How to handle data format Compatibility break in Redis Store ?

[sbernard31]

Sometime during development phase or between 2 stable version, the data format used in Redis Store can change.
This issue aims to discuss about how to handle this in general.

Here is some (none-exclusive) ideas mentioned in other discussion :

1. For Registration Store, just drop all data as this is just a kind of "session" store client need to re-register. (see Plan for 2.0.0-M11 🎯  #1401 (comment))
2. Write migration script.
3. Write a Redis implementation store which is able read previous format.
4. Introduce a data version (to help to discard OR support migration.

Let discuss how we should handle this ?

[sbernard31]

@cyril2maq, you could be interested to participate into this discussion as you are directly concerned.

@jvermillard said (at #1401 (comment)) :

maybe we should just introduce a "version" so we can either discard or introduce some migration script?

Could you describe a bit what you have in mind ? 🙏

[JaroslawLegierski]

I've thought about this a bit. We have a problem with session information - this is ephemeral data which disappear after deregistration or will be updated during client re-registering.
Therefore, I do not know if we need to manage this data ?

[sbernard31]

@JaroslawLegierski , Could you double check with @cyril2maq because by the past I understand that was an issue. (#1401 (comment))

[sbernard31]

Uups I missed this comment at #1445 (comment):

I commented this #1417 (comment) (I also confirmed this with my French colleagues).