fix: removeUser - handle connections in frontends, db changes in backend

[antobinary]

What does this PR do?

Reorganized the handling of UserLeftMeetingEvtMsg by bbb-html5 so that the backends handle processing to update MongoDB and the frontends handle processing to update the ClientConnections. This way there's no overlap/unpredictability

• split the handling of logic for UserLeft message - backend handles the updates for Mongo, frontend handles the updates to ClientConnections

• removed the 1 second delay since now only backend handles the userleft+user ejected messages and they are syncronous

• no longer initialize ClientConnections on backend instances

Closes Issue(s)

Closes #12080 since we are now guaranteed to be processing sequentially the two relevant events in a single NodeJS instance:

Jun 30 20:04:35 anton.vm systemd_start.sh[36803]: warn: Received event to handle {"date":"2021-06-30T20:04:35.385Z","eventName":"UserEjectedFromMeetingEvtMsg"}
Jun 30 20:04:35 anton.vm systemd_start.sh[36803]: warn: Received event to handle {"date":"2021-06-30T20:04:35.386Z","eventName":"UserLeftMeetingEvtMsg"}

Motivation

We were looking into ways to remove the 1000 ms delay added in #12057 and particularly why the re-ordering of events processing was happening.

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
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No Coverage information
0.0% Duplication

[mabras]

Hello @antobinary ,

We were testing this in our env.

If the moderator removes a viewer, the viewer's client will throw an exception and the app crashed.

This where the error happens:

  // THIS LINE:
  if (meeting.lockSettingsProps.hideUserList && currentUser.role === USER_CONFIG.role_viewer) {
    selector.role = { $ne: USER_CONFIG.role_viewer };
  }

It sounds to me it is related to hiding the user list. Actully we do hide the user list:

sed -i 's/lockSettingsHideUserList=.*/lockSettingsHideUserList=true/g' /usr/share/bbb-web/WEB-INF/classes/bigbluebutton.properties

Reverting this commit solves the issue.
showing the user list also solves the issue.

Thanks,

[antobinary]

Thanks for reporting this @mabras

I am able to reproduce, opened #12714 (comment)
It might be related to #12691