Micronaut 5

r2d1-micronaut conditionally creates the framework-neutral R2D1 bean from Micronaut-managed resources. It does not add Micronaut APIs to the base r2d1 artifact.

Dependency and runtime

implementation("dev.nexcraft:r2d1-micronaut:<version>")

Micronaut 5 and this integration currently require Java 25. The core and JDBC artifacts remain compiled for Java 21. For a JDBC index, add r2d1-jdbc and the application-selected JDBC driver; the Micronaut module does not add a pool or driver transitively.

Enable the integration

The integration is disabled unless r2d1.enabled=true. It creates R2D1 eagerly, so incomplete configuration fails during application startup.

r2d1:
  enabled: true
  index:
    type: jdbc
  jdbc:
    datasource: default
    execution-mode: platform-thread
    max-concurrency: 4
    max-pending: 64

datasources:
  default:
    url: jdbc:h2:file:./data/r2d1

The index backend is jdbc or d1 when no application IndexStore bean exists. A single or @Primary DataSource is selected when r2d1.jdbc.datasource is omitted; multiple candidates require an exact bean name.

Cloudflare configuration

The owned-client path uses the same adapter configuration as the framework-neutral API:

r2d1:
  enabled: true
  index:
    type: d1
  r2:
    endpoint: https://<account-id>.r2.cloudflarestorage.com
    access-key-id: ${R2_ACCESS_KEY_ID}
    secret-access-key: ${R2_SECRET_ACCESS_KEY}
    bucket-name: documents
    region: auto
  d1:
    account-id: ${CLOUDFLARE_ACCOUNT_ID}
    database-id: ${CLOUDFLARE_D1_DATABASE_ID}
    api-token: ${CLOUDFLARE_D1_API_TOKEN}

Secret-bearing configuration objects redact values from toString(). If the application supplies a unique or @Primary S3AsyncClient or Java HttpClient, the integration borrows it and does not close it. Otherwise it creates and closes the adapter resource it owns.

JDBC ownership and execution

r2d1.jdbc.executor can name an application-owned Executor. Micronaut wraps it with bounded admission and never shuts it down. Do not configure execution-mode alongside an external executor. Without an external executor, the integration owns and closes JdbcExecution.

The integration never starts or closes a DataSource, connection pool, or database server. A remote H2 URL and an embedded H2 URL use the same R2D1 wiring; the DataSource determines the endpoint.

Overrides and native images

Application beans take precedence over integration-created resources in this order:

1. R2D1
2. R2D1.CollectionFactory
3. DocumentStore, IndexStore, DocumentCodec, and the collection initializer

The verified native smoke path is Micronaut ApplicationContext with the H2 JDBC backend. Document types used in a native image require explicit reflection registration, for example with @ReflectiveAccess. R2 and D1 native runtime execution is not currently a verified support path.

This module does not provide Micronaut Data repositories, HTTP endpoints, metrics, tracing, Spring compatibility, R2DBC, retry policy, or database-server lifecycle management.