Modules¶

Modules are the building blocks of a dijay application. They encapsulate providers and manage dependencies between different parts of your system.

Defining a Module¶

Use the @module decorator to define a module:

from dijay import module

@module(
    imports=[DatabaseModule],
    providers=[UserService, UserRepository],
    exports=[UserService],
)
class UserModule: ...

Parameter	Description
`imports`	Modules whose exports become available here.
`providers`	Classes or `Provide` entries to register.
`exports`	Providers to make available to importing modules.
`globals`	If `True`, exports are available globally.

Module Hierarchy¶

Modules form a tree. The root module imports feature modules, which import infrastructure modules:

AppModule
├── UserModule
│   └── DatabaseModule
├── AuthModule
│   └── DatabaseModule
└── HttpModule

@module(imports=[UserModule, AuthModule, HttpModule])
class AppModule: ...

Dynamic Modules¶

For conditional configuration (e.g., swapping implementations by environment), use a static method that returns a DynamicModule:

import os
from dijay import DynamicModule, module

from .fake import FakeDatabaseModule
from .postgres import PostgresDatabaseModule

@module(
    imports=[FakeDatabaseModule],
    exports=[FakeDatabaseModule],
)
class DatabaseModule:
    @staticmethod
    def for_root() -> DynamicModule:
        db_module = {
            "fake": FakeDatabaseModule,
            "postgres": PostgresDatabaseModule,
        }[os.getenv("DB_PROVIDER", "fake")]

        return DynamicModule(
            module=DatabaseModule,
            imports=[db_module],
            exports=[db_module],
        )

The DynamicModule is a TypedDict with the following keys:

Key	Type	Description
`module`	`Any`	The module class being configured.
`providers`	`list[Any]`	Additional providers to register.
`imports`	`list[Any]`	Additional modules to import.
`exports`	`list[Any]`	Additional providers to export.
`globals`	`bool`	Whether exports are globally available.

Tip

The default @module metadata serves as fallback. The DynamicModule returned by for_root() overrides or extends it at container creation time.