HBase

The connector provides sources, flows and sinks to interact with HBase database.

HBase is a column family NoSQL Database backed by HDFS. For more information about HBase, please visit the HBase documentation.

Project Info: Apache Pekko Connectors HBase
Artifact	org.apache.pekko pekko-connectors-hbase 1.0.2 Snapshots are available
JDK versions	OpenJDK 8 OpenJDK 11 OpenJDK 17
Scala versions	2.13.14, 2.12.20, 3.3.3
JPMS module name	pekko.stream.connectors.hbase
License	Apache-2.0
API documentation	API (Scaladoc)
Forums	Github Discussions
Release notes	GitHub releases
Issues	Github issues
Sources	https://github.com/apache/pekko-connectors

Artifacts

sbt

val PekkoVersion = "1.0.3"
libraryDependencies ++= Seq(
  "org.apache.pekko" %% "pekko-connectors-hbase" % "1.0.2",
  "org.apache.pekko" %% "pekko-stream" % PekkoVersion
)

Maven

<properties>
  <pekko.version>1.0.3</pekko.version>
  <scala.binary.version>2.13</scala.binary.version>
</properties>
<dependencies>
  <dependency>
    <groupId>org.apache.pekko</groupId>
    <artifactId>pekko-connectors-hbase_${scala.binary.version}</artifactId>
    <version>1.0.2</version>
  </dependency>
  <dependency>
    <groupId>org.apache.pekko</groupId>
    <artifactId>pekko-stream_${scala.binary.version}</artifactId>
    <version>${pekko.version}</version>
  </dependency>
</dependencies>

Gradle

def versions = [
  PekkoVersion: "1.0.3",
  ScalaBinary: "2.13"
]
dependencies {
  implementation "org.apache.pekko:pekko-connectors-hbase_${versions.ScalaBinary}:1.0.2"
  implementation "org.apache.pekko:pekko-stream_${versions.ScalaBinary}:${versions.PekkoVersion}"
}

The table below shows direct dependencies of this module and the second tab shows all libraries it depends on transitively.

Converters

Converters map the domain object to a list of HBase mutations (Append, Delete, Increment, Put).

Put

Scala

copysourceimplicit def toBytes(string: String): Array[Byte] = Bytes.toBytes(string)
case class Person(id: Int, name: String)

val hBaseConverter: Person => immutable.Seq[Mutation] = { person =>
  val put = new Put(s"id_${person.id}")
  put.addColumn("info", "name", person.name)
  List(put)
}

Java

copysourceFunction<Person, List<Mutation>> hBaseConverter =
    person -> {
      try {
        Put put = new Put(String.format("id_%d", person.id).getBytes("UTF-8"));
        put.addColumn(
            "info".getBytes("UTF-8"), "name".getBytes("UTF-8"), person.name.getBytes("UTF-8"));

        return Collections.singletonList(put);
      } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
        return Collections.emptyList();
      }
    };

Append

Scala

copysourceval appendHBaseConverter: Person => immutable.Seq[Mutation] = { person =>
  // Append to a cell
  val append = new Append(s"id_${person.id}")
  append.add("info", "aliases", person.name)
  List(append)
}

Java

copysourceFunction<Person, List<Mutation>> appendHBaseConverter =
    person -> {
      try {
        Append append = new Append(String.format("id_%d", person.id).getBytes("UTF-8"));
        append.add(
            "info".getBytes("UTF-8"), "aliases".getBytes("UTF-8"), person.name.getBytes("UTF-8"));

        return Collections.singletonList(append);
      } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
        return Collections.emptyList();
      }
    };

Delete

Scala

copysourceval deleteHBaseConverter: Person => immutable.Seq[Mutation] = { person =>
  // Delete the specified row
  val delete = new Delete(s"id_${person.id}")
  List(delete)
}

Java

copysourceFunction<Person, List<Mutation>> deleteHBaseConverter =
    person -> {
      try {
        Delete delete = new Delete(String.format("id_%d", person.id).getBytes("UTF-8"));

        return Collections.singletonList(delete);
      } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
        return Collections.emptyList();
      }
    };

Increment

Scala

copysourceval incrementHBaseConverter: Person => immutable.Seq[Mutation] = { person =>
  // Increment a cell value
  val increment = new Increment(s"id_${person.id}")
  increment.addColumn("info", "numberOfChanges", 1)
  List(increment)
}

Java

copysourceFunction<Person, List<Mutation>> incrementHBaseConverter =
    person -> {
      try {
        Increment increment = new Increment(String.format("id_%d", person.id).getBytes("UTF-8"));
        increment.addColumn("info".getBytes("UTF-8"), "numberOfChanges".getBytes("UTF-8"), 1);

        return Collections.singletonList(increment);
      } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
        return Collections.emptyList();
      }
    };

Complex and noop mutations

To ignore an object return an empty List - this will have no effect on HBase. You can also combine mutations to perform complex business logic:

Scala

copysourceval mutationsHBaseConverter: Person => immutable.Seq[Mutation] = { person =>
  if (person.id != 0) {
    if (person.name.isEmpty) {
      // Delete the specified row
      val delete = new Delete(s"id_${person.id}")
      List(delete)
    } else {
      // Insert or update a row
      val put = new Put(s"id_${person.id}")
      put.addColumn("info", "name", person.name)

      val increment = new Increment(s"id_${person.id}")
      increment.addColumn("info", "numberOfChanges", 1)

      List(put, increment)
    }
  } else {
    List.empty
  }
}

Java

copysourceFunction<Person, List<Mutation>> complexHBaseConverter =
    person -> {
      try {
        byte[] id = String.format("id_%d", person.id).getBytes("UTF-8");
        byte[] infoFamily = "info".getBytes("UTF-8");

        if (person.id != 0 && person.name.isEmpty()) {
          Delete delete = new Delete(id);
          return Collections.singletonList(delete);
        } else if (person.id != 0) {
          Put put = new Put(id);
          put.addColumn(infoFamily, "name".getBytes("UTF-8"), person.name.getBytes("UTF-8"));

          Increment increment = new Increment(id);
          increment.addColumn(infoFamily, "numberOfChanges".getBytes("UTF-8"), 1);

          return Arrays.asList(put, increment);
        } else {
          return Collections.emptyList();
        }
      } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
        return Collections.emptyList();
      }
    };

If you return a list of mutations they will be applied in the same order. The list of mutations are not applied in an transaction, each mutation is independent.

Settings

HBase combinators require HTableSettings. If the table referenced in the settings does not exist, it will be created on demand.

Scala

copysourceval tableSettings =
  HTableSettings(HBaseConfiguration.create(), TableName.valueOf("person"), immutable.Seq("info"), hBaseConverter)

Java

copysourceHTableSettings<Person> tableSettings =
    HTableSettings.create(
        HBaseConfiguration.create(),
        TableName.valueOf("person1"),
        Collections.singletonList("info"),
        hBaseConverter);

Source

Scala

copysourceval scan = new Scan(new Get(Bytes.toBytes("id_100")))

val f = HTableStage
  .source(scan, tableSettings)
  .runWith(Sink.seq)

Java

copysourceScan scan = new Scan(new Get("id_300".getBytes("UTF-8")));

CompletionStage<List<Result>> f =
    HTableStage.source(scan, tableSettings).runWith(Sink.seq(), system);

Flow

Scala

copysourceval flow = HTableStage.flow[Person](tableSettings)

val f = Source(11 to 20).map(i => Person(i, s"zozo_$i")).via(flow).runWith(Sink.fold(0)((a, d) => a + d.id))

Java

copysourceFlow<Person, Person, NotUsed> flow = HTableStage.flow(tableSettings);
Pair<NotUsed, CompletionStage<List<Person>>> run =
    Source.from(Arrays.asList(200, 201, 202, 203, 204))
        .map((i) -> new Person(i, String.format("name_%d", i)))
        .via(flow)
        .toMat(Sink.seq(), Keep.both())
        .run(system);

Sink

Scala

copysourceval sink = HTableStage.sink[Person](tableSettings)

val f = Source(1 to 10).map(i => Person(i, s"zozo_$i")).runWith(sink)

Java

copysourcefinal Sink<Person, CompletionStage<Done>> sink = HTableStage.sink(tableSettings);
CompletionStage<Done> o =
    Source.from(Arrays.asList(100, 101, 102, 103, 104))
        .map((i) -> new Person(i, String.format("name %d", i)))
        .runWith(sink, system);

HBase administration commands

To manage HBase database, startup HBase shell ($HBASE_HOME/bin/shell), and run following commands:

list // list tables
scan "person" // select * from person
disable "person" // Disable table "person", before drop
drop "person"