Spring Boot Reactive Mongo Hangs on startup - spring

Question

I have a Spring Boot application that uses reactive Mongo DB drivers that hangs on startup.
Logs:
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.0.1.RELEASE)
2018-05-20 13:45:47.923 DEBUG 26675 --- [ main] s.b.w.r.c.StandardReactiveWebEnvironment : Adding PropertySource 'systemProperties' with lowest search precedence
2018-05-20 13:45:47.924 DEBUG 26675 --- [ main] s.b.w.r.c.StandardReactiveWebEnvironment : Adding PropertySource 'systemEnvironment' with lowest search precedence
2018-05-20 13:45:47.924 DEBUG 26675 --- [ main] s.b.w.r.c.StandardReactiveWebEnvironment : Initialized StandardReactiveWebEnvironment with PropertySources [MapPropertySource {name='systemProperties'}, SystemEnvironmentPropertySource {name='systemEnvironment'}]
2018-05-20 13:45:48.018 INFO 26675 --- [ main] c.a.m.mobsters.MobstersApplication : Starting MobstersApplication on Adrians-iMac.local with PID 26675 (/Users/adrian/IdeaProjects/MobstersREST/backend/target/classes started by adrian in /Users/adrian/IdeaProjects/MobstersREST)
2018-05-20 13:45:48.018 INFO 26675 --- [ main] c.a.m.mobsters.MobstersApplication : The following profiles are active: prod
2018-05-20 13:45:48.018 DEBUG 26675 --- [ main] o.s.boot.SpringApplication : Loading source class com.adrian.mobstersrest.mobsters.MobstersApplication
2018-05-20 13:45:48.092 DEBUG 26675 --- [ main] o.s.b.c.c.ConfigFileApplicationListener : Activated profiles prod
2018-05-20 13:45:48.093 DEBUG 26675 --- [ main] o.s.b.c.c.ConfigFileApplicationListener : Loaded config file 'file:/Users/adrian/IdeaProjects/MobstersREST/backend/target/classes/application.yml' (classpath:/application.yml) for profile prod
2018-05-20 13:45:48.093 DEBUG 26675 --- [ main] o.s.b.c.c.ConfigFileApplicationListener : Loaded config file 'file:/Users/adrian/IdeaProjects/MobstersREST/backend/target/classes/application.yml' (classpath:/application.yml)
2018-05-20 13:45:48.097 INFO 26675 --- [ main] onfigReactiveWebServerApplicationContext : Refreshing org.springframework.boot.web.reactive.context.AnnotationConfigReactiveWebServerApplicationContext#2f9f7dcf: startup date [Sun May 20 13:45:48 EDT 2018]; root of context hierarchy
2018-05-20 13:45:48.098 DEBUG 26675 --- [ main] onfigReactiveWebServerApplicationContext : Bean factory for org.springframework.boot.web.reactive.context.AnnotationConfigReactiveWebServerApplicationContext#2f9f7dcf: org.springframework.beans.factory.support.DefaultListableBeanFactory#2525ff7e: defining beans [org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.event.internalEventListenerProcessor,org.springframework.context.event.internalEventListenerFactory,mobstersApplication]; root of factory hierarchy
2018-05-20 13:45:49.075 DEBUG 26675 --- [ main] o.s.b.a.AutoConfigurationPackages : #EnableAutoConfiguration was declared on a class in the package 'com.adrian.mobstersrest.mobsters'. Automatic #Repository and #Entity scanning is enabled.
2018-05-20 13:45:49.662 DEBUG 26675 --- [ main] onfigReactiveWebServerApplicationContext : Unable to locate MessageSource with name 'messageSource': using default [org.springframework.context.support.DelegatingMessageSource#619bd14c]
2018-05-20 13:45:49.662 DEBUG 26675 --- [ main] onfigReactiveWebServerApplicationContext : Unable to locate ApplicationEventMulticaster with name 'applicationEventMulticaster': using default [org.springframework.context.event.SimpleApplicationEventMulticaster#323e8306]
2018-05-20 13:45:49.969 INFO 26675 --- [ main] s.w.r.r.m.a.RequestMappingHandlerMapping : Mapped "{[/],methods=[GET]}" onto public java.lang.String com.adrian.mobstersrest.mobsters.api.v1.controller.IndexController.index()
2018-05-20 13:45:49.982 INFO 26675 --- [ main] s.w.r.r.m.a.RequestMappingHandlerMapping : Mapped "{[/api/v1/mobsters/{username}/queue],methods=[POST]}" onto public org.reactivestreams.Publisher<java.lang.Void> com.adrian.mobstersrest.mobsters.api.v1.controller.MobsterController.queue(java.lang.String)
2018-05-20 13:45:49.983 INFO 26675 --- [ main] s.w.r.r.m.a.RequestMappingHandlerMapping : Mapped "{[/api/v1/mobsters],methods=[GET]}" onto public reactor.core.publisher.Flux<com.adrian.mobstersrest.mobsters.domain.Mobster> com.adrian.mobstersrest.mobsters.api.v1.controller.MobsterController.getMobsters()
2018-05-20 13:45:49.983 INFO 26675 --- [ main] s.w.r.r.m.a.RequestMappingHandlerMapping : Mapped "{[/api/v1/mobsters],methods=[POST]}" onto public org.reactivestreams.Publisher<java.lang.Void> com.adrian.mobstersrest.mobsters.api.v1.controller.MobsterController.addMobster(org.reactivestreams.Publisher<com.adrian.mobstersrest.mobsters.domain.Mobster>)
2018-05-20 13:45:50.054 INFO 26675 --- [ main] o.s.w.r.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.reactive.resource.ResourceWebHandler]
2018-05-20 13:45:50.055 INFO 26675 --- [ main] o.s.w.r.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.reactive.resource.ResourceWebHandler]
2018-05-20 13:45:50.503 INFO 26675 --- [ main] org.mongodb.driver.cluster : Cluster created with settings {hosts=[ds157599.mlab.com:57599], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}
2018-05-20 13:45:50.830 INFO 26675 --- [ main] org.mongodb.driver.cluster : Cluster created with settings {hosts=[ds157599.mlab.com:57599], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}
2018-05-20 13:45:51.129 INFO 26675 --- [.mlab.com:57599] org.mongodb.driver.connection : Opened connection [connectionId{localValue:1, serverValue:133602}] to ds157599.mlab.com:57599
2018-05-20 13:45:51.161 INFO 26675 --- [.mlab.com:57599] org.mongodb.driver.cluster : Monitor thread successfully connected to server with description ServerDescription{address=ds157599.mlab.com:57599, type=REPLICA_SET_PRIMARY, state=CONNECTED, ok=true, version=ServerVersion{versionList=[3, 4, 14]}, minWireVersion=0, maxWireVersion=5, maxDocumentSize=16777216, logicalSessionTimeoutMinutes=null, roundTripTimeNanos=30750252, setName='rs-ds157599', canonicalAddress=ds157599-a.mlab.com:57599, hosts=[ds157599-a.mlab.com:57599], passives=[], arbiters=[], primary='ds157599-a.mlab.com:57599', tagSet=TagSet{[]}, electionId=7fffffff0000000000000001, setVersion=1, lastWriteDate=Sun May 20 13:45:45 EDT 2018, lastUpdateTimeNanos=67395842952667}
2018-05-20 13:45:51.198 INFO 26675 --- [.mlab.com:57599] org.mongodb.driver.connection : Opened connection [connectionId{localValue:2, serverValue:133603}] to ds157599.mlab.com:57599
2018-05-20 13:45:51.239 INFO 26675 --- [.mlab.com:57599] org.mongodb.driver.cluster : Monitor thread successfully connected to server with description ServerDescription{address=ds157599.mlab.com:57599, type=REPLICA_SET_PRIMARY, state=CONNECTED, ok=true, version=ServerVersion{versionList=[3, 4, 14]}, minWireVersion=0, maxWireVersion=5, maxDocumentSize=16777216, logicalSessionTimeoutMinutes=null, roundTripTimeNanos=41193458, setName='rs-ds157599', canonicalAddress=ds157599-a.mlab.com:57599, hosts=[ds157599-a.mlab.com:57599], passives=[], arbiters=[], primary='ds157599-a.mlab.com:57599', tagSet=TagSet{[]}, electionId=7fffffff0000000000000001, setVersion=1, lastWriteDate=Sun May 20 13:45:45 EDT 2018, lastUpdateTimeNanos=67395921620843}
2018-05-20 13:45:51.456 INFO 26675 --- [ main] o.s.b.a.e.web.EndpointLinksResolver : Exposing 2 endpoint(s) beneath base path '/actuator'
2018-05-20 13:45:51.467 INFO 26675 --- [ main] .b.a.e.w.r.WebFluxEndpointHandlerMapping : Mapped "{[/actuator/health],methods=[GET],produces=[application/vnd.spring-boot.actuator.v2+json || application/json]}" onto public org.reactivestreams.Publisher<org.springframework.http.ResponseEntity<java.lang.Object>> org.springframework.boot.actuate.endpoint.web.reactive.AbstractWebFluxEndpointHandlerMapping$ReadOperationHandler.handle(org.springframework.web.server.ServerWebExchange)
2018-05-20 13:45:51.468 INFO 26675 --- [ main] .b.a.e.w.r.WebFluxEndpointHandlerMapping : Mapped "{[/actuator/info],methods=[GET],produces=[application/vnd.spring-boot.actuator.v2+json || application/json]}" onto public org.reactivestreams.Publisher<org.springframework.http.ResponseEntity<java.lang.Object>> org.springframework.boot.actuate.endpoint.web.reactive.AbstractWebFluxEndpointHandlerMapping$ReadOperationHandler.handle(org.springframework.web.server.ServerWebExchange)
2018-05-20 13:45:51.469 INFO 26675 --- [ main] .b.a.e.w.r.WebFluxEndpointHandlerMapping : Mapped "{[/actuator],methods=[GET],produces=[application/vnd.spring-boot.actuator.v2+json || application/json]}" onto protected java.util.Map<java.lang.String, java.util.Map<java.lang.String, org.springframework.boot.actuate.endpoint.web.Link>> org.springframework.boot.actuate.endpoint.web.reactive.WebFluxEndpointHandlerMapping.links(org.springframework.web.server.ServerWebExchange)
2018-05-20 13:45:51.562 INFO 26675 --- [ main] o.s.w.r.r.m.a.ControllerMethodResolver : Looking for #ControllerAdvice: org.springframework.boot.web.reactive.context.AnnotationConfigReactiveWebServerApplicationContext#2f9f7dcf: startup date [Sun May 20 13:45:48 EDT 2018]; root of context hierarchy
2018-05-20 13:45:52.538 INFO 26675 --- [ntLoopGroup-2-2] org.mongodb.driver.connection : Opened connection [connectionId{localValue:3, serverValue:133604}] to ds157599.mlab.com:57599
My reactive Mongo configuration:
package com.adrian.mobstersrest.mobsters.config;
import com.mongodb.ConnectionString;
import com.mongodb.reactivestreams.client.MongoClient;
import com.mongodb.reactivestreams.client.MongoClients;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration;
import org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration;
import org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.DependsOn;
import org.springframework.data.mongodb.config.AbstractReactiveMongoConfiguration;
import org.springframework.data.mongodb.core.mapping.event.LoggingEventListener;
import org.springframework.data.mongodb.repository.config.EnableReactiveMongoRepositories;
#SpringBootApplication(exclude = {MongoAutoConfiguration.class, MongoDataAutoConfiguration.class})
#EnableReactiveMongoRepositories
#AutoConfigureAfter(EmbeddedMongoAutoConfiguration.class)
public class MongoConfig extends AbstractReactiveMongoConfiguration {
#Value("${spring.data.mongodb.uri}")
private String uri;
#Override
#Bean
#DependsOn("embeddedMongoServer")
public MongoClient reactiveMongoClient() {
return MongoClients.create(new ConnectionString(uri));
}
#Override
protected String getDatabaseName() {
return "mobsters";
}
#Bean
public LoggingEventListener mongoEventListener() {
return new LoggingEventListener();
}
}
It looks like mongo is hanging according to the logs, it just sits at Opened connection, but never says that my application has been initialized.
This also happens when connecting to a local instance of Mongo ran in a Docker container.

Answer 1

It seems like you should not be using #SpringBootApplication in this class.
You should have a "main" class with a main method that already has #SpringBootApplication and you can add the exclusions there, you shouldn't have more than one #SpringBootApplication in your project. After doing that just delete that annotation from
the MongoConfig class.
#EnableReactiveMongoRepositories
#AutoConfigureAfter(EmbeddedMongoAutoConfiguration.class)
public class MongoConfig extends AbstractReactiveMongoConfiguration {
Edit: i just now noticed that this was posted more than 2 years ago..............