Beans, injection and lifecycle

@component, @service, and @configuration mark classes. @bean marks a module function or a configuration instance method; factories are synchronous and need a concrete return type.

from pythonboot import bean, configuration, service, autowired, postconstruct, ondestroy

@service(name="mailService", qualifiers=("notification",), primary=True)
class MailService:
    @postconstruct
    async def connect(self): ...
    @ondestroy
    async def disconnect(self): ...

@configuration
class Infra:
    @bean(name="clock")
    def clock(self) -> Clock: return SystemClock()

@service
class NoticeService:
    mail: MailService = autowired(qualifier="notification")
    clock: Clock = autowired()

All component declarations take name=None, init_method=None, destroy_method=None, lazy=False, scope="singleton", primary=False, qualifiers=(), and depends_on=(). A singleton is application-cached; a prototype is created per lookup, is not eagerly created, and is not automatically destroyed.

autowired() attribute injection is recommended. Constructor arguments require type annotations and remain supported for compatibility. Candidates are filtered by name/qualifier, then a unique primary is selected. Use Annotated[Type, autowired(name="...")] for constructor metadata. Attribute injection requires both a type and autowired(name=None, required=True, lazy=False, qualifier=None). Missing optional attributes become None; lazy attributes resolve on first access. Lazy constructor injection is unsupported. Attribute cycles can resolve; constructor and prototype cycles fail.

@postconstruct and @ondestroy accept instance methods with only self. Postconstruct callbacks run base-to-derived before init_method; destroy callbacks run in reverse creation order and derived-to-base. Lifecycle methods are never advised.

ApplicationContext.get_bean / aget_bean take a class or name plus name=None and qualifier=None. ContextUtil.use(context) binds a container for standalone work.

@Service("mailService")
@Primary
@Qualifier("notification")
class MailService {
    @PostConstruct
    void connect() {}

    @PreDestroy
    void disconnect() {}
}

@Configuration
class Infra {
    @Bean
    Clock clock() {
        return Clock.systemUTC();
    }
}