Sort the paths in routes to ensure matcher picks nearest regex to req…

…uest uri

When the default backend routes are registered, currently it is as per unordered map. This means that the routes can have "" or "\api\v1" before "api\v1\query_range". When the router matches the regex expression (Refs: https://gecgithub01.walmart.com/Telemetry/trickster-v2/blob/main/pkg/router/route.go#L40 https://gecgithub01.walmart.com/Telemetry/trickster-v2/blob/main/pkg/router/regexp.go#L323) with the routes map, if partial routes appears first that will be considered as a match, which causes request to be "Proxy-Only".
Thus, with sorting we will ensure that routes will be a sorted array in the descending order of path lengths, meaning: "\api\v1\query_range" would appear before "api\v1" and "" so that we have appropriate match.
Issue:trickstercache#594

README.md

@@ -18,7 +18,7 @@ Trickster is hosted by the [Cloud Native Computing Foundation](https://cncf.io)
 
 Note: Trickster v1.1 is the production release, sourced from the [v1.1.x](https://github.com/trickstercache/trickster/tree/v1.1.x) branch. The `main` branch sources Trickster 2.0, which is currently in beta.
 
-## HTTP Reverse Proxy Cache ##
+## HTTP Reverse Proxy Cache
 
 Trickster is a fully-featured HTTP Reverse Proxy Cache for HTTP applications like static file servers and web API's.
 

pkg/routing/routing.go

@@ -383,7 +383,20 @@ func RegisterDefaultBackendRoutes(router router.Router, bknds backends.Backends,
 			}
 			tl.Info(logger,
 				"registering default backend handler paths", tl.Pairs{"backendName": o.Name})
-			for _, p := range o.Paths {
+
+			// Sort by key length(Path length) to ensure /api/v1/query_range appear before /api/v1 or / path in regex path matching
+			keylist := make([]string, 0, len(o.Paths))
+			for key := range o.Paths {
+				keylist = append(keylist, key)
+			}
+			sort.Sort(ByLen(keylist))
+			for i := len(keylist)/2 - 1; i >= 0; i-- {
+				opp := len(keylist) - 1 - i
+				keylist[i], keylist[opp] = keylist[opp], keylist[i]
+			}
+
+			for _, k := range keylist {
+				var p = o.Paths[k]
 				if p.Handler != nil && len(p.Methods) > 0 {
 					tl.Debug(logger, "registering default backend handler paths",
 						tl.Pairs{"backendName": o.Name, "path": p.Path, "handlerName": p.HandlerName,