Updated on 2024-01-23 GMT+08:00

Scala Example Code

Development Description

The CloudTable HBase and MRS HBase can be connected to DLI as data sources.

  • Prerequisites

    A datasource connection has been created on the DLI management console. For details, see Enhanced Datasource Connections.

    Hard-coded or plaintext passwords pose significant security risks. To ensure security, encrypt your passwords, store them in configuration files or environment variables, and decrypt them when needed.

  • Constructing dependency information and creating a Spark session
    1. Import dependencies.
      Maven dependency involved
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      <dependency>
        <groupId>org.apache.spark</groupId>
        <artifactId>spark-sql_2.11</artifactId>
        <version>2.3.2</version>
      </dependency>
      
      Import dependency packages.
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      import scala.collection.mutable
      import org.apache.spark.sql.{Row, SparkSession}
      import org.apache.spark.rdd.RDD
      import org.apache.spark.sql.types._
      
    2. Create a session.
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      val sparkSession = SparkSession.builder().getOrCreate()
      
    3. Create a table to connect to an HBase data source.
      • The sample code is applicable, if Kerberos authentication is disabled for the interconnected HBase cluster:
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        sparkSession.sql("CREATE TABLE test_hbase('id' STRING, 'location' STRING, 'city' STRING, 'booleanf' BOOLEAN, 
                'shortf' SHORT, 'intf' INT, 'longf' LONG, 'floatf' FLOAT,'doublef' DOUBLE) using hbase OPTIONS (
        	'ZKHost'='cloudtable-cf82-zk3-pa6HnHpf.cloudtable.com:2181,
                          cloudtable-cf82-zk2-weBkIrjI.cloudtable.com:2181,
                          cloudtable-cf82-zk1-WY09px9l.cloudtable.com:2181',
        	'TableName'='table_DupRowkey1',
        	'RowKey'='id:5,location:6,city:7',
            'Cols'='booleanf:CF1.booleanf,shortf:CF1.shortf,intf:CF1.intf,longf:CF1.longf,floatf:CF1.floatf,doublef:CF1.doublef')"
        )
        
      • The sample code is applicable, if Kerberos authentication is enabled for the interconnected HBase cluster:
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        sparkSession.sql("CREATE TABLE test_hbase('id' STRING, 'location' STRING, 'city' STRING, 'booleanf' BOOLEAN, 
                'shortf' SHORT, 'intf' INT, 'longf' LONG, 'floatf' FLOAT,'doublef' DOUBLE) using hbase OPTIONS (
        	'ZKHost'='cloudtable-cf82-zk3-pa6HnHpf.cloudtable.com:2181,
                          cloudtable-cf82-zk2-weBkIrjI.cloudtable.com:2181,
                          cloudtable-cf82-zk1-WY09px9l.cloudtable.com:2181',
        	'TableName'='table_DupRowkey1',
        	'RowKey'='id:5,location:6,city:7', 
            'Cols'='booleanf:CF1.booleanf,shortf:CF1.shortf,intf:CF1.intf,longf:CF1.longf,floatf:CF1.floatf,doublef:CF1.doublef',
            'krb5conf'='./krb5.conf',
            'keytab' = './user.keytab',
        	'principal' = 'krbtest')")
        
      Table 1 Parameters for creating a table

      Parameter

      Description

      ZKHost

      ZooKeeper IP address of the HBase cluster.

      You need to create a datasource connection first. For details, see Enhanced Datasource Connections.

      • To access the CloudTable cluster, specify the ZooKeeper connection address in the internal network.
      • To access the MRS cluster, specify the IP addresses and port numbers of the ZooKeeper nodes. The format is as follows: ZK_IP1:ZK_PORT1,ZK_IP2:ZK_PORT2

      RowKey

      Row key field of the table connected to DLI. The single and composite row keys are supported. A single row key can be of the numeric or string type. The length does not need to be specified. The composite row key supports only fixed-length data of the string type. The format is attribute name 1:Length, attribute name 2:Length.

      Cols

      Mapping between the fields in the DLI table and the CloudTable table. In this mapping, the DLI table field is placed before the colon (:) and the CloudTable table field is placed after the colon (:). The period (.) is used to separate the column family and column name of the CloudTable table.

      For example: DLI table field 1:CloudTable table.CloudTable table field 1, DLI table field 2:CloudTable table.CloudTable table field 2, DLI table field 3:CLoudTable table.CloudTable table field 3

      krb5conf

      Path of the krb5.conf file. This parameter is required when Kerberos authentication is enabled. The format is './krb5.conf'. For details, see Completing Configurations for Enabling Kerberos Authentication.

      keytab

      Path of the keytab file. This parameter is required when Kerberos authentication is enabled. The format is './user.keytab.'. For details, see Completing Configurations for Enabling Kerberos Authentication.

      principal

      Username created for Kerberos authentication.

Accessing a Data Source Using a SQL API

  1. Insert data.
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    sparkSession.sql("insert into test_hbase values('12345','abc','guiyang',false,null,3,23,2.3,2.34)")
    
  2. Query data.
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    sparkSession.sql("select * from test_hbase").show ()
    

    Response

Accessing a Data Source Using a DataFrame API

  1. Construct a schema.
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    val attrId = new StructField("id",StringType)
    val location = new StructField("location",StringType)
    val city = new StructField("city",StringType)
    val booleanf = new StructField("booleanf",BooleanType)
    val shortf = new StructField("shortf",ShortType)
    val intf = new StructField("intf",IntegerType)
    val longf = new StructField("longf",LongType)
    val floatf = new StructField("floatf",FloatType)
    val doublef = new StructField("doublef",DoubleType)
    val attrs = Array(attrId, location,city,booleanf,shortf,intf,longf,floatf,doublef)
    
  2. Construct data based on the schema type.
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    val mutableRow: Seq[Any] = Seq("12345","abc","city1",false,null,3,23,2.3,2.34)
    val rddData: RDD[Row] = sparkSession.sparkContext.parallelize(Array(Row.fromSeq(mutableRow)), 1)
    
  3. Import data to HBase.
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    sparkSession.createDataFrame(rddData, new StructType(attrs)).write.insertInto("test_hbase")
    
  4. Read data from HBase.
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    val map = new mutable.HashMap[String, String]()
    map("TableName") = "table_DupRowkey1"
    map("RowKey") = "id:5,location:6,city:7"
    map("Cols") = "booleanf:CF1.booleanf,shortf:CF1.shortf,intf:CF1.intf,longf:CF1.longf,floatf:CF1.floatf,doublef:CF1.doublef"
    map("ZKHost")="cloudtable-cf82-zk3-pa6HnHpf.cloudtable.com:2181,
                   cloudtable-cf82-zk2-weBkIrjI.cloudtable.com:2181,
                   cloudtable-cf82-zk1-WY09px9l.cloudtable.com:2181"
    sparkSession.read.schema(new StructType(attrs)).format("hbase").options(map.toMap).load().show()
    

    Returned result:

Submitting a Spark Job

  1. Generate a JAR package based on the code and upload the package to DLI.

    For details about console operations, see Creating a Package. For details about API operations, see Uploading a Package Group.

  2. (Optional) Add the krb5.conf and user.keytab files to other dependency files of the job when creating a Spark job in an MRS cluster with Kerberos authentication enabled. Skip this step if Kerberos authentication is not enabled for the cluster.
    Figure 1 Adding dependency files
  3. In the Spark job editor, select the corresponding dependency module and execute the Spark job.

    For details about console operations, see Creating a Spark Job. For details about API operations, see Creating a Batch Processing Job.
    • If the Spark version is 2.3.2 (will be offline soon) or 2.4.5, set Module to sys.datasource.hbase when you submit a job.
    • If the Spark version is 3.1.1, you do not need to select a module. Set Spark parameters (--conf).

      spark.driver.extraClassPath=/usr/share/extension/dli/spark-jar/datasource/hbase/*

      spark.executor.extraClassPath=/usr/share/extension/dli/spark-jar/datasource/hbase/*

    • For details about how to submit a job on the console, see the description of the table "Parameters for selecting dependency resources" in Creating a Spark Job.
    • For details about how to submit a job through an API, see the description of the modules parameter in Table 2 "Request parameters" in Creating a Batch Processing Job.

Complete Example Code

  • Maven dependency
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    <dependency>
      <groupId>org.apache.spark</groupId>
      <artifactId>spark-sql_2.11</artifactId>
      <version>2.3.2</version>
    </dependency>
    
  • Connecting to data sources through SQL APIs
    • Sample code when Kerberos authentication is disabled
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      import org.apache.spark.sql.SparkSession
      
      object Test_SparkSql_HBase {
        def main(args: Array[String]): Unit = {
          // Create a SparkSession session.
          val sparkSession = SparkSession.builder().getOrCreate()
      
          /**
           * Create an association table for the DLI association Hbase table
           */
          sparkSession.sql("CREATE TABLE test_hbase('id' STRING, 'location' STRING, 'city' STRING, 'booleanf' BOOLEAN, 
              'shortf' SHORT, 'intf' INT, 'longf' LONG, 'floatf' FLOAT,'doublef' DOUBLE) using hbase OPTIONS (
      	'ZKHost'='cloudtable-cf82-zk3-pa6HnHpf.cloudtable.com:2181,
      	          cloudtable-cf82-zk2-weBkIrjI.cloudtable.com:2181,
      	          cloudtable-cf82-zk1-WY09px9l.cloudtable.com:2181',
      	'TableName'='table_DupRowkey1',
      	'RowKey'='id:5,location:6,city:7',
      	'Cols'='booleanf:CF1.booleanf,shortf:CF1.shortf,intf:CF1.intf,
      		longf:CF1.longf,floatf:CF1.floatf,doublef:CF1.doublef')")
      
          //*****************************SQL model***********************************
          sparkSession.sql("insert into test_hbase values('12345','abc','city1',false,null,3,23,2.3,2.34)")
          sparkSession.sql("select * from test_hbase").collect()
      
          sparkSession.close()
        }
      }
      
    • Sample code when Kerberos authentication is enabled
      import org.apache.spark.SparkFiles
      import org.apache.spark.sql.SparkSession
       
      import java.io.{File, FileInputStream, FileOutputStream}
       
      object Test_SparkSql_HBase_Kerberos {
       
        def copyFile2(Input:String)(OutPut:String): Unit ={
          val fis = new FileInputStream(Input)
          val fos = new FileOutputStream(OutPut)
          val buf = new Array[Byte](1024)
          var len = 0
          while ({len = fis.read(buf);len} != -1){
            fos.write(buf,0,len)
          }
          fos.close()
          fis.close()
        }
       
        def main(args: Array[String]): Unit = {
          // Create a SparkSession session.
          val sparkSession = SparkSession.builder().getOrCreate()
          val sc = sparkSession.sparkContext
          sc.addFile("OBS address of krb5.conf")
          sc.addFile("OBS address of user.keytab")
          Thread.sleep(10)
       
          val krb5_startfile = new File(SparkFiles.get("krb5.conf"))
          val keytab_startfile = new File(SparkFiles.get("user.keytab"))
          val path_user = System.getProperty("user.dir")
          val keytab_endfile = new File(path_user + "/" + keytab_startfile.getName)
          val krb5_endfile = new File(path_user + "/" + krb5_startfile.getName)
          println(keytab_endfile)
          println(krb5_endfile)
       
          var krbinput = SparkFiles.get("krb5.conf")
          var krboutput = path_user+"/krb5.conf"
          copyFile2(krbinput)(krboutput)
       
          var keytabinput = SparkFiles.get("user.keytab")
          var keytaboutput = path_user+"/user.keytab"
          copyFile2(keytabinput)(keytaboutput)
          Thread.sleep(10)
          /**
           * Create an association table for the DLI association Hbase table
           */
          sparkSession.sql("CREATE TABLE testhbase(id string,booleanf boolean,shortf short,intf int,longf long,floatf float,doublef double) " +
            "using hbase OPTIONS(" +
            "'ZKHost'='10.0.0.146:2181'," +
            "'TableName'='hbtest'," +
            "'RowKey'='id:100'," +
            "'Cols'='booleanf:CF1.booleanf,shortf:CF1.shortf,intf:CF1.intf,longf:CF2.longf,floatf:CF1.floatf,doublef:CF2.doublef'," +
            "'krb5conf'='" + path_user + "/krb5.conf'," +
            "'keytab'='" + path_user+ "/user.keytab'," +
            "'principal'='krbtest') ")
       
        //*****************************SQL model***********************************
        sparkSession.sql("insert into testhbase values('newtest',true,1,2,3,4,5)")
        val result = sparkSession.sql("select * from testhbase")
        result.show()
       
        sparkSession.close()
        }
      }
  • Connecting to data sources through DataFrame APIs
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    import scala.collection.mutable
    
    import org.apache.spark.sql.{Row, SparkSession}
    import org.apache.spark.rdd.RDD
    import org.apache.spark.sql.types._
    
    object Test_SparkSql_HBase {
      def main(args: Array[String]): Unit = {
        // Create a SparkSession session.
        val sparkSession = SparkSession.builder().getOrCreate()
    
        // Create an association table for the DLI association Hbase table
        sparkSession.sql("CREATE TABLE test_hbase('id' STRING, 'location' STRING, 'city' STRING, 'booleanf' BOOLEAN, 
            'shortf' SHORT, 'intf' INT, 'longf' LONG, 'floatf' FLOAT,'doublef' DOUBLE) using hbase OPTIONS (
    	'ZKHost'='cloudtable-cf82-zk3-pa6HnHpf.cloudtable.com:2181,
    	          cloudtable-cf82-zk2-weBkIrjI.cloudtable.com:2181,
    	          cloudtable-cf82-zk1-WY09px9l.cloudtable.com:2181',
    	'TableName'='table_DupRowkey1',
    	'RowKey'='id:5,location:6,city:7',
    	'Cols'='booleanf:CF1.booleanf,shortf:CF1.shortf,intf:CF1.intf,longf:CF1.longf,floatf:CF1.floatf,doublef:CF1.doublef')")
    
        //*****************************DataFrame model***********************************
        // Setting schema
        val attrId = new StructField("id",StringType)
        val location = new StructField("location",StringType)
        val city = new StructField("city",StringType)
        val booleanf = new StructField("booleanf",BooleanType)
        val shortf = new StructField("shortf",ShortType)
        val intf = new StructField("intf",IntegerType)
        val longf = new StructField("longf",LongType)
        val floatf = new StructField("floatf",FloatType)
        val doublef = new StructField("doublef",DoubleType)
        val attrs = Array(attrId, location,city,booleanf,shortf,intf,longf,floatf,doublef)
    
        // Populate data according to the type of schema
        val mutableRow: Seq[Any] = Seq("12345","abc","city1",false,null,3,23,2.3,2.34)
        val rddData: RDD[Row] = sparkSession.sparkContext.parallelize(Array(Row.fromSeq(mutableRow)), 1)
    
        // Import the constructed data into Hbase
        sparkSession.createDataFrame(rddData, new StructType(attrs)).write.insertInto("test_hbase")
    
        // Read data on Hbase
        val map = new mutable.HashMap[String, String]()
        map("TableName") = "table_DupRowkey1"
        map("RowKey") = "id:5,location:6,city:7"
        map("Cols") = "booleanf:CF1.booleanf,shortf:CF1.shortf,intf:CF1.intf,longf:CF1.longf,floatf:CF1.floatf,doublef:CF1.doublef"
        map("ZKHost")="cloudtable-cf82-zk3-pa6HnHpf.cloudtable.com:2181,
                       cloudtable-cf82-zk2-weBkIrjI.cloudtable.com:2181,
                       cloudtable-cf82-zk1-WY09px9l.cloudtable.com:2181"
        sparkSession.read.schema(new StructType(attrs)).format("hbase").options(map.toMap).load().collect()
    
        sparkSession.close()
      }
    }