Spring Boot: Make property non-configurable

Question

In Spring Boot I have several options to externalize my configuration. However, how can I make such properties non-configurable, i.e. readonly.

Concretly, I want to set server.tomcat.max-threads to a fixed value and do not want somebody who is going to start the application to have the ability to change it. This could easily be done by passing it as a command line argument for instance.

It's probably not possible by default, maybe someone could suggest workarounds?

Answer 1

You have 2 options

1. Set System.setProperty("prop", "value") Property hard coded

2. Use properties that will override all other properties

3. Set system property hard coded

       public static void main(String[] args) {
         System.setProperty("server.tomcat.max-threads","200");
         SpringApplication.run(DemoApplication.class, args);
       }
   

4. Properties in secure.properties will override all others (see, Prevent overriding some property in application.properties - Spring Boot)

   @Configuration
   public class SecurePropertiesConfig {
   
   @Autowired
   private ConfigurableEnvironment env;
   
   @Autowired
   public void setConfigurableEnvironment(ConfigurableEnvironment env) {
     try {
       final Resource resource = new 
       ClassPathResource("secure.properties");
       env.getPropertySources().addFirst(new 
           PropertiesPropertySource(resource.getFilename(), 
           PropertiesLoaderUtils.loadProperties(resource)));
     } catch (Exception ex) {
       throw new RuntimeException(ex.getMessage(), ex);
     }
   }