Bug in locking mechanism

[timgdavies]

Issue: Researchers have reported frequently seeing the message: "Locked
This survey has been taken over by another user, or you have opened another window. You must reload to continue."

Reproduction: I've been able to reproduce this issue specifically in relation to the Supporting evidence fields when adding two resources in quick succession.

[timgdavies]

Possible resolution:

• Short term advice to researchers to always wait for the yellow updating bar to disappear when using the resource manager
• Remove the 'survey taken over warning'
  • There is a risk this could lead to data loss if the survey is opened in another window?
• Add client-side blocking mechanism so resource-related updates block further actions
• Fix the locking mechanism

[timgdavies]

On further investigation - need to check if this is a more general timing issue with updates at https://github.com/GlobalDataBarometer/barometer-survey-tool/blob/master/htdocs/js/w3f-survey.js#L780 (though only revealed when we have uploads as they take more than 10 seconds to complete).

[keeganmcbride]

Hi @timgdavies I am a researcher working on this survey and also chronically experiencing this issue. Most recently at 30 July 2021 20:35 Estonian time. I have the log files if needed, I guess you can get them also from Nicolas.

[keeganmcbride]

Okay, just happened again at 20:59. The lockout occurs right after API calls start to fail and 524. CloudFlare issue? Basically I notice it bugs out saving a change and then it locks up.
See below.

[timgdavies]

@keeganmcbride Thanks for all your patience with these issues - and help in debugging.

We've been trying to work out where this CloudFlare issue is coming from - and have just boosted the server capacity of the app in case it's down to an interaction between server and client side latency.

We've got some support in to look at the issue more - so hoping we've got fix in place ASAP.

[keeganmcbride]

I noticed that when it happened often a number of saves were building up before it crashes out. What I mean by this is that instead of the simple "saving..." it would be for ex "saving 3 changes..." or something along those lines.

[timgdavies]

@aliblackwell is working on updates that will mean the resource manager only allows one upload at a time - to avoid the update queue becoming too full with large file uploads.

We're also in #27 looking at whether the client correctly handles cases where the API is slowing down or unable to complete a write, and if we can handle that differently.