Environment Post-Processor API Reference

/**
 * Environment post-processor activating profiles based on @EnableAgents annotation.
 * Runs early in Spring Boot startup (HIGHEST_PRECEDENCE).
 * Registered via META-INF/spring.factories.
 */
public class EnvironmentPostProcessor
    implements org.springframework.boot.env.EnvironmentPostProcessor,
               org.springframework.core.Ordered {

    /**
     * Property key for logging theme.
     * Value: "embabel.agent.logging.personality"
     */
    public static final String LOGGING_THEME_PROPERTY =
        "embabel.agent.logging.personality";

    /**
     * Processes environment to set properties from @EnableAgents annotation.
     *
     * @param environment Spring environment to modify
     * @param application Spring application (source of annotation)
     */
    void postProcessEnvironment(ConfigurableEnvironment environment,
                                SpringApplication application);

    /**
     * Returns HIGHEST_PRECEDENCE for earliest execution.
     */
    int getOrder();
}

org.springframework.boot.env.EnvironmentPostProcessor=\
  com.embabel.agent.config.annotation.spi.EnvironmentPostProcessor

// Pseudocode
public void postProcessEnvironment(ConfigurableEnvironment env,
                                  SpringApplication app) {
    // Find @EnableAgents
    EnableAgents annotation = findAnnotation(app);

    // Extract theme
    String theme = annotation != null ? annotation.loggingTheme() : "";

    // Set property if not empty
    if (!theme.isEmpty()) {
        env.getPropertySources().addFirst(
            new MapPropertySource("loggingThemeSource",
                Map.of(LOGGING_THEME_PROPERTY, theme))
        );
    }
}

Spring Boot Startup:
1. SpringApplication constructor
2. Prepare environment
3. → EnvironmentPostProcessor.postProcessEnvironment() [HIGHEST_PRECEDENCE]
4. Other EnvironmentPostProcessors
5. Load application context
6. Create beans
7. Application ready

// Static initialization (pseudocode)
static {
    if (IS_WINDOWS) {
        configureUTF8Console();
        setupOptimalFont();
    }
}

interface ConfigurableEnvironment {
    MutablePropertySources getPropertySources();
    void addActiveProfile(String profile);
}

interface SpringApplication {
    Set<Object> getAllSources();
}

interface Ordered {
    int HIGHEST_PRECEDENCE = Integer.MIN_VALUE;
    int getOrder();
}

class MapPropertySource extends PropertySource<Map<String, Object>> {
    MapPropertySource(String name, Map<String, Object> source);
}

@EnableAgents(loggingTheme = "starwars")
public class App { }

// After post-processing:
// Property "embabel.agent.logging.personality" = "starwars"

@Value("${embabel.agent.logging.personality:}")
private String theme;

@Configuration
@ConditionalOnProperty(
    name = "embabel.agent.logging.personality",
    havingValue = "starwars"
)
public class StarWarsConfig { }