Custom Process

Why Create a Custom Process?

• Subclassing multiprocessing.Process is useful when you need to encapsulate specific data or behavior for each process. (Like LitData DataWorker, a process class that downloads data, processes it, and saves it to a database.)
• Allows defining a custom run() method, which will be executed when the process starts.

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Implementation 🤓

creating custom process

• Very similar to creating custom thread.
• We can inherit Process class and create our own implementation of run method.
• We only need to implement __init__ and run method.
• Then, we can use start, join and other methods as we did with Process class.

from multiprocessing import Process

class MyProcess(Process):
    def __init__(self, num):
        self.num = num
        super().__init__() # calling the parent class constructor (required)

    def run(self):
        for i in range(10):
            print(f"I'm process: {self.num} => {i}")

if __name__ == "__main__":
    my_p = []
    for i in range(5):
        curr_p = MyProcess(i+1)
        my_p.append(curr_p)

    print("=== start all the processes ===")
    for p in my_p:
        p.start()

    for p in my_p:
        p.join()

    print("=== all processes finished ===")