Issue
I have to change my custom defined spring properties (defined via @ConfigurationProperties beans) during runtime of my Spring Boot application.
Is there any elegant way of doing this using Spring Cloud Config?
I don't want to use an external application.properties in a git repository (as the spring boot application gets shipped to customers and I dont' want to create a git repository for everyone of them).
I just want to access and change the local application.properties (the one in the classpath, located in src/main/resources) file in my Spring container or (if thats not possible) in the Spring Cloud Config Server, which I could embed into my Spring Boot app. Is that possible somehow?
BTW: The goal is to create a visual editor for the customers, so that they can change the application.properties during runtime in their spring boot app.
Solution
It actually is possible and in the end quite easy to achieve. It just took me a whole day to get all the information together. Maybe this helps someone:
You basically just need Spring Actuator, but for a certain endpoint, you also need the spring cloud dependency. (to make Post requests to the /env endpoint of Spring Actuator)
To alter your config at runtime, just add the following to your application.properties:
management.endpoints.web.exposure.include: env,refresh
management.endpoint.env.post.enabled: true //this property is only available when spring cloud is added as dependency to your project
If you (like me) don't need the feature of an externalized config, then you also have to add the following (otherwise, your Spring app will not start and throw an error that some config is missing)
spring.cloud.config.enabled: false
Now, if you send a POST request to /actuator/env endpoint with an object in the HTTP body in the form of {"name":"...", "value":"..."} (name is the name of a config property), then your config gets changed. To check that, you can do a GET request to /actuator/env/[name_of_config_property] and see that your config property has changed. No need to restart your app.
Don't forget to secure the /actuator endpoint in your SecurityConfig if you use a custom one.
It seems to me that you neither need the @RefreshScope annotation at your config classes nor the /actuator/refresh endpoint to "apply" the config changes.
Answered By - Wallnussfolie
