FractionalPercent when using with RouteMatch

[belyalov]

Title: Log debug/info/whatever message when FractionalPercent.numerator greater than FractionalPercent.denominator
Description: When using FractionalPercent with RouteMatch it is possible to mess up with values on denominator / numerator so the underlying condition

(random_value % denominator) < numerator

Will be always evaluated to true because of numerator exceeds denominator. It becomes hard to debug why configuration does not work (no logs, just shows that clusterN has been selected).

Do you guys think it is make sense to add some kind of logging to simplify configuration debuggability?
If so I can add this.

Thanks

[snowp]

Alternatively we could add in configuration validation that will reject configuration where numerator > denominator, unless there are use cases where you'd want to do that?

[belyalov]

This is not clear to me:

• route configuration simply depends on runtime key, basically string, seems nothing to validate here
• update runtime values through rtds or any other methods could not be validated as well (simply ignore unacceptable values?)

[snowp]

I see, this is about using RuntimeFractionalPercent, not a FractionalPercent proto configured via xDS.

Seems like logging the numerator/denominator as debug/trace would be the best way to handle this since there is no validation framework around runtime values.

[belyalov]

Ok, I'll take care of... :)

[stale]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or other activity occurs. Thank you for your contributions.