Why is Spring #ConstructorBinding not binding for Kotlin #ConfigurationProperties class? - spring

Question

I have a Spring auto configuration library I'm developer for Swagger. It's written in Kotlin using Spring Boot 2.2.6.
My main auto configuration is defined as:
package io.opengood.autoconfig.swagger
import org.apache.commons.lang3.StringUtils
import org.slf4j.LoggerFactory.getLogger
import org.springframework.boot.autoconfigure.condition.ConditionalOnExpression
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty
import org.springframework.boot.context.properties.EnableConfigurationProperties
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import springfox.documentation.builders.AuthorizationCodeGrantBuilder
import springfox.documentation.builders.OAuthBuilder
import springfox.documentation.builders.PathSelectors
import springfox.documentation.service.*
import springfox.documentation.spi.DocumentationType
import springfox.documentation.spi.service.contexts.SecurityContext
import springfox.documentation.spring.web.plugins.Docket
import springfox.documentation.swagger.web.SecurityConfiguration
import springfox.documentation.swagger.web.SecurityConfigurationBuilder
import springfox.documentation.swagger2.annotations.EnableSwagger2
import java.time.LocalDate
import java.time.LocalDateTime
import java.time.LocalTime
import java.sql.Date as SqlDate
import java.sql.Time as SqlTime
import java.util.Date as UtilDate
#Configuration
#ConditionalOnProperty("swagger.enabled")
#EnableConfigurationProperties(value = [SwaggerProperties::class, OAuth2Properties::class])
#EnableSwagger2
class SwaggerAutoConfiguration(
val swaggerProperties: SwaggerProperties = SwaggerProperties(),
val swaggerVersion: SwaggerVersion = DefaultSwaggerVersion(),
val oAuth2Properties: OAuth2Properties = OAuth2Properties()
) {
val paths = swaggerProperties.paths
.takeIf { !it.isNullOrEmpty() }
.let { it?.joinToString(",") } ?: SwaggerProperties.DEFAULT_PATH
val version = swaggerVersion.version
.takeIf { it.isNotBlank() } ?: swaggerProperties.version
val authUri = oAuth2Properties.resource.authorizationServerUri
.takeIf { it.isNotBlank() } ?: OAuth2Properties.DEFAULT_AUTH_URI
val tokenUri = oAuth2Properties.tokenUri
.takeIf { it.isNotBlank() } ?: OAuth2Properties.DEFAULT_TOKEN_URI
#Bean
fun productApi(): Docket {
log.info("Setup Swagger product configuration")
val productApi = Docket(DocumentationType.SWAGGER_2)
.groupName(swaggerProperties.groupName)
.directModelSubstitute(LocalDateTime::class.java, UtilDate::class.java)
.directModelSubstitute(LocalDate::class.java, SqlDate::class.java)
.directModelSubstitute(LocalTime::class.java, SqlTime::class.java)
.apiInfo(apiInfo())
.select()
.paths(PathSelectors.regex(paths))
.build()
if (oAuth2Properties.enabled && !authUri.contains("localhost")) {
productApi.securitySchemes(listOf(securitySchemes()))
productApi.securityContexts(listOf(securityContext()))
}
return productApi
}
#Bean
fun apiInfo(): ApiInfo {
log.info("Setup Swagger API configuration")
return ApiInfo(
swaggerProperties.title,
swaggerProperties.description,
version,
swaggerProperties.termsOfServiceUrl,
Contact(
swaggerProperties.contact.name,
swaggerProperties.contact.url,
swaggerProperties.contact.email),
swaggerProperties.license.type,
swaggerProperties.license.url,
listOf())
}
#Bean
#ConditionalOnProperty("swagger.security.oauth2.enabled")
fun securityInfo(): SecurityConfiguration {
log.info("Setup Swagger security configuration")
return if (OAuth2Properties.GrantType.CLIENT_CREDENTIALS == oAuth2Properties.grantType) {
SecurityConfigurationBuilder.builder()
.clientId(StringUtils.EMPTY)
.clientSecret(StringUtils.EMPTY)
.scopeSeparator(" ")
.build()
} else {
SecurityConfigurationBuilder.builder()
.useBasicAuthenticationWithAccessCodeGrant(true)
.build()
}
}
private fun securitySchemes(): SecurityScheme {
return if (OAuth2Properties.GrantType.CLIENT_CREDENTIALS == oAuth2Properties.grantType) {
OAuthBuilder()
.name(SECURITY_REFERENCE_NAME)
.grantTypes(listOf(ClientCredentialsGrant(authUri)))
.scopes(scopes())
.build()
} else {
OAuthBuilder()
.name(SECURITY_REFERENCE_NAME)
.grantTypes(listOf(AuthorizationCodeGrantBuilder()
.tokenEndpoint(TokenEndpoint(tokenUri, TOKEN_NAME))
.tokenRequestEndpoint(TokenRequestEndpoint(authUri, "", ""))
.build()))
.scopes(scopes())
.build()
}
}
private fun securityContext(): SecurityContext {
return SecurityContext.builder()
.securityReferences(listOf(SecurityReference(SECURITY_REFERENCE_NAME, scopes().toTypedArray())))
.forPaths(PathSelectors.regex(paths))
.build()
}
private fun scopes(): List<AuthorizationScope> {
return oAuth2Properties.client.scopes
.takeIf { it.isNotEmpty() }
.let { it?.values?.map { s -> AuthorizationScope(s, "") } }
?: emptyList()
}
companion object {
const val SECURITY_REFERENCE_NAME = "spring_oauth2"
const val TOKEN_NAME = "oauth2_token"
#Suppress("JAVA_CLASS_ON_COMPANION")
#JvmStatic
private val log = getLogger(javaClass.enclosingClass)
}
}
I have several classes, see main one below, that are injected into the above class as beans using #ConfigurationProperties. I wanted to use the new #ConstructorBinding to remove the ugly lateint var from my main auto config class.
package io.opengood.autoconfig.swagger
import org.springframework.boot.context.properties.ConfigurationProperties
import org.springframework.boot.context.properties.ConstructorBinding
#ConfigurationProperties(prefix = "swagger")
#ConstructorBinding
data class SwaggerProperties(
val enabled: Boolean = true,
val groupName: String = "",
val paths: List<String> = listOf(DEFAULT_PATH),
val title: String = "",
val description: String = "",
val version: String = "",
val termsOfServiceUrl: String = "",
val contact: Contact = Contact(),
val license: License = License()
) {
#ConstructorBinding
data class Contact(
val name: String = "",
val url: String = "",
val email: String = ""
)
#ConstructorBinding
data class License(
val type: String = "",
val url: String = ""
)
companion object {
const val DEFAULT_PATH = ".*"
}
}
Source code is stored in my GitHub repo at https://github.com/opengoodio/swagger-auto-configuration.
The main auto config project is under lib/src/main/kotlin/io/opengood/autoconfig/swagger.
I have another project test-app that has a test class test-app/src/test/kotlin/io/opengood/autoconfig/swagger/app called AccessSwaggerTest:
package io.opengood.autoconfig.swagger.app
import org.junit.jupiter.api.Test
import org.junit.jupiter.api.extension.ExtendWith
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc
import org.springframework.boot.test.context.SpringBootTest
import org.springframework.test.context.junit.jupiter.SpringExtension
import org.springframework.test.web.servlet.MockMvc
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get
import org.springframework.test.web.servlet.result.MockMvcResultMatchers.status
#SpringBootTest(classes = [SwaggerTestApplication::class])
#ExtendWith(SpringExtension::class)
#AutoConfigureMockMvc
class AccessSwaggerTest {
#Autowired
lateinit var mockMvc: MockMvc
#Test
fun `swagger UI endpoint is accessible`() {
mockMvc.perform(get("/swagger-ui.html"))
.andExpect(status().is2xxSuccessful)
.andReturn();
}
#Test
fun `swagger API docs endpoint is accessible`() {
mockMvc.perform(get("/v2/api-docs?group=test-group"))
.andExpect(status().is2xxSuccessful)
.andReturn();
}
}
If you run the first test, it fails with:
java.lang.IllegalStateException: Failed to load ApplicationContext
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:132)
at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:123)
at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:190)
at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:132)
at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:244)
at org.springframework.test.context.junit.jupiter.SpringExtension.postProcessTestInstance(SpringExtension.java:98)
at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeTestInstancePostProcessors$5(ClassBasedTestDescriptor.java:337)
at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.executeAndMaskThrowable(ClassBasedTestDescriptor.java:342)
at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeTestInstancePostProcessors$6(ClassBasedTestDescriptor.java:337)
at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1654)
at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
at java.base/java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining(StreamSpliterators.java:312)
at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:735)
at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:734)
at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:658)
at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.invokeTestInstancePostProcessors(ClassBasedTestDescriptor.java:336)
at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.instantiateAndPostProcessTestInstance(ClassBasedTestDescriptor.java:259)
at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$testInstancesProvider$2(ClassBasedTestDescriptor.java:252)
at java.base/java.util.Optional.orElseGet(Optional.java:369)
at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$testInstancesProvider$3(ClassBasedTestDescriptor.java:251)
at org.junit.jupiter.engine.execution.TestInstancesProvider.getTestInstances(TestInstancesProvider.java:29)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$prepare$0(TestMethodTestDescriptor.java:106)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.prepare(TestMethodTestDescriptor.java:105)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.prepare(TestMethodTestDescriptor.java:69)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$prepare$1(NodeTestTask.java:107)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.prepare(NodeTestTask.java:107)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:75)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:229)
at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute$6(DefaultLauncher.java:197)
at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:211)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:191)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:128)
at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:69)
at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'io.opengood.autoconfig.swagger.OAuth2Properties': #EnableConfigurationProperties or #ConfigurationPropertiesScan must be used to add #ConstructorBinding type io.opengood.autoconfig.swagger.OAuth2Properties
at org.springframework.boot.context.properties.ConfigurationPropertiesBeanDefinitionValidator.validate(ConfigurationPropertiesBeanDefinitionValidator.java:66)
at org.springframework.boot.context.properties.ConfigurationPropertiesBeanDefinitionValidator.postProcessBeanFactory(ConfigurationPropertiesBeanDefinitionValidator.java:45)
at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:286)
at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:174)
at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:706)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:532)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:315)
at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:126)
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99)
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124)
... 63 more
If I boot run the simple app, it fails with a similar error.
The main auto config has #EnableConfigurationProperties(value = [SwaggerProperties::class, OAuth2Properties::class]) as the error suggests but still fails. I tried the #ConfigurationPropertiesScan on the test-app main class but same error.
I have searched for solutions over the past few months and cannot find a solid reason why this is occurring.
What is causing the #ConstructorBinding to not bind correctly?

Answer 1

My guess is: Your #SpringBootApplication annotated class is in package io.opengood.autoconfig.swagger.app and it scans for components in this package an all sub-packages. Your configuration file in the lib is in package io.opengood.autoconfig.swagger and therefore it might not be scanned. So you have two options:
Change package of your #SpringBootApplication annotated class
Add scanBasePackages to #SpringBootApplication, i.e. #SpringBootApplication(scanBasePackages = {"io.opengood.autoconfig.swagger", io.opengood.autoconfig.swagger.app})