Deploy mysql during build from Dockerfile - mysql

Question

I am building an application which has parent and child dependency and to build of my application which is the final stage of build i need to connect to mysql for it during build stage itself.
In this i am getting the error:
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
I have mentioned my docker file code i am using and for mysql i have pulled image from dockerhub following instructions from below link:
https://dev.mysql.com/doc/mysql-installation-excerpt/5.5/en/docker-mysql-getting-started.html
And i was planning to run this as a separate container using bridge to communicate with my above container using below command:
docker run -d -name app-container-name --link mysql-container-name app-image-name
FROM maven:3.5.4-jdk-8 as maven
COPY ZP ZP
COPY CommonApp CommonApp
RUN cd ZP && mvn clean install
RUN cd CommonApp && mvn clean install package -U && mvn install:install-file -Dfile=/CommonApp/target/commonapp-0.0.1-SNAPSHOT.jar -DgroupId=com.z -DartifactId=commonapp -Dversion=0.0.1-SNAPSHOT -Dpackaging=jar;
FROM mysql:5.7
# ROOT PASSWORD
ENV MYSQL_ROOT_PASSWORD=root
ENV MYSQL_USER=root
ENV MYSQL_PASSWORD=root
ENV MYSQL_DATA_DIR=/var/lib/mysql \
MYSQL_RUN_DIR=/run/mysqld \
MYSQL_LOG_DIR=/var/log/mysql
RUN /etc/init.d/mysql start && \
mysql -u root -p$MYSQL_ROOT_PASSWORD -e "GRANT ALL PRIVILEGES ON *.* TO 'root'#'%' IDENTIFIED BY 'root';FLUSH PRIVILEGES;"
#PORT
EXPOSE 3306
FROM maven:3.5.4-jdk-8
COPY ZCApp ZCApp
RUN cd ZCApp && mvn clean package -U
How should i approach this problem. How can i build mysql along with the application itself using dockerfile.?

Answer 1

Had the same issue when built maven project. What makes this different from similar requests is that here you don't link two running containers but instead you link docker daemon, preforming build process, to running container.
For Docker to get access to database during build you have to expose ports of database. Using --link will have no effect because it links containers (and you dont have second container at the moment) and btw is considered as obsolete technique.
You have to explicitly start database container before build process and somehow expose its ports for docker daemon to access them.
Option 1 - using host networking.
First start database:
docker run -d --network=host mysql
Then build:
docker built -t foo .
Docker will see database on localhost during build process because database uses host's network and doesn't need any port exposion.
Option 2 - Expose ports
First start database:
docker run -d -p 3306:3306 mysql
Then build:
docker built -t foo .
Docker will again see database on localhost during build process because port is exposed.
What you have to double check is your connection string in mvn. It has to use localhost and default tcp port 3306