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Table of Contents

Micronaut Cassandra

Provides integration between Micronaut and Cassandra

Version:

1 Introduction

The micronaut-cassandra module includes support for integrating Micronaut services with Cassandra.

2 Release History

For this project, you can find a list of releases (with release notes) here:

https://github.com/micronaut-projects/micronaut-cassandra/releases

3 Setting up Cassandra

Using the CLI

If you are creating your project using the Micronaut CLI, supply the cassandra feature to include Cassandra configuration in your project:

$ mn create-app my-app --features cassandra

To enable the Cassandra configuration, add the following dependency to your application:

implementation("io.micronaut.cassandra:micronaut-cassandra:5.1.1")
<dependency>
    <groupId>io.micronaut.cassandra</groupId>
    <artifactId>micronaut-cassandra</artifactId>
    <version>5.1.1</version>
</dependency>

Micronaut supports Cassandra configuration by using the Datastax Java Driver. Configuration values can be supplied a property source such as below. The property name is derived from the builder methods in CqlSessionBuilder. Micronaut will create a CqlSession bean. This bean can be then injected into any other Micronaut bean.

Supply Single Configuration
cassandra:
  default:
    advanced:
      metadata:
        schema:
          enabled: false
    basic:
      contact-points:
        - "127.0.0.1:9042"
        - "127.0.0.2:8042"
      load-balancing-policy:
        local-datacenter: datacenter1

Multiple Cluster instances can be configured as follows:

Supply Multiple Configuration
cassandra:
  default:
    advanced:
      metadata:
        schema:
          enabled: false
    basic:
      contact-points:
        - "127.0.0.1:9042"
      load-balancing-policy:
        local-datacenter: datacenter1
  secondary:
    advanced:
      metadata:
        schema:
          enabled: false
    basic:
      contact-points:
        - "127.0.0.1:9043"
      load-balancing-policy:
        local-datacenter: datacenter2

4 Health Checks

When the cassandra module is activated a CassandraHealthIndicator is activated resulting in the /health endpoint and CurrentHealthStatus interface resolving the health of the Cassandra cluster.

"cassandra": {
  "status": "UP",
  "details": {
    "session": "OPEN",
    "cluster_name": "Test Cluster",
    "nodes_count": 1,
    "nodes_state": {
      "UP": 1
    }
    "nodes (10 max.)": {
      "4a9e6e53-7eed-4c1f-b497-4f93715b2b04": {
        "endpoint": "localhost/0:0:0:0:0:0:0:1:32834",
        "broadcast_address": "/172.17.0.3",
        "state": "UP",
        "distance": "LOCAL",
        "open_connections": "2",
        "cassandra_version": "3.11.2",
        "datacenter": "datacenter1",
        "rack": "rack1",
        "uptime_ms": "1593462452206",
        "is_reconnecting": "false"
      }
    }
  }
}
To disable the Cassandra health indicator entirely, add endpoints.health.cassandra.enabled: false.

See the section on the Health Endpoint for more information.

5 Additional Notes

The Datastax Cassandra driver is configured using lightbend/config under the field datastax-java-driver.\*.

The equivalent bean created for micronaut is mapped under the cassandra... fields provided in your application.conf, but the bean will fallback on the datastax-java-driver.\* values if they are present.

These config values are provided to the CqlSession under the hood. Datastax does not provide a class that maps to all the various possible config keys, but a full list of values that can be provided can be found in the DefaultDriverOption enum.

datastax configuration under lightbend/config - application.conf
datastax-java-driver {
    basic {
        contact-points = [ "1.2.3.4:9042", "5.6.7.8:9042" ]
        load-balancing-policy.local-datacenter = datacenter1
    }
}
micronaut bean configuration - application.yml
cassandra:
  default:
    basic:
      contact-points:
        - "127.0.0.1:9042"
        - "5.6.7.8:9042"
      load-balancing-policy:
        local-datacenter: datacenter1

6 GraalVM support

Micronaut Cassandra is compatible with GraalVM so it is possible to create native images without any additional configuration.

See the section on GraalVM in the user guide for more information.

7 Repository

You can find the source code of this project in this repository:

https://github.com/micronaut-projects/micronaut-cassandra