priority property
For routeRules within a given pathMatcher, priority determines the order in which a load balancer interprets routeRules.
RouteRules are evaluated in order of priority, from the lowest to highest number. The priority of a rule decreases as its number increases (1, 2, 3, N+1). The first rule that matches the request is applied. You cannot configure two or more routeRules with the same priority. Priority for each rule must be set to a number from 0 to 2147483647 inclusive. Priority numbers can have gaps, which enable you to add or remove rules in the future without affecting the rest of the rules. For example, 1, 2, 3, 4, 5, 9, 12, 16 is a valid series of priority numbers to which you could add rules numbered from 6 to 8, 10 to 11, and 13 to 15 in the future without any impact on existing rules.
Implementation
core.int? priority;