turbobus 1.0.0a4

TurboBus is an opinionated implementation of Command Responsibility Segregation pattern in python.

TurboBus

TurboBus is an opinionated implementation of Command Responsibility Segregation pattern in python.

Simple usage

Let's see an example using python typings. You can omit all the typing stuffs if you want to.

God Mode ⚡

from  dataclasses  import  dataclass
from  typing  import  TypeAlias

from  turbobus.bus  import  Command, CommandHandler, CommandBus
from  turbobus.decorators  import  command, injectable

LogHandlerType: TypeAlias  =  "ILogHandler"

@dataclass
class  LogCommand(Command[LogHandlerType]):
	content: str  


class  ILogHandler(CommandHandler[str]):
	...


@command(LogCommand)
class  LogHandler(ILogHandler):
	def  execute(self, cmd: LogCommand) -> str:
		return  cmd.content


if __name__ == '__main__':
	bus  =  CommandBus()

	result  =  bus.execute(
		LogCommand('Hello dude!')
	)
	print(result)  # Hello dude

Human Mode 🥱

from  dataclasses  import  dataclass

from  turbobus.bus  import  Command, CommandHandler
from  turbobus.decorators  import  command, injectable

@dataclass
class  LogCommand(Command):
	content


class  ILogHandler(CommandHandler):
	...

@command(LogCommand)
class  LogHandler(ILogHandler):
	def  execute(self, cmd: LogCommand) -> str:
		return  cmd.content


if __name__ == '__main__':
	bus  =  CommandBus()

	result  =  bus.execute(
		LogCommand('Hello dude!')
	)
	print(result)  # Hello dude

Dependency injection

In many cases we're going to need to inject dependencies to our command handler. To accomplish that we have two important tools: @injectable decorator and injecting function.

With the injectable decorator we can specify a class that is implementing the functionalities of the dependency. For example:

from turbobus.decorators import injectable
from log.axioma.log import ILogger


class ILogger(ABC):

    @abstractmethod
    def logger(self, text: str) -> None:
        ...


@injectable(ILogger)
class Logger:

    def logger(self, text: str) -> None:
        print('from logger', text)


@command(LogCommand)
@dataclass(kw_only=True)
class LogHandler(ILogHandler):

    logger = injecting(ILogger)

    def execute(self, cmd: LogCommand) -> str:
        if self.logger is not None:
            self.logger.logger(cmd.content)

        return cmd.content

As you can see in the example above, we're defining an abstract class with the logger method. Then we're doing the implementation of the ILogger and we're indicating that in the @injectable(ILogger).

Then, using the injecting function, TurboBus is going to map that dependency and inject the instance in the attribute.