Develop Reference

Managing Chrome memory usage with Selenium

I have an 4GB Raspberry Pi doing unit running a Selenium webscraper. Over the course of hours, Chrome's memory footprint eats up all the available memory and the entire bot crashes as a result. Is there a way for Selenium to automatically manage/reduce Chrome's memory usage? I've noticed that if I refresh the page, the memory heep is cleared.

If refreshing the page seems to work, you can just use the following code in a loop that runs every so often.
driver.navigate().refresh();

Selenium using too much RAM with Firefox

I am using selenium with Firefox to automate some tasks on Instagram. It basically goes back and forth between user profiles and notifications page and does tasks based on what it finds.
It has one infinite loop that makes sure that the task keeps on going. I have sleep() function every few steps but the memory usage keeps increasing. I have something like this in Python:
while(True):
expected_conditions()
...doTask()
driver.back()
expected_conditions()
...doAnotherTask()
driver.forward()
expected_conditions()
I never close the driver because that will slow down the program by a lot as it has a lot of queries to process. Is there any way to keep the memory usage from increasing overtime without closing or quitting the driver?
EDIT: Added explicit conditions but that did not help either. I am using headless mode of Firefox.

Well, This the serious problem I've been going through for some days. But I have found the solution. You can add some flags to optimize your memory usage.
options = Options()
options.add_argument("start-maximized")
options.add_argument("disable-infobars")
options.add_argument("--disable-extensions")
options.add_argument('--no-sandbox')
options.add_argument('--disable-application-cache')
options.add_argument('--disable-gpu')
options.add_argument("--disable-dev-shm-usage")
These are the flags I added. Before I added the flags RAM usage kept increasing after it crosses 4GB (8GB my machine) my machine stuck. after I added these flags memory usage didn't cross 500MB. And as DebanjanB answers, if you running for loop or while loop tries to put some seconds sleep after each execution it will give some time to kill the unused thread.

To start with Selenium have very little control over the amount of RAM used by Firefox. As you mentioned the Browser Client i.e. Mozilla goes back and forth between user profiles and notifications page on Instagram and does tasks based on what it finds is too broad as a single usecase. So, the first and foremost task would be to break up the infinite loop pertaining to your usecase into smaller Tests.
time.sleep()
Inducing time.sleep() virtually puts a blanket over the underlying issue. However while using Selenium and WebDriver to execute tests through your Automation Framework, using time.sleep() without any specific condition defeats the purpose of automation and should be avoided at any cost. As per the documentation:
time.sleep(secs) suspends the execution of the current thread for the given number of seconds. The argument may be a floating point number to indicate a more precise sleep time. The actual suspension time may be less than that requested because any caught signal will terminate the sleep() following execution of that signal’s catching routine. Also, the suspension time may be longer than requested by an arbitrary amount because of the scheduling of other activity in the system.
You can find a detailed discussion in How to sleep webdriver in python for milliseconds
Analysis
There were previous instances when Firefox consumed about 80% of the RAM.
However as per this discussion some of the users feels that the more memory is used the better because it means you don't have RAM wasted. Firefox uses RAM to make its processes faster since application data is transferred much faster in RAM.
Solution
You can implement either/all of the generic/specific steps as follows:
Upgrade Selenium to current levels Version 3.141.59.
Upgrade GeckoDriver to GeckoDriver v0.24.0 level.
Upgrade Firefox version to Firefox v65.0.2 levels.
Clean your Project Workspace through your IDE and Rebuild your project with required dependencies only.
If your base Web Client version is too old, then uninstall it and install a recent GA and released version of Web Client.
Some extensions allow you to block such unnecessary content, as an example:
uBlock Origin allows you to hide ads on websites.
NoScript allows you to selectively enable and disable all scripts running on websites.
To open the Firefox client with an extension you can download the extension i.e. the XPI file from https://addons.mozilla.org and use the add_extension(extension='webdriver.xpi') method to add the extension in a FirefoxProfile as follows:
from selenium import webdriver
profile = webdriver.FirefoxProfile()
profile.add_extension(extension='extension_name.xpi')
driver = webdriver.Firefox(firefox_profile=profile, executable_path=r'C:\path\to\geckodriver.exe')
If your Tests doesn't requires the CSS you can disable the CSS following the this discussion.

Use Explicit Waits or Implicit Waits.
Use driver.quit() to close all
the browser windows and terminate the WebDriver session because if
you do not use quit() at the end of the program, the WebDriver
session will not be closed properly and the files will not be cleared
off memory. And this may result in memory leak errors.

Creating new firefox profile and use it every time while running test cases in Firefox shall eventually increase the performance of execution as without doing so always new profile would be created and caching information would be done there and if driver.quit does not get called somehow before failure then in this case, every time we end up having new profiles created with some cached information which would be consuming memory.
// ------------ Creating a new firefox profile -------------------
1. If Firefox is open, close Firefox.
2. Press Windows +R on the keyboard. A Run dialog will open.
3. In the Run dialog box, type in firefox.exe -P
Note: You can use -P or -ProfileManager(either one should work).
4. Click OK.
5. Create a new profile and sets its location to the RAM Drive.
// ----------- Associating Firefox profile -------------------
ProfilesIni profile = new ProfilesIni();
FirefoxProfile myprofile = profile.getProfile("automation_profile");
WebDriver driver = new FirefoxDriver(myprofile);
Please share execution performance with community if you plan to implement this way.

There is no fix for that as of now.
I suggest you use driver.close() approach.
I was also struggling with the RAM issue and what i did was i counted the number of loops and when the loop count reached to a certain number( for me it was 200) i called driver.close() and then start the driver back again and also reset the count.
This way i did not need to close the driver every time the loop is executed and has less effect on the performance too.
Try this. Maybe it will help in your case too.

Python, Selenium and Chromedriver - endless loop using find_element_by_id causes CPU problem

Good day to all! I've been experiencing this problem for a week now but I don't think I can solve it and I also do not see any solution based on articles online. Hopefully someone can help me here...
My scenario:
I need to monitor prices from 6 different tables in one page that changes almost every second. By end of day, I would close the browser (by pressing the X button) and terminate the script (by pressing Control+C) then run again in the morning and let it run through out the day. The script is written in python and is using selenium to read the prices. The browser I use is Chrome. My OS is Windows 2008 R2; Selenium version is 3.14.1
here is partial part of the code. It is just plainly reading the prices within the tables using find_elements_by_id inside an infinite loop with 1 second interval.
While True:
close1 = float(browser.find_element_by_id('bnaBox1').find_elements_by_id('lastprc1')[0].text.encode('ascii','ignore'))
close2 = float(browser.find_element_by_id('bnaBox2').find_elements_by_id('lastprc2')[0].text.encode('ascii','ignore'))
close3 = float(browser.find_element_by_id('bnaBox3').find_elements_by_id('lastprc3')[0].text.encode('ascii','ignore'))
close4 = float(browser.find_element_by_id('bnaBox4').find_elements_by_id('lastprc4')[0].text.encode('ascii','ignore'))
close5 = float(browser.find_element_by_id('bnaBox5').find_elements_by_id('lastprc5')[0].text.encode('ascii','ignore'))
close6 = float(browser.find_element_by_id('bnaBox6').find_elements_by_id('lastprc6')[0].text.encode('ascii','ignore'))
time.sleep(1)
...
During the first few minutes of the run, the scripts consumes minimal amount of CPU (approx 20~30 percent) but after few more minutes, consumption slowly shoots up to 100%! There is no other processes running in the machine than the script.
Troubleshooting I've done so far (they all did not solve my issue)
upgraded my chrome to latest version - v71 and chromerdriver 2.44
rolled back Chrome to previous versions (v62, v68, v69, v70)
rolled back Chromedriver version to 2.42 and 2.43
cleared my %TEMP% files -
rebooted machine (multiple times)
The program only gets values within tables but I suspect that somewhere in the background, as the the script runs, unnecessary data is piling-up which causes the CPU to hit the ceiling.
Hoping that someone can help me figure out what causes this problem in the CPU and resolve the issue.

It would be tough to guess the exact reason of 100% CPU Usage without any visibility to your code blocks specifically the WebDriver configuration. So the answer will be pretty much based on generic guidelines as follows:
Never close the browser (by pressing the X button). Always invoke driver.quit() within tearDown(){} method to close & destroy the WebDriver and Web Client instances gracefully.
You can find a detailed discussion in PhantomJS web driver stays in memory
Never terminate the script (by pressing Control+C). Incase there are presence of zombie WebDriver or Web Browser instances you can programatically remove them.
You can find a detailed discussion in Selenium : How to stop geckodriver process impacting PC memory, without calling driver.quit()?
A couple of useful ChromeOptions() and their usage are as follows:
options.addArguments("start-maximized"); // open Browser in maximized mode
options.addArguments("disable-infobars"); // disabling infobars
options.addArguments("--disable-extensions"); // disabling extensions
options.addArguments("--disable-gpu"); // applicable to windows os only
options.addArguments("--disable-dev-shm-usage"); // overcome limited resource problems
options.addArguments("--no-sandbox"); // Bypass OS security model
Using hardcoded sleeps in the form of time.sleep(1) is a big No.
You can find a detailed discussion in How to sleep webdriver in python for milliseconds
Incase you are using Chrome in headless mode, there had been a lot of discussion going around about the unpredictable CPU and Memory Consumption by Chrome Headless sessions.
You can find a detailed discussion in Limit chrome headless CPU and memory usage
Always keep your Test Environment updated with the latest released binaries as follows:
Upgrade ChromeDriver to current ChromeDriver v2.44 level.
Keep Chrome version between Chrome v69-71 levels. (as per ChromeDriver v2.44 release notes)
Clean your Project Workspace through your IDE and Rebuild your project with required dependencies only.
If your base Web Client version is too old, then uninstall it through Revo Uninstaller and install a recent GA and released version of Web Client.
Take a System Reboot.
Execute your #Test.
From Space and Memory Management perspective:
(WindowsOS only) Use CCleaner tool to wipe off all the OS chores before and after the execution of your Test Suite.
(LinuxOS only) Free Up and Release the Unused/Cached Memory in Ubuntu/Linux Mint before and after the execution of your Test Suite.

Have you tried releasing memory into the loop?
Maybe by picking up the values (list out of the loop?) and then resetting those variables to None you can avoid excessive memory consumption.
...
while True:
...
close1 = close2 = close3 = close4 = close5 = close6 = None
...
You can also try forcing the garbage collector:
import gc
while True:
...
gc.collect()
If you think that the reason may be a script another another solution to detect the problem might be to enable Chrome to do remote debug and debug the page.
--remote-debugging-port=9222
I hope some of this helps you.

Why does a page keep loading in the loop?

In python(Selenium)
driver = webdriver.Chrome()
driver.get("https://www.baidu.com")
for keywords in open('klist','r'):
driver.get("https://www.baidu.com")
driver.find_element_by_class_name('...').click()
....
Although the whole page appears, it just hangs and keeps loading. So a lot of time is wasted.
Not every time it freezes. But once it freezes, it can hang for several minutes before the next step.

I guess it hangs because some resource loads slowly. You can emulate such behavior manually by setting low bandwidth speed in network tab in developer tools (chrome).
In order to find what exact resource causing the problem in case if it's not reproducible by hands you can use proxy like Fiddler, Browsermob or whatever your favorite proxy is.

PhantomJS exceeds 1GB memory usage and dies loading 50MB of json

I am attempting to download ~55MB of json data from a webpage with PhanotomJS and python on Windows 10.
The PhantomJS process dies with "Memory exhausted" upon reaching 1GB of memory usage.
The load is made by entering a username and password and then using
myData = driver.page_source
on a page that just contains a simple header and the 55MB of text that makes up the json data.
It dies even if I'm not asking PhantomJS to do anything with it, just get the source.
If I load the page in chrome it takes about a minute to load, and lists it as having loaded 54MB, exactly as expected.
The phantomJS process takes about as long to reach 1GB RAM usage and die.
This used to work perfectly, until recently when the data to be downloaded exceeded about 50MB.
Is there a way to stream the data directly to a file from PhantomJS, or just some setting to not have it explode to 20x the necessary RAM usage? (The computer has 16GB of ram, the 1GB limit is apparently a problem in PhantomJS that they won't fix).
Is there an alternative, equally simple, way of entering a username and password and grabbing some data that doesn't have this flaw? (And does not pop up a browser window while working)