Tomcat 应用程序部署在 Docker 上：可以连接到 Postgres，但新数据未显示在数据库中

Question

I have deployed a Tomcat app to Docker (using Windows) and in my terminal it shows that it connected to the database:

PostgreSQL init process complete; ready for start up.
app-db_1   |
app-db_1   | LOG:  database system was shut down at 2021-04-25 19:15:05 UTC
app-db_1   | LOG:  MultiXact member wraparound protections are now enabled
app-db_1   | LOG:  autovacuum launcher started
app-db_1   | LOG:  database system is ready to accept connections

The app uses JPA with Hibernate. I already have a database on my host and we interact nicely when we are not on Docker. I call persist on an entity and there is no exception thrown. And otherwise behavior is expected. But when I run a SELECT * FROM users; in pgAdmin, the new entity does not appear in the database.

Here is docker-compose:

app-web:
  build: .
  ports:
    - "8080:8080"
  links:
    - app-db


app-db:
  build: ./db
  expose:
    - "5432"

app-db-data:
  image: cogniteev/echo
  command: echo 'Data Container for PostgreSQL'
  volumes:
    - /var/lib/postgresql/data

I have also tried having as volumes postgres_data:/var/lib/postgresql/data/ without having app-db-data but I was getting the same result.

This is Dockerfile for web app:

FROM tomcat:10.0.5-jdk8-openjdk
MAINTAINER test

EXPOSE 8080

RUN rm -rf /usr/local/tomcat/webapps/*

COPY ./target/timetraveling-microservice-1.0-SNAPSHOT.war /usr/local/tomcat/webapps/ROOT.war

CMD ["catalina.sh","run"]

And in persistence.xml I have:

...
<property name="hibernate.connection.url" value="jdbc:postgresql://app-db:5432/my-database" />
...
<property name="hibernate.hbm2ddl.auto" value="update" />
...

And the Dockerfile for the database is

FROM postgres:latest
MAINTAINER test

ENV POSTGRES_USER user
ENV POSTGRES_PASSWORD password
ENV POSTGRES_DB my-database

I didn't find many resources online to help me because they use Spring and I am not allowed to use Spring. I am obviously new to Docker:( So why does the persisting work fine without throwing exceptions, but the actual data doesn't show up in the database I kindly created for my web app?

EDIT:

When I run docker ps:

CONTAINER ID   IMAGE                                COMMAND                  CREATED          STATUS          PORTS                    NAMES
4a67709429b6   timetraveling-microservice_app-web   "catalina.sh run"        32 minutes ago   Up 32 minutes   0.0.0.0:8080->8080/tcp   timetraveling-microservice_app-web_1
74f1c1d1cc40   timetraveling-microservice_app-db    "docker-entrypoint.s…"   32 minutes ago   Up 32 minutes   5432/tcp                 timetraveling-microservice_app-db_1

Answer 1

pg-admin doesnt have any access to the docker private network in which containers run and communicate. If you want to be able to access app-db you should use ports: -5432:5432 in ur docker-compose for that ( expose doesnt publish ports in latest versions of docker and is used for informative purposes about the image).

app-db:
  build: ./db
  ports:
    - 5432:5432

for reference https://docs.docker.com/compose/networking/