How to handle versioning of structs

[suren4Kites]

Hi,

I am trying to cache a go struct, am setting the expiry as 1 day.
Lets say my struct is {a:"aa", b:"bb"} and the key is K1, its expiry is 1 day. But I changed the struct to have one field, let's say {a:"aa", b:"bb", c:"cc"}, if the Key is not expired, it will not get updated since the same key.
I want to have an option to identify the version of struct change, before get or set cache.
Please let me know if there is any way.

[vmihailenco]

The problem here is that such functionality would require cooperation with library that encodes the struct, e.g. https://github.com/vmihailenco/msgpack or encoding/json. encoding/json would have to provide list of fields it used to encode the struct and/or some versioning key. That is a lot of trouble in order to solve this problem.