Springboot mongo docker-compose fail to connect - spring

Question

My docker-compose.yml is as shown
version: '3'
services:
backend-service:
image: 'storio-360-service:v1.0'
build: .
container_name: storio-360-service
ports:
- 8090:8080
depends_on:
- db_mongo
links:
- db_mongo
db_mongo:
image: 'mongo'
container_name: db_mongo
ports:
- 27018:27017
volumes:
- /home/bob/Bob/data:/data/db
restart: always
My Dockerfile is
FROM openjdk:8u111-jdk-alpine
VOLUME /tmp
ADD /target/backend-service-1.0.1-SNAPSHOT.jar app.jar
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
CMD curl "db_mongo:27018"
Because of this set up, my repository in my spring has this code
#Repository
public class WatcherRepository {
private MongoOperations mongoOps;
#Autowired
public WatcherRepository() {
String myHost = "db_mongo";
this.mongoOps = new MongoTemplate(new SimpleMongoDbFactory(new MongoClient(myHost), MongoConstant.DATABASE_NAME));
}
// Other code to access the mongo db
}
However, when i run docker-compose up --build,
I get the following when Spring boot is starting up,
02:24:55.871 [main] INFO org.mongodb.driver.cluster - Cluster created with settings {hosts=[localhost:27017], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}
storio-360-service | 02:24:55.923 [cluster-ClusterId{value='5d3faa779470450001317225', description='null'}-localhost:27017] INFO org.mongodb.driver.cluster - Exception in monitor thread while connecting to server localhost:27017
storio-360-service | com.mongodb.MongoSocketOpenException: Exception opening socket
storio-360-service | at com.mongodb.connection.SocketStream.open(SocketStream.java:62)
storio-360-service | at com.mongodb.connection.InternalStreamConnection.open(InternalStreamConnection.java:126)
storio-360-service | at com.mongodb.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:114)
storio-360-service | at java.lang.Thread.run(Thread.java:745)
storio-360-service | Caused by: java.net.ConnectException: Connection refused (Connection refused)
storio-360-service | at java.net.PlainSocketImpl.socketConnect(Native Method)
storio-360-service | at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
storio-360-service | at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
storio-360-service | at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
storio-360-service | at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
storio-360-service | at java.net.Socket.connect(Socket.java:589)
storio-360-service | at com.mongodb.connection.SocketStreamHelper.initialize(SocketStreamHelper.java:59)
storio-360-service | at com.mongodb.connection.SocketStream.open(SocketStream.java:57)
storio-360-service | ... 3 common frames omitted
storio-360-service | 02:24:56.060 [main] INFO org.mongodb.driver.cluster - Cluster created with settings {hosts=[127.0.0.1:27017], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500
Then Spring boot will shown that it is waiting for calls as it sets up successfully.
02:34:39.274 [main] INFO o.d.i.i.storio.service.Service - Started Service in 5.353 seconds (JVM running for 6.085)
However, when i make the api call which will call the mongodb, it shows me the error
Timed out after 30000 ms while waiting to connect. Client view of cluster state is {type=UNKNOWN, servers=[{address=127.0.0.1:27017, type=UNKNOWN, state=CONNECTING, exception={com.mongodb.MongoSocketOpenException: Exception opening socket}, caused by {java.net.ConnectException: Connection refused (Connection refused)}}]; nested exception is com.mongodb.MongoTimeoutException: Timed out after 30000 ms while waiting to connect. Client view of cluster state is {type=UNKNOWN, servers=[{address=127.0.0.1:27017, type=UNKNOWN, state=CONNECTING, exception={com.mongodb.MongoSocketOpenException: Exception opening socket}, caused by {java.net.ConnectException: Connection refused (Connection refused)}}]
I am new to Docker and it is clear that my springboot cannot access mongo. What am i doing wrong in my Dockerfile or docker-compose? thanks

Answer 1

Looks like you are forwarding your mongodb port to 27018
- 27018:27017
and you haven't specified 27018 in Spring config.
Hence Spring boot by default tries to connect to 27017
Solution:
Either remove the port forwarding, or update Spring Boot config to use mongo at 27018
Update:
Here are some Spring Boot's mongo auto configuration tips for the OP.
Have dependency on a mongodb starter for spring boot
<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-data-mongodb -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-mongodb</artifactId>
<version>2.1.6.RELEASE</version>
</dependency>
Provide Mongo DB details in application properties.
spring.data.mongodb.database= # Database name.
spring.data.mongodb.host= # Mongo server host. Cannot be set with URI.
spring.data.mongodb.password= # Login password of the mongo server. Cannot be set with URI.
spring.data.mongodb.port= # Mongo server port. Cannot be set with URI.
spring.data.mongodb.username= # Login user of the mongo server. Cannot be set with URI
(Here the OP needs to specify his mongodb host and port)
Now, the only thing left is to autowire MongoTemplate, where ever you want to use.
#Autowired
private MongoTemplate mongoTemplate;