22.3. Using the Lambda Data Store Programmatically

22.3.1. 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.id", "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.data.DataStore dataStore = org.geotools.data.DataStoreFinder.getDataStore(parameters);

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

22.3.2. Lambda Data Store Parameters

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

Parameter

Type

Description

lambda.accumulo.instance.id *

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 New 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.generate

Boolean

Toggle collection of statistics for newly created feature types

geomesa.query.caching

Boolean

Toggle caching of results

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