dropwizard-cassandra

Provides easy integration for Dropwizard applications with the Datastax Cassandra java driver..

This bundle comes with out-of-the-box support for:

• YAML-based configuration and built-in strongly typed configuration validation
• Cluster connection lifecycle management
• Cluster health checks
• Metrics integration for Cassandra driver stats using your applications MetricRegistry

Future improvements

• Schema migrations functionality, similar to what flyway and liquibase offer for SQL databases.

Dropwizard Version Support Matrix

dropwizard-cassandra	Dropwizard v1.3.x	Dropwizard v2.0.x	Dropwizard v2.1.x	Dropwizard v3.0.x	Dropwizard v4.0.x
v1.3.x	✅	✅	✅	❌	❌
v1.4.x	✅	✅	✅	❌	❌
v2.0.x	❓	✅	✅	❌	❌
v3.0.x	❌	❌	❌	✅	❌
v4.0.x	❌	❌	❌	❌	✅

Usage

Add dependency on library.

Maven:

<dependency>
  <groupId>io.dropwizard.modules</groupId>
  <artifactId>dropwizard-cassandra</artifactId>
  <version>4.0.0</version>
</dependency>

Gradle:

compile "io.dropwizard.modules:dropwizard-cassandra:4.0.0"

Usage

Minimal

cassandra:
  type: basic
  contactPoints:
    - host: localhost
      port: 9041
  loadBalancingPolicy:
    type: default
    localDataCenter: DC1

Comprehensive

cassandra:
  type: basic
  sessionName: name
  sessionKeyspaceName: keyspace
  requestOptionsFactory:
    requestTimeout:5s
    requestConsistency: local
    requestPageSize: 12
    requestSerialConsistency: local
    requestDefaultIdempotence: true
  metricsEnabled: true
  protocolVersion:
    type: default
    version: V5
  ssl:
    type: default
    cipherSuites: ["a", "b"]
    hostValidation: true
    keyStorePassword: keyStorePassword
    keyStorePath: keyStorePath
    trustStorePassword: trustStorePassword
    trustStorePath: trustStorePath
  compression: lz4
  contactPoints:
    - host: localhost
      port: 9041
  authProvider:
    type: plain-text
    username: admin
    password: hunter2
  retryPolicy:
    type: default
  speculativeExecutionPolicy:
    type: constant
    delay: 1s
    maxSpeculativeExecutions: 3
  poolingOptions:
    maxRequestsPerConnection: 5
    maxRemoteConnections: 10
    maxLocalConnections: 20
    heartbeatInterval: 5s
    connectionConnectTimeout: 10s
  addressTranslator:
    type: ec2-multi-region
  timestampGenerator:
    type: atomic
  reconnectionPolicyFactory:
    type: exponential
    baseConnectionDelay: 10s
    maxReconnectionDelay: 30s
  loadBalancingPolicy:
    type: default
    localDataCenter: local
    dataCenterFailoverAllowLocalConsistencyLevels: true
    slowAvoidance: true
    dcFailoverMaxNodesPerRemoteDc: 2
  cassandraOptions: # to add options which are not supported by default. Full list can be found at https://docs.datastax.com/en/developer/java-driver/4.11/manual/core/
    - type: long
      name: advanced.protocol.max-frame-length
      value: 12
  sessionMetrics:
    - continuous-cql-requests
  nodeMetrics:
    - bytes-sent
  schema:
    agreementIntervalMilliseconds: 200
    agreementTimeoutSeconds: 10
    agreementWarnOnFailure: true

Note on Multi-Environment Configuration

If you have different contact points per deployment environment your application runs in, it may be easier to avoid having to define multiple YAML files per environment by inserting a placeholder in your YAML file that you then override in each environment (via whatever means you normally override config values, whether that's properties, environment variables, or whatever else), and then override that placeholder with a single entry JSON string defining all contact points, to avoid having to deal with YAML lists.

contactPoints: [${commaSeparatedContactPoints}]

commaSeparatedContactPoints = {"host": "host1", "port": "9142"}, {"host": "host2", "port": "9142"}

Acknowledgements

This library was originally built to extend https://github.com/composable-systems/dropwizard-cassandra, but was forked due to some needs that were unmet (for instance, being able to define different CassandraFactory implementations, if a modified client is used), and due to lack of maintenance. Big thanks to @stuartgunter for his module, which inspired this one heavily, and for which this module borrows a lot of ideas and code.