Feat: Support semantic versioning in Constraint

[zakazai]

I have a use case where I want to limit a segment using semantic versioning (e.g only enable feature when version >= 5.1.0, etc)

Expected Behavior

I can specify constraint using semantic versioning on flagr UI

Current Behavior

I don't think this is available yet. I've tried this at https://play.golang.org/p/9NYt1V1B_RB

Update : I think we can define it by creating multiple segments for each version that available for now

Possible Solution

We can use https://github.com/blang/semver/ and maybe introduce a new operator perhaps at https://github.com/zhouzhuojie/conditions.

Context

I'm currently evaluating flagr and I have a use case to limit certain feature based on the app version.

[zhouzhuojie]

Thanks for reporting the feature request. I think semver maybe a little bit specific to be added for a generic condition's operator. I was thinking of supporting general functions in the constraints, that may work to cover the semver use case.

Before that, how about your application can parse the semver and pass the components as entity context? For example:

{
  "entityContext": {
    "major": 1,
    "minor": 0,
    "patch": 3
  }
}

And you can specify the conditions like major <= 1 or major <= 1 and minor >= 0.

[zakazai]

Thanks for the prompt reply.

That's a good idea, I haven't thought about that. I think that'll be enough for my use case