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