Spring WebFlux with OpenApi /Swagger Specification (Code Generation) File not Found - spring-webflux

Question

I already have the generated code in my spring webflux project, but when a run, its throw me an exception that "openapi.yaml" file does not exists. I searched this file and he is in the resource folder of the generated project(generated by openapi). As you can see, HomeController get this file with the classpath:/openapi.yaml in the Resource attribute declaration.
I'm just making this question because this is an error of a generated class, and i dont know if this should happen or not.
The resource declaration
#Value("classpath:/openapi.yaml")
private Resource openapi;
HomeController class
package org.openapitools.configuration;
import com.fasterxml.jackson.dataformat.yaml.YAMLMapper;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.core.io.Resource;
import org.springframework.stereotype.Controller;
import org.springframework.util.StreamUtils;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.reactive.function.server.RouterFunction;
import org.springframework.web.reactive.function.server.ServerResponse;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.nio.charset.Charset;
import static org.springframework.web.reactive.function.server.RequestPredicates.GET;
import static org.springframework.web.reactive.function.server.RouterFunctions.route;
/**
* Home redirection to OpenAPI api documentation
*/
#Controller
public class HomeController {
private static YAMLMapper yamlMapper = new YAMLMapper();
#Value("classpath:/openapi.yaml")
private Resource openapi;
#Bean
public String openapiContent() throws IOException {
try(InputStream is = openapi.getInputStream()) {
return StreamUtils.copyToString(is, Charset.defaultCharset());
}
}
#GetMapping(value = "/openapi.yaml", produces = "application/vnd.oai.openapi")
#ResponseBody
public String openapiYaml() throws IOException {
return openapiContent();
}
#GetMapping(value = "/openapi.json", produces = "application/json")
#ResponseBody
public Object openapiJson() throws IOException {
return yamlMapper.readValue(openapiContent(), Object.class);
}
#Bean
RouterFunction<ServerResponse> index() {
return route(
GET("/"),
req -> ServerResponse.temporaryRedirect(URI.create("swagger-ui/index.html?url=../openapi.json")).build()
);
}
}
The error recivied.
Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2020-10-16 00:23:12.728 ERROR 30601 --- [ main] o.s.boot.SpringApplication : Application run failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'openapiContent' defined in class path resource [org/openapitools/configuration/HomeController.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [java.lang.String]: Factory method 'openapiContent' threw exception; nested exception is java.io.FileNotFoundException: class path resource [openapi.yaml] cannot be opened because it does not exist
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:655) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:483) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1336) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1176) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:556) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:897) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:879) ~[spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:551) ~[spring-context-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.boot.web.reactive.context.ReactiveWebServerApplicationContext.refresh(ReactiveWebServerApplicationContext.java:62) ~[spring-boot-2.3.4.RELEASE.jar:2.3.4.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:758) ~[spring-boot-2.3.4.RELEASE.jar:2.3.4.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:750) ~[spring-boot-2.3.4.RELEASE.jar:2.3.4.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.3.4.RELEASE.jar:2.3.4.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.3.4.RELEASE.jar:2.3.4.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1237) ~[spring-boot-2.3.4.RELEASE.jar:2.3.4.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.3.4.RELEASE.jar:2.3.4.RELEASE]
at com.gabriel.forum.ForumApplication.main(ForumApplication.java:10) ~[main/:na]
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [java.lang.String]: Factory method 'openapiContent' threw exception; nested exception is java.io.FileNotFoundException: class path resource [openapi.yaml] cannot be opened because it does not exist
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [java.lang.String]: Factory method 'openapiContent' threw exception; nested exception is java.io.FileNotFoundException: class path resource [openapi.yaml] cannot be opened because it does not exist
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:650) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
... 20 common frames omitted
Caused by: java.io.FileNotFoundException: class path resource [openapi.yaml] cannot be opened because it does not exist
Caused by: java.io.FileNotFoundException: class path resource [openapi.yaml] cannot be opened because it does not exist
at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:180) ~[spring-core-5.2.9.RELEASE.jar:5.2.9.RELEASE]
at org.openapitools.configuration.HomeController.openapiContent(HomeController.java:36) ~[main/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.2.9.RELEASE.jar:5.2.9.RELEASE]
... 21 common frames omitted
> Task :ForumApplication.main() FAILED
Execution failed for task ':ForumApplication.main()'.
> Process 'command '/usr/lib/jvm/java-1.11.0-openjdk-amd64/bin/java'' finished with non-zero exit value 1
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
The resource folder and the project structure.

Answer 1

I found a solution.
Just add a config option in your build.gralde or pom.xml "interfaceOnly": "true".
That configuration will generate only the interfaces and classes that you declared in the inputSpec file, and the HomeController will no longer exists to seek the openapi.yml file.
That solution is only for spring webflux projects.
Heres is the config options in gradle syntax:
configOptions = [
dateLibrary: "java8",
reactive: "true",
"interfaceOnly": "true"
]
Maven syntax:
<configOptions>
<reactive>true</reactive>
<java8>true</java8>
<interfaceOnly>true</interfaceOnly>
</configOptions>