Setting up swagger documentation for a multi-module micro-service spring boot application

Question

Before I go to my main question, Is it possible to setup a swagger documentation for the entire project (all micro-services)?

At the moment I have a multi-module spring-boot application and I want to configure swagger documentation that handles all sub-modules (micros-services). What I have done so far is, I have created another module to handle the swagger documentation.

The swagger module contains two classes; code is shown below. Swagger Config

@Configuration
@EnableSwagger2
public class SwaggerConfig {
    @Bean
    public Docket api(){
        return new Docket(DocumentationType.SWAGGER_2)
                .apiInfo(apiInfo())
                .select()
                .apis(RequestHandlerSelectors.any())
                .paths(PathSelectors.regex("/api.*"))
                .build();
    }

    private ApiInfo  apiInfo(){
        return new ApiInfoBuilder().title("API")
                .build();
    }
}

SwaggerService

@SpringBootApplication
public class SwaggerService {
    public static void main(String[] args) {
        SpringApplication.run(SwaggerService.class, args);
    }
}

This does compile anyways, I get the following messages

2020-05-22 12:15:42.719  INFO 29248 --- [           main] service.SwaggerService             : No active profile set, falling back to default profiles: default
2020-05-22 12:15:43.226 ERROR 29248 --- [           main] o.s.boot.SpringApplication               : Application run failed

java.lang.IllegalStateException: Error processing condition on org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration.propertySourcesPlaceholderConfigurer
    at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:60) ~[spring-boot-autoconfigure-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.context.annotation.ConditionEvaluator.shouldSkip(ConditionEvaluator.java:108) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForBeanMethod(ConfigurationClassBeanDefinitionReader.java:184) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:144) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitions(ConfigurationClassBeanDefinitionReader.java:120) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:331) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:236) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:280) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:96) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:706) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:532) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at service.SwaggerService.main(SwaggerService.java:14) ~[classes/:na]
Caused by: java.lang.IllegalStateException: Failed to introspect Class [springfox.documentation.swagger2.configuration.Swagger2DocumentationConfiguration] from ClassLoader [jdk.internal.loader.ClassLoaders$AppClassLoader@368239c8]
    at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:481) ~[spring-core-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:358) ~[spring-core-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.util.ReflectionUtils.getUniqueDeclaredMethods(ReflectionUtils.java:414) ~[spring-core-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.lambda$getTypeForFactoryMethod$2(AbstractAutowireCapableBeanFactory.java:743) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1705) ~[na:na]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getTypeForFactoryMethod(AbstractAutowireCapableBeanFactory.java:742) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineTargetType(AbstractAutowireCapableBeanFactory.java:681) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:649) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1608) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doGetBeanNamesForType(DefaultListableBeanFactory.java:526) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:497) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.boot.autoconfigure.condition.OnBeanCondition.collectBeanNamesForType(OnBeanCondition.java:230) ~[spring-boot-autoconfigure-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.OnBeanCondition.getBeanNamesForType(OnBeanCondition.java:223) ~[spring-boot-autoconfigure-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.OnBeanCondition.getBeanNamesForType(OnBeanCondition.java:213) ~[spring-boot-autoconfigure-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.OnBeanCondition.getMatchingBeans(OnBeanCondition.java:167) ~[spring-boot-autoconfigure-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.OnBeanCondition.getMatchOutcome(OnBeanCondition.java:142) ~[spring-boot-autoconfigure-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:47) ~[spring-boot-autoconfigure-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    ... 17 common frames omitted
Caused by: java.lang.NoClassDefFoundError: org/springframework/web/servlet/HandlerMapping
    at java.base/java.lang.Class.getDeclaredMethods0(Native Method) ~[na:na]
    at java.base/java.lang.Class.privateGetDeclaredMethods(Class.java:3167) ~[na:na]
    at java.base/java.lang.Class.getDeclaredMethods(Class.java:2310) ~[na:na]
    at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:463) ~[spring-core-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    ... 33 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.springframework.web.servlet.HandlerMapping
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:583) ~[na:na]
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178) ~[na:na]
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) ~[na:na]
    ... 37 common frames omitted

2020-05-22 12:15:43.228  WARN 29248 --- [           main] o.s.boot.SpringApplication               : Unable to close ApplicationContext

java.lang.IllegalStateException: Failed to introspect Class [springfox.documentation.swagger2.configuration.Swagger2DocumentationConfiguration] from ClassLoader [jdk.internal.loader.ClassLoaders$AppClassLoader@368239c8]
    at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:481) ~[spring-core-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:358) ~[spring-core-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.util.ReflectionUtils.getUniqueDeclaredMethods(ReflectionUtils.java:414) ~[spring-core-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.lambda$getTypeForFactoryMethod$2(AbstractAutowireCapableBeanFactory.java:743) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1705) ~[na:na]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getTypeForFactoryMethod(AbstractAutowireCapableBeanFactory.java:742) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineTargetType(AbstractAutowireCapableBeanFactory.java:681) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:649) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1608) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doGetBeanNamesForType(DefaultListableBeanFactory.java:526) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:497) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType(DefaultListableBeanFactory.java:619) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType(DefaultListableBeanFactory.java:611) ~[spring-beans-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.getBeansOfType(AbstractApplicationContext.java:1242) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    at org.springframework.boot.SpringApplication.getExitCodeFromMappedException(SpringApplication.java:869) ~[spring-boot-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.SpringApplication.getExitCodeFromException(SpringApplication.java:857) ~[spring-boot-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.SpringApplication.handleExitCode(SpringApplication.java:844) ~[spring-boot-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.SpringApplication.handleRunFailure(SpringApplication.java:795) ~[spring-boot-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:325) ~[spring-boot-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.7.RELEASE.jar:2.2.7.RELEASE]
    at service.SwaggerService.main(SwaggerService.java:14) ~[classes/:na]
Caused by: java.lang.NoClassDefFoundError: org/springframework/web/servlet/HandlerMapping
    at java.base/java.lang.Class.getDeclaredMethods0(Native Method) ~[na:na]
    at java.base/java.lang.Class.privateGetDeclaredMethods(Class.java:3167) ~[na:na]
    at java.base/java.lang.Class.getDeclaredMethods(Class.java:2310) ~[na:na]
    at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:463) ~[spring-core-5.2.6.RELEASE.jar:5.2.6.RELEASE]
    ... 21 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.springframework.web.servlet.HandlerMapping
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:583) ~[na:na]
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178) ~[na:na]
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) ~[na:na]
    ... 25 common frames omitted

I'm pretty sure there is more to be done.

Answer 1

Use the below swagger dependencies to your pom.xml

https://mvnrepository.com/artifact/io.springfox/springfox-swagger2/2.6.1 https://mvnrepository.com/artifact/io.springfox/springfox-swagger-ui/2.6.1

Add annotation @EnableSwagger2 in your main Class (containing main method and annotated with @SpringBootApplication ).

Run the application. If 8080 is your port, then swagger docs will be available on localhost:8080/swagger-ui.html

Answer 2

This might be causing an issue

java.lang.ClassNotFoundException: org.springframework.web.servlet.HandlerMapping 

There was a bug reported with springfox bug in springfox

You can have a look at it, might helps you. I don't know if it has already been resolved with latest release. SO you can try with latest release versions.

To answer your multi-module micro service, Not sure what do you mean all micro services. All micro services would have their own swagger documentation, This is what microServices stands for, breaking services in to smaller, manageable services. If you are clubbing things together to make a large application, then you are deviating what MS stands for. All the controllers of your micro services will support the same swagger documentations as long as they are under single SpringBootApplication.

By multi modules, if you mean to say that you're developing a REST API with other dependent modules(Libraries), then you don't need swagger in libs as Libraries might provide merely plain java APIs(methods) with no spring feature in it.

Take a look spring multi module application