spring - Spring Boot creating multiple (functioning) webmvc applications using auto configuration

Question

Updated

My question is how do I initialise an isolated spring webmvc web-app in spring boot. The isolated Web application should:

1. Should not initialise itself in the application class. We want to do these in a starter pom via auto configuration. We have multiple such web-apps and we need the flexibility of auto configuration.
2. Have the ability to customise itself using interfaces like: WebSecurityConfigurer (we have multiple web-apps, each does security in its own way) and EmbeddedServletContainerCustomizer (to set the context path of the servlet).
3. We need to isolate beans specific to certain web-apps and do not want them to enter the parent context.

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Progress

The configuration class below is listed in my META-INF/spring.factories.

The following strategy does not lead to a functioning web-mvc servlet. The context path is not set and neither is the security customised. My hunch is that I need to include certain webmvc beans that process the context and auto configure based on what beans are present -- similar to how I got boot based property placeholder configuration working by including PropertySourcesPlaceholderConfigurer.class.

@Configuration
@AutoConfigureAfter(DaoServicesConfiguration.class)
public class MyServletConfiguration {
    @Autowired
    ApplicationContext parentApplicationContext;

    @Bean
    public ServletRegistrationBean myApi() {
        AnnotationConfigWebApplicationContext applicationContext = new AnnotationConfigWebApplicationContext();
        applicationContext.setParent(parentApplicationContext);
        applicationContext.register(PropertySourcesPlaceholderConfigurer.class);
        // a few more classes registered. These classes cannot be added to 
        // the parent application context.
        // includes implementations of 
        //   WebSecurityConfigurerAdapter
        //   EmbeddedServletContainerCustomizer

        applicationContext.scan(
                // a few packages
        );

        DispatcherServlet ds = new DispatcherServlet();
        ds.setApplicationContext(applicationContext);

        ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean(ds, true, "/my_api/*");
        servletRegistrationBean.setName("my_api");
        servletRegistrationBean.setLoadOnStartup(1);
        return servletRegistrationBean;
    }
}

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