python-dependency-injector/examples/providers/dependency.py
Roman Mogylatov c4b33749d2
Providers docs update (#289)
* Update callable provider docs

* Update coroutine provider docs

* Edit object docs

* Edit list provider docs

* Edit configuration provider docs

* Edit selector provider docs

* Fix mypy stub of the ``DeclarativeContainer`` to specify the ``__init__`` interface

* Edit Dependency provider docs
2020-09-01 21:39:23 -04:00

51 lines
1.1 KiB
Python

"""`Dependency` provider example."""
import abc
import dataclasses
from dependency_injector import containers, providers, errors
class DbAdapter(metaclass=abc.ABCMeta):
...
class SqliteDbAdapter(DbAdapter):
...
class PostgresDbAdapter(DbAdapter):
...
@dataclasses.dataclass
class UserService:
database: DbAdapter
class Container(containers.DeclarativeContainer):
database = providers.Dependency(instance_of=DbAdapter)
user_service = providers.Factory(
UserService,
database=database,
)
if __name__ == '__main__':
container1 = Container(database=providers.Singleton(SqliteDbAdapter))
container2 = Container(database=providers.Singleton(PostgresDbAdapter))
assert isinstance(container1.user_service().database, SqliteDbAdapter)
assert isinstance(container2.user_service().database, PostgresDbAdapter)
container3 = Container(database=providers.Singleton(object))
try:
container3.user_service()
except errors.Error as exception:
print(exception)
# The output is:
# <object object at 0x107ce5c40> is not an
# instance of <class '__main__.DbAdapter'>