Ray with JupyterHub

import ray

import time

ray.init()

items = [ "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten" ]

def get_item(idx: int):

    time.sleep(idx / 10.)

    return idx, items[idx]

@ray.remote

def retrieve_task(item):

    return get_item(item)

def print_runtime(data, start_time):

    print(f"Runtime: {time.time() - start_time:.2f} seconds, data: ")

    print(*data, sep="\n")

start = time.time()

data = [get_item(item) for item in range(len(items))]

print("Time to do it the synchronous way:")

print_runtime(data, start)

start = time.time()

object_refs = [ retrieve_task.remote(item) for item in range(len(items))]

data = ray.get(object_refs)

print("Time to do it with ray:")

print_runtime(data, start)