Closed Bug 1471201 Opened 2 years ago Closed 2 years ago
Increase Keep-Alive connection drop timeout
59 bytes, text/x-review-board-request
It was reported in various recent geckodriver issues, including but not limited to https://github.com/mozilla/geckodriver/issues/1304, that various (Selenium?) WebDriver clients do not have proper support for HTTP/1.1 Keep-Alive connections. Whilst increasing the inactive connection drop timeout duration will not resolve the above problem (patches are needed in clients), the default five second timeout that hyper operates with is probably too low for regular WebDriver use. whimboo did some investigation of this in https://github.com/mozilla/geckodriver/issues/1304#issuecomment-400229653 and there is some more background from me in https://github.com/mozilla/geckodriver/issues/1304#issuecomment-400290438.
The question is, what would a good timeout duration be? As I understand it the connection is kept alive for as long as it remains active within the current five second period. The problem arises when the client opens a connection, issues a command, then doesn’t do anything before the timeout elapses. To slightly rephrase the question: For how long would we expect a client to not provide any data?
I actually don't have an idea right now. As already said on IRC if people see that when using eg. `time.sleep()` calls in their Selenium tests, they should first change those to make use of the `Wait` methods. But something we have to count in for the timeout is clearly the network latency, which in nearly all of the cases shouldn't be that high. I would suggest we wait a bit longer and see how enabling keep-alive affects users.
See my comment https://github.com/mozilla/geckodriver/issues/1304#issuecomment-402685923 about why this change will not fundamentally fix the BadStatusLine exceptions we are seeing reported in the Selenium Python client. Due to _the nature_ of how WebDriver works it would benefit users for the connection to persist longer. WebDriver tests are usually rather slow and the lifetime of continuous operations tends to be longer than your average web document request. Having to make fewer HTTP connections for the duration of a test seems like a potential performance win.
In our meeting on Monday we agreed we would increase the HTTPD Keep-Alive timeout duration to 60 seconds: https://wiki.mozilla.org/WebDriver/Meetings/2018-07-02#Minutes
Apparently the default Keep-Alive timeout in a more recent version of hyper is 90 seconds. I propose we use that number so that when we upgrade to this newer version in the future, we will get the hyper default without having to change this value twice.
Comment on attachment 8989966 [details] Bug 1471201 - Increase webdriver HTTPD Keep-Alive timeout to 90s. https://reviewboard.mozilla.org/r/254974/#review261832
Attachment #8989966 - Flags: review?(dburns) → review+
Pushed by firstname.lastname@example.org: https://hg.mozilla.org/integration/autoland/rev/6637d206368f Increase webdriver HTTPD Keep-Alive timeout to 90s. r=automatedtester
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