Docker Compose + Spring Boot + Postgres connection

问题:

I have a Java Spring Boot app which works with a Postgres database. I want to use Docker for both of them. I initially put just the Postgres in Docker, and I had a docker-compose.yml file defined like this:

version: '2' services:     db:         container_name: sample_db         image: postgres:9.5         volumes:             - sample_db:/var/lib/postgresql/data         environment:             - POSTGRES_PASSWORD=sample             - POSTGRES_USER=sample             - POSTGRES_DB=sample             - PGDATA=/var/lib/postgresql/data/pgdata         ports:             - 5432:5432  volumes:     sample_db: {} 

Then, when I issued the commands sudo dockerd and sudo docker-compose -f docker-compose.yml up, it was starting the database. I could connect using pgAdmin for example, by using localhost as server and port 5432. Then, in my Spring Boot app, inside the application.properties file I defined the following properties.

spring.datasource.url=jdbc:postgresql://localhost:5432/sample spring.datasource.username=sample spring.datasource.password=sample spring.jpa.generate-ddl=true 

At this point I could run my Spring Boot app locally through Spring Suite, and it all was working fine. Then, I wanted to also add my Spring Boot app as Docker image. I first of all created a Dockerfile in my project directory, which looks like this:

FROM java:8 EXPOSE 8080 ADD /target/manager.jar manager.jar ENTRYPOINT ["java","-jar","manager.jar"] 

Then, I entered to the directory of the project issued mvn clean followed by mvn install. Next, issued docker build -f Dockerfile -t manager . followed by docker tag 9c6b1e3f1d5e myuser/manager:latest (the id is correct). Finally, I edited my existing docker-compose.yml file to look like this:

version: '2' services:     web:       image: myuser/manager:latest       ports:            - 8080:8080       depends_on:           - db     db:         container_name: sample_db         image: postgres:9.5         volumes:             - sample_db:/var/lib/postgresql/data         environment:             - POSTGRES_PASSWORD=sample             - POSTGRES_USER=sample             - POSTGRES_DB=sample             - PGDATA=/var/lib/postgresql/data/pgdata         ports:             - 5432:5432  volumes:     sample_db: {} 

But, now if I issue sudo docker-compose -f docker-compose.yml up command, the database again starts correctly, but I get errors and exit code 1 for the web app part. The problem is the connection string. I believe I have to change it to something else, but I don't know what it should be. I get the following error messages:

web_1  | 2017-06-27 22:11:54.418 ERROR 1 --- [           main] o.a.tomcat.jdbc.pool.ConnectionPool      : Unable to create initial connections of pool. web_1  |  web_1  | org.postgresql.util.PSQLException: Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections 

Any ideas?

回答1:

Each container has its own network interface with its own localhost. So change how Java points to Postgres:

spring.datasource.url=jdbc:postgresql://localhost:5432/sample 

To:

spring.datasource.url=jdbc:postgresql://db:5432/sample 

db will resolve to the proper Postgres IP.

---

Bonus. With docker-compose you don't need to build your image by hand. So change:

web:   image: myuser/manager:latest 

To:

web:   build: . 

文章来源: Docker Compose + Spring Boot + Postgres connection