21.3. Using the Lambda Data Store Programmatically¶

21.3.1. Creating a Data Store¶

An instance of a Lambda data store can be obtained through the normal GeoTools discovery methods, assuming that the GeoMesa code is on the classpath:

Map<String, String> parameters = new HashMap<>;
parameters.put("lambda.accumulo.instance.name", "myInstance");
parameters.put("lambda.accumulo.zookeepers", "zoo1,zoo2,zoo3");
parameters.put("lambda.accumulo.user", "myUser");
parameters.put("lambda.accumulo.password", "myPassword");
parameters.put("lambda.accumulo.tableName", "my_table");
parameters.put("lambda.kafka.brokers", "kafka1:9092,kafka2:9092");
parameters.put("lambda.kafka.zookeepers", "zoo1,zoo2,zoo3");
parameters.put("lambda.expiry", "10 minutes");
org.geotools.api.data.DataStore dataStore =
    org.geotools.api.data.DataStoreFinder.getDataStore(parameters);

More information on using GeoTools can be found in the GeoTools user guide.

21.3.2. Lambda Data Store Parameters¶

The data store takes several parameters (required parameters are marked with *):

Parameter	Type	Description
`lambda.accumulo.instance.name *`	String	The instance ID of the Accumulo installation
`lambda.accumulo.zookeepers *`	String	A comma separated list of zookeeper servers (e.g. “zoo1,zoo2,zoo3” or “localhost:2181”)
`lambda.accumulo.catalog *`	String	The name of the GeoMesa catalog table
`lambda.accumulo.user *`	String	Accumulo username
`lambda.accumulo.password`	String	Accumulo password
`lambda.accumulo.keytab.path`	String	Path to a Kerberos keytab file containing an entry for the specified user
`lambda.kafka.brokers *`	String	A comma separated list of kafka brokers (e.g. `broker1:9092,broker2:9092`)
`lambda.kafka.zookeepers *`	String	A comma separated list of zookeeper servers (e.g. `zoo1,zoo2,zoo3` or `localhost:2181`)
`lambda.kafka.partitions`	Integer	Number of partitions used to create new topics. You should generally set this to the number of writer instances you plan to run
`lambda.kafka.consumers`	Integer	Number of consumers used to load data into the in-memory cache
`lambda.kafka.producer.options`	String	Java-properties-formatted string that is passed directly to the Kafka producer. See Producer Configs
`lambda.kafka.consumer.options`	String	Java-properties-formatted string that is passed directly to the Kafka consumer. See Consumer Configs
`lambda.expiry *`	String	A duration for how long features are kept in memory before being persisted (e.g. `10 minutes`). Using `Inf` will cause the data store to not participate in persisting expired entries
`lambda.persist`	Boolean	Whether expired features should be persisted to Accumulo or just discarded
`geomesa.security.auths`	String	Comma-delimited superset of authorizations that will be used for queries via Accumulo
`geomesa.security.force-empty-auths`	Boolean	Forces authorizations to be empty
`geomesa.security.auth-provider`	String	Class name for an `AuthorizationsProvider` implementation
`geomesa.query.audit`	Boolean	Audit queries being run. Queries will be stored in a `<catalog>_queries` table
`geomesa.query.timeout`	String	The max time a query will be allowed to run before being killed. The timeout is specified as a duration, e.g. `1 minute` or `60 seconds`
`geomesa.query.threads`	Integer	The number of threads to use per query
`geomesa.query.loose-bounding-box`	Boolean	Use loose bounding boxes - queries will be faster but may return extraneous results
`accumulo.query.record-threads`	Integer	The number of threads to use for record retrieval
`accumulo.write.threads`	Integer	The number of threads to use for writing records
`geomesa.stats.enable`	Boolean	Toggle collection of statistics for newly created feature types

Note: one (but not both) of lambda.accumulo.password and lambda.accumulo.keytab.path must be provided.