【问题标题】:Spark Structured Streaming with Hbase integration与 Hbase 集成的 Spark 结构化流
【发布时间】:2018-04-19 12:08:04
【问题描述】:

我们正在对从 MySQL 收集的 kafka 数据进行流式处理。现在,一旦完成所有分析,我想将我的数据直接保存到 Hbase。我通过了 spark 结构化流文档,但找不到任何带有 Hbase 的接收器。我用来从 Kafka 读取数据的代码如下。

 val records = spark.readStream.format("kafka").option("subscribe", "kaapociot").option("kafka.bootstrap.servers", "XX.XX.XX.XX:6667").option("startingOffsets", "earliest").load
 val jsonschema = StructType(Seq(StructField("header", StringType, true),StructField("event", StringType, true)))
 val uschema = StructType(Seq(
             StructField("MeterNumber", StringType, true),
             StructField("Utility", StringType, true),
             StructField("VendorServiceNumber", StringType, true),
             StructField("VendorName", StringType, true),
             StructField("SiteNumber",  StringType, true),
             StructField("SiteName", StringType, true),
             StructField("Location", StringType, true),
             StructField("timestamp", LongType, true),
             StructField("power", DoubleType, true)
             ))
 val DF_Hbase = records.selectExpr("cast (value as string) as Json").select(from_json($"json",schema=jsonschema).as("data")).select("data.event").select(from_json($"event", uschema).as("mykafkadata")).select("mykafkadata.*")

现在最后,我想将 DF_Hbase 数据帧保存在 hbase 中。

【问题讨论】:

标签: scala apache-spark apache-kafka hbase spark-streaming


【解决方案1】:

1- 将这些库添加到您的项目中:

      "org.apache.hbase" % "hbase-client" % "2.0.1"
      "org.apache.hbase" % "hbase-common" % "2.0.1"

2-将此特征添加到您的代码中:

   import java.util.concurrent.ExecutorService
   import org.apache.hadoop.hbase.client.{Connection, ConnectionFactory, Put, Table}
   import org.apache.hadoop.hbase.security.User
   import org.apache.hadoop.hbase.{HBaseConfiguration, TableName}
   import org.apache.spark.sql.ForeachWriter

   trait HBaseForeachWriter[RECORD] extends ForeachWriter[RECORD] {

     val tableName: String
     val hbaseConfResources: Seq[String]

     def pool: Option[ExecutorService] = None

     def user: Option[User] = None

     private var hTable: Table = _
     private var connection: Connection = _


     override def open(partitionId: Long, version: Long): Boolean = {
       connection = createConnection()
       hTable = getHTable(connection)
       true
     }

     def createConnection(): Connection = {
       val hbaseConfig = HBaseConfiguration.create()
       hbaseConfResources.foreach(hbaseConfig.addResource)
       ConnectionFactory.createConnection(hbaseConfig, pool.orNull,                      user.orNull)

     }

     def getHTable(connection: Connection): Table = {
       connection.getTable(TableName.valueOf(tableName))
     }

     override def process(record: RECORD): Unit = {
       val put = toPut(record)
       hTable.put(put)
     }

     override def close(errorOrNull: Throwable): Unit = {
       hTable.close()
       connection.close()
     }

     def toPut(record: RECORD): Put

   }

3- 将其用于您的逻辑:

    val ds = .... //anyDataset[WhatEverYourDataType]

    val query = ds.writeStream
           .foreach(new HBaseForeachWriter[WhatEverYourDataType] {
                            override val tableName: String = "hbase-table-name"
                            //your cluster files, i assume here it is in resources  
                            override val hbaseConfResources: Seq[String] = Seq("core-site.xml", "hbase-site.xml") 

                            override def toPut(record: WhatEverYourDataType): Put = {
                              val key = .....
                              val columnFamaliyName : String = ....
                              val columnName : String = ....
                              val columnValue = ....

                              val p = new Put(Bytes.toBytes(key))
                              //Add columns ... 
                   p.addColumn(Bytes.toBytes(columnFamaliyName),
                               Bytes.toBytes(columnName), 
                               Bytes.toBytes(columnValue))

                              p
                            }

                          }
           ).start()

         query.awaitTermination()

【讨论】:

  • 这样的做法是对的,是否也可以添加更复杂的逻辑让这个sink幂等实现exact-once-delivery语义。
【解决方案2】:

即使使用 pyspark,这种方法也适用于我:https://github.com/hortonworks-spark/shc/issues/205

package HBase
import org.apache.spark.internal.Logging
import org.apache.spark.sql.execution.streaming.Sink
import org.apache.spark.sql.sources.{DataSourceRegister, StreamSinkProvider}
import org.apache.spark.sql.streaming.OutputMode
import org.apache.spark.sql.{DataFrame, SQLContext}
import org.apache.spark.sql.execution.datasources.hbase._

class HBaseSink(options: Map[String, String]) extends Sink with Logging {
  // String with HBaseTableCatalog.tableCatalog
  private val hBaseCatalog = options.get("hbasecat").map(_.toString).getOrElse("")

  override def addBatch(batchId: Long, data: DataFrame): Unit = synchronized {   
    val df = data.sparkSession.createDataFrame(data.rdd, data.schema)
    df.write
      .options(Map(HBaseTableCatalog.tableCatalog->hBaseCatalog,
        HBaseTableCatalog.newTable -> "5"))
      .format("org.apache.spark.sql.execution.datasources.hbase").save()
  }
}

class HBaseSinkProvider extends StreamSinkProvider with DataSourceRegister {
  def createSink(
                  sqlContext: SQLContext,
                  parameters: Map[String, String],
                  partitionColumns: Seq[String],
                  outputMode: OutputMode): Sink = {
    new HBaseSink(parameters)
  }

  def shortName(): String = "hbase"
}

我将名为 HBaseSinkProvider.scala 的文件添加到 shc/core/src/main/scala/org/apache/spark/sql/execution/datasources/hbase 并构建它,示例完美运行

这是一个例子,如何使用(scala):

inputDF.
   writeStream.
   queryName("hbase writer").
   format("HBase.HBaseSinkProvider").
   option("checkpointLocation", checkPointProdPath).
   option("hbasecat", catalog).
   outputMode(OutputMode.Update()).
   trigger(Trigger.ProcessingTime(30.seconds)).
   start

以及我如何在 python 中使用它的示例:

inputDF \
    .writeStream \
    .outputMode("append") \
    .format('HBase.HBaseSinkProvider') \
    .option('hbasecat', catalog_kafka) \
    .option("checkpointLocation", '/tmp/checkpoint') \
    .start()

【讨论】:

  • 请考虑描述解决方案(不仅仅是链接不同的站点)。 “自包含”答案是首选,因为它们不依赖于将来可能更改/消失的外部资源,而且它们让用户可以立即访问他们所追求的信息,而不是打开另一个浏览器选项卡。
  • 请在 pyspark 中提供完整的解决方案,正如许多人在链接中所说的那样,它不起作用
【解决方案3】:

您是否正在处理来自 Kafka 的数据?还是只是将其泵送到 HBase?要考虑的一个选项是使用Kafka Connect。这为您提供了一种基于配置文件的方法,用于将 Kafka 与其他系统(包括 HBase)集成。

【讨论】:

  • 我刚查了一下,找不到hbase连接器
  • 至少有两个(虽然我没有尝试过):google.com/…
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