feat: property-driven template composition for Spring Boot and Ktor

[zantvoort]

Motivation

A default application should not need Storm's core SPI. The starters auto-configure one ORMTemplate for a single-candidate DataSource; an application that defines its own template beans — for several data sources, or a single one whose composition it customizes — backed that off and hand-composed everything, importing ExceptionMapper, QueryObserver and SqlCommenter to wire by hand exactly what the starter wires from properties. The Ktor plugin had the mirrored gaps: OTel semantic conventions required constructing and registering a convention instance (one product for every database), and applying a template decorator meant composing a second template outside the plugin — which the plugin's repositories never used.

Spring Boot: OrmTemplateFactory

@Bean
fun orderTemplate(factory: OrmTemplateFactory) = factory.create(orderDataSource, "orders") {
    decorator { it.withTableNameResolver(...) }
}

Each created template carries the property-driven integration of the auto-configured one: Spring connection/transaction providers, SQL failure translation per storm.exception-translation.enabled with the mapper created against the template's own data source, observations per storm.observations.* with conventions resolved from the template's own JDBC URL and the template named as the low-cardinality storm.database key value, and the trace commenter per storm.tracing.sql-comments. The trailing block applies application-specific composition after the integration; the single-candidate condition moves from the auto-configuration class to the template bean, so the factory exists exactly where the single template backs off.

Ktor: configuration parity

• storm.observations.semanticConventions = otel selects the OTel conventions from configuration, resolved per database from its own data source, overridable under storm.databases.<name>.observations.semanticConventions, validated at installation. A convention registered in the dependency container keeps taking precedence.
• A customize slot on the plugin and per database block applies composition such as a template decorator after the integration is wired, inheriting the plugin-level block unless the database sets its own.

Shared composition

Observer composition lives in the new QueryObservers in storm-micrometer; storm-spring's StormQueryObservers and the Ktor plugin both delegate to it, so the stacks resolve conventions and the storm.database identity identically and cannot drift.

Documentation

spring-integration.md gains a Composing Your Own Templates section; ktor-integration.md's decorator section goes through customize and its observability section leads with the configuration key; configuration.md lists the Ktor key. All observation and factory docs describe storm.database as naming the template the observation came from, written from the composition's perspective rather than any application shape.

Testing

Both starters' StormAutoConfigurationTest cover the factory (single template backs off, distinct templates per data source, customize runs); StormObservabilityTest covers the configured conventions resolving from the database's own data source and customize composing after (and overriding) the wired integration. Full sweeps over storm-micrometer, storm-spring, storm-ktor, storm-ktor-test, both starters and the @DataStormTest parity slice pass.

[codecov]

Codecov Report

❌ Patch coverage is 79.31034% with 24 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...pring/boot/autoconfigure/StormAutoConfiguration.kt	65.51%	7 Missing and 3 partials ⚠️
storm-ktor/src/main/kotlin/st/orm/ktor/Storm.kt	86.66%	0 Missing and 4 partials ⚠️
...ing/boot/autoconfigure/StormAutoConfiguration.java	84.00%	2 Missing and 2 partials ⚠️
...rc/main/java/st/orm/micrometer/QueryObservers.java	87.50%	1 Missing and 1 partial ⚠️
.../spring/boot/autoconfigure/OrmTemplateFactory.java	50.00%	2 Missing ⚠️
...rm/spring/boot/autoconfigure/OrmTemplateFactory.kt	66.66%	1 Missing ⚠️
...n/java/st/orm/spring/boot/StormQueryObservers.java	66.66%	0 Missing and 1 partial ⚠️

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