Loading Precedence of Application.yml, Bootstrap.yml and VM Arguments in Spring Cloud

When you work with microservices, you will work with different property loading sources. Knowing loading precedence of the sources are very important. In this post, i will try to explain the precedence process for different sources.

I have six sources for loading values as below;

My test class and the result that is in console are as below;

We can say;

• servicename-profile.yml files have the highest priority. Because, ‘a’ is present in all files, but the value(5) in test-service-dev.yml file was read.
• servicename.yml files(like test-service.yml) which don’t have “-profile” suffix are ignored. Because, The value ‘b’(3) in application-dev.yml was read instead of the value ‘b’(4) in test-service.yml. instead
• application.yml files have lower priority than application-profile.yml files(like application-dev.yml). Because, The value ‘c(3)’ in application-dev.yml was read instead of the value ‘c(2)’ in application.yml.
• VM arguments has lower priority than application.yml. Because, The value ‘d(2)’ in application.yml was read instead of the value ‘d(1)’ in VM arguments.
• VM arguments has higher priority than bootstrap.yml Because, The value ‘e(0)’ in VM arguments was read instead of the value ‘e(1)’ in bootstrap.yml file. But; when you have values as below, you will see servicename.yml files(like test-service.yml) is higher priority than VM arguments and bootstrap.yml file.

test result in console

• bootstrap.yml has lowest priority. When you don’t have any source, your values in bootstrap is valid (like the value ‘g(1)’ in bootstrap.yml file)

Summary

Order of precedence is servicename-profile.yml > appication-profile.yml > application.yml > servicename.yml > VM arguments > bootstrap.yml