Hi Pat / all,
I’ve been experiencing an issue where capturing the timeline can cause some test to not return correctly. Specifically, for example:
webpagetest test https://www.carters.com/ -f -R --location=labclient2_wptdriver -s --poll 1 --timeout 30
returns a nice JSON result, whereas this (just omitting -M):
$ webpagetest test https://www.carters.com/ -f -R -M --location=labclient2_wptdriver -s --poll 1 --timeout 30
(also tried setting timeout to 60)
In the second case, I see that the test actually completes successfully within 5-7 seconds, but the agent does not seem to be able to retrieve the results afterwards.
The same things works fine for other test targets, e.g.
webpagetest test https://www.forever21.com/ -f -R -M --location=labclient2_wptdriver -s --poll 1 --timeout 30
returns a json just fine, while for others it sometimes times out and sometimes it fetches a result (so it looks like the particular page/structure seems to trigger more/always for some cases).
I verified that this is not an issue with the npm wrapper: When I start the same tests from the web interface with the same arguments, they display results fine when not capturing the timeline, but they hang at “waiting” when capturing it. In the meantime I observe that the test actually completes fine on the test machine an the driver goes back to waiting for more work.
I also verified that manually exporting a timeline using the same Chrome build on the same test machine against the same target page works fine.
What would you say is the best way to troubleshoot this to see why capturing timelines sometimes leads to timeouts when trying to fetch the test results?