将 Spring 引导容器连接到 Mongo 容器：java.net.UnknownHostException：mongo：系统错误？

Question

I have created a simple Spring Boot Rest Application that I have dockerized and is working as expected when I use mongo locally.

However I have now tried to use Docker Compose to run a Mongo container to connect to rather than my local host.

Docker-compose up -d works but when I try to hit my endpoint that queries Monogo I get:

Caused by: java.net.UnknownHostException: mongo: System error
    at java.base/java.net.Inet4AddressImpl.lookupAllHostAddr(Native Method) ~[na:na]
    at java.base/java.net.InetAddress$PlatformNameService.lookupAllHostAddr(Unknown Source) ~[na:na]
    at java.base/java.net.InetAddress.getAddressesFromNameService(Unknown Source) ~[na:na]
    at java.base/java.net.InetAddress$NameServiceAddresses.get(Unknown Source) ~[na:na]
    at java.base/java.net.InetAddress.getAllByName0(Unknown Source) ~[na:na]
    at java.base/java.net.InetAddress.getAllByName(Unknown Source) ~[na:na]
    at java.base/java.net.InetAddress.getAllByName(Unknown Source) ~[na:na]
    at com.mongodb.ServerAddress.getSocketAddresses(ServerAddress.java:203) ~[mongodb-driver-core-3.11.2.jar!/:na]

In my application.properties file I have:

spring.data.mongodb.uri=mongodb://mongo:27017/pokerStats

My Docker file for my spring boot app (called pokerStats):

#
FROM adoptopenjdk/openjdk11:alpine-jre

#
ARG JAR_FILE=/build/libs/pokerStats-0.0.1-SNAPSHOT.jar

#
WORKDIR /opt/app

#
COPY ${JAR_FILE} app.jar

#
ENTRYPOINT ["java","-jar","app.jar"]

My docker-compose.yml file:

version: "3"
services:
  pokerStats:
    image: pokerStats
    ports:
      - 8080:8080
    depends_on: 
      - db
  db:
    image: mongo
    volumes:
      - ./database:/data
    ports:
      - "27017:27017"

Answer 1

The properties file specifies the host mongo , but containers are discoverable via the container name, which is db .

Either the properties need to be changed to use the right name or the container name changed to what the properties file expects.