Execution resources and lifecycle

Isolate WebClient resources from the server

AbstractWebClientConfig creates dedicated LoopResources, ReactorResourceFactory, ReactorClientHttpConnector, ExchangeStrategies, and WebClient beans. isUseGlobalResources = false separates the client from global Reactor resources used by a server or another client.

@Configuration
class PartnerWebClientConfig : AbstractWebClientConfig() {
    override val threadCount: Int = 8
    override val connectTimeoutMillis: Int = 2_000
    override val shutdownTimeout: Duration = Duration.ofSeconds(10)
    override val maxInMemorySize: Int = 4 * 1024 * 1024
}

Isolation reduces shared failure impact but consumes additional threads and direct memory. Use separate loops at boundaries with a clear traffic or isolation requirement.

Timeouts and SSL

The response timeout defaults to PT30S and can be changed with bluetape4k.webclient.response-timeout. Override the subclass property for connect timeout.

The default sslContext() validates server certificates using the JDK trust store. insecureSslContext() trusts every certificate and belongs only in development or tests. Connect private CAs through a custom trust store and SslContext in production.

Codec memory limit

exchangeStrategies() changes only the default codec maxInMemorySize, which defaults to 16 MiB. It is a limit for what codecs aggregate in memory, not a total size limit for every streaming payload. Consider streaming or payload design before increasing it for large JSON or multipart data.

Controller coroutine scopes

AbstractCoroutineDefaultController, AbstractCoroutineIOController, and AbstractCoroutineVTController create separate CoroutineScope instances with SupervisorJob. Their @PreDestroy method cancels the job when the Spring bean is destroyed.

These scopes are not children of the request coroutine. Request cancellation and Reactor or Spring Security context do not follow automatically. Run request-lifetime work in the current suspend context, and hand longer work to an explicitly owned application service scope.

Virtual-thread configuration

VirtualThreadAutoConfiguration registers a virtual-thread-enabled SimpleAsyncTaskExecutor only when no AsyncTaskExecutor bean exists.

@Import(VirtualThreadAutoConfiguration::class)
class AsyncConfiguration

There is no auto-configuration imports metadata, so @Import is required. @ConditionalOnMissingBean makes the configuration back off when the application already owns an executor.

AbstractVirtualThreadController.virtualThreadExecutor is a process-wide companion object created by newVirtualThreadPerTaskExecutor(). The class has no close hook. Prefer an application-owned executor bean when shutdown control matters.

Source and tests

• AbstractWebClientConfig.kt
• AbstractCoroutineDefaultController.kt
• AbstractCoroutineIOController.kt
• AbstractCoroutineVTController.kt
• VirtualThreadAutoConfiguration.kt
• AbstractVirtualThreadController.kt
• CustomWebClientConfigTest.kt

Next chapter

Testing and ecosystem paths maps focused test anchors and the next modules to study.