shadow traffic routing issues

[szuecs]

Assume we have 2 routes without shadow traffic. v1 is used to enter your site and in case you have a "valid" cookie you trust the client to enter the trusted part of our application.

v1: * -> "https://first.example.org"
v1cookie: Cookie("pseudo-auth") -> "https://first-trusted.example.org"

Let's assume you built a replacement of v1, and want to test with some percentage of traffic, you would add a third route with Traffic() predicate:

v1: * -> "https://first.example.org"
v2: Traffic(.01) -> "https://second.example.org"
v1cookie: Cookie("pseudo-auth") -> "https://first-trusted.example.org"

It looks like you have a successful shadow traffic route, but now you have a routing problem, because v2 and v1cookie have the same amount of predicates and theses are equally weighted.

The current fix is to use True() as a hack:

v1: * -> "https://first.example.org"
v2: Traffic(.01) -> "https://second.example.org"
v1cookie: Cookie("pseudo-auth") && True() -> "https://first-trusted.example.org"

I would propose, that we set Traffic() predicate to have weight 1 and all other predicates to have weight 2 as default.
This would solve the problem of having to add True().

Do you have other use cases for Traffic where it does not make sense to change this weight?