[py] speed up Service launch (sleep depending on the number of attempts to check if the service has started)

[deedy5]

Description

Python client. Problem file: py/selenium/webdriver/common/service.py
When the driver is initialized, the service starts, and then a loop checks to see if it has started.
But there is a constant delay of 0.5 seconds in the loop. Here the delay logic changes - instead of the constant 0.5 seconds, it increases in increments of 0.05, starting at 0.01 and going up to 0.5.

Motivation and Context

When a driver with many options is started, there is a 0.5 second delay. For one request it is not noticeable, but for many requests, when it is necessary to initialize the driver each time, it results in significant time loss.

Line_profiler

Line #      Hits         Time  Per Hit   % Time  Line Contents
==============================================================
    90                                               @profile
    91                                               def start(self) -> None:
    92                                                   """Starts the Service.
    93                                           
    94                                                   :Exceptions:
    95                                                    - WebDriverException : Raised either when it can't start the service
    96                                                      or when it can't connect to the service
    97                                                   """
    98         1        911.6    911.6      0.2          self._start_process(self._path)
    99         1          4.3      4.3      0.0          t0 = time()
   100         1          1.4      1.4      0.0          count = 0
   101         2          4.7      2.4      0.0          while True:
   102         2        460.8    230.4      0.1              logger.warning(f"start() {count=} {time() - t0=}")
   103         2         44.1     22.0      0.0              self.assert_process_still_running()
   104         2       5225.4   2612.7      1.0              if self.is_connectable():
   105         1          1.8      1.8      0.0                  break
   106                                                       
   107         1          1.9      1.9      0.0              count += 1
   108         1     500111.7 500111.7     98.7              sleep(0.5)
   109         1          5.2      5.2      0.0              if count == 60:
   110                                                           raise WebDriverException(f"Can not connect to the Service {self._path}")

Reproduce the problem

test.py

from itertools import cycle
from random import choice, randint
from time import time

from selenium import webdriver

DEBUG_PORT = (x for x in cycle(range(9000, 9999)))


class Driver:
    def __init__(self, headless=False):
        self.options = webdriver.ChromeOptions()
        if headless:
            self.options.add_argument("--headless=new")
        self.options.add_experimental_option("excludeSwitches", ["enable-automation"])
        self.options.add_experimental_option("useAutomationExtension", False)
        self.options.add_argument("--disable-blink-features=AutomationControlled")
        self.options.add_argument("--no-sandbox")
        self.options.add_argument("--disable-gpu")
        self.options.add_argument(f"--window-size={randint(1024, 1920)},{randint(768, 1080)}")
        self.options.add_argument(f"--remote-debugging-port={next(DEBUG_PORT)}")
        self.options.add_argument("--disable-dev-shm-usage")
        self.options.add_argument("--lang=en")
        self.options.add_argument("--incognito")
        self.options.add_argument("--log-level=3")
        self.options.add_argument("--no-default-browser-check")
        self.options.add_argument("--no-first-run")
        self.options.add_argument("--ignore-certificate-errors")
        self.options.page_load_strategy = "eager"
        prefs = {"profile.managed_default_content_settings.images": 2}  # disable images
        self.options.add_experimental_option("prefs", prefs)
        self.driver = webdriver.Chrome(options=self.options)
        
    def quit(self):
        self.driver.quit()

    def __enter__(self):
        return self.driver

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.driver.quit()


def get_url_selenium(url):
    with Driver(headless=False) as driver:
        driver.set_page_load_timeout(100)
        driver.get(url)
        return driver.page_source


if __name__ == "__main__":
    url = "https://bot.sannysoft.com/"
    for _ in range(10):
        r = get_url_selenium(url)

Edit selenium/webdriver/common/service.py - remove sleep and logging where service will be started:

def start(self) -> None:
        """Starts the Service.

        :Exceptions:
         - WebDriverException : Raised either when it can't start the service
           or when it can't connect to the service
        """
        self._start_process(self._path)

        count = 0
        t0 = time()  # Add start time
        while True:
            self.assert_process_still_running()
            if self.is_connectable():
                logger.warning(f"{count=} elapsed={time() - t0}")  # Add logging message
                break

            count += 1
            #sleep(0.5)  # Remove sleep
            if count == 60000:  # Increase count
                raise WebDriverException(f"Can not connect to the Service {self._path}")

run test.py

count=68 elapsed=0.010582923889160156
count=84 elapsed=0.008266687393188477
count=55 elapsed=0.005543947219848633
count=61 elapsed=0.006617546081542969
count=36 elapsed=0.0072443485260009766
count=114 elapsed=0.010538339614868164
count=82 elapsed=0.008222818374633789
count=43 elapsed=0.008531808853149414
count=113 elapsed=0.010515928268432617
count=49 elapsed=0.005129098892211914

Here we see that the startup time is <= 0.01.
So there is no point in waiting for 0.5 seconds, it is just a waste of time.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[CLAassistant]

All committers have signed the CLA.

[diemol]

Good improvement, thank you, @deedy5!