User colors are not consistent across the cluster - Githubissues

vaadin / collaboration-engine

The simplest way to build real-time collaboration into web apps

https://vaadin.com/collaboration

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User colors are not consistent across the cluster #66

Closed heruan closed 1 year ago

heruan commented 2 years ago

Describe the bug Users connecting to app instances on different nodes will most probably see different colors assigned to the same users.

To Reproduce Steps to reproduce the behavior:

Run the application in a cluster
Navigate to a view with a CollaborationAvatarGroup
Navigate to the same view targeting a different node

Expected behavior User colors used in the avatars are consistent in the two nodes.

Versions

Vaadin version: 21.0
Collaboration Engine version: 5.0
Java version: 11

MatthewVaadin commented 2 years ago

This could be a good opportunity to introduce a topic for internal use that can store data like the user colors and distribute them across nodes in a cluster.

We already use this pattern with the LicenseHandler so we could either expand the use of that, or incorporate it into a new combined topic.

Note: We need to guard against accidental (or malicious) tampering of the topic. One way we could do this is to prefix all developer-generated topics with something (e.g. '$') and any internal topics either have different prefix or none.