Spring boot + MySQL. Docker - mysql

Question

I`m create simple app on spring boot + MySQL. On local pc it works correctly, but when i package it in docker, i catch some errors: container with DB works well, i can connect to it via workbanch, the container with the application crashes on startup with an error:
"java.sql.SQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
...
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure
...
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
...
Caused by: java.net.ConnectException: Connection refused
..."
My Dockerfile:
FROM openjdk:17-alpine
ADD /target/tests-0.0.1-SNAPSHOT.jar backend.jar
ENTRYPOINT ["java", "-jar", "backend.jar"]
My docker-compose.yml:
version: '3'
services:
personsdb:
image: 'mysql:8.0.31'
container_name: 'persons-db'
environment:
- 'MYSQL_ROOT_PASSWORD=Qwer'
- 'MYSQL_DATABASE=persons'
- 'MYSQL_USER=mysql'
- 'MYSQL_PASSWORD=Qwer'
ports:
- '3305:3306'
app:
container_name: 'persons-app'
ports:
- 8088:8080
environment:
SPRING_DATASOURCE_URL: jdbc:mysql://personsdb:3305/persons?autoReconnect=true&useSSL=false
depends_on:
- 'personsdb'
build: ./
My application.properties:
spring.jpa.hibernate.ddl-auto=update
spring.datasource.url=jdbc:mysql://personsdb:3305/persons
spring.datasource.username=root
spring.datasource.password=Qwer
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
I tried to
run: docker-compose down --rmi all
rename service
upgrade MySQL Connector
add more dependences to pom.xml
...

Answer 1

It seems you have to create a bridge to let them communicate.
Please check the link below
https://www.tutorialworks.com/container-networking/
when they are in the same host, below configuration also worked for me.
datasource:
driver-class-name: org.postgresql.Driver
url: jdbc:postgresql://host.docker.internal:5432/DB-NAME