">KafkaInputDescriptor</span><span class="o"><</span><span class="n">KV</span><span class="o"><</span><span class="n">String</span><span class="o">,</span> <span class="n">String</span><span class="o">>></span> <span class="n">inputDescriptor</span> <span class="o">=</span> + <span class="n">kafkaSystemDescriptor</span><span class="o">.</span><span class="na">getInputDescriptor</span><span class="o">(</span><span class="n">INPUT_STREAM_ID</span><span class="o">,</span> + <span class="n">KVSerde</span><span class="o">.</span><span class="na">of</span><span class="o">(</span><span class="k">new</span> <span class="n">StringSerde</span><span class="o">(),</span> <span class="k">new</span> <span class="n">StringSerde</span><span class="o">()));</span> + <span class="n">KafkaOutputDescriptor</span><span class="o"><</span><span class="n">KV</span><span class="o"><</span><span class="n">String</span><span class="o">,</span> <span class="n">String</span><span class="o">>></span> <span class="n">outputDescriptor</span> <span class="o">=</span> + <span class="n">kafkaSystemDescriptor</span><span class="o">.</span><span class="na">getOutputDescriptor</span><span class="o">(</span><span class="n">OUTPUT_STREAM_ID</span><span class="o">,</span> + <span class="n">KVSerde</span><span class="o">.</span><span class="na">of</span><span class="o">(</span><span class="k">new</span> <span class="n">StringSerde</span><span class="o">(),</span> <span class="k">new</span> <span class="n">StringSerde</span><span class="o">()));</span> + + <span class="c1">// Obtain a handle to a MessageStream that you can chain operations on</span> + <span class="n">MessageStream</span><span class="o"><</span><span class="n">KV</span><span class="o"><</span><span class="n">String</span><span class="o">,</span> <span class="n">String</span><span class="o">>></span> <span class="n">lines</span> <span class="o">=</span> <span class="n">streamApplicationDescriptor</span><span class="o">.</span><span class="na">getInputStream</span><span class="o">(</span><span class="n">inputDescriptor</span><span class="o">);</span> + <span class="n">OutputStream</span><span class="o"><</span><span class="n">KV</span><span class="o"><</span><span class="n">String</span><span class="o">,</span> <span class="n">String</span><span class="o">>></span> <span class="n">counts</span> <span class="o">=</span> <span class="n">streamApplicationDescriptor</span><span class="o">.</span><span class="na">getOutputStream</span><span class="o">(</span><span class="n">outputDescriptor</span><span class="o">);</span> + <span class="o">}</span> +<span class="o">}</span></code></pre></figure> + +<p>The above example creates a <a href="/learn/documentation/latest/api/javadocs/org/apache/samza/operators/MessageStream.html">MessageStream</a> which reads from an input topic named <code>sample-text</code>. It also defines an output stream that emits results to a topic named <code>word-count-output</code>. Next letâs add our processing logic. </p> + +<h3 id="add-word-count-processing-logic">Add word count processing logic</h3> + +<p>Kafka messages typically have a key and a value. Since we only care about the value here, we will apply the <code>map</code> operator on the input stream to extract the value. </p> + +<figure class="highlight"><pre><code class="language-java" data-lang="java"><span></span><span class="n">lines</span><span class="o">.</span><span class="na">map</span><span class="o">(</span><span class="n">kv</span> <span class="o">-></span> <span class="n">kv</span><span class="o">.</span><span class="na">value</span><span class="o">)</span></code></pre></figure> + +<p>Next, we will tokenize the message into individual words using the <code>flatmap</code> operator.</p> + +<figure class="highlight"><pre><code class="language-java" data-lang="java"><span></span><span class="o">.</span><span class="na">flatMap</span><span class="o">(</span><span class="n">s</span> <span class="o">-></span> <span class="n">Arrays</span><span class="o">.</span><span class="na">asList</span><span class="o">(</span><span class="n">s</span><span class="o">.</span><span class="na">split</span><span class="o">(</span><span class="s">"\\W+"</span><span class="o">)))</span></code></pre></figure> + +<p>We now need to group the words, aggregate their respective counts and periodically emit our results. For this, we will use Samza’s session-windowing feature.</p> + +<figure class="highlight"><pre><code class="language-java" data-lang="java"><span></span><span class="o">.</span><span class="na">window</span><span class="o">(</span><span class="n">Windows</span><span class="o">.</span><span class="na">keyedSessionWindow</span><span class="o">(</span> + <span class="n">w</span> <span class="o">-></span> <span class="n">w</span><span class="o">,</span> <span class="n">Duration</span><span class="o">.</span><span class="na">ofSeconds</span><span class="o">(</span><span class="mi">5</span><span class="o">),</span> <span class="o">()</span> <span class="o">-></span> <span class="mi">0</span><span class="o">,</span> <span class="o">(</span><span class="n">m</span><span class="o">,</span> <span class="n">prevCount</span><span class="o">)</span> <span class="o">-></span> <span class="n">prevCount</span> <span class="o">+</span> <span class="mi">1</span><span class="o">,</span> + <span class="k">new</span> <span class="n">StringSerde</span><span class="o">(),</span> <span class="k">new</span> <span class="n">IntegerSerde</span><span class="o">()),</span> <span class="s">"count"</span><span class="o">)</span></code></pre></figure> + +<p>Let’s walk through each of the parameters to the above <code>window</code> function: +The first parameter is a “key function”, which defines the key to group messages by. In our case, we can simply use the word as the key. The second parameter is the windowing interval, which is set to 5 seconds. The third parameter is a function which provides the initial value for our aggregations. We can start with an initial count of zero for each word. The fourth parameter is an aggregation function for computing counts. The next two parameters specify the key and value serializers for our window. </p> + +<p>The output from the window operator is captured in a <a href="/learn/documentation/latest/api/javadocs/org/apache/samza/operators/windows/WindowPane.html">WindowPane</a> type, which contains the word as the key and its count as the value. We add a further <code>map</code> to format this into a <code>KV</code>, that we can send to our Kafka topic. To write our results to the output topic, we use the <code>sendTo</code> operator in Samza.</p> + +<figure class="highlight"><pre><code class="language-java" data-lang="java"><span></span><span class="o">.</span><span class="na">map</span><span class="o">(</span><span class="n">windowPane</span> <span class="o">-></span> + <span class="n">KV</span><span class="o">.</span><span class="na">of</span><span class="o">(</span><span class="n">windowPane</span><span class="o">.</span><span class="na">getKey</span><span class="o">().</span><span class="na">getKey</span><span class="o">(),</span> + <span class="n">windowPane</span><span class="o">.</span><span class="na">getKey</span><span class="o">().</span><span class="na">getKey</span><span class="o">()</span> <span class="o">+</span> <span class="s">": "</span> <span class="o">+</span> <span class="n">windowPane</span><span class="o">.</span><span class="na">getMessage</span><span class="o">().</span><span class="na">toString</span><span class="o">()))</span> +<span class="o">.</span><span class="na">sendTo</span><span class="o">(</span><span class="n">counts</span><span class="o">);</span></code></pre></figure> + +<p>The full processing logic looks like the following:</p> + +<figure class="highlight"><pre><code class="language-java" data-lang="java"><span></span><span class="n">lines</span> + <span class="o">.</span><span class="na">map</span><span class="o">(</span><span class="n">kv</span> <span class="o">-></span> <span class="n">kv</span><span class="o">.</span><span class="na">value</span><span class="o">)</span> + <span class="o">.</span><span class="na">flatMap</span><span class="o">(</span><span class="n">s</span> <span class="o">-></span> <span class="n">Arrays</span><span class="o">.</span><span class="na">asList</span><span class="o">(</span><span class="n">s</span><span class="o">.</span><span class="na">split</span><span class="o">(</span><span class="s">"\\W+"</span><span class="o">)))</span> + <span class="o">.</span><span class="na">window</span><span class="o">(</span><span class="n">Windows</span><span class="o">.</span><span class="na">keyedSessionWindow</span><span class="o">(</span> + <span class="n">w</span> <span class="o">-></span> <span class="n">w</span><span class="o">,</span> <span class="n">Duration</span><span class="o">.</span><span class="na">ofSeconds</span><span class="o">(</span><span class="mi">5</span><span class="o">),</span> <span class="o">()</span> <span class="o">-></span> <span class="mi">0</span><span class="o">,</span> <span class="o">(</span><span class="n">m</span><span class="o">,</span> <span class="n">prevCount</span><span class="o">)</span> <span class="o">-></span> <span class="n">prevCount</span> <span class="o">+</span> <span class="mi">1</span><span class="o">,</span> + <span class="k">new</span> <span class="n">StringSerde</span><span class="o">(),</span> <span class="k">new</span> <span class="n">IntegerSerde</span><span class="o">()),</span> <span class="s">"count"</span><span class="o">)</span> + <span class="o">.</span><span class="na">map</span><span class="o">(</span><span class="n">windowPane</span> <span class="o">-></span> + <span class="n">KV</span><span class="o">.</span><span class="na">of</span><span class="o">(</span><span class="n">windowPane</span><span class="o">.</span><span class="na">getKey</span><span class="o">().</span><span class="na">getKey</span><span class="o">(),</span> + <span class="n">windowPane</span><span class="o">.</span><span class="na">getKey</span><span class="o">().</span><span class="na">getKey</span><span class="o">()</span> <span class="o">+</span> <span class="s">": "</span> <span class="o">+</span> <span class="n">windowPane</span><span class="o">.</span><span class="na">getMessage</span><span class="o">().</span><span class="na">toString</span><span class="o">()))</span> + <span class="o">.</span><span class="na">sendTo</span><span class="o">(</span><span class="n">counts</span><span class="o">);</span></code></pre></figure> + +<h3 id="configure-your-application">Configure your application</h3> + +<p>In this section, we will configure our word count example to run locally in a single JVM. Let us add a file named âword-count.propertiesâ under the config folder. </p> + +<figure class="highlight"><pre><code class="language-jproperties" data-lang="jproperties"><span></span><span class="na">job.name</span><span class="o">=</span><span class="s">word-count</span> +<span class="c"># Use a PassthroughJobCoordinator since there is no coordination needed</span> +<span class="na">job.coordinator.factory</span><span class="o">=</span><span class="s">org.apache.samza.standalone.PassthroughJobCoordinatorFactory</span> +<span class="na">job.coordination.utils.factory</span><span class="o">=</span><span class="s">org.apache.samza.standalone.PassthroughCoordinationUtilsFactory</span> + +<span class="na">job.changelog.system</span><span class="o">=</span><span class="s">kafka</span> + +<span class="c"># Use a single container to process all of the data</span> +<span class="na">task.name.grouper.factory</span><span class="o">=</span><span class="s">org.apache.samza.container.grouper.task.SingleContainerGrouperFactory</span> +<span class="na">processor.id</span><span class="o">=</span><span class="s">0</span> + +<span class="c"># Read from the beginning of the topic</span> +<span class="na">systems.kafka.default.stream.samza.offset.default</span><span class="o">=</span><span class="s">oldest</span></code></pre></figure> + +<p>For more details on Samza’s configs, feel free to check out the latest <a href="/learn/documentation/latest/jobs/configuration-table.html">configuration reference</a>.</p> + +<h3 id="run-your-application">Run your application</h3> + +<p>We are ready to add a <code>main()</code> function to the <code>WordCount</code> class. It parses the command-line arguments and instantiates a <code>LocalApplicationRunner</code> to execute the application locally.</p> + +<figure class="highlight"><pre><code class="language-java" data-lang="java"><span></span><span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="o">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="o">)</span> <span class="o">{</span> + <span class="n">CommandLine</span> <span class="n">cmdLine</span> <span class="o">=</span> <span class="k">new</span> <span class="n">CommandLine</span><span class="o">();</span> + <span class="n">OptionSet</span> <span class="n">options</span> <span class="o">=</span> <span class="n">cmdLine</span><span class="o">.</span><span class="na">parser</span><span class="o">().</span><span class="na">parse</span><span class="o">(</span><span class="n">args</span><span class="o">);</span> + <span class="n">Config</span> <span class="n">config</span> <span class="o">=</span> <span class="n">cmdLine</span><span class="o">.</span><span class="na">loadConfig</span><span class="o">(</span><span class="n">options</span><span class="o">);</span> + <span class="n">LocalApplicationRunner</span> <span class="n">runner</span> <span class="o">=</span> <span class="k">new</span> <span class="n">LocalApplicationRunner</span><span class="o">(</span><span class="k">new</span> <span class="n">WordCount</span><span class="o">(),</span> <span class="n">config</span><span class="o">);</span> + <span class="n">runner</span><span class="o">.</span><span class="na">run</span><span class="o">();</span> + <span class="n">runner</span><span class="o">.</span><span class="na">waitForFinish</span><span class="o">();</span> +<span class="o">}</span></code></pre></figure> + +<p>Before running <code>main()</code>, we will create our input Kafka topic and populate it with sample data. You can download the scripts to interact with Kafka along with the sample data from <a href="https://github.com/apache/samza-hello-samza/blob/latest/quickstart/wordcount.tar.gz";>here</a>.</p> + +<figure class="highlight"><pre><code class="language-bash" data-lang="bash"><span></span>> ./scripts/grid install zookeeper <span class="o">&&</span> ./scripts/grid start zookeeper +> ./scripts/grid install kafka <span class="o">&&</span> ./scripts/grid start kafka</code></pre></figure> + +<figure class="highlight"><pre><code class="language-bash" data-lang="bash"><span></span>> ./deploy/kafka/bin/kafka-topics.sh --create --zookeeper localhost:2181 --topic sample-text --partition <span class="m">1</span> --replication-factor <span class="m">1</span> +> ./deploy/kafka/bin/kafka-console-producer.sh --topic sample-text --broker localhost:9092 < ./sample-text.txt</code></pre></figure> + +<p>Letâs kick off our application and use gradle to run it. Alternately, you can also run it directly from your IDE, with the same program arguments.</p> + +<figure class="highlight"><pre><code class="language-bash" data-lang="bash"><span></span>> <span class="nb">export</span> <span class="nv">BASE_DIR</span><span class="o">=</span><span class="sb">`</span><span class="nb">pwd</span><span class="sb">`</span> +> ./gradlew run --args<span class="o">=</span><span class="s2">"--config-factory=org.apache.samza.config.factories.PropertiesConfigFactory --config-path=file://</span><span class="nv">$BASE_DIR</span><span class="s2">/src/main/config/word-count.properties"</span></code></pre></figure> + +<p>The application will output to a Kafka topic named “word-count-output”. We will now fire up a Kafka consumer to read from this topic:</p> + +<figure class="highlight"><pre><code class="language-bash" data-lang="bash"><span></span>> ./deploy/kafka/bin/kafka-console-consumer.sh --topic word-count-output --zookeeper localhost:2181 --from-beginning</code></pre></figure> + +<p>It will show the counts for each word like the following:</p> + +<figure class="highlight"><pre><code class="language-bash" data-lang="bash"><span></span>well: <span class="m">4</span> +complaining: <span class="m">1</span> +die: <span class="m">3</span> +but: <span class="m">22</span> +not: <span class="m">50</span> +truly: <span class="m">5</span> +murmuring: <span class="m">1</span> +satisfied: <span class="m">3</span> +the: <span class="m">120</span> +thy: <span class="m">8</span> +gods: <span class="m">8</span> +thankful: <span class="m">1</span> +and: <span class="m">243</span> +from: <span class="m">16</span></code></pre></figure> + +<p>Congratulations! You’ve successfully run your first Samza application.</p> + +<h3 id="more-examples"><a href="/startup/code-examples/latest">More Examples >></a></h3> + + + </div> + </div> + + </div> + + + <!-- footer starts here --> + + <!-- + Licensed to the Apache Software Foundation (ASF) under one or more + contributor license agreements. See the NOTICE file distributed with + this work for additional information regarding copyright ownership. + The ASF licenses this file to You under the Apache License, Version 2.0 + (the "License"); you may not use this file except in compliance with + the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +--> + +<footer> + <div class="footer-inner"> + <div class="side-by-side"> + <div> + <div class="footer__heading">Learn More</div> + <div class="footer__items"> + <a class="footer__item" href="/meetups/">Meetups</a> + <a class="footer__item" href="/blog/">Blog</a> + <a class="footer__item" href="/learn/documentation/latest/introduction/background.html">About</a> + </div> + </div> + <div> + <div class="footer__heading">Community</div> + <div class="footer__items"> + <a class="footer__item" href="/community/contact-us.html">Contact Us</a> + <a class="footer__item" href="/contribute/contributors-corner.html">Contributors' Corner</a> + <a class="footer__item" href="/community/committers.html">PMC members and committers</a> + <a class="footer__item" href="/powered-by/">Powered By</a> + </div> + </div> + + <div> + <div class="quick-links"> + <a class="quick-link" href="/startup/download" target="_blank"> + <i class="icon ion-md-download"></i> + </a> + <a class="quick-link" href="https://git-wip-us.apache.org/repos/asf?p=samza.git;a=tree"; target="_blank"> + <i class="icon ion-md-code"></i> + </a> + <a class="quick-link" href="https://twitter.com/samzastream"; target="_blank"> + <i class="icon ion-logo-twitter"></i> + </a> + </div> + + <p> + <script>document.write(new Date().getFullYear());</script> © samza.apache.org</p> + </div> + + </div> + </div> + +</footer> + + +<script> + var tryFile = function (url, cb) { + var myRequest = new Request(url); + fetch(myRequest).then((response, cb) => { + console.log(response.status); // returns 200 + cb(response.status != 404); + }); + } + + tryFile(window.location.pathname, function (status) { + // do something with the status + console.log(status); + }); +</script> + + +<!-- Google Analytics --> +<script> + (function (i, s, o, g, r, a, m) { + i['GoogleAnalyticsObject'] = r; i[r] = i[r] || function () { + (i[r].q = i[r].q || []).push(arguments) + }, i[r].l = 1 * new Date(); a = s.createElement(o), + m = s.getElementsByTagName(o)[0]; a.async = 1; a.src = g; m.parentNode.insertBefore(a, m) + })(window, document, 'script', '//www.google-analytics.com/analytics.js', 'ga'); + + ga('create', 'UA-43122768-1', 'apache.org'); + ga('send', 'pageview'); + +</script> +<script src="/js/main.new.js"></script> + +</body> + +</html> \ No newline at end of file
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