Using env variable in Spring Boot's application.properties

Question

We are working on a Spring Boot web app and the database we are using is MySql;

• the setup we have is we first test it locally (means we need to instal MySql on our PC);

• then we push to Bitbucket;

• Jenkins automatically detects the new push to Bitbucket and does a build on it (for Jenkins mvn build to pass we also need to install MySql on the virtual machines that is running Jenkins).

• if Jenkins build passes we push the code to our application on OpenShift (using the Openshift deployment plugin on Jenkins).

The problem we have as you may have already figured it out is that:

• in application.properties we can not hard code the MySql info. Since our project will be running in 3 different places (local, Jenkins, and OpenShift) we need to make the datasource field dynamic in application.properties (we know there are different way's of doing it but we are working on this solution for now).

  spring.datasource.url = 
  spring.datasource.username = 
  spring.datasource.password = 
  

The solution we came up with is we create system environment variables locally and in the Jenkins vm (naming them the same way OpenShift names them) and assigning them the right values respectively:

export OPENSHIFT_MYSQL_DB_HOST="jdbc:mysql://localhost"
export OPENSHIFT_MYSQL_DB_PORT="3306"
export OPENSHIFT_MYSQL_DB_USERNAME="root"
export OPENSHIFT_MYSQL_DB_PASSWORD="123asd"

We have done this and it works. We have also checked with Map<String, String> env = System.getenv(); that the environment variables can be made into java variables as such:

String password = env.get("OPENSHIFT_MYSQL_DB_PASSWORD");   
String userName = env.get("OPENSHIFT_MYSQL_DB_USERNAME");   
String sqlURL = env.get("OPENSHIFT_MYSQL_DB_HOST"); 
String sqlPort = env.get("OPENSHIFT_MYSQL_DB_PORT");

Now the only thing left is we need to use these java variables in our application.properties and that is what we are having trouble with.

In which folder, and how, do we need to assign the password, userName, sqlURL, and sqlPort variables for application.properties to be able to see them and how do we include them in application.properties?

We have tried many things one of them being:

spring.datasource.url = ${sqlURL}:${sqlPort}/"nameofDB"
spring.datasource.username = ${userName}
spring.datasource.password = ${password}

No luck so far. We are probably not putting these env variables in the right class/folder or are using them incorrectly in application.properties.

Your help is highly appreciated!!

Thanks!

Answer 1

You don't need to use java variables. To include system env variables add the following to your application.properties file:

spring.datasource.url = ${OPENSHIFT_MYSQL_DB_HOST}:${OPENSHIFT_MYSQL_DB_PORT}/"nameofDB"
spring.datasource.username = ${OPENSHIFT_MYSQL_DB_USERNAME}
spring.datasource.password = ${OPENSHIFT_MYSQL_DB_PASSWORD}

But the way suggested by @Stefan Isele is more preferable, because in this case you have to declare just one env variable: spring.profiles.active. Spring will read the appropriate property file automatically by application-{profile-name}.properties template.