Github user zsxwing commented on a diff in the pull request: https://github.com/apache/spark/pull/15102#discussion_r82030551 --- Diff: docs/structured-streaming-kafka-integration.md --- @@ -0,0 +1,239 @@ +--- +layout: global +title: Structured Streaming + Kafka Integration Guide (Kafka broker version 0.10.0 or higher) +--- + +Structured Streaming integration for Kafka 0.10 to poll data from Kafka. + +### Linking +For Scala/Java applications using SBT/Maven project definitions, link your application with the following artifact: + + groupId = org.apache.spark + artifactId = spark-sql-kafka-0-10_{{site.SCALA_BINARY_VERSION}} + version = {{site.SPARK_VERSION_SHORT}} + +For Python applications, you need to add this above library and its dependencies when deploying your +application. See the [Deploying](#deploying) subsection below. + +### Creating a Kafka Source Stream + +<div class="codetabs"> +<div data-lang="scala" markdown="1"> + + // Subscribe to 1 topic + val ds1 = spark + .readStream + .format("kafka") + .option("kafka.bootstrap.servers", "host1:port1,host2:port2") + .option("subscribe", "topic1") + .load() + ds1.selectExpr("CAST(key AS STRING)", "CAST(value AS STRING)") + .as[(String, String)] + + // Subscribe to multiple topics + val ds2 = spark + .readStream + .format("kafka") + .option("kafka.bootstrap.servers", "host1:port1,host2:port2") + .option("subscribe", "topic1,topic2") + .load() + ds2.selectExpr("CAST(key AS STRING)", "CAST(value AS STRING)") + .as[(String, String)] + + // Subscribe to a pattern + val ds3 = spark + .readStream + .format("kafka") + .option("kafka.bootstrap.servers", "host1:port1,host2:port2") + .option("subscribePattern", "topic.*") + .load() + ds3.selectExpr("CAST(key AS STRING)", "CAST(value AS STRING)") + .as[(String, String)] + +</div> +<div data-lang="java" markdown="1"> + + // Subscribe to 1 topic + Dataset<Row> ds1 = spark + .readStream() + .format("kafka") + .option("kafka.bootstrap.servers", "host1:port1,host2:port2") + .option("subscribe", "topic1") + .load() + ds1.selectExpr("CAST(key AS STRING)", "CAST(value AS STRING)") + + // Subscribe to multiple topics + Dataset<Row> ds2 = spark + .readStream() + .format("kafka") + .option("kafka.bootstrap.servers", "host1:port1,host2:port2") + .option("subscribe", "topic1,topic2") + .load() + ds2.selectExpr("CAST(key AS STRING)", "CAST(value AS STRING)") + + // Subscribe to a pattern + Dataset<Row> ds3 = spark + .readStream() + .format("kafka") + .option("kafka.bootstrap.servers", "host1:port1,host2:port2") + .option("subscribePattern", "topic.*") + .load() + ds3.selectExpr("CAST(key AS STRING)", "CAST(value AS STRING)") + +</div> +<div data-lang="python" markdown="1"> + + # Subscribe to 1 topic + ds1 = spark + .readStream() + .format("kafka") + .option("kafka.bootstrap.servers", "host1:port1,host2:port2") + .option("subscribe", "topic1") + .load() + ds1.selectExpr("CAST(key AS STRING)", "CAST(value AS STRING)") + + # Subscribe to multiple topics + ds2 = spark + .readStream + .format("kafka") + .option("kafka.bootstrap.servers", "host1:port1,host2:port2") + .option("subscribe", "topic1,topic2") + .load() + ds2.selectExpr("CAST(key AS STRING)", "CAST(value AS STRING)") + + # Subscribe to a pattern + ds3 = spark + .readStream() + .format("kafka") + .option("kafka.bootstrap.servers", "host1:port1,host2:port2") + .option("subscribePattern", "topic.*") + .load() + ds3.selectExpr("CAST(key AS STRING)", "CAST(value AS STRING)") + +</div> +</div> + +Each row in the source has the following schema: +<table class="table"> +<tr><th>Column</th><th>Type</th></tr> +<tr> + <td>key</td> + <td>binary</td> +</tr> +<tr> + <td>value</td> + <td>binary</td> +</tr> +<tr> + <td>topic</td> + <td>string</td> +</tr> +<tr> + <td>partition</td> + <td>int</td> +</tr> +<tr> + <td>offset</td> + <td>long</td> +</tr> +<tr> + <td>timestamp</td> + <td>long</td> +</tr> +<tr> + <td>timestampType</td> + <td>int</td> +</tr> +</table> + +The following options should be set for the Kafka source. + +<table class="table"> +<tr><th>Option</th><th>value</th><th>meaning</th></tr> +<tr> + <td>subscribe</td> + <td>A comma-separated list of topics</td> + <td>The topic list to subscribe. Only one of "subscribe" and "subscribePattern" options can be + specified for Kafka source.</td> +</tr> +<tr> + <td>subscribePattern</td> + <td>Java regex string</td> + <td>The pattern used to subscribe the topic. Only one of "subscribe" and "subscribePattern" + options can be specified for Kafka source.</td> +</tr> +<tr> + <td>kafka.bootstrap.servers</td> + <td>A comma-separated list of host:port</td> + <td>The Kafka "bootstrap.servers" configuration.</td> +</tr> +</table> + +The rest configurations are optional: --- End diff -- done
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