json murshal/unmarhsal struct that was got using custom interface type

[Viacheslav Biriukov]

Hi, 

I want to marshal/unmarshal object for saving in key/value storage. 

The question is: if I got this object using function, that accepts interface type, lets say for example: base.Pricer. And there are more than one type struct that satisfy this interface. I know while marshaling what type this object have (using reflection), and theoretically can save this type in storage. But when I try to load this object – I want to get exactly that type what was before serialization. But I don't know how to do this and is this is a good pattern?

Thank you.

[nathan....@docker.com]

Viacheslav,

Your best bet here in my opinion is to have an intermediate object that contains type information which you Unmarshal into first to get the concrete type.  Then, you have a switch to Unmarshal the remainder of the object into the real deal.  We did a similar mechanic to this on Docker Machine at one point where the various Drivers would contain a string indicating which type they "actually" are.

Nathan

[Viacheslav Biriukov]

Hi Nathan,

Thank you for reply. Yes I thought about this approach. But it looks  a little ugly. Every time you add new struct that can be used – you should  don't forget to update switch. But it seems that there is no other way.

Thank you!