new CassandraWriterBolt( async( simpleQuery("INSERT INTO album (title,year,performer,genre,tracks) VALUES (?, ?, ?, ?, ?);") .with( fields("title", "year", "performer", "genre", "tracks") ) ) );
new CassandraWriterBolt( async( simpleQuery("INSERT INTO album (title,year,performer,genre,tracks) VALUES (?, ?, ?, ?, ?);") .with( all() ) ) );
new CassandraWriterBolt( async( simpleQuery("INSERT INTO titles_per_album (title,year,performer,genre,tracks) VALUES (?, ?, ?, ?, ?);").with(all())), simpleQuery("INSERT INTO titles_per_performer (title,year,performer,genre,tracks) VALUES (?, ?, ?, ?, ?);").with(all())) ) );
new CassandraWriterBolt( async( simpleQuery("INSERT INTO album (title,year,perfomer,genre,tracks) VALUES (?, ?, ?, ?, ?);") .with(all())) ) )
new CassandraWriterBolt( async( boundQuery("INSERT INTO album (title,year,performer,genre,tracks) VALUES (?, ?, ?, ?, ?);") .bind(all()); ) );
new CassandraWriterBolt( async( boundQuery("INSERT INTO album (title,year,performer,genre,tracks) VALUES (:ti, :ye, :pe, :ge, :tr);") .bind( field("ti"),as("title"), field("ye").as("year")), field("pe").as("performer")), field("ge").as("genre")), field("tr").as("tracks")) ).byNamedSetters() ) );
new CassandraWriterBolt( boundQuery(named("insertIntoAlbum")) .bind(all());
new CassandraWriterBolt( boundQuery(namedByField("cql")) .bind(all());
// Logged new CassandraWriterBolt(loggedBatch( simpleQuery("INSERT INTO titles_per_album (title,year,performer,genre,tracks) VALUES (?, ?, ?, ?, ?);").with(all())), simpleQuery("INSERT INTO titles_per_performer (title,year,performer,genre,tracks) VALUES (?, ?, ?, ?, ?);").with(all())) ) ); // UnLogged new CassandraWriterBolt(unLoggedBatch( simpleQuery("INSERT INTO titles_per_album (title,year,performer,genre,tracks) VALUES (?, ?, ?, ?, ?);").with(all())), simpleQuery("INSERT INTO titles_per_performer (title,year,performer,genre,tracks) VALUES (?, ?, ?, ?, ?);").with(all())) ) );
The interface ExecutionResultHandler can be used to custom how an execution result should be handle.
public interface ExecutionResultHandler extends Serializable { void onQueryValidationException(QueryValidationException e, OutputCollector collector, Tuple tuple); void onReadTimeoutException(ReadTimeoutException e, OutputCollector collector, Tuple tuple); void onWriteTimeoutException(WriteTimeoutException e, OutputCollector collector, Tuple tuple); void onUnavailableException(UnavailableException e, OutputCollector collector, Tuple tuple); void onQuerySuccess(OutputCollector collector, Tuple tuple); }
By default, the CassandraBolt fails a tuple on all Cassandra Exception (see BaseExecutionResultHandler) .
new CassandraWriterBolt(insertInto("album").values(with(all()).build()) .withResultHandler(new MyCustomResultHandler());
A CassandraBolt can declare output fields / stream output fields. For instance, this may be used to remit a new tuple on error, or to chain queries.
new CassandraWriterBolt(insertInto("album").values(withFields(all()).build()) .withResultHandler(new EmitOnDriverExceptionResultHandler()); .withStreamOutputFields("stream_error", new Fields("message"); public static class EmitOnDriverExceptionResultHandler extends BaseExecutionResultHandler { @Override protected void onDriverException(DriverException e, OutputCollector collector, Tuple tuple) { LOG.error("An error occurred while executing cassandra statement", e); collector.emit("stream_error", new Values(e.getMessage())); collector.ack(tuple); } }
Murmur3StreamGrouping can be used to optimise cassandra writes. The stream is partitioned among the bolt's tasks based on the specified row partition keys.
CassandraWriterBolt bolt = new CassandraWriterBolt( insertInto("album") .values( with(fields("title", "year", "performer", "genre", "tracks") ).build()); builder.setBolt("BOLT_WRITER", bolt, 4) .customGrouping("spout", new Murmur3StreamGrouping("title"))
storm-cassandra support Trident state
API for inserting
data into Cassandra.
CassandraState.Options options = new CassandraState.Options(new CassandraContext()); CQLStatementTupleMapper insertTemperatureValues = boundQuery( "INSERT INTO weather.temperature(weather_station_id, weather_station_name, event_time, temperature) VALUES(?, ?, ?, ?)") .bind(with(field("weather_station_id"), field("name").as("weather_station_name"), field("event_time").now(), field("temperature"))); options.withCQLStatementTupleMapper(insertTemperatureValues); CassandraStateFactory insertValuesStateFactory = new CassandraStateFactory(options); TridentState selectState = topology.newStaticState(selectWeatherStationStateFactory); stream = stream.stateQuery(selectState, new Fields("weather_station_id"), new CassandraQuery(), new Fields("name")); stream = stream.each(new Fields("name"), new PrintFunction(), new Fields("name_x")); stream.partitionPersist(insertValuesStateFactory, new Fields("weather_station_id", "name", "event_time", "temperature"), new CassandraStateUpdater(), new Fields());
Below state
API for querying
data from Cassandra.
CassandraState.Options options = new CassandraState.Options(new CassandraContext()); CQLStatementTupleMapper insertTemperatureValues = boundQuery("SELECT name FROM weather.station WHERE id = ?") .bind(with(field("weather_station_id").as("id"))); options.withCQLStatementTupleMapper(insertTemperatureValues); options.withCQLResultSetValuesMapper(new TridentResultSetValuesMapper(new Fields("name"))); CassandraStateFactory selectWeatherStationStateFactory = new CassandraStateFactory(options); CassandraStateFactory selectWeatherStationStateFactory = getSelectWeatherStationStateFactory(); TridentState selectState = topology.newStaticState(selectWeatherStationStateFactory); stream = stream.stateQuery(selectState, new Fields("weather_station_id"), new CassandraQuery(), new Fields("name"));
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